Aftmast rigs??? [Archive] - Page 2

brian eiland

10-22-2010, 09:08 AM

I've invested quite a lot of money in the mast, rigging, and sails and don't want to make a mistake.

Thanks Philip Maise
I'm afraid it is too late for that.

I genuinely feel sorry for people who make decisions like this based on their best attempt at due diligence. Sadly there is so much nonsense published and presented as fact that it makes things more difficult for people to make a well-reasoned choice.

When it comes time to solve the problems associated with this choice I doubt the cheerleaders for this sailplan will be helping defray the costs that the owner will have to endure.
First off let me say that that Philip Maise approached me about his wanting to look at the aftmast option for rerigging the previously de-masted vessel that he had recently purchased. He supplied me with some very preliminary dimensions of where some structural members were located, but no drawings or a sketch of what he had in mind. Before I could even find time to look these dimensions over, he sent me a note that he had elected to go with a crab claw arrangement, and announced that on this forum at posting #199 . So please don’t infer that I misled this gentleman into his choices. I think he will confirm these facts.

With reference to “so much nonsense published and presented as fact”, I might remind you this is a forum discussion, not a formal technical paper that is being published. It contains both positive and negative viewpoints, and well as supporting documentation and by way of reference to other related forum discussions.

Over the years I’ve gotten hundreds of inquires about this aftmast setup. I have turned many of them down right at the beginning, when I recognize it is not the solution for them. I have forewarned others that this is still untried technology, and that there are extra rig loads that must be accounted for. This may not be a rig you want to slap onto an existing vessel without properly determining that the vessel itself will accept the loading points. I am truly concerned that someone does not waste their money on this technology without fully realizing that they are on the cutting edge.

So Paul I might suggest that you stay off the Group P bench ….that’s ‘P’ for Progressive.
You certainly wouldn’t be a person who might enjoy the huge international Oshkosh Air Show…particularly the experimental section:
The Experimental Aircraft Association's Fly-In Convention, now known as EAA AirVenture Oshkosh (http://www.airventure.org/about/history.html)

These guys not only EXPERIMENT, they do it with objects that fly up in the air…less forgiving than sailing across the water :!:;)

brian eiland

10-22-2010, 09:29 AM

I was looking for another image, and I happened upon this one I had forgotten about. Thought it might be time to post it before I forgot about it again.

From most of which I have read Bolger found this rig to be superior in its sailing performance, BUT it was hard to sail in non-steadystate conditions due to having to keep that 'very fine' leading edge of the headsail properly oriented.

I believe Tom Speer did a very fine analysis of this problem with fine leading edges over in the SAIL AERODYNAMICS subject thread...don't know the exact posting # at this time?

Paul B

10-22-2010, 12:34 PM

..I have read Bolger found this rig to be superior in its sailing performance,

Hilarious!

MikeJohns

10-22-2010, 05:28 PM

So 'Relentless' was a failure, some of us predicted that for several reasons already outlined.

Bold experiments get good press but the vessels are still subject to some immutable principles. Ignoring those principles because you are ignorant of them is not progressive, but it helps the 'innovator' to imagine that their dream design is being unfairly criticised.

I think you should be concentrating on is the compromises and their tradeoffs, rather than imagining it's all roses and the detractors are just luddites.

brian eiland

10-22-2010, 06:11 PM

So 'Relentless' was a failure, some of us predicted that for several reasons already outlined.
Well I'm not so sure they were failures. There were two vessels built, one tall rig version, one short. Orca was the short rig version.

The owner of Orca wrote this over on the other subject thread:
"Best wishes for the new year. I have made some contact with - of all things - Mr Fred Greenway's former bus driver. This man knew Fred and his wife very well and as he was a longtime tug boat operator he too knows boats.
We will be meeting soon I think to discuss what he knows of Fred and Orca, but he already been stated that Orca went around the Horn from West to East and came back through the canal. Heresay at this pt. More as we get it."
http://www.boatdesign.net/forums/boat-design/wishbone-sailing-rig-1999-7.html#post247796

Fred Greenway was the designer of these two vessels

brian eiland

10-22-2010, 06:20 PM

So, Mr. Internet Expert is skeptical, besides without seeing the boat and rig drawings. If You have ever been on the boat, You would immediately note pair of lower shrouds. Those hold inner stay attachment point form aft/side. I have read the email You sent to the builder, and told him this is complete ******** :D

FYI: The top of mast on that boat is bending forward, so the aft-swept spreaders are what is needed. We are engineers here, not amateurs posting unproven concepts in Internet :D
I'm sorry you have to be so combative in your postings on this particular subject thread. It would be much nicer if you offered your criticisms in a more civil manner

That said I must apologize to you and the builder for an error I made in reviewing this design. The primary problem arose as a result of an optical illusion that appeared to me when I viewed that first photo I posted at #254 (http://www.boatdesign.net/forums/sailboats/aftmast-rigs-623-17.html#post410214)
1) I did not detect any backstay(s) running from that lower forestay attachment point. This was further reinforced in my mind by the lack of any lower ones on the profile dwg that's posted there.
2) When I looked at the photo I mistakenly identified the aft backstay jumper strut to be the raked spreader on the near side of the mast. In other words I thought the builder had possible modified the rig shown in the dwg such that there was now NO aft jumper strut for a backstay from the masthead to passover....thus no masthead backstay.

I thought maybe the designer or builder had decided there was no reason for a mizzen sail, and thus no reason for that backstay. Instead they had decided that the raked-back spreaders would substitute for the masthead backstay...ala many 3 pt catamaran rigs, or a B&R rig.

Now that I look much closer at the photo I can detect the aft backstay from the masthead, and the two lower backstays. I feel much more positive about your rendition now, and in fact made a comment to the builder that I thought the overall appearance was very satisfactory.

Fanie

10-22-2010, 06:34 PM

I doubt the aft mast sail will be the perfect one. No other sail can claim that either, it sounds like some of you are close though :D

The first week I was on this forum I was told boats are one big compromise from start to end. Seems sails are the same compromising disaster.

Is a sail only successful when it's the fastest ? Then I assume some of you must be seriously into racing.

Fortunately for me I am not, and it's not important who is going to win the next whatever where ever that is going to be.

For me this sail offers everything that none of the others sails could offer.

Simplicity, if the one sail fills the boat goes. Some of you have so many by the time you are reefing I'll be there already. Some of you need a crew good grief.

Easy and quick to reef, super for fishing.

No clutter. I bet some of you don't know what all those ropes are for. I have two per sail.

My experience with the small tri I used as an experiment to test the sail with was an ok one, although I'm not nearly as experienced as probably any of you, in my amateur experience it wasn't too bad compared to some other much better developed boats.

And cheap ! If you know how stingy I am... I can maybe afford one too.

For the life of me I don't know why any one would put this sail on a mono hull. I seriously doubt it can be successful but that's the amateur in me that doesn't see what professionals see. If you heel, how long is the sailing edge then ? Half ? And where is the second leading edge... on the lee side behind the boat?

This is a multihul rig, it functions upright, but that's just my unprofessional opinion. I was on the tri fiddling with it when ahhhh so what the... It took me a while. If you sit behind it you will see it, and no it's not a jib.

I haven't received any two cents yet - cannot get the next disaster done without it so come on guys, those two cents ! Lets prove this thing a failure once and for all.

Do I get the feeling some of you are scared it may actually become successful ???

Fanie

10-22-2010, 07:10 PM

I have a question.

By having a boom in front of a sail, how many pointing degrees do you sacrifice in a close haul ?

brian eiland

10-22-2010, 07:37 PM

Hilarious!

Lets see, I may have to reorganize this material, and/or add to it, but here are a few reference documents for Bolger's Staysail Cat.
...and a letter he writes to a client about its potential

Paul B

10-22-2010, 08:01 PM

Lets see, I may have to reorganize this material, and/or add to it, but here are a few reference documents for Bolger's Staysail Cat.
...and a letter he writes to a client about its potential

You just don't get it.

Alik

10-22-2010, 09:40 PM

I'm sorry you have to be so combative in your postings on this particular subject thread. It would be much nicer if you offered your criticisms in a more civil manner

Brian, You have posted pictures of my projects in different forums, with 'criticism' of what and how is done, without knowledge of particular project and boat. Every boat is a compromise of properties, and every project is compromise - of technical issues, budget, customer's wishes, builder's capabilities, designer's vision, regulatory requirements... So if You do not have knowledge of these components and inputs, what kind of useful critique can You provide? It is just annoying bla-bla-bla from Your side. If You can do better - do it and show to us! Nobody have ever seen any of Your concepts launched, but You feel Yourself in position to act as design expert - this is amazing behaviour!

That said I must apologize to you and the builder for an error I made in reviewing this design.
So now You are reviewing my designs... Do You really feel that You are qualified to do it? How one can 'review' the designs without seeing the boat or drawings? Your mentor's tone is irrelevant...

in fact made a comment to the builder that I thought the overall appearance was very satisfactory.
Thanks Sir, now I feel highly honoured! :D

That 40' boat is designed to become a powercat if sailing rig does not work. Take out the mast and add bimini to the flybridge - and it is a cool boat with potentially better resale value than 'mast in the ass' solution.

ChiefOren

10-23-2010, 03:15 AM

Again, the reason for adopting an Aft mast rig is not to win races but more to the liking of long haul cruising. The ease of handling by single handed sailor, less rigging, etc etc. As Eiland has stated quite often, this rig may not achieve the best speed in light conditions, but who cares. If you wish to get somewhere fast, Motor!. If you aren't in a hurry, wait out the conditions. That is cruiser mentality, not racer mentality. What are your looking for in sailing? To beat the waves or to beat the other guy?

Alik

10-23-2010, 03:22 AM

The ease of handling by single handed sailor, less rigging, etc etc.

Have You ever tried to tack boat with such rig, with 2 jibs, with long foot and huge overlap? Definitely the procedure is not for single handed sailor...

brian eiland

10-23-2010, 06:54 AM

...It is just annoying bla-bla-bla from Your side.

.....So now You are reviewing my designs... Do You really feel that You are qualified to do it? How one can 'review' the designs without seeing the boat or drawings? Your mentor's tone is irrelevant...

....potentially better resale value than 'mast in the ass' solution.
If you are so annoyed, then I suggest you ignore this subject thread. BTW, this is a forum discussion where EVERYONE can offer their opinions...not just certain snobbish designers.

Have You ever tried to tack boat with such rig, with 2 jibs, with long foot and huge overlap? Definitely the procedure is not for single handed sailor...
You brought this subject up previously if I remember correctly. and I pointed out that BOTH my mizzen and staysail (main) were SELF-TACKING. It was only necessary to tack the genoa headsail, and even that could be delayed until after the turn was completed.

I think part of your 'annoyance' with this sail plan (and me maybe) is that your client insisted on using such a sailplan above your objections. That's the only reason I can think of for you to have utilized the rig....as you certainly are objectionable about it. So go read some other threads, and take your nasty demeanor with you.

Alik

10-23-2010, 07:23 AM

If you are so annoyed, then I suggest you ignore this subject thread. BTW, this is a forum discussion where EVERYONE can offer their opinions...not just certain snobbish designers.

Yes, if those opinions based on facts and experience. You know no facts, and have no experience (and no qualification) to discuss the work done by us.

This is not first time You discussing our projects in such manner. Few years ago You posted photos of our 87' trimaran on yachforums, making conclusions without even being on board and without knowledge that it was a refit project. If You just come on board and ask me to show the boat - I will explain why and what is done. But You choose another tactics - entertaining Your audience with Your own ill-informed guesses!

For decades, You fool people with advantages of aft-mast rig that has never been tested by You. Why don't You put big red disclaimer on Your web saying 'this type of rig is not tested'? You are referenced on many multihull websites as as yacht designer - the designer who has never built any boat! :D

You brought this subject up previously if I remember correctly. and I pointed out that BOTH my mizzen and staysail (main) were SELF-TACKING. It was only necessary to tack the genoa headsail, and even that could be delayed until after the turn was completed.
In theory - yes. YOUR mizzen and jibs are tested... on paper only.

I think part of your 'annoyance' with this sail plan (and me maybe) is that your client insisted on using such a sailplan above your objections. That's the only reason I can think of for you to have utilized the rig....as you certainly are objectionable about it. So go read some other threads, and take your nasty demeanor with you.
My annoyance comes from fact that someone is writing about design mistakes to the builder, without seeing drawings and boat. No professional will do it.

That 40' client basically has no sailing experience. This is the reason why this junk seems attractive to him, after reading convincing writings of 'aft-mast professor'.

yipster

10-23-2010, 08:59 AM

without going into this argument, i do like the idea and looks of that motorsailer in post #254
so if it performs reasonably well i would think something new and good has resulted from it all

Alik

10-23-2010, 09:15 AM

without going into this argument, i do like the idea and looks of that motorsailer in post #254
so if it performs reasonably well i would think something new and good has resulted from it all

Overall it performs as good as similar cat (SA/weight) with conventional rig. This boat has got very narrow hulls, only 1.1m at WL for 40' length. But windward performance is worse due to slack of stays, wider sails (i.e. lower aspect ratio) and reduced abilities for sails tuning. This boat has no main ('mizzen' in Brian's terms), only 2 jibs.

Setting main/mizzen hang on spreader does not seem feasible.

Fanie

10-23-2010, 09:25 AM

Many engineers that has never built anything. Many architects has never picked up a brick and laid mortar on it. Neither has many very fine boat designers ever applied a layer of glass. Many civel engineers cannot weld but their bridges get put up.

I for one am glad that Brian Eiland had the aft mast rig on his website Alik. If you have a personal score to settle then take it off the forum. Some critic is welcome but keep it unipersonal. We don't care who said what elsewhere, or what happened, it has no bearing on this thread.

Alik

10-23-2010, 09:36 AM

Many engineers that has never built anything. Many architects has never picked up a brick and laid mortar on it. Neither has many very fine boat designers ever applied a layer of glass. Many civel engineers cannot weld but their bridges get put up.

This is not the issue; the issue is that no aft-mast boat 'designed' by Brian has ever been built by anyone.

P.S. I can weld and do FRP work. And I built my first 3.6m dinghy design myself, at the age of 14 :) How one can do engineering work without understanding the process?

I for one am glad that Brian Eiland had the aft mast rig on his website Alik. If you have a personal score to settle then take it off the forum. Some critic is welcome but keep it unipersonal. We don't care who said what elsewhere, or what happened, it has no bearing on this thread.
The argument started from Brian's claim that something is wrong in the rig (without having seen it). If he pretends to 'review' our designs, then I retain the right to review his experience and qualifications.

Fanie

10-23-2010, 10:29 AM

This is not the issue; the issue is that no aft-mast boat 'designed' by Brian has ever been built by anyone.
What does it matter ? He has always been involved with it and has always been in favour of it as far as I can tell. No one was interested in it up to now, I don't think it would be fair to discredit him because it wasn't precisely 'his boat'.

Every person here has a skill and some knowledge no one else have, the idea would be to benefit from it and enhance your own. Let's build on that !

Alik

10-23-2010, 10:39 AM

What does it matter ? He has always been involved with it and has always been in favour of it as far as I can tell. No one was interested in it up to now, I don't think it would be fair to discredit him because it wasn't precisely 'his boat'.

I agree that he is a dreamer and enthusiast, but he is not really a designer as he does not design (and build) anything to his designs. And also not a design expert capable to 'review' the designs developed (and tested) by professionals.

Every person here has a skill and some knowledge no one else have, the idea would be to benefit from it and enhance your own. Let's build on that !
Let's treat each others as colleagues here; no mentors and 'professors'. And it will work.

Fanie

10-23-2010, 10:51 AM

Well in that case I'm a dreamer too and so is a lot of other people here. Just look in their boat design galleries. I have designed many many things I never made or built. He did however make some drawings which those that chooses can benefit from, so it wasn't all only dreaming.

There is a time to teach and there is a time to learn. I find no shame in it to learn from someone else, I do find shame in not knowing enough.

Alik

10-23-2010, 11:06 AM

Well in that case I'm a dreamer too and so is a lot of other people here. Just look in their boat design galleries. I have designed many many things I never made or built.

It is normal that some designs are built, some are not. But at certain stage some pictures should start becoming real stuff. But if someone is drawing pictures for 30 years without having a single boat built - is he a boat designer?

He did however make some drawings which those that chooses can benefit from, so it wasn't all only dreaming.

Those are not drawings but pictures. How about mizzen hang on spreader? Is there any engineering behind?

There is a time to teach and there is a time to learn. I find no shame in it to learn from someone else, I do find shame in not knowing enough.
Exactly! And someone who has never tested the boat (never designed, never built, etc.) should probably listen those who did. Listen with respect at least like colleagues, not like professor listening a remedial student.

brian eiland

10-23-2010, 01:06 PM

Overall it performs as good as similar cat (SA/weight) with conventional rig. This boat has got very narrow hulls, only 1.1m at WL for 40' length. But windward performance is worse due to slack of stays, wider sails (i.e. lower aspect ratio) and reduced abilities for sails tuning. This boat has no main ('mizzen' in Brian's terms), only 2 jibs.

Setting main/mizzen hang on spreader does not seem feasible.

You posted some photos of the boat, but nothing under sail...and its the rig we are discussing??:rolleyes:

And since your office did the design perhaps we could see an updated dwg that shows the 'as built' rigging rather than the only dwg that was forwarded to me??

Alik

10-23-2010, 01:24 PM

You posted some photos of the boat, but nothing under sail...and its the rig we are discussing??:rolleyes:

I was on the boat when we did sea trails under sails; so could not picture the boat from outside :p

And since your office did the design perhaps we could see an updated dwg that shows the 'as built' rigging rather than

We have complete set of rig drawings, including details of mast, chainplates, etc. And these drawings show 2 pairs for backstays. It is how it was first - designed and then - built.

the only dwg that was forwarded to me??
So You say You have dwg? Wonder where You can get it, I never gave dwg to anyone, even to builder, only pdf and printed copy.

What is the reason for forwarding/showing dwg or other plans to You? Who You are? Certification body? NO. Expert? NO. Customer? NO. Explain me the reason why I should give this information to You? :D

brian eiland

10-23-2010, 01:32 PM

We launched our HK 40 aft mast , finally , after some adjustments .

I tested the boat only 2 time and we still don't have the main sail rigged (hopefully soon) . But I must say that I am extremely happy about the rig . The boat is fast , being a 10 ton displacement vessel , and I have seen 9.5 knts under sail , in the typical light wind of Pattaya Bay .

Very easy tacking and the boat is pointing in the wind extremely well . I need some more tests to provide some numbers , but let me say by now that the project is successful . A very nice design and a real good concept and idea!

The boat drags a lot of attention in the Marina !! We receive visitors every
day .

I started the construction of other 2 units , to be delivered in Bali and
to stay in Thailand .
Interesting...seems to be working out according to the builder.

I would suggest to publish something on my website , indicating your name and if you like to write something yourself , I will be more then happy to publish in full . Can be the story of this idea , how you developed it and a description of the advantages .
I suggested to the builder that we hold off on this 'announcement' about the boat's success until more testing had been done.....specificlly so it would not be misleading information until further testing was done.

BTW, here is a portion of the note I sent to the builder:
I'm wondering how is the mast-aft boat doing?

As I look thru the two photos you sent to me, I noticed the built boat does NOT have the mizzen sail arrangement shown in the drawings, nor its jack stay. I also noticed it has its speaders raked aft. I suspect this puts quite a large bending load on the mast at the attachment of the smaller, lower headsail. In fact I suspect too much loading...those aft swept spreaders are pushing forward on the mast, and the lower headstay is pulling forward. There is practically no resistance rearward.

So I'm interested to hear of your experiences with that rig.

As you can discern from my note to the builder, I had 'read' the photos and dwg the builder sent me incorrectly, and thus my concern for the loads at the hounds as I saw no masthead bacstay, nor lower backstays.

brian eiland

10-23-2010, 01:42 PM

without going into this argument, i do like the idea and looks of that motorsailer in post #254
so if it performs reasonably well i would think something new and good has resulted from it all
I want to get away from this silly argument as well. I resisted replying to Alik's continued attacks on me till I could no longer ignore it. He has some sort of ax to burn with me, so hopefully he will get a life and move on to other subjects.

Yes, that vessel does appear to be a nice looking rendition, and the builder seems to be satisfied,...and is building several more.

Alik

10-23-2010, 01:43 PM

Yes, it seems to work out; but there are no real advantages, and there are some difficulties as I expected. Also pls note that it is our design that works, not Yours :D

For Your notes sent to the builder - who is interested to read it and reply on that? Be realistic, You do not have any professional knowledge to give such comments.

Alik

10-23-2010, 01:46 PM

I want to get away from this silly argument as well. I resisted replying to Alik's continued attacks on me till I could no longer ignore it. He has some sort of ax to burn with me, so hopefully he will get a life and move on to other subjects.

To stop it, a) just stop sending Your useless comments to the builder b) stop commenting any of our projects on the web. And then stay relaxed dreaming about Your virtual boats.

Fanie

10-23-2010, 05:15 PM

Brian and Alik,

Neither of you can win this augmenting, and it's trashing the thread. Every one is waiting for you two to finish so we can continue discussion.

How about it - please.

peterAustralia

10-23-2010, 07:53 PM

Just a small point that no one has mentioned previously

I have noticed on many of these aft mast rigs that there is not a lot of horizontal separation between the mast base and the rear stay.

Say for example, that the boat was designed from the very beginning to accept this rig, then perhaps a stern that slopes rearwards would be more suitable, perhaps something along the double ended designs of Wharram cats.

The advantage as I see it is,
for the same forestay tension, the compressive loads on the mast would be less. Note of course that backstay tension is the same as rearstay tension (I assume so, otherwise the mast tip would be bending).

I know that modern catamarans often have the transom sloping forward so as to reduce weight and windage for a given waterline length. If the transom sloped aft, as per Wharram cats, and the transom was built strongly (as it has to be on Wharram cats to accept the rudder loads) then the compressive loads on the masts or bipod would be less. This in turn would allow for slightly lighter and smaller masts, with less resulting windage.

I am able to do the maths if desired, it is just high school statics.

The other issue, that I do not really understand, is that often the aft mast boats seem to have the mast raked forward.

How is the forward mast rake determined, is it by sail center of effort?

I guess in my own mind, I am thinking of more bipod on cats and trimarans. It seems that such an arrangement on a double ended craft, would have quite low loads in mast compression, so that by increasing the distance between mast base and rear stay position, compressive loads are reduced.

Note that this is not a linear relatiionship, double the horizontal distance, half the load... nothing like that. but looking at some of these diagrams, my estimate, prior to doing the maths, is that using a stongly built aft sloping transom (or double ender) would reduce compressive loads by about ten percent.

I can do the maths if anyone wants.......

brian eiland

10-23-2010, 08:24 PM

Brian and Alik,
Neither of you can win this augmenting, and it's trashing the thread. Every one is waiting for you two to finish so we can continue discussion.
How about it - please.
I agree to that...thank you Fanie for pointing that out.

Peter Austrailia, I'll get back to you on those questions, but it might not be till Monday as I may have to go out of town tomorrow, Sunday

Fanie

10-24-2010, 01:23 AM

Hi Peter,

What I did was to cad the sail up and rotated the mast at different angles. For me the best position was the mast vertical, and it has the biggest sail area then. Imo there is not much down pressure, the weight of the mast, but there is a foreward pull from the forestay like a fishing rod. I had the mast supported on it's foot and the upper part supported against the deck of the hull, no stays, so you want a stiff mast.

As I see it, the sail force has a foreward component and an upwards component. Light vessels will benefit but heavy ones won't have much of an advantage from the lift. The lift also keeps the boat from heeling as much as other sails would. On my friend's windrider I could sink the ama, with the little tri the ama could not even get the whole length wet.

When running I often got the impression that enough wind could pick you up and carry you over the water instead of sailing over it. Never happened though but I do need to lose a bit of weight :D

MikeJohns

10-24-2010, 01:55 AM

Just a small point that no one has mentioned previously

I have noticed on many of these aft mast rigs that there is not a lot of horizontal separation between the mast base and the rear stay........

AKA the backstay angle.

That's why the mast and it's supports will be heavier.

Fanie's setup is probably where the tradeoffs may give some benefit. On a larger heavier boat I have some very severe doubts ( Sorry Brian :-)).

Brian
You would have calculated the rig loads, mast compression stay tensions surely?

The vertical lift is one tradeoff for such a long lazy luff. There is a loss of drive which is instead trying to lift ( it won't by much no matter how much weight Fanie loses).

Fanie

10-24-2010, 02:41 AM

Mike, the lift will of course always make a difference. I think there would be a relationship between the hull's shape/drag and the lift. If a mast is not free standing then it will have to be supported properly - obviously. I think Brian's sketches was just ideas at the time, and probably not intended for production as is. A bit like drawing a boat and not putting the motor where it can function - the idea may well be to just indicate it's pressence as a possibility.

The taller the mast the less the relative vertical lift - and the more foreward force. So it may well be that the vertical lift stays about the same for any size sail foot length, but by lengthening the mast the foreward force increase.

There were no tradeoff's made with my rig, I haven't lost any weight yet ;)
Bloody gravity. Makes everything work but it also buggers everything up.
God's sense of humour perhaps. Let me give them something they cannot resolve...

Something else I noticed. When you sail to wind the sail dumps aft. When you run the sail dumps down which would also contribute to lift as well as foreward force.

I asked before, if someone knows, by how much does the mast in front of the luff affect the pointing ability ?

Alik

10-24-2010, 03:47 AM

AKA the backstay angle.

That's why the mast and it's supports will be heavier.

Fanie's setup is probably where the tradeoffs may give some benefit. On a larger heavier boat I have some very severe doubts ( Sorry Brian :-)).

With mast sloped fwd, measures should be taken to transfer the load to hull structure. Aft cabin buklhead is vertical and usually has big door openings; it is no efficient to take the loads. We provided cross-beam at bridgedeck that forms door coaming, and the mast is stepped on that beam. Anyway there is some bending as its section modulus can not be competed with mast bulkhead of conventional rig arrangement. I would say with this scheme the whole boat is more flexible compared with conventional cat.

Brian
You would have calculated the rig loads, mast compression stay tensions surely?
Brian's rig has never been engineered. Period. If You ask this question to him, he would post another two pages of text based on thoughts and internet links, but without numbers or load diagram.

Alik

10-24-2010, 03:53 AM

I asked before, if someone knows, by how much does the mast in front of the luff affect the pointing ability ?

C.Marchai has the graphs in his books.

Fanie

10-24-2010, 03:56 AM

Another possibility I was thinking about. Since you can quite easily use electronics to auto steer, it may well be possible to adjust the sailing speed with an electric furling roller. If you're fishing for instance and you want to trawl at a specific speed, the furling roller and winch can now control the sailing speed.

I wonder how well this would hold up in a storm. If Manie wasn't completely lying about the pointing ability it may be possible to sail into the storm at a narrow angle, possibly even at a negative speed if the steering reverse steer and the mast assist in lagging the stern. You won't have to fiddle with drogues and sea anchors and one less thing you must have.

Fanie

10-24-2010, 04:08 AM

Thanks Alik, but unfortunately I don't have the book. Any rough indications what it says ? 2 - 5 degrees ?

And stop stabbing will you. Each time you do that another two pages gets wasted.
Albert Einstein was a theoretical physicist, philosopher and author who is widely regarded as one of the most influential and best known scientists and intellectuals of all time... If he got everything just right then there wouldn't have been anything left for us to develop.

Alik

10-24-2010, 04:19 AM

Thanks Alik, but unfortunately I don't have the book. Any rough indications what it says ? 2 - 5 degrees ?

I have that book in office; can check on Tuesday.

Albert Einstein was a theoretical physicist, philosopher and author who is widely regarded as one of the most influential and best known scientists and intellectuals of all time... If he got everything just right then there wouldn't have been anything left for us to develop.
Besides Einstein was a unique genius, he was publishing his research in scientific magazines. This is completely different level and those are publications peer-reviewed and accepted in scientific community. Posts in the Internet are not, anyone can play as self-named expert :)

It is important that thread readers get correct information on what is real-life experience with aft-mast rig, and that decision to build such boat is a gamble for their own money. Unfortunately I met few guys who got wrong impression from reading convincing posts of 'professor' :D

Fanie

10-24-2010, 04:24 AM

Fanie

10-24-2010, 04:28 AM

Besides Einstein was a unique genius, he was publishing his research in scientific magazines. This is completely different level and those are publications peer-reviewed and accepted in scientific community. Posts in the Internet are not, anyone can play as self-named expert

It is important that thread readers get correct information on what is real-life experience with aft-mast rig, and that decision to build such boat is a gamble for their own money. Unfortunately I met few guys who got wrong impression from reading convincing posts of 'professor'

I'm actually trying to tel you something. Come on man, have a bit of class.

Alik

10-24-2010, 04:35 AM

If you have a 45m^2 sail, then if I remember right the force in 20km/hr winds is like 7kg/sq meter, resulting in a total of 315kg, devide by 3 for the 3 tie points ~ 105kg.

A conventional sail would be bearing a larger load since it carries the full sail, the boom assisting a bit though.

The force in the structure from the mast head should be the 105kg times the lever ratio length of the lower support vs the above deck mast.

In brief - it is wrong; sail is not supported by 3 tie points; pressure is not evenly distributed, etc. etc. And this is not the way to calculate the load on the mast.

If one is interested, I suggest to look at Larsson/Eliasson 'Principles of Yacht Design', they have general method of rig dimensioning there, with sample. There are also other publications, requiring different levels of background - from Skene and Herreshoff to Claughton's 'Yacht Design' series and new Fossati's 'Aero-hydrodynamics'.

gggGuest

10-24-2010, 05:11 AM

C.Marchai has the graphs in his books.
You may find that Marchaj has been superceded on some of the finer points by new CFD based work. I can't find the reference right now, but, for instance, I came across something quite recently which suggested the drag of a spar with a sail behind is very substantially less - I think it was between a third and a half - than one without a sail.

Alik

10-24-2010, 05:19 AM

You may find that Marchaj has been superceded on some of the finer points by new CFD based work.

I would not rely on CFD only in such comparisons; CFD is something that needs verification first of all.

yipster

10-24-2010, 05:52 AM

its hard not to theorise astro physics, quantum mechanics and this rig
got C Marchaj out to follow performance and wonder if srouding
is with sprits and a bok this aft mast on a tabernacle can be lowered (http://www.boicey.com/sailboats/pics/cnc_27_mast_raising_05.jpg)
Fanie is sitting in front of his and eventhough its in dutch he keeps that secret

peterAustralia

10-24-2010, 06:37 AM

before I call it a night, and go to work tomorrow....

firstly, it would be nice if we kept it civil. Even it a person is verbally attacked in this forum, it is up to the person attacked as to how they choose to reply. It is possible to make a point whilst remaining polite. Example someone can attack me, saying I have only built one crappy little outrigger sailing canoe, I will try and reply civily all the same.

As to professionalism and all that, if the rules of this forum were professionals only, then most of us would gladly disappear, but this forum is open to the public, as such people with constructive ideas should be able to be heard.

The standard marconi rig cant be all that bad. It is so common. A couple of downsides is that it is relatively expensive, and difficult to reef single handed. I can speak from first hand experience in just a few boats, my sailing experience is pretty limited, but when I have had to do reefing, it has not been a fun easy process. Sailing on my cousins 27ft steel yacht, reefing was not fun whilst he steered. Sailing my outrigger canoe on Port Phillp Bay alone at 10pm at night, 5km from shore and trying to get the sail down when the southerly front came through was not fun at all!

The points made on difficulty in tacking in aft mast rigs may have some merit, but perhpas they can be worked on. The idea of having an inner jib kept taught, whilst loosening off the larger forward jib/genoa makes a lot of sense. It should bring the center of effort aft and assist with tacking. Trying to attach a mizzen to the rear stay seems difficult, with forward rake and all.

A fellow called Kris Seluga tried a crab claw sail suspended from an 'A frame' bipod on a 20ft catamaran. He commented he found it hard to tack. Most aft placed rid seen in this thread seem to have a much migher aspect ratio, and that combined with a smaller sail further aft, should assist with tacking.

Does Fanie have any problem with tacking?

An inner jib would make the boom that Fanie uses on his trimaran more difficult. I personally am a little confused as to why the boom is required. Perhaps Fanie can explain why he added it, I assume there must be some benefits otherwise he would not have done so.

Say there was no boom, then for a given tack, the clew of the sail could be controlled with 2 lines, one from the centerline, and one from out towards the outrigger, thus the positition of the clew in 3 dimensions could be controlled. I am just a bit puzzled by why a boom was used.

As to the maths. is a little complicated, depends on wind angle, wind speed etc etc. Say for a trimaran of Fanie's size, what would the typical forestay tension be? 500kg - 700kg - 900kg? (just a guess). If someone can tell me a typical forestay tension for a boat teh size that Fanie sails, then this week I will attempt a description of loads, that everyone and anyone is able to comment and on for good or otherwise. Loads at both no wind and at moderate wind. I will just to static loads as taught in high school engineering science, nothing too high tech.

What I meant to write eariler was that I assume that forestay tension is the same as backstay tension.

As to loads on the hull, a backstay would have a horizontal component, putting the rear deck in compression. If the backstay angle was increased so that it was more horizontal, then the horizontal compression loads on the rear deck would be greater, additionally they would be delivered over a longer area, thus a bit more weight would be needed to ensure the deck was strong enough to withstand these compressive loads.

If the backstay angle is less, then a very high upward force would be imparted where the backstay meets the hull, and this area would need to be reinforced, but horizontal compressive deck loads would be less.

One little idea that i had. Say for example that Fanie wanted to lower his mast at sea, how would he do it? My guess is that he would have a spar that lays on the rear deck, from mast base, to the rear stay. It would lay flush with the deck, possibly recessed and out of the way.

When a cyclone comes along, Fanie starts to tilt his rig forward, the short spar which was laying horizontal is slowly raised until it becomes vertical. In this way the spar would support the mast as it was being lowered down. In normal sailing, this spar could take the horizontal compressive loads forward to the mast base. By having this spar at deck level, possibly recessed, then windage is eliminated, and center of gravity is kept low.

If Fanie had a bipod say with a 10ft wide base, then I assume that instead of a single spar, a short horizontal laying bipod would take its place. In my own mind, I am trying to work out what otehr uses such a short horizontal bipod could be used for. Trailing fishing lines... hmmm, no that is silly...

The ability to lay a rig horizontal whilst in a big storm might be a big plus. Assuming of course that the rig is not so high as to overlap teh bow too much and move the center of gravity too far forward, and upset the trim

Laying the rig down would reduce windage and center of gravity, probably both pretty good things in a bad storm or cyclone.

all these words will be better with diagrams...

is 10.30pm here, and i have to go to work tomorrow...give me 4 or 5 days...

brian eiland

10-24-2010, 08:20 AM

..How is the forward mast rake determined, is it by sail center of effort?
Peter this rig idea started out as just a twin headsail arrangement in my mind with the headsails separated by a greater distance than usual at the time (1973). And I was looking for some manner to attach a mainsail, but avoid putting it directly attached to the mast (the thing I most wanted to avoid). I hit upon the idea of putting a mizzen on that one backstay, then I tried to arrange the whole sail plan over the vessel such that it would be balanced. Here is one of the original published dwgs:
http://www.runningtideyachts.com/archives/OrgMagArt.php

The rake in the mast just happened as a result of the geometry, and my attempt to not make the rig look too radically different than normal sailing vessels. Over the years I have NOT found any need to put more rake in it, and besides that would be more problematic. I have played with a version of less rake (about 6 degrees) along with a bigger mizzen. I've not found that this would be any less of an engineering problem that the 9-10 degree rake. I am convinced I would not care to go more than 10 degrees rake...besides it would not represent any additional gain.

You might note on that original dwg I had no forward jumper struts at the hounds. All the dwgs on my website at present do show such a jumper arrangement. I have other newer ones that are unpublished, and that have an even newer arrangement than that, both in geometry, and a variation that takes advantage of the newer rigging materials we have available today.

It was not long after I showed this rig idea to a professional sailing captain friend of mine that he came back from a trip to Central America with this aft rig version here (check out the mast rake, almost same as mine)
http://www.runningtideyachts.com/archives/othermansboat1.php

This idea has gone into hibernation on a number of occasions when I got too busy with other projects to pursue it. At several points in time I considered just dropping the whole thing, as it was going to be an even tougher sales effort than that I spent selling multihull vessels to the American public in those early years. But the idea keeps emerging.
I wrote about that here on this subject thread..
…..reference posting #98, Aft-mast Origination & Justification (http://www.boatdesign.net/forums/sailboats/aftmast-rigs-623-7.html#post198605)
...and posting #104, Sails in Combination (http://www.boatdesign.net/forums/sailboats/aftmast-rigs-623-7.html#post198774)

The other issue that I do not really understand, is that often the aft mast boats seem to have the mast raked forward.
I believe you might find that the most of the aftmast boats have their mast verticle rather than raked.

I am able to do the maths if desired, it is just high school statics.
The static situation is relatively easy to do with force vector analysis. I'm presently re-looking at this this static situation as I am considering some new variations in the rigging....some more modern materials and methods of attaching them. I will private message you about this. Perhaps you can review my work?

I repeat, “it sure would be nice to do a three dimensional space frame computer modeling of the rig where lots of variables could be changed around to arrive at the most ideal form of this rig.”

The dynamic analysis is more difficult. It was my hope that an adventurous client with a few extra dollars would come forth and we might employ a real professional rigging analysis such as Chris Michell at AES (http://www.aes.net.nz/)

Fanie

10-24-2010, 10:03 AM

How many tie points are there then ? :D

And what difference would a few kg either way make ?

Looks to me like whatever pull I put on the clew will be devided by the mast head and furling roller.

RHough

10-24-2010, 10:10 AM

How many tie points are there then ? :D

And what difference would a few kg either way make ?

Looks to me like whatever pull I put on the clew will be devided by the mast head and furling roller.

For a *very* rough estimate. Use your 105kg and apply it to the middle of the tensioned stay. See how much the stay deflects and how that effects the tension.

R

Alik

10-24-2010, 10:14 AM

How many tie points are there then ? :D

If the jib is fixed to stay, and stay is reasonably tight it is not 3-point attachment. Stay will take distributed load. Any engineer will tell You the same.

Fanie

10-24-2010, 11:55 AM

Yipster,

I have no secrets, should I have ? Ask what you want to know. You all have helped out so many times...

Thanks Peter,

Hope you can sleep tonight :D

At times I had problems tacking, but considering the hull it is not surprising, and it was no where near fast either. When I sat at the back the stern made a lot of drag because it was submerged, moving foreward had a significant increase in speed and tacking bacame easier, but made steering and playing with the sail difficult.

Although a pesky thing on any boat, the boom had a few bonusses, I think it made a big difference to how close to the wind you can sail. Of course the closer to the wind the slower you would go to where you finally stop. What I suspect is that the foot of the sail becomes another leading edge. My arms was too thin to keep the foot taunt for more than a few minutes, especially when the wind was up, so I added the boom.

While pointing more and more, the sail kept it's shape almost right to the point where it feels like you are going into the wind, which is what Manie referred to. I didn't think he would notice, but he's a lot sharper than meets the eye :D

While turning gradually into the wind, right to the point where the sail form would collapse there is foreward movement. When the sail collapses however, there seems to be an offset you have to overcome before the sail would catch and function again. To compensate for this you can of course just push the boom sideways and reverse steer, keep in mind you'd be in irons here by now.

When sailing at some speed, tacking wasn't that big a problem. I don't think it was more difficult than tacking with the windrider tri. I never fitted the auto tacking thingy.

You cannot sail directly downwind with the aft mast without a boom, simply because the sail would fold in. In theory the sail should fly open and stay open but in practice the clew support will have to be taken too far sideways. While sailing downwind I had to tack without a boom.

You will notice that the ball joint I had on the boom is a little ways in front of the furling roller - this made the foot taunt when reaching but gave it slack when running so the sail would dump downwards. It worked very well. The boom made it possible to sail any direction downwind without any problems and I could decide how flat or ball the sail should be by lengthening or shortening the clew line... dumping the wind downwards to sustain the lift I like. Made me feel thinner :D

In a close haul the sail would look like an arrow from the rear, and would dump the wind towards the stern. The foot of the sail looked like a leading edge as much as the stayed leading egde. By moving the boom up and down I could also change the shape of the sail, ie how flat/ round it was.

Re the forces on the mast and the tie point dispute :D
Clipping the furling roller in place I suspect there was about 10 maybe 15 kg's of load on the stay.

At this point if one consider this as a zero load on the stay because it is in rest then if the sail is open and stretched out flat then the load on the stay would also be zero.

Bringing the clew down so that the sail can begin to fill, would increase the load. If the pull on the clew is say 20kg's, I cannot see that this can be exceeded anywhere else, there has to be distribution. What further lessens the tension in the stay imo is the fact that the sail is flying upwards and against the direction of the sail pulling the stay, but at an angle.

Sitting right against the mast looking up there was some slight bent in the mast, but it never became much more than that. The mast was a 100mm x 80 x 3mm Alu one and six meters long, the sail was 12m^2. The clew once lifted me out of the hull and dragged me onto the trampoline in a bit of wind. Unfortunately I wasn't watching the mast or it's bend, I was trying to stay out of the water :D

Mostly the times when the mast bent a bit, I got the impression it was bending more sideways than foreward, but probably more at an angle between the two.

Putting the mast up or taking it down was not difficult. I made a slot where the mast foot would push into and you can right it. On a larger rig the same setup should work well but with the use of a winch and a gin pole, one person can do. The sail stay would keep the mast from going up and would keep it snug in place. Lowering it you would clip the furler loose and the mast can hinge backwards and down.

yipster

10-24-2010, 01:56 PM

sorry, ginpole is the word not "bok" as i wrote
mast up from a slot is almost a tabernacle
and setting and strinking 6m goes easy you say
apart from possible advantages in the sail plan
my filosofy on these systems is they can perhaps
better transfer a boat from motor to sail or vicaversa
as Spiv's aft mast drawings show here (http://www.boatdesign.net/forums/boat-design/wishbone-sailing-rig-1999-8.html#post275840)
for the mathemathicians bipod mast calcs (http://www.rclandsailing.com/catamaran/mast_forces.htm)

brian eiland

10-24-2010, 04:24 PM

...was looking at aft mast, wishbone and bipod bridges, frame drag at various wind and points still in a search... http://images.travelpod.com/users/bronandjosh09/1.1255805462.new-bridge-being-built-note-harp-design.jpg
That bridge reminded me of the illustrations I posted back at #44....;):D
http://www.boatdesign.net/forums/sailboats/aftmast-rigs-623-3.html#post120157

brian eiland

10-24-2010, 04:51 PM

... but, for instance, I came across something quite recently which suggested the drag of a spar with a sail behind is very substantially less - I think it was between a third and a half - than one without a sail.
In general this is true. There are more indepth discussions over HERE:
http://www.boatdesign.net/forums/sailboats/sail-aerodynamics-457-24.html

BTW I have an idea about reducing the drag on my spar that will be relatively cheap and simple. At one time I was also working on a idea to reduce standing rigging drag via some replacable 'shroud covers'. Forgot where I put that info.

pbmaise

10-25-2010, 11:59 AM

This may not be a rig you want to slap onto an existing vessel without properly determining that the vessel itself will accept the loading points. I am truly concerned that someone does not waste their money on this technology without fully realizing that they are on the cutting edge.

Brian..Thanks for posting your storm experience. I've not had to run or stand in front of waves the size you described. One difficulty I foresee is managing the change from running to having to deploying the para-anchor. If you kept running to the point it was no longer feasible..the situation would not be conducive to doing a lot of activity on deck to deploy the para-anchor. Therefore, I'm almost thinking it would be best not do any running and just deploy the para-anchor BEFORE seas are too big.

Yes, I did have some contact with Brian before I made up my mind to go with the aft-mast configuration on my boat. Yes I kind of came up with the approach of putting a "crab claw" sail in front of the mast. I put in those quotation marks as some say I really have a lanteen.

I most certainly looked very carefully at my boat before making the change. From the start..the rear box wall of my boat was designed to support the two ama, and it was designed to be a lifting point to lift the boat by crane. I have a photograph of that.

I also took care to reinforce the box wall just in case.

We started painting the decks today. I'm leaving Thailand on November 7th.

Cheers Phil

p.s. Yes I invested big money in this ...however..it would have been far bigger money if I went with a full baton main. A solution to the problem I know I didn't want.

MikeJohns

10-25-2010, 05:14 PM

Brian..Thanks for posting your storm experience. I've not had to run or stand in front of waves the size you described. One difficulty I foresee is managing the change from running to having to deploying the para-anchor. If you kept running to the point it was no longer feasible..the situation would not be conducive to doing a lot of activity on deck to deploy the para-anchor. Therefore, I'm almost thinking it would be best not do any running and just deploy the para-anchor BEFORE seas are too big.
.........

There are myriads of anecdotal tales but the tales are largley eclipsed by the work of people like C.Marchaj, A.Claughton and M.Renilson and others who have looked in detail at boat behaviour in large waves.

Just be careful, Brian's obseravtion is for one particular event on one vessel ( a wooden ketch). On another vessel with something as simple as a better rudder arrangement and the experience may have been quite different. In Naval Architecture you cannot extrapolate form very limited observation unfortunately.

In a cat it's probably not such an Achilles heel to have so much windage stacked aft under bare poles. Since they do seem to survive better when lying to a drogue. The real danger for a cat is being picked up under the bridge deck by a breaker and surging out of control.

Upwind a mast will have a significantly lower drag with a sail attached (it prevents vortex shedding ). It seems a poor choice to have a non-attached luff on the sail abaft the mast for windward work. You lose both on the sail operating in the masts turbulence and a high drag factor from the mast itself.

brian eiland

10-25-2010, 05:37 PM

Not really an aftmast setup
but very much the single "foresail" setup, i dont really know what you call this
but it works :D

http://www.youtube.com/watch?v=8TtcZjAuF4A

nice sailing anyway:D
I was going back over this subject thread and ran across that video you posted Manie.

WOW, I wonder what they are using as a forestay material. Everyone of those boats appear to have a very rigid, straight forestay. And it must be reasonable light weight material considering the motion as they swing it around the mast....very interesting. :idea:
http://www.youtube.com/watch?v=8TtcZjAuF4A

Does anyone know this class of sailing boat, and where additional info could be found?

RHough

10-25-2010, 05:48 PM

brian eiland

10-25-2010, 05:58 PM

Brian..Thanks for posting your storm experience. I've not had to run or stand in front of waves the size you described. One difficulty I foresee is managing the change from running to having to deploying the para-anchor. If you kept running to the point it was no longer feasible..the situation would not be conducive to doing a lot of activity on deck to deploy the para-anchor. Therefore, I'm almost thinking it would be best not do any running and just deploy the para-anchor BEFORE seas are too big.
You are exactly right in my opinion Philip,....do it, and settle in BEFORE it gets to bad...besides are you in a big hurry. That old adage, 'haste makes waste'

Here is that sea anchoring subject thread I mentioned. I'm sure you can find many other tales and websites.
http://www.boatdesign.net/forums/boat-design/parachute-anchors-para-anchor-sea-anchor-10448.html
Regreatably I've not had time to follow thru with Richard Wood's tale, and there have not been that many other contributors to the thread subject.

And HERE specifically for some more reference sites
http://www.boatdesign.net/forums/boat-design/parachute-anchors-para-anchor-sea-anchor-10448-2.html#post270910

brian eiland

10-25-2010, 06:03 PM

They are Lateen rigs.
Well I suspected that...nice looking as well. What do you think they make that forespar out of??

RHough

10-25-2010, 06:14 PM

[QUOTE=RHough;411390]They are Lateen rigs.
Well I suspected that...nice looking as well. What do you think they make that spar out of??

My guess is that the newer boats are using carbon fibre.

I don't read Spanish well enough but class rules (http://www.federacionvelalatinadebotes.org/reglamentos.php) are here. They seem to specify a modulus limit for arts of the boat.

R

brian eiland

10-25-2010, 06:21 PM

As to the maths. is a little complicated, depends on wind angle, wind speed etc etc. Say for a trimaran of Fanie's size, what would the typical forestay tension be? 500kg - 700kg - 900kg? (just a guess). If someone can tell me a typical forestay tension for a boat teh size that Fanie sails, then this week I will attempt a description of loads, that everyone and anyone is able to comment and on for good or otherwise. Loads at both no wind and at moderate wind. I will just to static loads as taught in high school engineering science, nothing too high tech.

What I meant to write eariler was that I assume that forestay tension is the same as backstay tension.

all these words will be better with diagrams...

is 10.30pm here, and i have to go to work tomorrow...give me 4 or 5 days...
Peter I might suggest you just use an even 1000kg for the forestay, then any multiple of that can be factored through to the rest of the rigging a static situation.

I can give you this diagram that you can enlarge as a starting point. It is not the most up to date one, as I changed the forward jumper strut arrangement quite a bit, but my scanner is not working at the moment so I can't post newer photos or dwgs.

brian eiland

10-25-2010, 06:41 PM

There are myriads of anecdotal tales but the tales are largley eclipsed by the work of people like C.Marchaj, A.Claughton and M.Renilson and others who have looked in detail at boat behaviour in large waves.
I believe those fellow's work is eclipsed by sailors out there in the soup.
...Fast surfing is only fun as long as you have the stamina to keep up with the situation...

Also 'slow' surfing is not nice and it's not only a matter of stamina, but survival. I've done that 30 years ago aboard a 40 years old 33' double ender ketch in the coast of Portugal. Got caught in strong north winds the same day the Fastnet race disaster took place. Main exploded when trying to motorsail into Figueira da Foz harbour and we had to run all night under storm sail from Figueira da Foz to Peniche. Waves were quite high and steep, many of them breaking over the cockpit. With every wave that broke over us the boat sat stern down from a while till the scuppers did their work. The tiller was almost impossible to handle and barely controlled the long keeled boat as the boat tried to broach with every wave. We were three aboard, steering for a couple of hours each and then going down to bail out the water from the bilges with a bucket, before 'splashing' into the bunk for some minutes rest.
Not a nice night at all...

brian eiland

10-25-2010, 07:26 PM

As I see it, the sail force has a foreward component and an upwards component. Light vessels will benefit but heavy ones won't have much of an advantage from the lift. The lift also keeps the boat from heeling as much as other sails would. On my friend's windrider I could sink the ama, with the little tri the ama could not even get the whole length wet.

When running I often got the impression that enough wind could pick you up and carry you over the water instead of sailing over it. Never happened though but I do need to lose a bit of weight :D
You've experienced it, I've experienced it, and a number of other folks....that upwards lift from the sails. Perhaps it more of a phenomena aboard multihuuls that are not heeling over and are unballasted.

I brought this up long ago back in posting #__. where I also referenced Herresoff's same observations:
Next I would comment that he is correct that there is a moment force created by the sail force centers (other than kites) above the hull resistance centers that does tend to drive our bows under. But the contributions by the headsails can be so much less than that of the Bermudian mainsail that it may appear as a bow lifting experience. Many sailors have expressed this sensation.

Even Herreshoff comented on these bow burying forces aboard his catamaran, and the lifting of the bows by the headsail: "Herreshoff's catamaran reasoning (http://boatdesign.net/forums/showthread.php?t=5843)"

I want to come back to this subject, so I posted this as a reminder.

MikeJohns

10-26-2010, 03:57 AM

I believe those fellow's work is eclipsed by sailors out there in the soup.

I don't agree Brian.

They can run survival situations with a myriad of models headings and wave types and tell you just what is likely to happen and why. Naval architecture has embraced all this factual knowledge. Also its important to understand that such knowledge doesnt get negated by generalisations from limited observation.

Alarmingly in the commercial world very experienced sailors gut feelings about a vessels safety stability etc are often quite wrong. Which is where myriads of wave tank tests end up driving good design principles and making vessels safer, more controllable and less prone to being lost at sea.

You really should read the material that comes from those wave tank tests on scale models. It provides invaluable insight to a designer of Blue water boats.

Guillermo

10-26-2010, 05:14 AM

I was going back over this subject thread and ran across that video you posted Manie.

WOW, I wonder what they are using as a forestay material. Everyone of those boats appear to have a very rigid, straight forestay. And it must be reasonable light weight material considering the motion as they swing it around the mast....very interesting. :idea:
http://www.youtube.com/watch?v=8TtcZjAuF4A

Does anyone know this class of sailing boat, and where additional info could be found?
Hi Brian!
Those are the VELA LATINA Class boats in the Canary islands, evolved from traditional boats. Pure racing machines nowadays.

There is a member of these forums who is a naval architect and crew in one of those teams and has written a very interesting and detailed book about the boats. He offered me one a few years ago. His name is Daniel and is nick here is danielro (http://www.boatdesign.net/forums/profile/danielro.html)

I'm going to bring his attention to this thread as he can explain everything about the boats much better than me.

All the best.

Guillermo

10-26-2010, 05:24 AM

My guess is that the newer boats are using carbon fibre.

I don't read Spanish well enough but class rules (http://www.federacionvelalatinadebotes.org/reglamentos.php) are here. They seem to specify a modulus limit for arts of the boat.

R
The mast has to be a wooden one weighting at least 70 kg (Rules point 5.4.1)
But an 60 mm exterior diameter inner tube of whatever material, to reinforce the mast, is allowed. A 2mm additional exterior laminate is also allowed.

Cheers.

brian eiland

10-26-2010, 06:30 AM

The mast has to be a wooden one weighting at least 70 kg (Rules point 5.4.1)
But an 60 mm exterior diameter inner tube of whatever material, to reinforce the mast, is allowed. A 2mm additional exterior laminate is also allowed.

Cheers.
Thanks Guillermo,
Is that the mast material, or the spar at the leading edge of the sail?

That spar is the one I'm interesred in.

brian eiland

10-26-2010, 06:38 AM

You really should read the material that comes from those wave tank tests on scale models. It provides invaluable insight to a designer of Blue water boats.
A major problem I would have with wave tank test of actual storm conditions at sea is I doubt they can replicate the orbital motion conditions that exist at the top and trough of big sea waves, particularly those wave energies that have been rolling along for miles. These are a big culprit in the broaching forces excerted on boats in big seas.

Guillermo

10-26-2010, 06:57 AM

Thanks Guillermo,
Is that the mast material, or the spar at the leading edge of the sail?

That spar is the one I'm interesred in.
The spar has to be also a wooden one weighting more than 25 kg (Rules 5.4.2). They call it "palanca".
Minimum diameter 85 mm, being at the ends no less than 50 mm.
Can be hollowed and have an up to 60 mm diameter reinforcing interior tube of whatever material, as well as an exterior 2mm GRP sheeting (Annex 1, page 34)

The only regulation for the size of the sail is that its length along the spar cannot be longer than 13.25 metres.

ChiefOren

10-26-2010, 07:51 AM

Alik, yes I have. However, I am not planning such a large overlap. only about half way over the inner jib. Also, I would have a third permanent stay for the storm jib. So any tacking would probably go like this. 1. Turn to the direction you wish to go! 2. inhaul the outer jib and pull it to the other side and deploy. 3. When done with that, THEN do the same for the inner jib.

You would think that backing the sails would be messy, but by backing the forward sail on the inner sail, you are actually helping the sail to pass over to the other side. Ditto for the inner jib on the storm stay.

Not very pretty, I must say, and very undignified maybe, but it works, and it's not so hard, esp. if using self-furling rigging.

Just my humble opinion. I am not a race bug that's for sure.

TeddyDiver

10-26-2010, 08:21 AM

brian eiland

10-26-2010, 08:31 AM

.. Also, I would have a third permanent stay for the storm jib...
No need to make that 3 stay a permanent one, particularly since you would utilize it so seldom...why work around that obstruction. Just make it a detachable stay, liking a running backstay or such. Many boats have featured such detachable inner stays, often to lend addition support to the mast when sailing under a reefed mainsail.

RHough

10-26-2010, 08:58 AM

The spar has to be also a wooden one weighting more than 25 kg (Rules 5.4.2). They call it "palanca".
Minimum diameter 85 mm, being at the ends no less than 50 mm.
Can be hollowed and have an up to 60 mm diameter reinforcing interior tube of whatever material, as well as an exterior 2mm GRP sheeting (Annex 1, page 34)

The only regulation for the size of the sail is that its length along the spar cannot be longer than 13.25 metres.

Thanks Guillermo!

Paul B

10-26-2010, 01:30 PM

As I see it, the sail force has a foreward component and an upwards component. Light vessels will benefit but heavy ones won't have much of an advantage from the lift. The lift also keeps the boat from heeling as much as other sails would.

When running I often got the impression that enough wind could pick you up and carry you over the water instead of sailing over it. Never happened though but I do need to lose a bit of weight :D

You've experienced it, I've experienced it, and a number of other folks....that upwards lift from the sails. Perhaps it more of a phenomena aboard multihuuls that are not heeling over and are unballasted.

Oh My. This is a perfect example of how old wives tales take on a life of their own on the internet.

I'm sure I will be reading about the "lifting" aspects of the aft mast rigs in posts written by others in the next 5 years, due only to someone else reading this nonsense.

Please provide a vector diagram showing this lifting component! Unless the rig is canted to windward there is no vertical lift. Raking the forestay more than a normal rig does not change the direction of the wind as well.

Mis-reading the writing of Capt. Nat doesn't make a fairy tale come true.

Fanie

10-26-2010, 02:02 PM

What can I say, except I was there...

Manie sailed with me once, maybe he can offer an understandable explanation.

Q. Why does a kite go up in the air ?

Unless the rig is canted to windward there is no vertical lift.
It could be our sails work off the vacuum created by it instead of the air pushing onto the sail, very similar to an aeroplane wing.

A 45 degree stay will do as much upward sailing as it would do foreward sailing.

gggGuest

10-26-2010, 02:24 PM

Raking the forestay more than a normal rig does not change the direction of the wind as well.
Yep this is 90% myth. But to be strictly accurate there is a tiny vertical component to any fore and aft sail with a raked leading edge which is sheeted off the centreline. It just isn't enough to make much practical difference. The one that is 100% myth is the one about such sails lifting the *bows*.

Always difficult to know what to do with a little correction like that, because you know that a percentage of the flat earthers are going to take it out of context and claim that its justification for their nonsense, but OTOH if you don't put the correction in then if they ever come across it then that's evidence of the conspiracy against their wonderful insights...

P Flados

10-26-2010, 06:54 PM

The amount of lift may be more than some think.

For a foresail, the center of lift is much closer to the front of the sail than the rear of the sail. When you are sheeted out way on a downwind run imagine a force vector perpendicular to the sail surface at say 35% back from the front edge.

With minimal forstay rake (very rare), this force vector will be nearly horizontal.

But if the rake is a lot, say 45°, the force vector will be way off vertical. The combination of rake and how far out your are sheeted is what produces a lift vector with an increasing upward component. With enough of a combination, you can get vertical lift that is close to or more than the forward lift. Go look at some of the 12' skiff videos on youtube (http://www.youtube.com/watch?v=_G7PlPrjkrw for example).

Fanie

10-26-2010, 08:30 PM

I agree with your argument P Flados, but not completely with that video as an example. In the video they are running, but I undestand what you're trying to show. The aft mast sail makes some lift in any direction you sail. I doubt it's going to be so much that it will lift the boat out of the water so you can parashute up an down, but the sail has two effects, there is defenately lift and it has more of a righting effect on the boat. I also doubt if this sail can be used to it's potential on a monohull, but on a multihull, yes.

MikeJohns

10-27-2010, 06:05 AM

A major problem I would have with wave tank test of actual storm conditions at sea is I doubt they can replicate the orbital motion conditions that exist at the top and trough of big sea waves, particularly those wave energies that have been rolling along for miles. These are a big culprit in the broaching forces excerted on boats in big seas.

The physics is exactly the same. Orbital velocity the works. These tanks are very sophisticated pieces of equipment, wave tank testing is mandatory for seakeeping characteristics of many vessels these days.

Alik

10-27-2010, 06:23 AM

The physics is exactly the same. Orbital velocity the works. These tanks are very sophisticated pieces of equipment, wave tank testing is mandatory for seakeeping characteristics of many vessels these days.

Yes, physics is the same.

For seakeeping, there is concern with surface tension, but if model is wider than 0.3m it usually is considered appropriate.

BATAAN

10-27-2010, 10:52 AM

Aftmast rigs made me remember the early 70s when a partner and I were re-rigging a fifty foot, 1901 SF bay oyster smack as a schooner. We'd stepped the mainmast and the bowsprit, but the foremast was still being hewn when we got a job in Vallejo, 30 miles away. The boat's the shop so....
No engine, no foremast.... we set the mainsail, strung 3 jibs and it worked fine, sailing downwind north to Napa river, then working our way up to anchor. Beating to windward down San Pablo bay also worked when the job was over. A week later we were back home and finishing the foremast and stepping it.
In Port Townsend WA is a 24' cabin aluminum motorboat which has had the engine removed, an outboard added, and a stern-mounted bipod mast with a huge roller genoa set up. It seems to work but I haven't examined it closely.

Guillermo

10-27-2010, 11:08 AM

The physics is exactly the same. Orbital velocity the works. These tanks are very sophisticated pieces of equipment, wave tank testing is mandatory for seakeeping characteristics of many vessels these days.
Yeap! They can analyze behaviour in breaking waves, i.e.

gggGuest

10-27-2010, 03:19 PM

Go look at some of the 12' skiff videos on youtube (http://www.youtube.com/watch?v=_G7PlPrjkrw for example).

Unfortunately you don't really understand what you are looking at. The 12s have an enormous pitch down pressure from their spinnakers: that's why they're hanging off the back of the boat. They even have the gunwhales extended aft of the transom in order to get the weight back far enough. If you let the spinnaker flap the bow lifts. If a spinnaker genuinely lifted the bow - as a kite sail can do - then when a gust hit the crew would be rushing the weight forward to keep the bow down.

P Flados

10-27-2010, 08:17 PM

Unfortunately you don't really understand what you are looking at. The 12s have an enormous pitch down pressure from their spinnakers: that's why they're hanging off the back of the boat. They even have the gunwhales extended aft of the transom in order to get the weight back far enough. If you let the spinnaker flap the bow lifts. If a spinnaker genuinely lifted the bow - as a kite sail can do - then when a gust hit the crew would be rushing the weight forward to keep the bow down.

As an engineer I have dealt with vector force balances on numerous occasions. I have also been reviewing sail / wing aerodynamics quite a bit for some time. I referred to the clip just to show the angle of the spinnaker while it was running. I understand the the overall force balance on this boat is requiring the crew to be a far aft as possible. I am pretty confident that my statements were factual as presented.

Much of the time, the force vector for the spinnaker was probably pretty close to being in alignment with the center of force for the water drag acting on the hull and boards. If the overall spinnaker force vector passes through a point forward of the drag forces resisting forward movement, the sail would tend to lift the nose. If it is more to the rear, the reverse could be true.

Note that in the context presented, lift is force directed straight up that tends push the overall boat up out of the water. Pitching moment is a force acting on a moment arm that tends cause rotation of the boat (bow up or bow down). A sail can provide lift and at the same produce a pitching moment that pushes the bow down. I have been on a run where the stern was lifted out of the water with the nose not being pushed down all that much.

However, for the specific example of the boat in the clip, it also has other sails that are providing minimal lift but are providing a lot of forward pitching moment. The overall force balance for the boat is the vector sum of all wind induced forces on the sails, boat and crew above the water line; the vector sum of the hull drag, hull planing, dagger board and rudder forces below the water line and the weight balance.

These forces are in a constant state of change. At times it looks like the lower portion of the sails are powered up and the upper regions are doing less. Other times it is reversed. This shifts the force vectors all over the place. The water forces on the hull are also unstable. As is obvious, the overall instability is causing a whole lot surging and rocking.

brian eiland

11-03-2010, 10:04 AM

Unfortunately you don't really understand what you are looking at. The 12s have an enormous pitch down pressure from their spinnakers: that's why they're hanging off the back of the boat. They even have the gunwhales extended aft of the transom in order to get the weight back far enough. If you let the spinnaker flap the bow lifts. If a spinnaker genuinely lifted the bow - as a kite sail can do - then when a gust hit the crew would be rushing the weight forward to keep the bow down.
Unfortuntionately I have to believe what my eyes are telling me. When the spinnaker in that video is flailing (no power), the bow of the boat settles down. When the spin is really under power it is lifting the bow. Its center of effort is far enough forward of the boat's drag center, such that the vertical lift that is being created by the spinnakar is lifting the bow. This lift is NOT to be confussed with 'aero lift' we refer to in sailing aero discussions as that 'perpendicular plane' force that the vertical wing of our sails creates and we see manifested in forward driving forces or heeling forces.

Yes the spinniker is driving the boat forward from a center of effort that is well above the drag center of the boat, and logically we say that the driving fwd force coupled with the drag force of the boat produces a bow down rotation force. So why isn't this boat driving its bow down?? (and don't tell me its just because of the crew weight on the rear).

Here is what I think. This boat is light enough that its drag center is well aft in this situation, and its drag is relatively small as it planes off (notice that ballasted monohulls will NOT experience this). So the bow never gets a chance to dig in and allow the fwd driving force of the spinnaker to rotate the bow down to any great degree. Surely as soon as they let that bow dig in that driving force of the spinnaker will rotate the bow down. Stay on plane boys!!

But I also would be willing to bet that if we could see the flow stream lines of the air passing over that spinnaker we would see a downward deflection of the air created by that top portion of that spinnikar. 'For every action there is an equal and opposite reaction' . A portion of that opposite reaction is vertical lift by that sail, and its well forward of the boats contact center with the water. That sail is producing vertical LIFT.

brian eiland

11-03-2010, 12:18 PM

I’ve promoted this aft-mast rig for a significant number of years, without a great deal of success in getting it into a full-scale application. I’ve not found that really enthusiastic person willing to spend the money (not that much really) on the in-depth force mapping study I had hoped to conduct to search for the most optimum configuration. But I continue to get quite a few enthusiastic inquiries from sailors who feel this approach to a ‘main-less’ sail plan is just what they have been searching for**.

So with no stress mapping study at hand, lets go back to the logic I used when first developing my rigging configuration for the aft-mast sail plan. Lets re-look at the force-vector diagram analysis, and see if it is really as ‘overstressed’ as some naysayers have touted.

MASTHEAD
Lets start at the masthead. There is the primary forestay, a backstay, and two shrouds…all rather traditional. I’ve chosen to represent the force in the forestay with a 5cm long vector. Lets say this vector represents 1000 force units, thus each 1cm on the force diagram will represent 200 force units.

At the masthead the forestay force is broken down into two perpendicular forces, the compression load down the mast and the forward pulling force. The fwd force needs to be offset by the aft pull of the backstay. The backstay is at a more shallow angle so it must pull a bit harder to exert its rearward force. At present we know:

Forestay Force............................................1000 kg
Backstay Force...........................................1260 kg
Forestay compression Load in Mast.................820 kg
Backstay Compression Load in Mast..............1150 kg
Total Compression Load in Mast....................1970 kg
(at very upper portion & disregarding shroud loads)

.....nothing very unusual....very conventional. The mast is experiencing compression loads from both the forestay and the backstay force components acting in the vertical direction. And it’s doubtful that those compression loads imparted to the mast by the backstay and forestay are much greater than in the case of a purely vertical standing sloop rig mast.

My masthead backstay then passes over an aft jumper strut that redirects its force down to the base structure supporting the mast.

[IMPORTANT NOTE] This backstay that originates at the masthead DOES NOT reattach to the base of the mast itself, but rather to a structure of the vessel, …and preferably to the structure that accepts the compression loads of the mast to the vessel.]
So we have one of the backstays that delivers a force of 1260 kg to the vessel.

AFT JUMPER STRUT
The masthead backstay now bends over the outer tip of an aft jumper strut that I’ve placed at the mast hounds location, and pushes in on the mast tube. Just as with a conventional spreader element the aft jumper strut is set to bisect the angled turn of this backstay. By vector analysis the backstay exerts two equal forces of 360 kg each push on the aft jumper strut.

Aft Jumper Strut Push Load to Mast.................720kg
Aft Jumper Compression Load in Mast.............negligible

FORWARD JUMPER STRUT
Now I propose that we offset this entire cross-load pushing by the aft jumper strut with an opposing forward jumper arrangement. In order to accommodate the inner forestay and its sail this fwd jumper fixture will likely assume a ‘V’ configuration that is somewhat conventional in form. BUT, the assembly is also unconventional in form. In the first place it is not set perpendicular to the mast tube, but rather in-line with the push of the aft jumper strut. And the included angle between the two struts might well be 60 degrees rather than the more common 90 degrees. AND it will NOT consist of two individual jumper stays (wire cables), but rather will be fashioned of a continuous loop of ‘cable’ that would wrap around the back-side of the mast at its lower ‘termination’, and might even do so at its upper ‘termination’.

The actual jumper stay ‘cable’ itself will be constructed from one of the new-age synthetic rigging materials such as Dyneema, Spectra, PBO, LCP, Aramid, C-6 carbon tow, etc. Ideally this stay material will have NO pre-stretch requirements thus no pre-loading. It should be very strong upon immediate application of force, and in a minimal diameter that it can be looped around the mast section in a continuous manner, at least on one end, maybe both. As a continuous loop, ‘both sides’ will always be carrying ½ the total load, rather than one side under load, while the other might be slack. There will also be a minimum of ‘fittings’ required to attach them to the mast (less weight, less failure pts). I imagine a simple ‘block’ of material attached to the mast around which the loop of this jumper stay can not slide any further along the mast….and one end needs to be adjustable

I call this whole assembly a ‘modernized diamond jumper’. It needs to offset the 720 kg force of the aft jumper with its four 4 cables….thus 180 kg each in their horizontal force component:

Front Jumper Push to Mast..........................................720 kg
Divided by 4 Strands..................................................180 kg each
Vertical Force Each Strand..........................................340 kg each
Total Compression Load in Mast Tube.........................1360 kg
[I](in between the upper and lower jumper cable turning blocks)[/I]

INNER FORESTAY
The inner forestay is approx 75% the length of the primary forestay, so to keep things equally taunt should require about 75% of the load of the forestay (maybe even less since the inner foresail is much smaller than the primary genoa).

Front Forestay Force................................................1000 kg
Inner Forestay Force.................................................750 kg
Inner Forestay Compression Load in Mast...................650 kg
Inner Forestay Fwd-Pulling Force..............................~350 kg

LOWER BACKSTAY(s)
Here is where we really load things up due to the shallow angles of the lower backstay(s). Lets explore 4 options:

1) Shallow angle backstay as originally drawn (about 10 degree angle with mast):
Backstay Load..........................................................1940 kg
Compression Load to Mast.........................................1900 kg

2) Broader angle backstay to sterns of vessel (about 14.5 degrees)
Backstay Load..........................................................1340 kg
Compression Load to Mast.........................................1280 kg

NOTE: Both of the two conditions above are based upon using the lower backstay(s) to resist the entire forward load of the inner forestay.

BUT, what if the forward jumper strut could accept some additional horizontal loading to help offset some of the forward pull by the inner forestay? Wouldn’t that take some loading requirements away from those lower backstays? (….to be explored in another posting).

_____________________________________________________________
Let's review the forces we’ve added to the mast column at this point due to the fore/aft rigging arrangement:
a) At the upper tip in the masthead area we’ve added virtually no additional compression forces over those experienced by a standard straight standing mast under the traditional loading of tight forestay and tight backstay.

b) In the hounds region we’ve added considerable additional compression loading associated with the diamond jumper stays ’pulling together’ from their upper and lower ‘turning block terminations’. These create extra compression loads within the mast column itself, but they cancel each other in terms of adding extra compression loading to the lower mast and the stepping base. This panel of the mast is relatively short, and the rigging is such that it is not easily drawn out of column, so a reasonably strong mast section for this panel section at the hounds should be able to sustain these higher compression loads.

c) The lower panels of the mast suffer from the higher compression loads exerted by the shallow lower backstay(s), but not nearly as much as some have exaggerated.

Compression Loads to Mast Column by Fore/Aft Rigging

1970 kg.........................Forestay + Backstay......................1970 kg
..660 kg.............................Inner Forestay............................660 kg
......0 kg.................Shallow angle Lower Backstay...............1900 kg
1280 kg.................Broader angle Lower Backstay....................0 kg
3910 kg.................................Totals...................................4530 kg

These figures don’t appear to be that excessive…certainly no where near the 4 to 6 times loading that some naysayers have claimed. And certainly something that can be dealt with relative ease.

Have I made any errors in those figures above??

_______________________________________________________

SHROUD LOADING
One of the other primary reasons I sought to develop this aftmast rig idea was to end up with a rig that could make optimum use of those nice headsails in sailing upwind without resorting to narrow spreaders….besides narrow spreaders on a multihull craft can really load up the mast. If the sails don’t overlap the mast, I can make use of the nice wide shroud angles at both the upper spreader and at the base.

I’ve chosen to go with a 20 degree cap shroud angle at the masthead. This cuts the compression loading to the mast by a full 100% (literally in half) of the loading at 10 degree angles used by many racing sloops. This can be very significant considering the ‘infinite nature’ of the stability/righting moments of big cruising multihulls.

And not only is this broader shroud angle effective at reducing mast loading in the top panels of the mast, but it propagates down at each spreader level.

HALYARD LOADING
Often ignored are the significant ‘duplication loads’ imposed by the halyards. All three of my sails are designed to be roller-furling (maybe even roller-reefing on some cruising vessels using modern sail materials and furlers). As such I definitely contemplate the use of halyard locks to hold the sails up rather than a traditional halyard tail back down the mast to just increase compression loads even more….again it can cut those mast compression loads in half.

Comments, suggestions, corrections welcomed
(I've attached a 'forum posting size' sketch that I used in this vector analysis. If you want a full size to-scale sketch, send me an email at brian.eiland@gmail.com)

REFERENCE:
**(two recent inquires: 1) a daysailing charter operator in a trade wind area who struggles several times a day with his full battened mainsail, and 2) another gentleman who recognizes the future of high fuel prices and desires to do a 55 foot ‘gamefishing-under-sail’ charter vessel)

brian eiland

11-05-2010, 08:31 AM

...you are right that Brian's mast has not been tested yet, however the concept is aerodynamically excellent.
You are mistaken if you say that aft masts have not been built as we already know of several, I repost their pics here.
I have spoken to the owner of boat No3 and he very happy with his rig and assures me that the she goes to windward exceptionally well.

My personal experience is that i could tack my 42' cat without problem when sailing with jib only.
Anyway, who wants to beat to windward when cruising???
There are 5 different boat photos attached at this posting #118

The first one is a what I refer to as a wishbone mast that is placed in the aft part of the vessel. The owner of that vessel "Orca"contacted me just the other day with a new photo and this short note:

A few days after this photo we got into some good stiff breezes and hove to (just to see what she would do) in a good rolling Puget Sound
SEaster. She sat so nice and quietly over on her side about 10 degrees in 25 knots with just the staysail backed a bit and rudder up a bit. Very comfortable. That big keel and 50% ballast did the trick.
On one long stretch with all sail up (both of them), in about 10-12 knots of wind, close hauled she sailed herself in perfect balance with the tide slack or near. I had been steering her, enjoying the ride, when I realized it didn't need me so I sat back and watched her work her way up, keeping the mark very nicely. What a joy!

Regards, Owner of Orca

BTW, for more on this Wishbone Rig subject there is a separate subject thread over HERE (http://www.boatdesign.net/forums/boat-design/wishbone-sailing-rig-1999.html)

brian eiland

11-13-2010, 09:06 AM

Comments, suggestions, corrections welcomed
(I've attached a 'forum posting size' sketch that I used in this vector analysis. If you want a full size to-scale sketch, send me an email
In a off-forum email recently I was asked the following;
I may be way off in my thinking but have you considered additional upper attachment of the backstays to the same site as the head of the aftmost " mizzen" sail? A rod or wire rigging from this aftmost part of the "backspreader" to the top of the mast taking the backstay force at a better angle to the sterns?
Actually I have given thought to having two backstays (either side) at this 'backspreader' tip location, but not really to help with the forestay loads. Rather these might be some sort of fixed or running backstays that might assist with athwartships movement of the outer tip of that aft jumper strut (backspreader) due to excess power developed by the mizzen sail. However extra backstays could also be detrimental as they might lessen the tension in the primary masthead backstay that I'm using in a double fashion as the forestay for my mizzen. This could allow excess sag in the mizzen forestay, and more tendency for back spreader to bend off sideways.

I don't see a big decrease in compression loads to the mast tube with these extra backstays, so I've chosen to leave them off initially. And besides this, my primary backstay is anchored into the primary structure of the vessel that accepts the mast compression loading. I think that is a plus factor.

brian eiland

11-14-2010, 08:57 AM

Aft Mast Alternative on Big Trimaran
Several years ago I was asked by a gentleman to come have a look at a big Kurt Hughes trimaran he was building, a 63 footer he had stretched to 65, if I remember correctly. He was VERY concerned about handling that big mainsail on that big sloop rig.

I spent a week as his guess at his home, and in the huge building shed outback he had erected to build this ultimate retirement vessel for himself, his wife and his kids. He is of Romanian decent, and has that Italian flare for home wine making (and drinking). Needless to say we had LOTS of fun drinking all sorts of home brewed wines and talking boats. :)

Here is what I came up with as a solution for him in the context of my mast aft theme. Please realize I was restricted by the existing structure of the vessel that was already well under way in construction...i.e., bulkhead placements, crossbeams, etc, etc.

There was one other nagging question he had, that needed to be taken into account....what if the fwd leaning mast idea would not work?? This persisted to be such a big question in his mind that I had to give considerations as to how my mast aft design could be converted back to a more standard rig configuration without a great deal of expense, and/or trouble to him.

I still chose an 'all-3 sails-furling' arrangement....my single-masted ketch concept. But I made the mast rake almost half (6 degrees) of the original design. And the mizzen sail was made a bit larger in proportion. Thus this rig could be converted to a straight standing cutter rig with the mizzen becoming a more traditional mainsail attached to the aft edge of the mast. Or a new larger mainsail could be constructed for the mast that could be extended upward (taller), but still stepped in same location. The cutter jibs would then both be fractional, but would not require modification.

Over all I sought to give him the same total sail area as the original design by Kurt Hughes. This was approx 1900 sq ft. BUT notice what happened to the mast height on these two versions !! The original sloop rig carried a 92' high rig. My rig carries that same sail area on a 73.5 foot mast !

With this significant reduction in the rig height and the 'all-furling' feature, I imagine this gentleman will be able to handle this rig without a lot of additional assistance, and he may well be able to SAFELY sail into higher wind conditions without as much fear of being overpowered....his sailing efficiency should be improved.

I had two options for the lower backstays here...1) anchored to the aft crossbeam ends (at a 13 degree angle to the mast), or 2) anchored to the ama hull ends (at a 20 degree angle). Both of these backstay angles are better than my original design, thus even less loading reqired of these backstays to offset the inner forestay loads.

I felt this shorter rig could justify a slightly shorter daggerboard, and we opted to move that daggerboard slightly forward to both be in a better balance with the new sail plan, and to better fit in with a saloon modification he had already planned.

To my knowledge at this time he is still thinking about his final rig design options, and his boat building processes have been put into a holding pattern while he attends to converting that original building shop into a multiple house dwelling. He then intends to build an even bigger shed to complete final assembly of this very big beamy trimaran. I'm not sure if he will chose my mast aft option, but I would be willing to place bets on it being a very good one for his needs.

[NOTE: The second aftmast sketch represents a more current modification of the masthead attachment of its backstay, and the ama anchoring of the lower backstay(s). These are just suggested options to the original sketch, and certainly not final ideas]

Spiv

11-14-2010, 06:38 PM

Brian,
Could you explain why you prefer a wishbone boom rather than a simple pole as it is normally used on sel-tacking jibs?

brian eiland

11-14-2010, 11:27 PM

Are you speaking about the boom on the mizzen, rather than the jib?....as I do not have a boom on the self tacking jib (although it could make use of a modified club boom arrangement if desired).

If that's the case then look how that mizzen roller furls around the backstay...that could not be accomplished with a traditional boom so easily. Besides I sought to keep any boom in this area off of the heads of the helmsman that might be found in this zone.

Spiv

11-15-2010, 05:54 AM

Yes, I am referring to the Mizzen-main.
I am contemplating replacing the main of my Salina with a roller furler sail, similarly to the one in the first two pics pic below.

The head-banging is of course to be considered, but at the moment I am swinging a 300mm boom and is well cleas of any standing person.
I could of course swing a lower sail if I had a wishbone boom wich would compensate for the loss of sqm of the square top sail that is now on my boat (last two pics).

brian eiland

11-15-2010, 08:23 AM

Yes, I am referring to the Mizzen-main.
I am contemplating replacing the main of my Salina with a roller furler sail, similarly to the one in the first two pics pic below.

I could of course swing a lower sail if I had a wishbone boom wich would compensate for the loss of sqm of the square top sail that is now on my boat (last two pics).
Ah-ha, another cruising sailor who is a little disenchanted with handling the tradtional mainsail. I'll have to think about that one.

Certainly you might lose that nice fat head shape with the roller furling main....maybe even more productive area than any you would gain at the bottom.

Might be interesting to see if the solution could be found using the vertical batten arrangement by Selden:
http://www.riggingandsails.com/pdf/selden-masts.pdf
scroll down to 'in mast furling'

NOTE: I just googled 'vertical battens' and found a lot more references and suppliers than I was aware of previuosly.

brian eiland

11-15-2010, 08:51 AM

Spiv

11-15-2010, 09:08 AM

A little disenchanted??
You know that it's at least 6y that I have been saying "I Hate" them....

In Mast furling would be nice if you don't already have a new mast.... I do and I am not going to buy a new mast.
However I am quite willing to explore the furler system.

Vertical Battens? Did not think of them before.
Do you think they are useful?
If that was the case we would see them in many headsails, or is it just the heard menthality that refuses them?

michael pierzga

11-15-2010, 09:42 AM

Those verticle battens do a good job ..but they make it very difficult to drop the main and hoist the main. Helped a boat out this summer. Took us 4 days to find a suitable windless afternoon to drop the main at the dock. Might be more trouble than they are worth

brian eiland

11-15-2010, 02:32 PM

...Vertical Battens? Did not think of them before.
Do you think they are useful?
I do not know enough about them, and how successful or unsuccessful thay have been. I would go looking for all I could find on the subject.

I had given thought to them in order to add roach onto my mizzen sail...which might only be an appearance thing. I had thought that if they were there to be furled up, and my furl would be external to a mast tube, then a 'sock' like affair could be used to cover them at rest or stored....like the ATN spinnaker sleeve (http://www.atninc.com/sleeve_en.php),.... or maybe just the good old std sewn-on sail cover.

If that was the case we would see them in many headsails, or is it just the heard menthality that refuses them?
No need to have roach on your headsails, so no need for vertical battens (at least full length ones). Besides they would be a real headache up there. I believe there are some short verticals for roller furling headsails.

pbmaise

11-17-2010, 08:16 PM

Well guys, exactly one year after buying a demasted rig, I, with the help of all of you, am pleased to report I have an aft-mast rig with crab claw sails that sails upwind!!! I focused on eliminating negative aspects of the Bermuda rig. I married what I thought was the best of all the ideas floating around, used some high-tech materials and some low tech, and came up with a few creative ideas on my own. It works great!

More importantly, I built a rig with fewer potential failure points, I eliminated most items that corrode, I can repair from the deck level most problems, and I have redundant lines that allow me to disconnect major support lines while working on them. I have all this on a rig that is lighter and less expensive to build and maintain.

I had limited wind and sea range on my trip down to Singapore from Thailand, however, it was enough to demonstrate that even in a light breeze my smaller crab claw sail powered my boat 3 knots at a 45 degree angle to the wind. Further, tacking, involved nothing more then pushing the buttons on my autopilot. Not a single line was touched and we were again sailing 45 degrees to the wind on the opposite tack. With stronger winds, or by removing all the stuff aboard, I expect a lower number.

Attached is preliminary report.

Philip Maise
Hot Buoys Trimaran
Volcano Hawaii

p.s. If you want to copy my rig, please call it by my name and I would gladly take paypal for a fraction of the thousands of dollars of reduced costs you gain from my hard work. No major research facility sponsored my work and now I need to recover some costs. I have no mast cars, no mast track, need only 3 winches to control two sails, no furlers, and reduced the number of sails needed to operate a boat. If you copy my rig, and eliminate these items too, you will save tens of thousands of dollars. 10% of your savings sound fair? Use pbmaise AT yahoo DOT com

brian eiland

11-20-2010, 11:22 AM

A few not so obvious questions regarding paper:
http://www.ignazioviola.com/ignazio_..._HPYDC2008.pdf

1) It is not definitely clear, how they account for drag of "bare" mast, when calculating the sails coefficients? (it looks like drag of the mast is excluded, but this to my view, invalidate results, as sails investigated simply CANNOT by flown without a mast behind them, and only coefficients with mast INCLUDED are of real significance );
2) It is not definitely clear how they deal with drag of bare mast in boat speed calculations;
I didn’t exactly understand how they dealt with drag of the rig either, but I did find these two quotes that were easy to miss…did you see them??

"At the end, some runs were performed on the bare hull and rigging (without sails) for both yacht models at different apparent wind angles and in different heeling conditions in order to measure windage. These values are subtracted from each of the measured data points in order to produce the sail force coefficients"

"Bare hull and rigging coefficients obtained by means of wind tunnel windage tests have been used in order to provide windage aerodynamic model input."

brian eiland

11-20-2010, 11:27 AM

I'm realizing from reading this thread and the masthead vs. fractional one that this type of rig would have the same type of "backwards" dynamic response in puffs, where the forestays sag and powers up the sails, just when you don't want it.
Yoke.
This is from 2006 ...Has anyone addressed this?
I am as much of a fan of tight forestays and great sail shapes as anyone. I just hate saggy rigging. To me it represents a sloppiness in someone’s approach to sailing.
Over the years there have been a number of postings suggesting that tight forestays are a MUST requirement, and that this aftmast rig will fail because it will be unable to maintain them.

That being said, there are a number of alternative views. Some interesting examples occurred over HERE (http://www.boatdesign.net/forums/sailboats/unstayed-mast-jibs-14732.html) where there were some discussions of utilizing a headsail on an unstayed-mast/free standing mast. Super taught headstays are not necessarily the only option,…’the saving grace’ so to say;

"One of the problems often cited with an unstayed mast is that jib luff tension is low. But why is this a problem? If the sailed is designed to have a large amount of luff sag, why should it perform any worse than a jib with a tight luff? Due to their very high speed, the asymmetric kite on a 49er operates at an angle of attack similar to most conventional yacht and dinghy jibs, so why aren't there any jibs that look like a 49er kite? Just curious."

"Perhaps I can be a bit parochial and suggest you take a look at a Sonata that is doing well at the moment in the class at a national level.

Originally David Thomas designed them with both cap and lower shrouds close to being in line with the mast, but with a fairly stiff top mast so the backstay would transmit some tension to the fractional forestay.

Then Proctor started to make masts with a bendy tapered top that allowed the backstay to depower the main but forestay tension was lost. So the measurement rules were 'exploited' to move the masts to their extreme allowable forward position, and the shrouds moved aft to theirs. Due to the vagaries of Hunter's building quality, some boats were better able to do this than others as their main bulkheads varied in their position. Cap shroud tension was then wound on (à la J24) to try and get forestay tension.

Well, this attempt to worship the 'god' of headsail luff tension actually only resulted in boats being pulled apart. The aft angles were so marginal that massive shround tension only ever gave marginal results. So ten years or so ago, Goacher Sails stopped fighting the problem and returned the masts to their 'inline' positions and cut genoas to match the sagging forestay. And they have been unbeaten since. It take a while to get used to the different interaction between the sail controls, but works in a wide range of sea states and windspeeds.

I think the modern Code Zeros set on their soft furlers probably have similar properties."

brian eiland

11-20-2010, 11:36 AM

...But any improvement in performance is by definition a quantitative issue, not a qualitative one...This is from 2004 ... 6 years ago. Anyone have NUMBERS yet?
I’m not so sure that we are going to be able to put a definitive, quantitative numbers to this issue. As Tom Speer said, “I can understand the desire to simplify sail handling with roller furling staysails”… (all roller furling sails in Brian’s aftmast). These trade offs in terms of handling ease may trump some of the small loses (if any) in performance.

We will probably have to be content with incremental indicators like this Italian wind tunnel study that show a superiority of the twin overlapping headsail arrangement to that of the single headsail sail, or non-overlapping configurations.

For the cruising sailor we don’t have to be necessarily better in performance than the conventional sloop, if we offer other attributes such as ease of use, etc.

RHough

11-20-2010, 12:13 PM

I am as much of a fan of tight forestays and great sail shapes as anyone. I just hate saggy rigging. To me it represents a sloppiness in someone’s approach to sailing.
Over the years there have been a number of postings suggesting that tight forestays are a MUST requirement, and that this aftmast rig will fail because it will be unable to maintain them.

That being said, there are a number of alternative views. Some interesting examples occurred over HERE (http://www.boatdesign.net/forums/sailboats/unstayed-mast-jibs-14732.html) where there were some discussions of utilizing a headsail on an unstayed-mast/free standing mast. Super taught headstays are not necessarily the only option,…’the saving grace’ so to say;

"One of the problems often cited with an unstayed mast is that jib luff tension is low. But why is this a problem? If the sailed is designed to have a large amount of luff sag, why should it perform any worse than a jib with a tight luff? Due to their very high speed, the asymmetric kite on a 49er operates at an angle of attack similar to most conventional yacht and dinghy jibs, so why aren't there any jibs that look like a 49er kite? Just curious."

"Perhaps I can be a bit parochial and suggest you take a look at a Sonata that is doing well at the moment in the class at a national level.

Originally David Thomas designed them with both cap and lower shrouds close to being in line with the mast, but with a fairly stiff top mast so the backstay would transmit some tension to the fractional forestay.

Then Proctor started to make masts with a bendy tapered top that allowed the backstay to depower the main but forestay tension was lost. So the measurement rules were 'exploited' to move the masts to their extreme allowable forward position, and the shrouds moved aft to theirs. Due to the vagaries of Hunter's building quality, some boats were better able to do this than others as their main bulkheads varied in their position. Cap shroud tension was then wound on (à la J24) to try and get forestay tension.

Well, this attempt to worship the 'god' of headsail luff tension actually only resulted in boats being pulled apart. The aft angles were so marginal that massive shround tension only ever gave marginal results. So ten years or so ago, Goacher Sails stopped fighting the problem and returned the masts to their 'inline' positions and cut genoas to match the sagging forestay. And they have been unbeaten since. It take a while to get used to the different interaction between the sail controls, but works in a wide range of sea states and windspeeds.

I think the modern Code Zeros set on their soft furlers probably have similar properties."

This does not address the question. The question is dynamic gust response, not static headstay tension. A good sail shape can be cut to fit any given headstay sag.

In a gust a stayed sail induces more sag, and thus more camber in the sail. Added camber increases the power and healing moment. If the boat needed more power before the gust, the sails would have been trimmed that way. Gusts in this context overpower the boat. Stayed sails increase power in gusts, just when less power is needed.

An unstayed rig or the unstayed portion of a mast above the hounds can be designed to fall off to leeward and ease the leech. Reducing heal and reducing power in response to a gust. This is an automatic proper gust response.

This correct gust response cannot be designed into a stayed sail. No matter what the static tension might be. This is one of the reasons that in area controlled development classes the sail plan evolves to either a fractional sloop or a single sail or wing. Overlapping sail plans and stayed masthead sails do do not evolve for performance unless other factors are in play.

Personally I find conventional mains to be quite docile. The sail is controlled well. I'd much rather deal with slab reefing a conventional main that have to dodge a flogging jib clew on my way to clear a fouled roller furling line. In mast or in boom roller reefing mains are every bit as easy to deal with as roller reefing headsails. I don't see a sail handling advantage to the aft mast design.

This leaves the question of sailing efficiency. No one has shown number that indicate that the aft mast configuration is better when the total rig is considered. In fact aerodynamic professionals doubt it.

This citation:
"At the end, some runs were performed on the bare hull and rigging (without sails) for both yacht models at different apparent wind angles and in different heeling conditions in order to measure windage. These values are subtracted from each of the measured data points in order to produce the sail force coefficients"

"Bare hull and rigging coefficients obtained by means of wind tunnel windage tests have been used in order to provide windage aerodynamic model input."

This is a built in error unless the documented drag reduction of a sail behind a bare mast is factored in. You cannot compare an aft mast rig with a conventional rig by ignoring the mast sail interaction.

I've read every post and followed this thread for years now. Still no hard number proof of any advantage to the aft mast configuration. Still no response to the dynamic gust response question.

All that remains is the ease of sail handling claim, which I don't see at all.

R

PS the 49'er claim about similar AWA is wrong.
J24's sail with full Genoas and flat mains to reduce weather helm, tight head stays on J24's are not an issue. If they were allowed to move the keel the headstay sag might become an issue, but the OD Class rules do not allow it.
Code Zeros are flown when the sailing angle and wind speed do not allow the boat to be fully powered with a Genoa. They were developed for a class that did not allow masthead Genoas. Code zeros have backward gust response too.

Dave Gudeman

11-20-2010, 03:04 PM

Personally I find conventional mains to be quite docile. The sail is controlled well. I'd much rather deal with slab reefing a conventional main that have to dodge a flogging jib clew on my way to clear a fouled roller furling line. In mast or in boom roller reefing mains are every bit as easy to deal with as roller reefing headsails. I don't see a sail handling advantage to the aft mast design.
With all due respect, I don't think that you are a good person to judge this. You are obviously a very experienced sailor. I'm sure that you react properly and almost without thought to conditions that would have casual sailors stressed out and scrambling.

To casual sailors, that boom seems like a disaster waiting to happen. We are always worried about accidental jibes going downwind, even when it is not really a danger, because we aren't confident of our own judgment of when it's not a danger and we aren't good-enough helmsmen to be sure we can keep out of the danger area.

In a family outing there are often kids or dumb teenagers running around and you are always worried that they are going to be in the way when the boom has to swing over. You still wouldn't want them in the way when a boomless sail swings over, but that is less dangerous if it does happen.

When I have to get up on top of the cabin to flake the main, there is usually someone even less experienced than me at the helm and I'm worried about the helms(wo)man keeping it into the wind. Occasionally I haven't been paying attention and wind conditions are already too high. In-mast or in-boom furling makes things easier, but the mechanism is more complicated than stay sail furling and more likely to jam (or so it seems to me --I've never actually had a jam).

Intellectually, I know that all of this is really pretty safe and that I'm not sailing anywhere near the limits of the craft and that the boat is small enough that I really can keep an eye on the kids, but it still creates a lot of stress and that limits my enjoyment of sailing. Getting rid of the boom seems like a great idea to me, even if I lost some performance. I don't have any desire to race. (I actually looked at a boat that had a boomless main, but it was a motor sailor without a cockpit --you had to sail from inside the pilothouse, and that didn't seem like real sailing to me).

Of course I really don't like the idea that power would increase in a gust. If that turns out to be a real problem then it might doom the astmast rig as the preferred rig for casual sailors but there are usually solutions to problems like that.

Fanie

11-20-2010, 03:35 PM

RHough,

You have to experience sailing with an aft mast. Although my rig was small, I could still experience a much different feel from my friend's 'normal' sail with a boom.

In a gust his boat would dip down and burrough the lee ama, while mine had a much lesser heeling effect. You could see the mast take force, and I could feel it in the line, but there was not that deffenate pushing it as if to try and capsize it. My leeward ama got hardly pushed down.

We don't have a lot to live by on the moment, but in a while there will be something. Like I said, you have to experience it. There just is something to it.

I would very much like to make one with a bit more racing in mind, but the funds... Huge potential there.

RHough

11-20-2010, 05:09 PM

With all due respect, I don't think that you are a good person to judge this. You are obviously a very experienced sailor. I'm sure that you react properly and almost without thought to conditions that would have casual sailors stressed out and scrambling.

...

Of course I really don't like the idea that power would increase in a gust. If that turns out to be a real problem then it might doom the astmast rig as the preferred rig for casual sailors but there are usually solutions to problems like that.

Thank you. I worked in a rig shop for a few years. I am indeed familiar with the solutions that make sail handling less stressful. Modern roller reefing booms a pretty darn nice. You get to keep a long lived full batten main and no longer have to stand on the cabin flaking a sail whilst your drunken cousin from Idaho tries to steer. :D For smaller boats a well thought out lazy jack system takes the terror out of reefing and allows the sail to be flakes properly after the anchor is down or back at the dock.

Most casual sailors don't sail with their boats fully powered up so proper gust response is not so much an issue. Fully powered up is more heel than most casual sailors find comfortable. They sail at 15 deg heel not the 20-25 deg that a fully powered boat would sail at. Gusts just heel the boat more than they should. After a few 25 deg gusts, the skipper reefs to keep the mate happy and dinner on the stove. This ends up with the casual sailor motoring more and sailing less because they are not comfortable sailing the boat at more than 70% of her speed potential. Wouldn't it be nice if the gusts that used to knock you from 15 deg to 25 deg only knocked you to 20 deg? After you have some sea time and are comfortable sailing harder, wouldn't it be nice if the boat made it easier and did not demand much more attention than it did when you were sailing at 15 deg of heel?

Cruising multi's are mostly under canvassed to begin with. One of the things we have done is gone sailing with cruising multi owners and offered advice on rig tune and sail trim. The usual result is they sail more and motor less. That big roach main can be trimmed so the leach opens and depowers in gusts, not so a masthead Genoa.

One of the posts here shows a rig with the same area and a lower mast. This cannot be more efficient than the same area on a taller mast. Basic aerodynamic theory here.

Three sails on centre cannot sail as high as two. Two cannot sail as high as one. Again, basic aero theory. This is as important to the casual cruising sailor as the racing sailor. Rig efficiency and the ability to sail to weather is a high priority when a squall hits and your anchor drags.

None of this even considers the weight distribution of placing the mast and rigging closer to the ends of the boat. Getting weight out of the ends is a holy grail for sailing in comfort.

I'd like to be convinced, but nothing seems to add up for me.

R

brian eiland

11-21-2010, 04:20 PM

...To casual sailors, that boom seems like a disaster waiting to happen. We are always worried about accidental jibes going downwind, even when it is not really a danger, because we aren't confident of our own judgment of when it's not a danger and we aren't good-enough helmsmen to be sure we can keep out of the danger area.

In a family outing there are often kids or dumb teenagers running around and you are always worried that they are going to be in the way when the boom has to swing over. You still wouldn't want them in the way when a boomless sail swings over, but that is less dangerous if it does happen.

Getting rid of the boom seems like a great idea to me, even if I lost some performance. I don't have any desire to race.
Getting rid of the boom was one of my objectives when I originally thought of getting rid of the traditional mainsail all together.

I became good friends with Peter Wormwood who became primary designer for the Stiletto catamarans (BTW a tremendously good sailor). A partner and myself became Stiletto's biggest dealer ever...we outsold all the other dealers combined, and we sponsored the first ever Stiletto Nationals here on the Chesapeake Bay (even Gary Jobson and Randy Smyth joined in).

Stiletto cats at that time were the largest pre-preg/nomex cored pieces ever made outside of the aircraft industry. Peter first developed the STILETTO 30 (http://www.stilettocatamarans.com/stiletto_30_catamaran_specifications.htm) from the original 27 by spreading the 27 hulls further apart, adding some length at the sterns, and balloning the cockpits over into the center area. Then he put a BOOMLESS mainsail onboard. What a great concept. We had plently of room to sheet this sail rearward, and we could almost make it a deck sweeper (didn't really) with out knocking everyone off the boat.

Next came a smaller boat, and a totally new design, the STILETTO 23 (http://www.stilettocatamarans.com/stiletto_23_catamaran_specifications.htm). It was also BOOMLESS as the idea had gone over so well on the 30. It also had a very pretty custom mast section design.

I did a fair amount of sailing in both of these designs. And the 30 to me is just a great weekend boat. Add a center cockpit tent and you are ready for just about anything cruising around the Chesapeake Bay. BUT because its BOOMLESS you have a little more trouble rigging that tent structure. Of course that no reason to include a boom :rolleyes:

Later on it became neccessary for me to redesign a 25' foot trimaran I was attempting to import, the original Dragonfly 25. I had learned some things from my Stiletto days, and one of them was GET RID OF THE BOOM. I found the perfect spot for a circular traveler (Stiletto did not have this luxury) at the rear of the cockpit, thus eliminating the boom AND the traveler track that split up the cockpit...WOW, everyone loved it. Not only that but I also employed that beautiful mast section Peter had drawn up. Our boat became the FIREFLY 26 (http://www.runningtideyachts.com/trimaran/). Very regrettably this project took me into bankrupcy due to some partnership problems and just not quite enought cash to do the whole project on my own. But what a great sailing boat, and no worries in that cockpit about radical manuvers.

NOTE: I made a mistake, the original 30 had a boom as seen in the bottom photo HERE (http://www.stilettocatamarans.com/stiletto_30.htm). It was the second boat Mirage, a custom racer that then went boomless. We raced that boat for the first time here on the Chesapeake Bay in what was known at the time as the Governor's Cup, one of the largest races on the East Coast at that time (something over 300 boats, and some fast monohulls). Multihulls at the time were only reluctantly allowed to race, and they put them all in a single start at the very end of the pack...16th if I remember correctly. You race down the bay overnight from Annapolis, Md, turn up the Potomac river, and tread your way up a winding river to the school at St Marys. We like to brag that we started last and ended up first boat to finish, but we never received even a single word of acknowledgement at the awards ceremony. :!:

brian eiland

11-21-2010, 04:39 PM

..In a family outing there are often kids or dumb teenagers running around and you are always worried that they are going to be in the way when the boom has to swing over. You still wouldn't want them in the way when a boomless sail swings over, but that is less dangerous if it does happen.
Kids and family sailing were uppermost in my mind with the Firefly Tri as you can see from this illustration.

brian eiland

11-21-2010, 05:22 PM

This does not address the question. The question is dynamic gust response, not static headstay tension. A good sail shape can be cut to fit any given headstay sag.

In a gust a stayed sail induces more sag, and thus more camber in the sail. Added camber increases the power and healing moment. If the boat needed more power before the gust, the sails would have been trimmed that way. Gusts in this context overpower the boat. Stayed sails increase power in gusts, just when less power is needed.

An unstayed rig or the unstayed portion of a mast above the hounds can be designed to fall off to leeward and ease the leech. Reducing heal and reducing power in response to a gust. This is an automatic proper gust response.

This correct gust response cannot be designed into a stayed sail. No matter what the static tension might be. This is one of the reasons that in area controlled development classes the sail plan evolves to either a fractional sloop or a single sail or wing. Overlapping sail plans and stayed masthead sails do do not evolve for performance unless other factors are in play.

Still no response to the dynamic gust response question.
A lot of your posting is directed at the 'gust response', and I will agree with you that in an upwind or beam reaching situation the genoa type sail can not be 'bled off' like the top prortion of a traditional mainsail. (However off the wind you might find the genoa sail's response quite productive :eek:).

In big gusty conditions going upwind and reaching both the racer and the cruiser can play the steering-up/falling-off routine to limit heel. And they both can play the mainsheet so as to spill wind from the top portion of the mainsail. However in those same conditions I don't believe you will find the pleasure sailor, nor the cruising sailor playing that in and out of the mainsail. Rather I think you would find that sailor reefing down that tall sail so as to not get overpowered by the conditions.

But wait a minute, isn't my rig already 'reefed down'?? My mast aft rig on the 65 foot cat is approx 15 feet shorter than the comparible fractional sloop rig of the same sail area on this other 65' foot cat. And the rig on that 65' trimaran is approx 15 feet shorter as well...same sail areas. I would call this quite a reef. :!:

Too often in the past the cruising sailor has been asked to bow before this altar of 'hi-aspect-ration-is-the-best' theme that permeates the racing crowds concerned with upwind performance...as though this is some sort of ultimate configuration. I think the cruising sailor will be much happier with the lower aspect ratios that Marchaji found VERY effective for all other points of sailing. My rig seeks to use those lower aspect ratios.

brian eiland

11-21-2010, 06:13 PM

....Next came a smaller boat, and a totally new design, the STILETTO 23 (http://www.stilettocatamarans.com/stiletto_23_catamaran_specifications.htm). It was also BOOMLESS as the idea had gone over so well on the 30. It also had a very pretty custom mast section design.
I was just informed today that a potential client has acquired two Stiletto 23's that he wants utilize to perform some experimental testing of a number of alternative rigs, including one on the aft mast configuration. He'll use one boat as the 'control boat' I believe and make mods to the other.

This should be interesting....and VERY challenging for my rig as this vessel would NOT be high on my list to place my rig on....total lack of deceit boat structure locations.

Personally I have a great interest in putting this rig on a Lightning class boat. I think this would make a fairly easy adaptation as a base structure, and there are lots of 'control boats' out there to sail-off against. Anyone have a good source of a Lightning at a real good price??

RHough

11-21-2010, 09:33 PM

A lot of your posting is directed at the 'gust response', and I will agree with you that in an upwind or beam reaching situation the genoa type sail can not be 'bled off' like the top prortion of a traditional mainsail. (However off the wind you might find the genoa sail's response quite productive :eek:).

For sailing off the wind you hoist a masthead screecher (with roller furling) or an asymmetric spinnaker on a bowsprit. Stayed Genoas suck off the wind unless they are poled out. Screechers for close reaching and A-Sails for broad reaching are the easy, safe, controllable and fast solution.

In big gusty conditions going upwind and reaching both the racer and the cruiser can play the steering-up/falling-off routine to limit heel. And they both can play the mainsheet so as to spill wind from the top portion of the mainsail. However in those same conditions I don't believe you will find the pleasure sailor, nor the cruising sailor playing that in and out of the mainsail. Rather I think you would find that sailor reefing down that tall sail so as to not get overpowered by the conditions.

The more the rig "self adjusts" the less steering and trimming you need to do. Why give that up? If your rig does not have proper gust response, the autopilot gives up, you reef and go slower. Would you rather be first into the anchorage or last?

But wait a minute, isn't my rig already 'reefed down'?? My mast aft rig on the 65 foot cat is approx 15 feet shorter than the comparible fractional sloop rig of the same sail area on this other 65' foot cat. And the rig on that 65' trimaran is approx 15 feet shorter as well...same sail areas. I would call this quite a reef. :!:

So you start EVERY day with a handicap. The 5-10 degree lower course or 5% lower speed does what for you when you leave Cabo San Lucas for Turtle Bay (460 miles away). Since you can't point you buy extra fuel and litter the deck with jerry cans. The aft mast rig has three sails, the other rig is a fractional sloop. Even if both rigs were the same height the sloop will kill the ketch on any upwind course. Give up 15 feet of height and you might as well motor.

Too often in the past the cruising sailor has been asked to bow before this altar of 'hi-aspect-ration-is-the-best' theme that permeates the racing crowds concerned with upwind performance...as though this is some sort of ultimate configuration. I think the cruising sailor will be much happier with the lower aspect ratios that Marchaji found VERY effective for all other points of sailing. My rig seeks to use those lower aspect ratios.

Do not confuse an IOR high aspect rig with a modern high aspect fractional rig. Not concerned with upwind performance? Not too many years ago the cruising fleet anchored off Cabo San Lucas was hit with a late season hurricane. As the boats started to drag onto the beach, they ran their engines to ease the load on the ground tackle. They still dragged. Many boats tried to sail off the beach and failed. Several boats tried to motor off and the rough conditions stirred up the crap in the tanks and killed their engines. Many boats ended up on the beach. The boats that were able to sail to windward made it out. How can a rig designed for a casual sailor NOT make windward ability a priority? Ask any sailor if they would give up 5-10 degrees of windward ability for perceived easier sail handling. Then ask them again after they have sailed from Cabo San Lucas to San Diego. Not placing sailing ability first in rig design is why most cruisers have a VDS (Vertical Dacron Stabilized) motor boat and are looking for fuel bladders. These are the non-racing "casual sailors" that might consider alternate rigs. Reducing their ability to sail to weather when their life's dream and maybe their life is at stake is a high price to pay for no boom.

I do not see the logic in trading sailing ability for ease of use. Lower aspect ratio on a cruising cat makes no sense to me unless you are up against a air draft limit for the ICW. Given the RM available for production cruising cats, the sail plan can go from stem to stern and up to ICW height with very little danger of the boat being over canvassed. If the boat is very light and the crew is spartan, a tall fractional rig with a masthead screecher and A-Sail retains windward ability for safety and allows all the added area you could want for reaching in the trades.

I just don't get it. I'm sorry to rain on your thread Brian, I'll try to avoid it in future.

R

brian eiland

11-21-2010, 11:26 PM

...Not too many years ago the cruising fleet anchored off Cabo San Lucas was hit with a late season hurricane. As the boats started to drag onto the beach, they ran their engines to ease the load on the ground tackle. They still dragged. Many boats tried to sail off the beach and failed. Several boats tried to motor off and the rough conditions stirred up the crap in the tanks and killed their engines. Many boats ended up on the beach. The boats that were able to sail to windward made it out.
I remember seeing pics of that...real shame.

How can a rig designed for a casual sailor NOT make windward ability a priority? Ask any sailor if they would give up 5-10 degrees of windward ability for perceived easier sail handling.
Here in lies one of our differences of opinion. I don't think I'm going to give up all that much windward capability. In fact I think this design will surprise a lot of folks with its windward capabilty. At its worst it shouldn't be much poorer that a traditional ketch. And by the way the extra drag of my ONE single bare mast (emphasis on ONE rather than two for a ketch) is not all that difficult to solve, particularly if I'm utilizing a std alum spar with an existing mainsail track.

I do not see the logic in trading sailing ability for ease of use. Lower aspect ratio on a cruising cat makes no sense to me unless you are up against a air draft limit for the ICW. Given the RM available for production cruising cats, the sail plan can go from stem to stern and up to ICW height with very little danger of the boat being over canvassed. If the boat is very light and the crew is spartan, a tall fractional rig with a masthead screecher and A-Sail retains windward ability for safety and allows all the added area you could want for reaching in the trades.
I'm 68 years old now, and I couldn't hoist that full battened mainsail on that 65' sloop cat without expending a great deal of energy. I'm still in good shape, but I just don't have the muscle tone for that job anymore. And I wouldn't relish reefing it up and down as the weather went up and down. But I would still like to be able to take that 65' of my design out for a daysail without a moments hesitation. I need ease of use.

And I find a lot of other sailors who are tried of wrestling with their mainsails.

If your rig does not have proper gust response, the autopilot gives up, you reef and go slower. Would you rather be first into the anchorage or last?
There is another way to look at this, and I learned it racing multihulls. On the downwind legs there were many times we would hustle our asses off in multiple gybing manuvers downwind only to arrive there at the same time that the other crew did sailing a straight line course at a leisurely manner on one gybe. There is something to be said for average consistancy as opposed to the up and downs. I actually think that this rig might be sailed at a higher average speed than one that might be accelerated and decelerated with every whim. The less threatening stability of the lower aspect ratio may allow for carrying a bigger sail area for longer periods of a passage.

I just don't get it. I'm sorry to rain on your thread Brian, I'll try to avoid it in future.
No problem Randy. I appreciate your comments...keeps me on my toes :p

CT 249

11-22-2010, 12:19 AM

I am as much of a fan of tight forestays and great sail shapes as anyone. I just hate saggy rigging. To me it represents a sloppiness in someone’s approach to sailing.
[/I]

Better tell that to the J/24 guys*, the Farr 40 guys, the 470 guys, the Tasar guys, the J/105 guys, the 420 guys, the Lightning guys, the Etchell guys, the Flying 15 guys, yada yada yada!:D All of those classes regularly induce extra forestay sag in light winds, because it's sometimes (literally, not figuratively) sloppy but it's also fast.

Even 10 years ago, some of the top Farr 40 guys readjusted their rig tension (D1s, D2s, etc) for increments of as little as 2 knots windspeed, to ensure that the forestay sagged enough in light winds. Such attention of detail is hardly a "sloppy" approach.

* and girls in each case, of course.

RHough

11-22-2010, 01:45 AM

I'm 68 years old now, and I couldn't hoist that full battened mainsail on that 65' sloop cat without expending a great deal of energy. I'm still in good shape, but I just don't have the muscle tone for that job anymore. And I wouldn't relish reefing it up and down as the weather went up and down. But I would still like to be able to take that 65' of my design out for a daysail without a moments hesitation. I need ease of use.

And I find a lot of other sailors who are tried of wrestling with their mainsails.

I hear you and I've spent hours taking to customers about this.

The answer for me is to use a powered winch for the main halyard and use a roller furling boom. Run the lines to the winch and you have a near zero effort system. Andersen (http://www.andersenwinches.com/p28.asp) makes a line of compact electric winches that are deck mounted.

I really like this option compared to in-mast systems. The sail shape is better (you can have a roach with full battens), almost as good as a standard main.

The only hassle that remains is the gybing terror. With a boom brake the violence is gone. Granted gybing a loose footed sail is next to no drama, a brake on the boom makes a standard rig pretty docile. We're cruising after all, use a second powered winch on the main sheet to grind it in, turn the boat and ease. The unintentional gybe is the scary one. The loose footed sail will fill on the wrong side and will stay backed until the sheets are eased. The boomed sail with brake will just come across and set on the new gybe with very little commotion, on mono's people rig preventers that make planned gybes more work than they should be just to avoid the accidental gybe. The preventer can actually become a liability if it holds the main backed and pins the boat.

When we think about reefing we should also consider weight aloft. A sail that roller reefs on it's luff keeps the weight at full hoist. Now that you've shared your age, I know you remember reefable hanked headsails. In mast mainsail reefing is a tripple whammy. The mast is heavier, the sail has no roach, and when reefed the sail's weight is still aloft. Slab reefing or in boom reefing keeps the mast light and the weight of the reefed sail is on or in the boom, reducing weight aloft and easing the motion of the boat.

Add to this the fact that a roller reefing boom is a great water catcher. Install a spigot and run a hose to the water tank ... how cool is that. This idea came from a few experiences with roller booms that had many gallons of water inside giving the crew a dousing ... we hadn't thought where the water that used to run off the main was going ... :(

If these newish solutions were not seaworthy, reliable options I can see much more value in having multiple sails on luff furlers. Now I see the rig as an answer to a problem that has been solved and can be easily retrofitted to almost any boat.

The last point in favour of a boomed main is the DDW situation. I've given up trying to get people to stop sailing DDW (its slow and leads to the dreaded unplanned gybe). How does a Genoa set when sailing deep angles unless you stroll forward to set a wisker pole? How does a standard main set? If you want or need to sail deep angles having the equivalent of two Genoas means you have poor sail shape or you have to wrestle with settting poles. This just abouts negates any easy sail handling. Even if you sail broad reaches, loose footed sails set poorly. Ease the main, hoist a downwind sail (on a continuous line furler) unroll the sail, trim, cleat, drink ... easy peasy. Sailing very deep the main is still fine (the boom is projecting the area), roll up the reaching sail, hoist the runner (in a sock), trim, cleat, drink.

I don't see it being any easier than this with the possible exception of an unstayed cat ketch like the Wylie 65-66. There you have wishbone booms that are high enough to not bang heads and nets to control the sail when reefed or doused.

R

brian eiland

11-22-2010, 03:45 PM

Looking back thru some older postings on this subject thread I ran across this one #46 (http://www.boatdesign.net/forums/sailboats/aftmast-rigs-623-4.html#post185838)

.......I am 56 years old and with that comes loss of muscle mass and flexability.

I want to world cruise and my biggest seagoing dilema is the mainsail. As you mentioned the full batten mainsail is a beast. i had considered putting a power wench near the mainsail for aid in lifting it....but when you are at sea and singlehanding...it can be so frightening ...when in the middle of the night
some weather blows up quickly...your thoughts are muddled and you are trying to figure out your best course of survival...ha ha ...even on a rotating mast getting the slides to cooperate, the battens not to get hung up on the jiffy sail lines is no laughing matter.

Recently while on a 41 foot Lagoon cat in Greece we went from 15 knot breeze to over 40 knots in a channel between islands. Now mind you, there were 8 of us board this monster of a boat. It took one steering into the wind, one on the mainsheet traveller, one on the mainsheet rope clutch and wench, two handling the mainsail...clawing like hell to pull the slides down, and one lookout watching the battens didn't get hung up in the jiffy lines...which happened several times...up a little...no, down a little,,,,no damnit...up a little you idiots...and so it went.

With your idea we would have just furled the jenny half way and struck the mizzen and we would have been fine.....

RHough

11-22-2010, 05:12 PM

Where do I start?

Originally Posted by Alan Smith
.......I am 56 years old and with that comes loss of muscle mass and flexability.

I'm 58 and singlehand often, are you saying that working to stay fit is a low priority?

I want to world cruise and my biggest seagoing dilema is the mainsail. As you mentioned the full batten mainsail is a beast. i had considered putting a power wench near the mainsail for aid in lifting it....but when you are at sea and singlehanding...it can be so frightening ...when in the middle of the night
some weather blows up quickly...your thoughts are muddled and you are trying to figure out your best course of survival...ha ha ...even on a rotating mast getting the slides to cooperate, the battens not to get hung up on the jiffy sail lines is no laughing matter.

Most sailors with a few years of experience don't think a full battened main is beastly in the least. They are very well mannered. If a dog won't come when called and sit on command, someone needs to spend more time training. "Blows up quickly" does not happen. If the forecast for 12 hours is not known, what is the boat doing at sea? Why did it leave port with a slide system that is not reliable? Jiffy lines hung up on battens? Why are the reef lines slack enough to allow that? Was the halyard dropped before the slab reef lines were free and under tension? How many times was the reefing drill practiced?

Recently while on a 41 foot Lagoon cat in Greece we went from 15 knot breeze to over 40 knots in a channel between islands. Now mind you, there were 8 of us board this monster of a boat. It took one steering into the wind, one on the mainsheet traveller, one on the mainsheet rope clutch and wench, two handling the mainsail...clawing like hell to pull the slides down, and one lookout watching the battens didn't get hung up in the jiffy lines...which happened several times...up a little...no, down a little,,,,no damnit...up a little you idiots...and so it went.

Funnel effects are usually well known local conditions. Why wasn't the information available? 41 feet is not a monster of a boat. The three ring circus described here sounds like a crew on a chartered boat that were learning to reef for the first time.

With your idea we would have just furled the jenny half way and struck the mizzen and we would have been fine.....

Want to bet they never practiced a MOB drill either? This post screams "I'm a novice sailor and I scared myself." How is that the fault of the rig?

pbmaise

11-23-2010, 08:20 AM

Just a quick update on the sea trials of my aft-mast 65ft trimaran. This Saturday I'm scheduled to head into the South China Sea for a quick sail to Brunei. Winds look like they will be light. Based upon my tests into the wind I will then decide route to Palau. I may cut through the Philippines and head dead East and into the wind, or go north of the Philippines where I can come down again.

I'm getting some interest from people here in Singapore that want to buy my rig for charters. The like the big open 40ft beam and fact the boat now sails with no reefing lines, no sheets, and only one sail. They really liked fact my boat tacks without turning on the engine or moving a single line.

Phil Maise

gggGuest

11-23-2010, 03:36 PM

Add to this the fact that a roller reefing boom is a great water catcher. Install a spigot and run a hose to the water tank ... how cool is that. This idea came from a few experiences with roller booms that had many gallons of water inside giving the crew a dousing ... we hadn't thought where the water that used to run off the main was going ... :(

A mate was involved in the rig design on Mirabella V. I understand they were well on the way to finalising the boom design when he ran some calculations for the weight of water the boom might hold in a really big downpour with the water coming down the sail faster than it could drain out of the spar. The stress calculations had to be revisited!

brian eiland

11-25-2010, 10:51 AM

Just a quick update on the sea trials of my aft-mast 65ft trimaran. Phil Maise
How would you compare your rig with this modification made to another aft-mast vessel??
http://www.boatdesign.net/forums/boat-design/wishbone-sailing-rig-1999-8.html#post283505

...also here
http://www.boatdesign.net/forums/boat-design/wishbone-sailing-rig-1999-8.html#post283525

You might consider looking thru these forums for other places to post your rig design (in addition to this one), that might bring you more responses in direct reply to your particular rig....such as dhow and lateen rigs (http://en.wikipedia.org/wiki/Dhow).

brian eiland

11-25-2010, 11:47 AM

...Most sailors with a few years of experience don't think a full battened main is beastly in the least. They are very well mannered. If a dog won't come when called and sit on command, someone needs to spend more time training. "Blows up quickly" does not happen. If the forecast for 12 hours is not known, what is the boat doing at sea? Why did it leave port with a slide system that is not reliable? Jiffy lines hung up on battens? Why are the reef lines slack enough to allow that? Was the halyard dropped before the slab reef lines were free and under tension? How many times was the reefing drill practiced?
I don't know what seas you sail in, but to say these conditions can not arise suddenly is just begging for interpetation. I've personally been off Hatteras sailing at night when the wind went from 10 knots to something over 30 in a matter of less the 1 minute....lets see triple the wind speed, square that figure for the wind pressure (6 times). On one other occassion it went from 10-15 knots to something over 60-70 in a matter of minutes.

More recently there was a situation where an Atlantic 57 catamaran with two experienced owners onboard capsized in the Pacific due to a violent 60+ knot squall. Here is an interesting website reference and analysis:
http://www.anything-sailing.com/showthread.php/6880-Capsize-of-Anna-a-Chris-White-Atlantic-57

....just a couple of excerpts:

...from the designer;
"looked like the others more or less, though I was concerned that its movement seemed different. In any case, a few minutes after the initial wind gust and rain, the wind really cranked up and headed us. Then it increased again and headed us more. There was way too much wind for the sail we carried, so I luffed up enough to depower Javelin, trying to walk the fine line between flogging the sails violently and keeping our boat speed down below 12 kts. It was exciting, too exciting, and when it did not let up after a few minutes we dropped the mainsail entirely. If truth be told, the whole event left me pretty rattled. We experienced an increase from 20 to 45 kts of wind in a fraction of a minute along with a 90 degree wind shift. I did not expect that at all. And that's the lesson. Sometimes a squall will dish out something that you don't expect and are not prepared for. It may only be one out of 50 or 100 squalls that are truly dangerous but you don't know and can never be sure which ones they are."

...from the owners of the Atlantic 57;
"I find that downwind in squally conditions a very deeply reefed main and a large light sail forward that can be completely eased off in an instant makes me more comfortable. Sails behind the mast are difficult to handle and impossible to depower quickly with the apparent wind aft of the beam."

The point is that these BIG wind conditions can pop up, and very often a cruising sailor will just opt for turning off the wind and running with it. But then that mainsail is pinned against the mast and rigging, and it gets real difficult to drag it down into a reefed position...particularly a full-battened mainsail. All the while that mainsail is driving your bows down. Personnally if I am shorthanded I'd just as soon be without that tall full-battened mainsail in these situations.

I've not done a similar calculation as Chris did on the overturning moment forces involved with this sail combo they were flying in those conditions, but I venture to guess my rig could have been carrying more sail area and not capsized in those same conditions.

Here is a series of analysis on Chris' web pages:
http://www.chriswhitedesigns.com/news/anna_capsize/index.shtml

RHough

11-25-2010, 01:28 PM

I don't know what seas you sail in, but to say these conditions can not arise suddenly is just begging for interpetation. I've personally been off Hatteras sailing at night when the wind went from 10 knots to something over 30 in a matter of less the 1 minute....lets see triple the wind speed, square that figure for the wind pressure (6 times). On one other occassion it went from 10-15 knots to something over 60-70 in a matter of minutes.

I don't doubt that such things happen. I have experienced them first hand. What I doubt is the "no warning" aspect. In every case upon review there was ample warning. At first I did not know what to look for, and later after I had more experience I had not been paying attention.

...from the designer;
"looked like the others more or less, though I was concerned that its movement seemed different. In any case, a few minutes after the initial wind gust and rain, the wind really cranked up and headed us. Then it increased again and headed us more. There was way too much wind for the sail we carried, so I luffed up enough to depower Javelin, trying to walk the fine line between flogging the sails violently and keeping our boat speed down below 12 kts. It was exciting, too exciting, and when it did not let up after a few minutes we dropped the mainsail entirely. If truth be told, the whole event left me pretty rattled. We experienced an increase from 20 to 45 kts of wind in a fraction of a minute along with a 90 degree wind shift. I did not expect that at all. And that's the lesson. Sometimes a squall will dish out something that you don't expect and are not prepared for. It may only be one out of 50 or 100 squalls that are truly dangerous but you don't know and can never be sure which ones they are."

The designers own words make my point. Not expected, not prepared, and allowed to continue for a few minutes.

...from the owners of the Atlantic 57;
"I find that downwind in squally conditions a very deeply reefed main and a large light sail forward that can be completely eased off in an instant makes me more comfortable. Sails behind the mast are difficult to handle and impossible to depower quickly with the apparent wind aft of the beam."

Design flaw, operator error, or lack of experience?

The point is that these BIG wind conditions can pop up, and very often a cruising sailor will just opt for turning off the wind and running with it. But then that mainsail is pinned against the mast and rigging, and it gets real difficult to drag it down into a reefed position...particularly a full-battened mainsail. All the while that mainsail is driving your bows down. Personnally if I am shorthanded I'd just as soon be without that tall full-battened mainsail in these situations.

I struggle not to sound sarcastic ... why would anyone decide: The wind is up, I shall run off rather than reduce sail area so I can maintain my course. I will let my very expensive main sail that is the prime mover for my boat chafe for some unknown amount of time and possibly destroy itself leaving me even worse off. I don't know what the safest thing to do is, so I shall do the easiest thing and hope for the best.

If the main does not come down when you release the halyard there is something wrong. Design flaw, operator error, or lack of experience?
If the boom drops when you do and thrashes about the cockpit there is something wrong. Design flaw, operator error, or lack of experience?

I've not done a similar calculation as Chris did on the overturning moment forces involved with this sail combo they were flying in those conditions, but I venture to guess my rig could have been carrying more sail area and not capsized in those same conditions.

Sailing for many is a hobby, like golf.
Golfers practice, they spend hours and $$ on lessons and to practice the shots they find most difficult.
Sailors? Just suggesting that a sailor might enjoy their hobby more if they got some lessons will start an argument.

If sailors would spend 30 minutes a day, hell an hour a week learning something about weather patterns they could better identify the conditions and seasons that produce winds that they find hard to handle. The "did not expect" aspect is reduced or eliminated. Then they could go out in progressively poorer conditions and practice responses. The "was not prepared" aspect is reduced or eliminated.

Why is it that a golf pro is always busy giving lessons at the local club so people can enjoy that hobby and very few yacht clubs have a full time pro to help people enjoy sailing?

BATAAN

11-25-2010, 01:42 PM

Here's another approach (not aft main) to battens that has worked for a long long long time.
This 1000 sq ft main has T6063 aluminum pipe battens against the mast, sets very well, and does as it's told 99% of the time. This is the vessel's second mainsail as the first was worn out after 20 years of use. The price of docility and durability is weight, requiring a vessel with great stability.

pool

11-25-2010, 03:54 PM

Would an A-frame mast with a furling jib fwd and a furling boomless main aft be an alternative to an aft mast rig?

Seems to have the pros of an aft mast setup, but easier to rig and sail being placed midships. It might also be easier on the eye to the traditionalist.

Apparently, it was put successfully on a prototype cat in South Africa, and now starting a production run as a "SMG50" http://www.sail-the-difference.com (http://www.sail-the-difference.com/).

Tried to find out more, but could not find much about A-masts on the web, except a brief note on the mast designer's page here http://www.yacht-mast.de (http://www.yacht-mast.de/).

Fanie

11-25-2010, 05:36 PM

That made some interesting reading (the capsize), such a shame it happened.

RHough I agree with you. People are too lazy or ignorant to prepare themselves and do not think things through. I always try to reflect back on any and all experiences and try to either learn from it or seek an improvement that would cure such a problem.

One of my own fears is exactly a squall you don't notice that can cause a problem - hence I was thinking again along the lines of a clutched cleat that can release a sail coming under excessive power. I cannot see it not working. It would be a small compromise to re-adjust the sails afterwards.

Re my own build, I'm playing around with my equipment and improve where I thing it would be required, but mostly everything seems to go according to plan. Hopefully next year is going to be a better one than this one in this pathetic crime riddled cuntry :(

So in good faith we're clinging in there - another aft mast may well be on the horizon...
And with a bit of luck, and some other things it may well be the one to change some minds. I hate circumstances.

CT 249

11-29-2010, 04:18 AM

We raced that boat for the first time here on the Chesapeake Bay in what was known at the time as the Governor's Cup, one of the largest races on the East Coast at that time (something over 300 boats, and some fast monohulls). Multihulls at the time were only reluctantly allowed to race, and they put them all in a single start at the very end of the pack...16th if I remember correctly. You race down the bay overnight from Annapolis, Md, turn up the Potomac river, and tread your way up a winding river to the school at St Marys. We like to brag that we started last and ended up first boat to finish, but we never received even a single word of acknowledgement at the awards ceremony.[/I] :!:

On the other hand, if people get into an event knowing that those who created it are reluctant to have them there, maybe they shouldn't be surprised if there is no acknowledgement.

Every sport, indeed every human activity, has some boundaries. Whether it's bicycle racing, fencing, surfing, windsurfing, snow sports, rowing, kayaking, race walking, many forms of motor sport, the local Jane Austen appreciation society, the Blue Hills Birdwatching club or the GWR Trainspotters Guild, they all have certain rules about what you do and what you don't.

Most people seem to handle it, as did most sailors. When organised dinghy racing started, they generally ran their own races. When canoes started racing in the 1800s, they made their own races. When small offshore boats started, they made their own races. When windsurfers started, they made their own races. When kitesailing started, they made their own races.

Why on earth do mono events get so much grief for staying mono-only, when so many other activities are similarly restricted, and the events that DO allow all types in rarely seem to benefit much from it?

My family's been into multis for three generations, and I married a Tornado worlds sailor, so I'm not anti-multi. But the ideas that multis have been picked on are a myth, just as the claim that Herreshoff's Amaryllis was banned from all racing is a complete and utter myth*. The idea that multis, unlike equipment in most other sports, somehow deserves to be given a start in every event is surely an attitude that's been setting back the type far more than any supposed bias ever did.

* The simple historical truth is that many NY clubs of the time allowed cats to race - they just normally put them in their own class, just like they separated catboats from knockabouts, schooners from cutters, sloops from yawls etc. Many of the rich and powerful had cats, including several YC commodores including the founder of the NYYC itself. But people, for their own reasons, seem to prefer the "they hate us and always have" line.

RHough

11-29-2010, 09:15 AM

Why on earth do mono events get so much grief for staying mono-only, when so many other activities are similarly restricted, and the events that DO allow all types in rarely seem to benefit much from it?

Can you find examples of activities that exclude women or minorities solely on that basis? Our annual regatta for cruisers has actively included multi-hulls for years and the multi's are our fastest growing segment. More sailors = more beer sold. It can also be shown that most of us have benefited from multi racing. Where do you think the alternative penalty came from? It was those pesky "Hobbie lifestyle" sailors that wanted no part of Yacht Clubs and establishment crap, so they raced off the beach and created the alternative penalty so that racing was more fun.

My family's been into multis for three generations, and I married a Tornado worlds sailor, so I'm not anti-multi. But the ideas that multis have been picked on are a myth, just as the claim that Herreshoff's Amaryllis was banned from all racing is a complete and utter myth*. The idea that multis, unlike equipment in most other sports, somehow deserves to be given a start in every event is surely an attitude that's been setting back the type far more than any supposed bias ever did.

Here I tend to agree. Adding multi's to an event will not create the demand. But excluding multi's where there is a demand is wrong, it is bias.

* The simple historical truth is that many NY clubs of the time allowed cats to race - they just normally put them in their own class, just like they separated catboats from knockabouts, schooners from cutters, sloops from yawls etc. Many of the rich and powerful had cats, including several YC commodores including the founder of the NYYC itself. But people, for their own reasons, seem to prefer the "they hate us and always have" line.

You are 100% correct that NYYC did have cat classes while there was interest. (Thank you for many hours of reading to prove myself wrong on that, I used to be one of the people that believed NYYC banned cats.)

You also have touched upon part of the problem from some multi-hullers. They have the "we are excluded unfairly" attitude and it can be self fulfilling.

There is a difference between excluding multi's because mono's don't want them in the fleet and no multi's in the fleet because no multi's want to sail. Not allowing motorcycles to enter a bicycle race is one thing. Limiting entries in a motorcycle race to one type or brand is another. I don't know if there are many recumbent bikes that want to race, but if there are would it be better to give them class and make your event bigger and better or to exclude them solely because they are "different"?

I think the face of sailing is changing. I think we will see more fast cruiser multi's and more interest in multi's in the future. If they decide to race they should be welcome, just as they were when NYYC ran classes for them.

Randy

michael pierzga

11-29-2010, 09:56 AM

CT 249

11-29-2010, 05:58 PM

You are 100% correct that NYYC did have cat classes while there was interest. (Thank you for many hours of reading to prove myself wrong on that, I used to be one of the people that believed NYYC banned cats.)

You also have touched upon part of the problem from some multi-hullers. They have the "we are excluded unfairly" attitude and it can be self fulfilling.

There is a difference between excluding multi's because mono's don't want them in the fleet and no multi's in the fleet because no multi's want to sail. Not allowing motorcycles to enter a bicycle race is one thing. Limiting entries in a motorcycle race to one type or brand is another. I don't know if there are many recumbent bikes that want to race, but if there are would it be better to give them class and make your event bigger and better or to exclude them solely because they are "different"?

I think the face of sailing is changing. I think we will see more fast cruiser multi's and more interest in multi's in the future. If they decide to race they should be welcome, just as they were when NYYC ran classes for them.

Randy

Thanks for reading the NY cat scene stuff. Like you, I believe that the "we have always been excluded unfairly" stuff really hurts the multi scene. Where we differ is that I believe that any club still has the right to decide that it's not worth opening up their events to other equipment, without other people claiming discrimination.

I don't agree that there is any comparison whatsoever between racism or sexism etc and excluding certain sorts of sports equipment from an event. In one there are divisions based on people themselves or their inherited characteristics, in the other there are divisions is based on the activity that people (of all types) chose to do. They are completely different things.

Groups of people must surely have the right to voluntarily form a group that concentrates on one activity, as long as it allows in anyone who does that activity. And surely the group has the right to work out how narrowly they define that activity, whether it's as wide as "sailing" or as narrow as "Corsair trimaran sailing" or "racing in competitive A Class catamarans."

By your definition, my local bicycle commuters activist group are akin to racists, because they don't have a section dedicated to car commuters. The dog-training club down the road is, by your definition, discriminating unfairly because they don't have a section for greyhound racing or cat fanciers. The labrador club is unfair because it doesn't have a section for fox terriers. The football club, by your standards, is discriminating because it doesn't have a gridiron team. The A Class cat association would have to run cruises for those who sail Hobie Waves, or be discriminating. It is obviously illogical, therefore, to say that all clubs or events MUST be all-inclusive.

This is not excluding an activity merely because it's "different". It's excluding it because much of the reason to have a club or competition is to concentrate on certain activities. The dog training club just wouldn't work if it had to include greyhound racing and Burmese breeding. The A Class association's volunteer RCs don't have the time to run races for Waves. The Governor's Cup may not need to have to run another class, and it may detract from the enjoyment of those who made the event into something others want to join.

Why in the world do we have sailing clubs at all? It's so people can concentrate on the sport of sailing, NOT basket weaving or kayaking or powerboating. It's not excluding people on who they are, but on what they chose to do for fun.

Yes, combining very different equipment can work, but often it doesn't work or at least poses major issues that can reduce the enjoyment of those who created the event and are its backbone. As someone who sails many different types, it's interesting to see that it's not a person problem (there are great people on every side) but a perspective problem - things look different when seen from a different deck, and it's easy to start thinking that it's the other type of craft that is the problem, instead of perspective that's the problem. It CAN be managed in a way that strengthens a club or event, but it CAN be a significant problem, and for many events it's simply not worth it.

Catering for different types of gear DOES often introduce logistical or safety issues. For example, at my local club one newer type of craft puts much higher demands on course layers and RCs than the traditional boats. What right does anyone have to come into an event and demand special treatment from volunteers? Allowing recumbent bikes into our races WOULD have very significant safety and logistical issues that would reduce the enjoyment of the club members as a whole. If recumbents want to race, fine - go what the founders of our club did and make a club (which is, of course, what they have done).

Where you stop when you say "you must allow everything in". Does the Governor's Cup have to allow windsurfers? A Class cats? Kites? Optis? Macgregor 26 power sailers under motor? Stand Up Paddleboards?

If a club decides that bringing in new groups is worth it, great. It often is. But IMHO there's a world of difference between allowing clubs to have free choice, and pressuring them to let you in and then insulting them afterwards as is often the case. The respect has to go both ways, and most of the time it doesn't seem to flow back from the faster craft to the slower ones. Going "woo hoo, we finished ahead of all the other type, they're slugs" is pretty silly when the other type competes under different rules - you could win the motorcycle GPs if you raced a F1 car, but no one would find the slightest sense in doing it.

Things can also be different in an area where the activity is not all that popular and you need critical mass. But that's not the case where the Governor's Cup is held, or where I sail. And even in smaller areas, bringing in different types can destroy the fun for some people, because it changes the accent of the club.

Look at your very own (as I understand it) port. One group felt so excluded by the change of accent in their club that they had to leave and form a new club. How is that fair to those who formed the first club and now have to form a new one?

That's happened a fair bit around my place, mainly by yachties taking over dinghy clubs and effectively driving them out or marginalising them. All it does is reduce diversity and opportunity, which can often best be fostered by clubs and events that are closely targeted to one type of sailing AND by other events being open to all if that happens to suit those who did the bloody work and created the event!

RHough

11-29-2010, 09:48 PM

Thanks for reading the NY cat scene stuff. Like you, I believe that the "we have always been excluded unfairly" stuff really hurts the multi scene. Where we differ is that I believe that any club still has the right to decide that it's not worth opening up their events to other equipment, without other people claiming discrimination.

I agree it is a case by case sort of thing. A sailing club is just that, a club who's members have a common interest - sailing. For the Pan-Am pre games we were faced with running three courses. Sailboards and Hobbies on the course I worked, Laser, Laser Radial, Laser Women, and Snipes on another course, and J-24's and Lightnings on the third course. It was a great three days.

You are 100% correct that the support requirements differ for each class, with the sailboard/Hobbie course needing 9 marks. I am not saying that every club MUST set courses to fit a class's special needs, but if you have a course that CAN be shared, like most mono keelboat courses it makes no sense to exclude multi's just because they have more than one hull. The sailing that cruiser/racer types enjoy works for bigger multi's too.

You some of this right:
Why in the world do we have sailing clubs at all? It's so people can concentrate on the sport of sailing, NOT basket weaving or kayaking or powerboating. It's not excluding people on who they are, but on what they chose to do for fun.

Multi sailors are sailors, they are not powerboaters, basket weavers, or kayackers. Why exclude fellow sailors?

Multi sailors chose to sail, yet they are excluded from sailing clubs? I find that hard to defend. How is the enjoyment of sailing the boat you like diminished by someone sailing another type?

I agree with the respect comments, but the fast guys in giant dinghy like "sports boats" are every bit as bad as multi-hullers. The 505 class used to claim they were "Overbearing in Victory, Obnoxious in Defeat", that attitude is not unique to multi-sailors. How are ULDB Sports Boats ok and mutli's not? Its okay for the old guard to put up with cheeky attitude from the ULDB guys because they aren't multi-hull sailors? That is anti-multi bigotry. Why didn't the keelboat faction just tell the sports boats guys to go start their own club?

Did the Dinghy Club get taken over by "Yachties" or did many on the members move into bigger boats as they aged and wanted to keep the same circle of friends? That is how some of the clubs in the SF Bay area evolved.

You sail more than one type of boat, do belong to several different clubs? Pay multiple dues? I can see not expecting your sailing club to hold bicycle races, or your bike club not running regattas. However it sounds like the recumbent bikes found a way to support their own races and YOUR club lost out on the dues and bar sales. If they are self supporting now, they would not have been a burden to your club and both groups now duplicate some resources that could have been shared ... that sounds short sighted to me.

We are WAY off topic. :)

RHough

11-29-2010, 09:53 PM

Knock it off...Modern racing..regattas... are controlled my measurement rules so that race officials can somehow compare apples to oranges. How would they form a handicap rule to include Multi's or any non standard hull form ? How would you provide guidance to owners and designers wishing to build boats ? How would you protect the value of existing owners yachts . ?

You confuse measurement rules with handicapping rules. None of what you say applies to performance based handicapping. Our handicapping committee can and does rate boats from 400 D/L cruisers to custom multi's. If you want to do it it can be done. It just is not as easy as picking a handicap number out of a book.

michael pierzga

11-30-2010, 12:37 AM

brian eiland

11-30-2010, 12:32 PM

That Handicap rule must be mighty complex !!!!! Even laying the course out must be a challenge.... I cant Imagine putting multi's in the same startline procedures as mono's. Yikes ! think of the smash ups.
Ive got nothing against Multihulls, great boats...just apples and oranges on a race course.
That is why the Governpr's Cup Race decided to give the multihull fleet, as an entity, its own start after there were enough of them inquiring as to entry into this fun race of the sunmmer (BIG party at the finish).

The commitee made no attempt to handicap the boats against the monohulls, but rather let the multihulls handicap themselves against one another. And start them in the very last sequence so as to not interfer with the rest of the monohull fleet. Very good choice.

http://www.smcm.edu/govcup (http://www.smcm.edu/govcup/)/

In June 1986, Yacht Racing and Cruising magazine (now Sailing World) ranked the Governor's Cup's day of celebration as one of the top ten post-race parties in the sailing world. In 1985, it called the Governor's Cup "the race that goes somewhere," and declared, "The race down the Bay, with its variable weather and currents, is an interesting one, and the enjoyable ambiance at the end of it provides a happy finale. The combination has made this increasingly popular event . . . a Bay Classic."

I think that year there was close to 400 boats.

BTW I was not complaining that we were discrimated against unfairly. Our crew aboard that Stiletto 30 were just disappointed that someone didn't mention the fact that we sailed thru the whole fleet of some pretty fast boats and ended up first out of 400 boats. Seems a little one-liner might have been appropriate.

michael pierzga

11-30-2010, 12:39 PM

Sure...my experience with regattas is that the organizers value every competitor. Everyone is welcome !!..But not everyone can be scored in fleet standing. The odd balls...too big, too fast, too slow, too many topless girls, compete as..." spirit of sail" and enjoy life. Not sure how they do it for a sprint down the Chesapeake to St Mary's city, but I'm sure they have some way to encourage all sailors

RHough

11-30-2010, 02:01 PM

That is why the Governpr's Cup Race decided to give the multihull fleet, as an entity, its own start after there were enough of them inquiring as to entry into this fun race of the sunmmer (BIG party at the finish).

The commitee made no attempt to handicap the boats against the monohulls, but rather let the multihulls handicap themselves against one another. And start them in the very last sequence so as to not interfer with the rest of the monohull fleet. Very good choice.

You answered your own question Brian. Until an attempt is made to rate ULDB's and Multi's on an comparable scale to the existing fleet, you cannot fairly say that a boat you can't/won't rate won.

Cheers

Randy

michael pierzga

11-30-2010, 02:08 PM

Its also dangerous. I worked the racing yachts for many years an big regattas like St Tropez or Antigua gradually became very dangerous at starting lines, mark rounding , finish lines. The sad story of Claude Graf the designer being run down and his crew killed by Mareitte. When different type boats mix it up trouble brews. Rules are rules..Im on Starboard !!!!!!!!!!! out of my way leads to disaster when one vessel is going 5 knots and the other 15 knts. .

CT 249

11-30-2010, 08:49 PM

At the risk of continuing the hijack (which, in my defence, did follow on from a remark of the OP).....

I agree it is a case by case sort of thing. A sailing club is just that, a club who's members have a common interest - sailing.

Glad we agree that it's case by case. I just feel that criticising those who don;t want to offer a multi class is not the right thing to do.

I've never heard of a sailing club whose members have a roughly equal common interest in ALL forms of sailing. A sailing club is almost always a club whose members all, or mainly, have a common interest in A PARTICULAR TYPE OF SAILING, and that's what they cater for.

For the Pan-Am pre games we were faced with running three courses. Sailboards and Hobbies on the course I worked, Laser, Laser Radial, Laser Women, and Snipes on another course, and J-24's and Lightnings on the third course. It was a great three days.

You are 100% correct that the support requirements differ for each class, with the sailboard/Hobbie course needing 9 marks. I am not saying that every club MUST set courses to fit a class's special needs, but if you have a course that CAN be shared, like most mono keelboat courses it makes no sense to exclude multi's just because they have more than one hull.

It does make sense IF the members of the club feel that adding multis (or windsurfers, or motorsailers, or kites, or Hobie kayaks with tiny sails, or J/24s or Stars) will not add to their enjoyment of the event that THEY decided to run for THEIR enjoyment.

If you run the British Columbia Fuschia and Begonia Society and you have a club night that CAN be shared, do you HAVE to have talks on cactii?

If you are a member of a Lotus car club and you have a racecourse that CAN be shared, do you HAVE to allow in racing trucks, motorbikes, recumbent bicycles, Citroen 2CVs, Formula Libre, Caravan "banger" racing, and drift events?

Down the road from me is a sportsground with an Australian Football (AFL) club. Do they HAVE to run American Football, Association Football (soccer), Rugby Union Football, Rugby League football, wheelchair rugby, etc?

Every club concentrates on certain things. When I switch disciplines (which is often) I'm more amazed at the DIFFERENCE between sailors and what they get out of an event than at the similarities.

Allowing events that cater for specific areas of the sport allows us to concentrate on those areas, which is why cat and tri sailors love running events just for themselves.

The sailing that cruiser/racer types enjoy works for bigger multi's too.

You some of this right:

Multi sailors are sailors, they are not powerboaters, basket weavers, or kayackers. Why exclude fellow sailors?

Read the rest of the posts - the point is that just about every other club or event excludes someone. My clubs have been approached by representatives of the rowing clubs from wealthy private schools, complete with offers of bags of cash if we'll just let them join. Their line is "we're all water users, we all enjoy competing on the bay, why draw the line at rowers?" which is simply another way of looking at where the line is. And even defining who a "sailor" is and how much they must be catered for can be problematic when you look at the guys who almost always just motor their Macgregor around, the guys with the Hobie kayaks with 0.25m sails, or the guys with Stand-Up paddleboards that take windsurfer rigs.

Multi sailors chose to sail, yet they are excluded from sailing clubs? I find that hard to defend. How is the enjoyment of sailing the boat you like diminished by someone sailing another type?

Because the club no longer has the ability to cater properly for my type of sailing. Because the event in which I am competing (or my fellows may be competing in) becomes just becomes a sideshow. Because the competitors have less in common with each other. The shared experience is reduced.

I agree with the respect comments, but the fast guys in giant dinghy like "sports boats" are every bit as bad as multi-hullers. The 505 class used to claim they were "Overbearing in Victory, Obnoxious in Defeat", that attitude is not unique to multi-sailors. How are ULDB Sports Boats ok and mutli's not? Its okay for the old guard to put up with cheeky attitude from the ULDB guys because they aren't multi-hull sailors?

The surly monohullers piss me off as much as anyone. Down here, the SBers normally race by themselves now.

The difference between them and multis can simply be that it's easy to define a multi, kite or windsurfer, whereas defining a "sportsboat" is very problematic.
That is anti-multi bigotry. Why didn't the keelboat faction just tell the sports boats guys to go start their own club?

Did the Dinghy Club get taken over by "Yachties" or did many on the members move into bigger boats as they aged and wanted to keep the same circle of friends? That is how some of the clubs in the SF Bay area evolved.

And sometimes those who created the dinghy clubs get marginalised, and once that occurs it's hard to come back. They become swamped by those who are interested in other things.

You sail more than one type of boat, do belong to several different clubs? Pay multiple dues?

Depends on what I'm racing. If I'm racing cats or yachts, it's completely impractical to expect the dinghy club to cater for me and vice versa. The cat club was formed by people who wanted to promote cat sailing, they shouldn't have to cater for my dinghy.

The dinghy club has windsurfer racing and it works there - but as someone who sails both types, it's easy to see that it could all fall apart without goodwill on both sides, particularly the dinghy-sailing majority.

I can see not expecting your sailing club to hold bicycle races, or your bike club not running regattas. However it sounds like the recumbent bikes found a way to support their own races No - like cruising multis, in many places they do not attract enough interest to support their own events.and YOUR club lost out on the dues and bar sales. If they are self supporting now, they would not have been a burden to your club and both groups now duplicate some resources that could have been shared ... that sounds short sighted to me.

Is it possible that those in a different discipline in a different sport in a different city in a different country may just possibly know more about running a successful club than you do, Randy?

It's impractical to combine the two for various reasons, and there's no real upside (as just one example, bar sales in an amateur cycling club are illegal and no one's interested). And the reason I, like many others, race at that club is because it's focussed on the disciplines in which we are interested. If it wasn't focussed, we'd go somewhere else and the club would lose much more than it would gain.

We are WAY off topic. :)

By the way, I've sailed just about everything from maxi monos to freestyle windsurfers, including canoes, skiffs, the loosest of classes, the tightest of classes, offshore and inshore multis, so I don't think I'm coming from the viewpoint of a closed mind.

The diversity in our sport is wonderful. Each flavour and each colour is terrific. But disciplines, IMHO, are just like flavours and colours, because if you add the right ones you can get something fantastic, but if you just throw them all together without care you end up with is a tasteless brown mess.

There is a reason that most of the biggest and most successful clubs and events don't cater for every discipline - that's because it doesn't work. Focus can be vital. I don't think there is a single club or event in the world that caters for all forms of sailing that it could cater for, and that in itself is an indication that by their very nature, sailing events are exclusionary to some extent.

Other opinions may, of course, differ. But when people start demanding that events MUST be open to every other discipline in that activity, they are expecting something that doesn't happen in any other form of human activity I'm aware of.

Anyway, I shall say no more for fear of further hijacking the thread.

CT 249

12-01-2010, 05:15 AM

Yes, but you said that a cycling club in Sydney is "short sighted" because of their attitude to adding a fourth discipline.

The fact that you have been involved in a different club in a different sport in a different part of a different city in a different country does not mean that you know more about running a cycling club in Sydney than those who do just that, quite successfully.

And since you don't know what club I'm talking about, you have no idea about whether it's more or less successful than the clubs in which you have been involved.

Basically, I was taking issue with the fact that you were criticising people when you knew nothing about the situation in which they are operating or how well they did it, and therefore had no logical basis for your criticism.

Fanie

12-01-2010, 10:05 AM

Don't worry guys, we won't compete against any of you when the aft masts are coming up :D

We'll just head out past you and go fish... ;)

CT 249

12-01-2010, 09:26 PM

I'm sorry that you took it as criticism. It is my opinion only. The arguments to exclude multi's sound exactly like the arguments used to resist integration in the US. So I react the same way. I don't see any logic in it.

Saying that someone has missed an opportunity sounds like criticism, which cannot be reasonable as you do not know the factors (the courses, the marshalling requirements, the complete lack of any bar to sell from, etc) related to the decision.

The argument, once more, has nothing to do with excluding people for what they are. The argument - which everyone from matchbox collecting clubs to those who run events just for skysurfers can understand - is that you can sometimes get more enjoyment by concentrating on a common interest, and that there can be many valid definitions of "common interest" - as attested to the fact that multi sailors, for example, will have regattas as broad as "all cruising multis" or as narrow as "Hobie 16 Masters".

Anyway, I look forward to you actively campaigning against your car club because of the fact that it excludes racing trucks, caravan racing, electric cars and motorcycles, and perhaps asking strong questions about the local beggonnia club's exclusion of cactii from their shows.:p

BTW having married into a family with a public profile for working against racism (including racism in sport) in a time and place where that could have VERY nasty consequences, the analogy with racism and excluding types of sailboats seems odd.

I'm wondering how my in-law who got international attention in his sport for obtaining an apology for the national body's past racism, or the one who sponsors a mixed-race "reconciliation" sporting team, will feel when I tell them that they are following logic that is akin to racism when they dare to compete in events that are only for one discipline of their sports?

Anyway, no more for me, since I'm never going to agree that my kitesurfing friends, for example, are following racist-type logic for daring to hold events just for kites, or that my multi-sailing mate is doing anything wrong in organising an event just for cruising multis.

Paul B

12-01-2010, 09:58 PM

I am very confused.

My Porsche Club does not allow Ferraris, Chevys, Fords, or any other marque in our autocross events and track days. I guess this makes us racist? The fact that our events are attended by folks of all ethnicities seems to refute that, as we have drivers descended from Europeans, Africans, Asians, Pacific Islanders, Middle Easterners, and Indians (and probably others).

On the other hand, my sailing club runs events that allow everything from low perforance dinghies to high performance dinghies, beach cats, foiling moths, keelboats, sportboats, and Sabots. But we have never had a race invitation that included IRC Boats, cruisig catamarans, or 12 Meters. So I guess that makes us bigots?

All this has what to do with Aftmast rigs?

brian eiland

12-02-2010, 09:24 PM

...All this has what to do with Aftmast rigs?
Thank You

brian eiland

12-03-2010, 07:30 PM

RHough

12-03-2010, 09:19 PM

Another interesting observation from the log books of an ocean cruising sailor:

The conclusion I have to come to for a cruising boat is that one should optimize reaching so long as the boat isn't un-safe. Lee shores are still dangerous."

This is very true. We have a huge data base to draw from. The days of commercial sail. The sailing routes work for fast passages using sailing vessels that did not go to weather very well. Racers have found that windward leeward courses provide the best tactical racing and reaching legs have been removed. Racing designs are optimized for Windward/Leeward courses and not for reaching.

This makes cruising designs based on the rigs and hull shapes that racers use less than optimum. A 50 foot schooner might well be a faster, more comfortable ride to Hawaii than a boat with a more modern rig.

My comments about giving up windward performance at your peril applies to the skipper as well as the boat. It comes down to don't anchor in a position you can't sail out of. Don't count on the same windward ability your boat had before you added 2000 pounds of cruising gear, kayaks and jerry cans on deck and that big hard dodger. :)

I'd look to compare a modern cruising rig with the rigs that worked for commercial sail. Easy to handle has value for both, fewer grew needed means higher profit for the same cargo. Speed under sail has value for both, first boat home gets the best prices for cargo (or fish).

Now the low aspect ratio and larger easy to handle area make great sense.

For mono hull types boomless sails don't set well at reaching angles, big mains and flying sails work better. On a wide platform like a cat, the sheeting point can be outboard and eliminate the need for booms and vangs at reaching angles. The sails will still suffer at very deep angles, but broad reaching and gybing down the rhumb-line should provide the same distance made good with more comfort and no worries about un-planned gybes.

If I was promoting a new rig for cruising short handed, I'd start with the popular cruising routes and optimize the rig for those sailing angles.

R

gggGuest

12-04-2010, 04:24 AM

Racing designs are optimized for Windward/Leeward courses and not for reaching.
Well western racing designs do. The racing Dhows of the middle east, for instance do passage racing. Different ships, different long splices.

There is something vaguely bizarre that at the moment the presumption is that racing sailors want to sail the fastest possible boats on the slowest points of sailing. In practice neither statement seems to be true for anything but a vocal minority.

In commercial days, of course, to have to do a lot of upwind sailing was to admit that you'd planned your journey badly and had got your use of wind and tide wrong. A skilled inshore fisherman would plan to use the fishing grounds that not only had the best chance of a catch but also for which the wind and tide would get him there and especially back to the market the quickest. The flaw of course was that if you do have to get upwind in an emergency you have to do so very badly, and every storm brought its fatality list to prove it.

RHough

12-04-2010, 08:37 AM

Well western racing designs do. The racing Dhows of the middle east, for instance do passage racing. Different ships, different long splices.

There is something vaguely bizarre that at the moment the presumption is that racing sailors want to sail the fastest possible boats on the slowest points of sailing. In practice neither statement seems to be true for anything but a vocal minority.

In commercial days, of course, to have to do a lot of upwind sailing was to admit that you'd planned your journey badly and had got your use of wind and tide wrong. A skilled inshore fisherman would plan to use the fishing grounds that not only had the best chance of a catch but also for which the wind and tide would get him there and especially back to the market the quickest. The flaw of course was that if you do have to get upwind in an emergency you have to do so very badly, and every storm brought its fatality list to prove it.

I agree and to some extent ocean racers are passage racing. As racing boats get faster they sail broad reaching angles down wind rather than running angles. The simple reason for windward/leeward course racing is that these legs provide the the most tactical options. For heavy boats, reaching is a "hull speed" parade with limited options. Passage racing (I like that term!) the tactics shift more to those of commercial sail. Picking the right course to get the best sailing conditions applies to both.

Windward performance cannot be ignored, but optimizing to get 40 deg off the wind at the expense of good reaching performance does not sound like a a good trade off for a passage racer or cruiser. A 45-50 deg boat that tacks well can have good VMG upwind. What I see are boats out cruising that were 45 deg boats in racing/daysailing trim loaded down with gear on deck and small, heavy cruising sails that now struggle to sail 50-55 deg to the wind.

In light air these boats motor much of the time and in heavy air their windward ability drops to near zero.

Cruising boats are modern cargo boats. Looking at haul-out weights, we've seen 30-40 foot boats cruising at 20% or more over the published displacement. Cruising boats and rigs should be designed to sail properly fully loaded. They will probably have a much more powerful rig than a similar sized day sailer. Heavy boats need huge sail areas to move in light air and the penalty for lower AR is not as severe at passage angles as it is for ultimate windward performance.

Alternatives rigs might well look very good in this context.

R

michael pierzga

12-04-2010, 09:12 AM

brian eiland

12-04-2010, 10:01 AM

I cant get my head around aftmast rigs simply because they cant set many sq metres of sail. Perhaps a motorsailor or special need vessel might benefit from an aft boomless rig, but for normal ocean sailing the vessel who sets the most sail area is favored. The reason a Ketch rig is so valued is its ability to set a cloud of sail.
Go back and look at posting #367
http://www.boatdesign.net/forums/sailboats/aftmast-rigs-623-25.html#post420889
The sail areas on the tall sloop 65 footer and the aft mast 65 footer are the same...it's just a shorter rig of lower aspect ratio...two sails spread out to three sails.

Same with that 63-65 foot trimaran...sail areas are the same.

michael pierzga

12-04-2010, 10:25 AM

brian eiland

12-05-2010, 11:42 AM

I must admit that the thread became so long that I never saw this sailplan drawing. It is indeed an inovative way to carry sails. The beam of a cat could give you some decent sheeting angles . Id have to think about it for a while to comment. Also I have little experience with cats. What would be the typical AWA in which you would expect your sailplan to operate at its best ?
I don't see any reasons that it shouldn't operate at all comparable apparent wind angles as any std rig.

I do believe that the leading edges of my headsails likely need be 'detuned' such that they don't produce too sharp of an incidence angle for the wind, and thus become to easy to stall the airfoil of the sail. Several experimenters have noted this problem including Bolgers aft mast rig. This actually could become a critical point to consider in designing/deploying this rig, and having the everyday sailor enjoy it. I've suggested a purely round (bulky) furling foil, which incidently furls the easist.

Aero drag is the other limiting factor to its upwind performance. But do I really have any more total drag than a two masted cruising boat ??...I have no second mast, nor assoiated rigging.

If I utililize an existing mast tube with its existing mainsail slot, couldn't I fly a piece of material (maybe even thin plastic) in it, that would greatly improve its aero drag characteristic, just as with a sail in this slot??

Or how about if I had no mainsail slot but rather a custom mast tube, could I attach two thin membrans of rigid plastic material (or other) to either side of the mast such that they extended into the wake of the mast and then slid against one another at their tips to produce a nice teardrop foil shape overall. I've got a sketch of that around here some where...will have to find it and scan it.

Meanwhile here is a top view with 3 different wind angles

So yes same AWA as normal rigs.

CT 249

12-05-2010, 06:28 PM

Another interesting observation from the log books of an ocean cruising sailor:

"Mike, a number of years ago I went through the log book of my trip through the S. Pacific to New Zealand and back. In 174 days at sea over 5 years the ketch Saga spent about 10 days actually on the wind. While there were certainly times when it would be good to go up wind better, taking a boat to sea that is hard to sail just to optimize those 10 days would be stupid.

During the same cruise I spent about 34 days with the chute up, where I didn't use the mizzen because it didn't do anything but slow me down. I was sailing about 160 to 170 degrees apparent wind.

The conclusion I have to come to for a cruising boat is that one should optimize reaching so long as the boat isn't un-safe. Lee shores are still dangerous."

Beau
This came as a response to this quote:

BTW, this posting came from a really good subject thread entitled
http://www.boatdesign.net/forums/boat-design/why-yawl-ketch-instead-sloop-27141.html

You're right that high-aspect rigs aren't always all they are cracked up to be (IMHO), but on the other hand, there have been people with considerable long-term cruising experience who say that there are places (like south-east Australia) where going upwind, often for long distances, is almost inevitable and therefore a boat with good upwind performance is vital.

The limited local cruising (and many deliveries) I've done has involved a lot of upwind sailing. In our typical summer breezes a boat that goes upwind well can spend a lot of time on the making tack, sailing almost parallel to the shoreline out of the current, with a short tack out to sea every few miles.

The poor guys with boats that can't point end up sagging into the shoreline and tacking out regularly. And quite often it seems that high-pointing boats can go straight up the coast close-hauled, while those who can't point well are still tacking and falling miles behind or, more often, motoring.

Even in smaller areas like the Whitsundays, upwind performance seems to be a great thing to have if you like sailing. The islands that are further upwind are normally much less crowded (in my very limited experience and apparently as a matter of course) because few people want to motor to them and few boats can sail to them effectively in the periods when the tide is not running strongly downwind. Last time I was there we made sure that we chartered a boat with good upwind performance, and watched many boats give up trying to sail upwind to islands, while we reveled in our Dehler slicing along nicely.

The corollary is that good light- and medium-air performance is important, because if you can't sail well in light winds you end up sailing in when the wind is strong, which is a hassle in an area with notoriously rough seas. And the modern fractional rig, IMHO, is superb for all this stuff.

brian eiland

12-05-2010, 11:17 PM

Here is another aft-mast design by a fellow Kees Radius. I originally saw this smaller boat in Holland years ago, and about a year or so ago he contacted me and sent some other pics. Thought I would post them here before I forgot about them.

michael pierzga

12-05-2010, 11:31 PM

From a practical point...unboomed sails are very difficult to handle reaching , light wind in a seaway. They flop around and ruin there shape and angle of attack. I frequently sail with the main sail triangulated.
Topping lift tight, mainsheet tight , preventer tight...to hold the sail at the correct angle of attack.
The cutter rigged foresails are very effective between 45 and 100 awa but after that they blanket each other and since they are boomless...difficult to keep them quite and trimmed at sea.
.On a cat, with its wide beam, you may be able to generate the leed angles to make it work...I cant see it working on a narrow monohull.

Remember, you frequently Motorsail with Main sheeted and prevented to add speed and dampen roll.

brian eiland

12-05-2010, 11:57 PM

michael pierzga

12-06-2010, 01:03 AM

Sure. The customer I presently work for is 81 years old. He pushed hard to eliminate booms and go with a schooner type rig. In the end the naval architect poo poo'd the idea.

I believe it will work fine...if your prepared to accept its shortcoming. Inshore...flat water, day cruising would be a very good application

Guillermo

12-06-2010, 01:48 AM

......................
The corollary is that good light- and medium-air performance is important, because if you can't sail well in light winds you end up sailing in when the wind is strong, which is a hassle in an area with notoriously rough seas. And the modern fractional rig, IMHO, is superb for all this stuff.
I totally agree it is most desirable to have reasonably good light air performance and weatherliness abilities in a cruising sailboat. Not all cruising is mostly passagemaking for most of the people, but rather involves a lot of coastal cruising. In such environments having a good upwind performance may prove not only convenient but vital.

I love my good old heavy and undercanvassed motorsailer Marie :), but I have to recognize I would like her to have more sailing abilities and not depend almost exclusively on motoring except when in force 4+ open rhumbs....

michael pierzga

12-06-2010, 02:39 AM

Ahh..."Marie" is a beautiful boat..... ketch rigged motorsailors with great big sun awnings rigged for burning hot Med afternoons . Mizzen and genoa set...cruising under the big awning , in the shade, while trolling for Lampuga ...AHHHHHHH. I also like the fisher motorsailors. When I grow up Im gonna get one !!!!!!!!!!!!!!!!

I would think that with attention to detail in sailplan and underwater surfaces that classic chunky, lets enjoy life, motorsailors could be much more lively when sailing.
Dont think that an aft oriented rig would be practical for day to day cruising simply because all the rigging is aft and intruding upon prime living space. Also the incredible practicality of a for and aft sailplan like a ketch would be missing. Guillermo's "Marie" under tightly sheeted mizzen to dampen role is a desirable feature.

pbmaise

12-07-2010, 08:53 AM

Aloha All
I've completed round two of my sea trials and attached a detailed writeup.
I also shot two videos I've posted on you-tube. See these links.

http://www.youtube.com/watch?v=4JSH1s6aGEQ
http://www.youtube.com/watch?v=XAVFh2heetA

In brief I am showing the boat self-tacking and headed windward. Here in S.E. Asia I continually learn from other sailors that nobody sails around here. Either there is no wind, or nasty short lived squalls that can leave you demasted. I demonstrated that all too well. You may find it odd, however, it was kind of a relief. I knew based upon my first trials that I was in essence putting duct-tape over problems that could only be corrected by starting the mast design again from scratch.

I'm excited at looking at this problem with a fresh eye. I can't wait to see what I come up with. Now don't laugh...for some reason I think a mast should be more like a sculpture.

Well more on that later, I'm going home for the Holidays.

Miri Malaysia is a good safe place to leave my boat and so I bid you guys good bye for a while.

Philip Maise

p.s. If anyone is excited about what I am up to and wants to take this project on from here or partner with me...I'm all ears. I'm not really good at marketing.

RHough

12-07-2010, 09:20 AM

The poor guys with boats that can't point end up sagging into the shoreline and tacking out regularly. And quite often it seems that high-pointing boats can go straight up the coast close-hauled, while those who can't point well are still tacking and falling miles behind or, more often, motoring.

This is also true going back up the Baja Coast from Mexico to the US to some extent. Hence my comments about cruisers with extra fuel strapped on deck that makes it even worse, they know they cannot said upwind so they just don't.

Even in smaller areas like the Whitsundays, upwind performance seems to be a great thing to have if you like sailing. The islands that are further upwind are normally much less crowded (in my very limited experience and apparently as a matter of course) because few people want to motor to them and few boats can sail to them effectively in the periods when the tide is not running strongly downwind. Last time I was there we made sure that we chartered a boat with good upwind performance, and watched many boats give up trying to sail upwind to islands, while we reveled in our Dehler slicing along nicely.

The corollary is that good light- and medium-air performance is important, because if you can't sail well in light winds you end up sailing in when the wind is strong, which is a hassle in an area with notoriously rough seas. And the modern fractional rig, IMHO, is superb for all this stuff.

I agree 100% Our Whitsunday chartered cat had no upwind performance to speak of. I think we sailed 3 days out of 7. We still had a great time and I wish other cruising areas were as friendly! I can only imagine how much nicer it would have been if we could have actually sailed!

Light air performance requires either light weight, large sail area or some combination of the two. It might mean reefing at 12 knots, many cruisers are so intimidated by the thought of reefing they would rather have little sails and motor when its light. Ad to that the macho idea that a "good" boat can carry full sails in to the high teens or low 20's and boats that reef in 12-15 are looked at as "tender" and not fit for cruising ... :(

Average wind strength on the oceans is about 10 knots. If you design a rig to be fully powered in 10 knots, you will be reefed in the trades or you need to be able to set light sails. Schooners and Ketch rigs are good for this, but a tall fractional with a well thought out reefing system or in boom roller reefing would be less work and more weatherly (while retaining good reaching performance)

How about a 3/4 fract rig with a big roach roller furling main and a light air masthead flying sail on a continuous line roller? At about 10-12 true you roll and douse the flying code zero and you have a manageable 10-16 knot rig at full hoist and a darn good rig reefed in 15+ Three sails plus an A-Sail for broad reaching in medium air ...

R

Fanie

12-07-2010, 09:31 AM

Awesome Philip !

Just one thing, the crab claw (clew) line to the mast rides high. I think you may improve power (and speed) if you make the leech radius smaller by pulling the sail foot down. The sail would be flatter then. I have found it to make quite a difference.

It would be interesting to know what angle you got from wind in the sail on starboard to again wind in the sail at port. I have found the smaller the angle to wind the less speed I had, but just increasing the angle a bit made a lot more power.

I'm impressed anyway. Very nice going and it's going to come together. It would also be interesting to see how far back your mast sits in the hull.

Fanie

12-07-2010, 09:39 AM

I have found the smaller the angle to wind the less speed I had, but just increasing the angle a bit made a lot more power.
Which made me think if you do land in a storm with high wind and you sail closer to wind you may make less speed but without additional stress on the rig (if you're not going to furl it some).

michael pierzga

12-07-2010, 09:54 AM

Yah, I reef in about 13 knots true, upwind, on a multi purpose cruiser. By reef I mean strike the Genoa, shift to staysail. At 15knot true Im fast, full main staysail..AWA 35, normal sea state.

No data supplied on the aft mast rig concerning wind angle ,wind strength and boat speed ? Difficult get a grip with whats going on.

BATAAN

12-07-2010, 09:55 AM

When I was building my modified SPRAY-type, BERTIE and designing her rig a fellow named Bernard Moitessier used to drop by the boatyard. He was living in town aboard his steel cruising boat and told stories about sailing around the world single-handed and all the problems that come up. He had grown up in Vietnam and explained a lot to me about fully battened lug rigs. One thing I really gleaned from him and other experienced voyagers like Sterling Hayden and Irving Johnson who I knew at the time was that a great deal of ocean sailing is done in 5 knots of wind or so, especially in the Pacific, and any serious cruising boat must deal with this. That means large sail area and a vessel that is not too overloaded. BERTIE is a cargo design, so eats tons of supplies with little outward effect, and her 1000 sq ft chinese-lug mainsail is a wonderful ghoster, making light sails not very necessary.
The second photo is the 1901 GOVERNOR M.B.M. on the beach for a scrub and paint. She's being re-rigged as a schooner and the foremast is not made yet. We sailed this boat quite a bit with a schooner gaff main and 3 headsails and it worked OK. We could tack and jibe, whatever was needed. Much better with the fore mast in though.... She ended up in Hawaii.

michael pierzga

12-07-2010, 10:01 AM

Yes Indeed Bataan....the ocean crossings yacht do are light wind. Big clouds of reaching sail are needed if you expect to turn the motor off. Unfortunatly many boats are under canvassed.

brian eiland

12-07-2010, 09:23 PM

....an aft oriented rig...Also the incredible practicality of a for and aft sail plan like a ketch would be missing.
I don't understand what you are saying? Haven't you read that this rig could be sailed under genoa/mizzen as well as under 'staysail' alone. And of course with todays materials that genoa could be roller furled to half its size

The single staysail configuration was thought to be applicable when trolling for fish under sail, as well as higher wind situations. The centers of effort remain balanced over the hull.

Wing and wing downwind for those cruising sailors that don't want to be bothered with fancier downwind sails, or those that want some piece of mind at night when short handed, and/or the recognition of foul weather might be more problematic.

cavalier mk2

12-07-2010, 09:43 PM

Very interesting. I was contemplating a a-frame mast for proas and realized that a mast offset sideways rig would do the same job with a furler in line with the mast towards the boat center for a main and a jib furler on an arced track so it wont bend the foil for shunting to each end to save having to have 2. It would be tensioned on each shunt/tack and eased for the shunt. Rolled it would be easy to handle, fitted to a track car it could be towed each way and controlled from the cockpit. Of course stays to the bows/ends and a stay to the ama (Pacific proa) and stay to the main hull by way of spreader. Any thoughts? The karman vortex street concept of the a frame I understand but think it might be diminished by the flow pattern channeled by the sails. A single mast of course would be lighter. So this is the equivalent of a proa mast aft rig.

Guillermo

12-08-2010, 04:50 AM

Ahh..."Marie" is a beautiful boat.....
Most true! http://www.freesmileys.org/smileys/smiley-love018.gif (http://www.freesmileys.org/smileys.php)

(Sorry Brian. Couldn't resist...:))

brian eiland

12-10-2010, 09:58 PM

Back in posting #254 (http://www.boatdesign.net/forums/sailboats/aftmast-rigs-623-17.html#post410214) I made reference to and included a few photos of a 40 foot cat being built over in Thailand, and making use of the aft-mast rig.

Here is a referece website page of that builder with more info and photos:

http://tinyurl.com/catamaran-power-sailing-HK40
...There are several more being built. In fact I've been told the second one is being launched today, and that I will receive some new photos soon.
The second Hong Kong 40 Powersailer has been launched a few days ago, and there are updated photos on that referenced webpage.

The builder sent along this note,
"Yesterday they were sailing to Kho Chang with 6.9 knts speed with only one sail. Top speed is 9.5 knts with 2 x 50 hp"

brian eiland

12-10-2010, 10:05 PM

... Dont think that an aft oriented rig would be practical for day to day cruising simply because all the rigging is aft and intruding upon prime living space.
Doesn't appear as though that mast and rigging is really intruding on the living spaces.

pbmaise

12-13-2010, 11:25 PM

How would you compare your rig with this modification made to another aft-mast vessel??
http://www.boatdesign.net/forums/boat-design/wishbone-sailing-rig-1999-8.html#post283505

...also here
http://www.boatdesign.net/forums/boat-design/wishbone-sailing-rig-1999-8.html#post283525

You might consider looking thru these forums for other places to post your rig design (in addition to this one), that might bring you more responses in direct reply to your particular rig....such as dhow and lateen rigs (http://en.wikipedia.org/wiki/Dhow).

My apologies Brian,

I missed your questions till now.

I followed the links and will attempt to answer your questions.

This boat builder built his mast to fly two fore-sails at different heights up the mast. So did I. In his case he went with roller furler sails which had camber and no spars in the feet. His sails drove the boat both forward and down. In my case i went with what I have been calling crab claw sails since my sails have zero camber and spars in the feet. These drove my boat both forward and upward and allowed me to self-tack. This is something he couldn't do on his boat.

I think we can assume by the after photo that this boat builder also suffered from a mast failure. Either that or he cut the mast down after doing sea-trials. In his case it appears the failure or mast reduction occurred above the mid-way point. His side column support looked excellent. I like the length of his spreader bars and the fact he went with a second set of spreaders 3/4 of the way up the mast. The area the before picture appears to be int he same area that my support was weak. It is the roughly 45 degrees behind the mast that is key. Had he switched from one back spar, and two spreaders mid-way up his mast to two back spars at 45 degrees behind his mast we probably would still be flying with the original mast size.

I have some doubts about the after photograph. I can clearly see a line going up into the sky in front of that roller furler. It obviously attaches somewhere, and the photograph is not showing the entire picture.

This said, we must now interrupt that is going on with that sail in the second photograph. Unquestionably it is odd. It reminds me of a windsurfer and how a windsurfer uses something we also call a wishbone to spread the sail apart. A windsurfer holds onto the wishbone when sailing. Wishbones are also used on other sail boats to hold the sail away from the mast.

Unfortunately we have been calling this mast design wishbone too. Perhaps to prevent confusion we should only refer to this type of mast as a-frame.

Back to the sail. It looks to me like a kite. A good old Charlie Brown get stuck in the tree kite. The innovation is that it looks like he just can unfurl it from that roller furler and and away he goes. Well, how fast he goes and how he controls this sail is beyond me. Sorry.

Regarding my own rig. I think I will be going with a carbon fiber mast from DK Yachting of Melaka Malaysia. However, it will take a few months to build and install. Except for the sand flies, Miri Malaysia is a good place to be based. Its nice to simply walk off my boat and down the road to a five star hotel and the local shops. At Ao Chalong it was always a trek.

Regarding the question whether my sail is better described as being lateen or lanteen, does it really matter? In all the links I see about lanteen and lateen the foot doesn't have a spar. It is a vital part of my sail which why I prefer crab claw.

Philip Maise

Phil

brian eiland

12-19-2010, 10:41 AM

The headline-grabber for the week was undoubtedly the Phuket King's Cup, which ended last Saturday with no less than 12 boats on the beach at Kata after a wild night of westerly wind and swell coming straight in from the Adaman Sea. And this after a King's Cup that is more likely to be remembered for indifferent weather than anything else (except the beachings).

12 grounded boats is quite a big deal, really. The multihulls just got carried up the beach beyond the high water mark to wait for more clement conditions and a re-launching, but the monohulls suffered a lot more. Judging by what we saw, there will likely be some write-offs – what the insurers call TCL, or Total Constructive Loss.

http://www.sail-world.com/Newsletter_show.cfm?nid=460575

Sounds like the multihulls faired very well

CT 249

12-19-2010, 05:52 PM

Reports say 12 boats grounded. Of them, five were multis. So if we want to try to learn things from this unfortunate event, we could note that 26% of the multis entered in the event hit the beach while just 9% of the monos hit the beach. In this case, there was a nice beach to leeward, but that's not always the case.

In Phuket, there was a beach of convenient size. In the recent Airlie Beach (Australia) cyclone, the shallow draft of the multis allowed a couple to float over the beach and into the seawall, where at least one suffered severe damage. Monos that went aground beside them may well have done better (or so it appears from the pics) because they stayed on the sand below the seawall.

http://forums.sailinganarchy.com/index.php?showtopic=105907&st=75

Different situations suit different boats. There are too many variables in such a situation to draw much of a lesson, surely.

pbmaise

12-19-2010, 08:34 PM

There is zero excuse for a single boat to have gone ashore in this bay. The bay is huge, it is shallow as far as 1 mile out and has all the room in the world to house this many boats safely. I know I've been there.

I own a multi-hull that is perhaps bigger then all the ones that drifted ashore. At 65ft long and 40ft wide I follow basic safety practices like:

1. Never leaving the boat without someone aboard who knows how to start engine, pickup anchor, and motor to safety.

2. Always having an anchor alarm on to alert us to movement, and sleeping beside said alarm at night.

3. Never depend on a mooring line unless it was specifically designed to handle the load of my boat, and it was tested under rough conditions WHILE someone was aboard.

These irresponsible owners were too close to shore so they could easily go party and go to the bar. They also probably all went ashore leaving their boat unattended. Further, it is said, many removed their heavy anchors and chain for racing purposes.

Any insurance firm that approves a claim in this incident is doing nothing but driving up the cost of insurance of responsible boat owners and rewarding the fat cats that view sailing as a good party.

Now. Back to the subject of our thread. Thanks Brian for the great pictures of Hong Kong 40. I think boats like this will accelerate the movement to aft-mast rigs. I also caught your picture of the cat designed by Radius. Comparing these two boats side by side you can see quite a difference in how designers think the mast should cant. I'm obviously more along the thinking of Radius.

I've been in Miri now two weeks and have been working on a new aft-mast design concept. I want to still use the sails and believe I am onto a winner there. Being right alongside dock has also been a blessing in that I finally have a chance to go from end to end of this boat and unload some of the thousands of pounds of excess weight. You wouldn't believe what the old owners accumulated over the years.

To say I was carrying around a lot of sh.t would be both truthful and an understatement. Both of my blackwater tanks have been full since the day I bought the boat a year ago. I broke into the tanks via the vent line and inserted a tube to manually pump them out. I figure i have decreased my boats weight by almost 70 gallons times 2 times 8 lbs/gallon or about 1120 lbs. (And I've been chiding myself for carrying 5 kayaks at about 40 lbs each Or 200 lbs.)

I've been seeking quotes for a new mast out of carbon fiber, however, given the fact that i can reduce weight in the boat in so many other areas I don't see much point in this route based upon weight savings alone. Therefore, I've located a source here in town for kiln dried lumber and may build from wood again. Of course I would be incorporating what I learned last time.

Philip Maise

brian eiland

12-21-2010, 09:51 PM

Reports say 12 boats grounded. Of them, five were multis. So if we want to try to learn things from this unfortunate event, we could note that 26% of the multis entered in the event hit the beach while just 9% of the monos hit the beach. In this case, there was a nice beach to leeward, but that's not always the case.
I really don't see how this satistical analysis has any meaning in this situation.

Likely we all assume that the multihulls with their very shallow draft will 'park' as close to the beach side festivities as possible, and particularly off of a sandy beach. In fact close enough to even get out and walk to the beach rather than dinghy. Come to think of it, they are racing in this event, and many of the vessels are likely not carrying their dinghys, but rather relying on the locals for rides to the beach. At any rate we all know how the surf picks up as it nears the beach. So I'm not surprised that more of the multi's were washed up on the beach.

But then, which of these vessels would I have wanted to be an owner of??

.............(photos courtesy of Sail-World.com (http:/http://www.sail-world.com/Newsletter_show.cfm?nid=460575/), Asia News,'Guy Nowell/Phuket King's Cup 2010')

brian eiland

12-21-2010, 10:42 PM

That is why the Governpr's Cup Race decided to give the multihull fleet, as an entity, its own start after there were enough of them inquiring as to entry into this fun race of the sunmmer (BIG party at the finish).

In June 1986, Yacht Racing and Cruising magazine (now Sailing World) ranked the Governor's Cup's day of celebration as one of the top ten post-race parties in the sailing world. In 1985, it called the Governor's Cup "the race that goes somewhere," and declared, "The race down the Bay, with its variable weather and currents, is an interesting one, and the enjoyable ambiance at the end of it provides a happy finale. The combination has made this increasingly popular event . . . a Bay Classic."
With well over 300 boats in this race, you can imagine the logistical problems of getting to shore from all of these boats (most not carrying their dinghy). We simply anchored the Stiletto 30 right off the small beach next to the college boat house and wadded ashore thru a foot or so of water.

On another occassion I did the same with a Louisiane 37 catamaran that drew 19 inches of water with the CB's up and the rudders kicked up.

Come to think of it I took that same Louisiane 37 down along the backside of the outer islands of Cape Hatteras, NC (there were times we were pulling the boat along while walking the shallows....what a great trip that was). I'm sure there are not many boats of that size that have ever made that trip.

CT 249

12-22-2010, 05:22 PM

I really don't see how this satistical analysis has any meaning at all in this situation.

Likely we all assume that the multihulls with their very shallow draft will park as close to the beach side festivities as possible, and particularly off of a sandy beach. In fact close enough to even get out and walk to the beach rather than dinghy. Come to think of it, they are racing in this event, and many of the vessels are likely not carrying their dinghys, but rather relying on the locals for rides to the beach. At any rate we all know how the surf picks up as it nears the beach. So I'm not surprised that more of the multi's were washed up on the beach.

But then, which of these vessels would I have wanted to be an owner of??

.............(photos courtesy of Sail-World.com (http:/http://www.sail-world.com/Newsletter_show.cfm?nid=460575/), Asia News,'Guy Nowell/Phuket King's Cup 2010')

I'd have thought that statistics are of great meaning when dealing with major issues, or else we can always just write off every lesson as a one-off.

Mainly, it's a matter of trying to get away from the multi v mono issue. Surely it is reasonable to point out the context of your post about the situation of the boats that ended up on the beach.

Yes, if I was one of the owners of the boats that hit the beach, I'd rather I owned a multi. But if I was one of the others of one of the boats IN THE EVENT, I'd rather it didn't hit the beach at all - and the chances of not hitting the beach were higher for a mono in this case.

Yes, the shoal-draft craft were probably anchored well inshore because they could be - that's great, it's an upside of shoal-draft boats (whether mono or multi). But if (as you say) in this case it comes with a downside (less room for dragging before hitting shore, more chance of being in the surf zone) then surely we should not just put our hands over our eyes and ignore it, should we?

My dreamboats are all centreboarders, so I don't think I'm biased against them, but can we ignore the downside when it is represented by an incident like this?

Note also that according to those who were there and posted on SA, many of the strandings were caused by a boat that came loose or dragged, struck anchored yachts and cut their anchor lines (which were often down to heavy anchors that were left on the bottom and buoyed while the boats raced). Therefore there is a very significant random factor that caused many of the mono strandings. If a single multi had come loose and cut the mooring lines of other multis that then ended on the beach, would you use that as example to show that multis faired poorly in that situation?

As an example of the issues about highlighting isolated situations, let's look at the recent strandings from Cyclone Ului at Airlie Beach, heart of Australia's greatest cruising area.

By my rough count, 21% of the boats anchored or moored to windward of the rescue base-marina area were multis. That's data from counting moored/anchored boats on Google maps, which may not be representative of the fleet that was in when the storm hit.

After coming up with that rough count, I then counted the boats pictured stranded or sunk on the SA thread and the linked news report. Eleven monos were pictured on the beach or the seawall or barge ramp, compared to five multis. One mono was in pieces after apparently being crushed by a maxi yacht, but no other mono has severe VISIBLE damage. One cat has a huge hole after hitting the rocks; another cat is pictured with just the vertical bows out of the water. A tri has filled almost to deck level.

So multis were disproportionately OVER-represented in losses and strandings (perhaps twice as likely to hit the bricks and be lost), according to the (admittedly scanty) evidence.

Am I saying that multis are more dangerous? NO! NO! NO! I have and will sail multis offshore and greatly respect them.

The point is that there are major issues in trying to highlight what type went well in a mass stranding. Also, after the Airlie storm where arguably the multis may have come off worse, no one posted anything like "the monohulls faired very well".

Paul B

12-22-2010, 05:58 PM

As an example of the issues about highlighting isolated situations, let's look at the recent strandings from Cyclone Ului at Airlie Beach, heart of Australia's greatest cruising area.

Since statistics don't matter:

Perhaps it should be noted that NOT ONE of the boats lost at the King's Cup or at Airlie had aft mast rigs, highlighting yet another positive characteristic of that type...

downunder

12-23-2010, 02:51 AM

Poor anchoring gear or improperly set tackle for conditions seems to cause more loss of vessels than any other reason.

This situation was simply inadequate anchor gear. Adequate gear could have been set up with a dingy and marked by a bouy if not carried on board.

doesn't matter if mono or multi if inadequate.

brian eiland

12-23-2010, 08:41 AM

I guess this 'anchoring discussion/accident' is easier to debase than the rigging force analysis I offered back in posting #345...almost no replies
.. :confused: :rolleyes:

Rigging Force Review (http://http://www.boatdesign.net/forums/sailboats/aftmast-rigs-623-23.html#post414479)

Kojii

12-23-2010, 01:04 PM

I would have but all the numbers made me sleepy....;) Rode out a 60+ mph storm at the dock November 21. That was a hoot. I'll go back and look at your analysis but you can't expect me to comment on what I don't understand, unlike some people....:D

brian eiland

12-23-2010, 01:09 PM

..Rode out a 60+ mph storm at the dock November 21. That was a hoot.
You guys are getting hammered out there this year. Pus its probably rather 'cool' wind ;) I don't envy you at all, nor anyone on the west coast of the USA this winter.

marshmat

12-23-2010, 06:51 PM

Re. the dragging ashore incidents: downunder got it right in post #435. If a boat drags anchor and ends up on shore (either on the beach for a cat, or on its side in the surf for a mono), the anchor was either too small or poorly set. Mono vs. multi has very little to do with it, as appropriate anchor selection methods for both types have been very well known for a long time. If you fit a boat with too small an anchor, then set it poorly on too little scope, it's not the weather's fault when the boat ends up on the beach.

(By the way, those "appropriate" anchor selection methods? There are more scientific ways of doing it, but this one's my favourite. Look at the manufacturer's recommendation tables, that's the absolute minimum in fair weather. Now ask "what's the biggest !@#$ anchor this boat can manage without causing problems", and that or a size down is about right. If this method conflicts with the manufacturer's tables, the boat has a design problem.)

Re. the aft mast rigs: I don't have much to offer at this exact moment, but I'm enjoying the discussion and the interesting ideas!

Paul B

12-23-2010, 07:27 PM

Re. the dragging ashore incidents: downunder got it right in post #435.

No, he didn't.

If a boat drags anchor and ends up on shore (either on the beach for a cat, or on its side in the surf for a mono), the anchor was either too small or poorly set.

Or, as seem to be the fact in this case, most of the boats that were grounded were anchored just fine. Then one boat came loose and tangled/cut other anchor lines. I would guess some of the boats that were freed then caused damage to other boats that were also anchored securely.

Some info about this was posted just 2 posts ahead of #435.

marshmat

12-23-2010, 07:40 PM

Paul B

12-23-2010, 07:56 PM

most yachts had stowed their large anchors and were carrying far-too-small anchors, if any, on the bow. (Large anchors may have come out later, but I suspect many did not do so.) These are racers, weight is critical to them, and skimping on ground tackle is not exactly uncommon.

Yes, many of the boats did stow their large anchors. They stowed them on the bottom of the harbour, with a float to be picked up after the day's racing.

You would not see an anchor on the bow of any serious race boat.

michael pierzga

12-23-2010, 11:00 PM

Alik

12-24-2010, 12:02 AM

The incident in Thailand looks to me like a classic case of poor seamanship. Exposed anchorage, no watchkeeper on duty.

They anchored too close to go-go bars :D

downunder

12-24-2010, 12:15 AM

What happens with many Multihull dragging disasters has nothing to do with windage, anchor size or skill in anchoring. Many Many times, because of their beam Multis can't fit into a harbour...no space, so they have no choice but to anchor off. At present, in front of this harbour, are 4 multis anchored, no monohulls, and exposed to violent weather. Its blowing force 8 right now. Under normal conditions NO SEAMAN, regardless of how big their anchor is , would ever knowingly anchor in this exposed bay. I can see waves sweeping their decks !!!

Another Bad habit I observe amoung the multis is that because of their shallow draft they can anchor very close to shore and they do. Obvoiusly, even when watch is being kept, if their anchor drags they have no time to escape before the bottom grabs them.

Any serious Multi sailor would be wise to carry the largest anchor and chain possible , perfect the various anchoring techniques and avoid the temptation to anchor close in to take advantage of their limited depth.

The incident in Thailand looks to me like a classic case of poor seamanship. Exposed anchorage, no watchkeeper on duty.

The incident in Thailand was a classic case of poor seamanship. Exposed anchorage, or no watchkeeper on duty.

Michael, I would however take issue with you that this is a multihull issue as its a general boating issue. More boats are damaged from poor anchoring than any other reason. As there are more monos in the water there will be more monos in the statistics.

"Any serious Multi sailor would be wise to carry the largest anchor and chain possible , perfect the various anchoring techniques and avoid the temptation to anchor close in to take advantage of their limited depth".

It's a sailor issue. If you have read Dashew's books (as good a reference for sailing as has been writen) your comment comes straight out of his recommendation for any vessel.

cheers.

brian eiland

12-24-2010, 12:17 AM

They anchored too close to the go-go bars :D
BIG LAUGH :D:D. I liked that one

downunder

12-24-2010, 12:20 AM

They anchored too close to go-go bars :D

Would be correct there.

brian eiland

12-24-2010, 12:30 AM

Paul: In all the articles linked in the last page or so, I saw only one explicit reference to an out-of-control boat probably cutting one other boat's rode (that of Miss Saigon). There was no one clump of beached boats; they're spread out over hundreds of metres.
I did, however, notice that in earlier photos from the race, most yachts had stowed their large anchors and were carrying far-too-small anchors, if any, on the bow. (Large anchors may have come out later, but I suspect many did not do so.) These are racers, weight is critical to them, and skimping on ground tackle is not exactly uncommon.
EXACTLY. How many racers do you know that carry around their heavest ground tackle during a race...no you put it in a shed and take along your lunch hook.

Besides I believe this King's Cup race is not know for heavy weather at all... I believe it has an element of 'party circuit' with some day races from resort to resort thrown in. I think they described this incident as quite unusual, so likely a number of the seasoned participants took their anchoring rather lightly.

michael pierzga

12-24-2010, 12:39 AM

Ive never quite understood how a Multi anchors ? I assume the ground tackle is set from the centerline . How do they store 150 meters of chain ? How do they set two anchors when exposed to tidal current ? How do they use a breast anchor ?

Can someone post the drawing of a typical cruising Multis stem head roller, anchor chain locker .

Alik

12-24-2010, 12:48 AM

Ive never quite understood how a Multi anchors ? I assume the ground tackle is set from the centerline . How do they store 150 meters of chain ?

On powercats and motorsailers, we usually run the chain aside into one hull, through plastic pipe. On high-performance sailing cat - yes, it could be a challenge as there is not enough chain drop.

michael pierzga

12-24-2010, 12:58 AM

Why don't multis handle anchors off the stem of each hull...then snub to centre line ? I can understand that weight forward in the hulls is not desirable but the versatility of two anchors, spread by the beam width, must be great. Breast anchoring, when you set the anchor, then go alongside is a very typical manoeuvre. The breast anchor keeps you off the seawall tidal range, clear of wave wash and is a very effective " bow thruster" when breaking off the dock with a beam wind.

Paul B

12-24-2010, 01:02 AM

EXACTLY. How many racers do you know that carry around their heavest ground tackle during a race...no you put it in a shed and take along your lunch hook.

This shows a basic lack of knowledge of racing rules.

Most organized races are run with requirements for participants to conform to, such as the ORC Special Regulations for whatever Category the race is being run under.

For a keelboat event like the Kings Cup the regs would require anchors, chain, and rode of the correct size/type/rating.

Anyone not carrying the correct equipment is subject to disqualification, so pretty much every serious racer complies. In the old days the anchor size and location was noted on the rating certificate, as was the length and size of the chain.

It is easier to bring along heavier tackle to be left as semi-permenant mooring during the day's racing rather than use the required equipment each night and have to pull it, clean it, and stow it every morning. Race boats do not have chain lockers, windlasses, or hoses to easily deal with tackle before each race.

michael pierzga

12-24-2010, 01:08 AM

Gee Paul, I raced yachts for many years. We never carried 100 meters of chain, anchor winch, stem roller and correct ground tackle. Never..all gear was minimum required...aluminum anchors short length of chain and rope.

Kojii

01-17-2011, 07:55 PM

That's the nice thing about aftmast rigs. They never run aground due to dragging ground tackle because the aftmast keeps the owner from leaving the boat when he shouldn't do so.

pbmaise

01-17-2011, 09:40 PM

Guys Please - Back on track
In fact it might be good if a moderator moved all this nice chit chat about anchoring to a separate forum. We are here for aft-mast design consideration and I want to get some input.

I am fortunate to be here in Miri Malayasia where several other sailors and fellow engineers have been going over the failure of my mast.

Brian--You might be happy to learn your name was mentioned by Peter of Tigger. His cat is a Bermuda, however, word of what we are up to is spreading fast in the sailing community.

My initial conclusion was side support. However, I now believe it was a matter of:

C>>>>>O>>>>M>>>M>P<R<<S<S<<I<<<<O<<<<<N

Lets review the events within 24 hours of the failure:

Aboard the sailboat I had a mono-hull sailor who was very uncomfortable with the amount of play in my mast. He was used to masts that stood completely rigid and had very small movement. So it was largely at his instance that I began the following changes:

1. I moved the sail from the 67 ft mark down to the 50 ft mark.
2. This freed up the block at the 67 ft mark. Rather then leaving it empty I led a line from the bow over the block down to the base of the mast.

Now I effectively had two lines to the bow I could tighten on a winch.

This in turn directly resulted in my forward leading side stays to become slack.

3. So I retightened my forward leading side stays. These were stays tied to two chain plates 17 ft in front of my mast on the two ama.

Items 1-3 greatly increased forward pull on the mast which was off set by the back stays led over the back spar.

4. To compound matters, for the first time I tightened the back spar tension lines using the power of a winch. That back spar and line was designed to prevent the mast from moving forward, which means it could add a tremendous pull backwards.

All 4 changes added more compression. Yes the mast was stiffer, however, too stiff is what we collective concluded. As part of the argument Peter asked where the break was and did the rigging fail. The break was at about 29 ft and I inspected all rigging and found zero failures. Peter response was COMPRESSION.

Live and learn.

I'm a strong advocate of keeping the forward leading side stays. These stays enable me to completely remove the combination forestay/halyard. However, as you can see in the above analysis they are interactive. Tightening the forward leading side stays loosens the forestay which in turn leads you to tighten that even more. Then you have to go back and tighten again. Each time adding compression.

I have already hinted about my line of thought to correct this situation. When I mentioned it to a sailor here from Spain he was so excited. He saw masts like these when he was a kid.

In the vast collective years of experience among you guys...have you ever seen a mast with a curve?

brian eiland

01-17-2011, 10:31 PM

...In the vast collective years of experience among you guys...have you ever seen a mast with a curve?
Absolutely, used loose diamond wires all the time to allow mast bend (big bend) on Prindle 19's, Tornados, Hobie 18's when in combination with rotation. Here is one reference:
http://www.hobiecat.com/forums/viewtopic.php?f=34&t=4344

You could find many more such references to bending the mast into curves to control sailshape for various wind conditions. So yeah, lots of 'curved mast'

The problem I am have in trying to evaluate your rig is I have NO definitive dwgs of what your rig looks like, and where each rigging piece is located. You talk about this 'new rig' of yours without proper definition. And I think you have deviated so far from my aftmast design that there are no comparisions to be made, other than the fact that you've placed the mast at the aft end of the vessel, and have some sort of long slopping forestay (I think?). Give us some dwgs that we can relate to if you wish for someone to comment on it with any intelligence.

Kojii

01-20-2011, 04:56 PM

I don't know much about rig design. I'm a geographer by training.
The following is based on my experience and conjecture, which I am fully aware of - so please everyone, let's skip the pissing contests and talk about ideas. The curved mast idea is interesting. Ours is a wishbone mast - two curves - forming a catenary or quasi-catenary arch with a pole on the top of the catenary to reduce windage/weight aloft. It is already bent so it is not being pulled and twisted at points along the span to keep it straight - contrary to all the dynamic forces on it which are effecting to bend it. The arches spread the tension/compression along the entire arch, or nearly so, rather than focus it on points of eventual failure (29 ft up). If it has built in modulus sufficient to sustain the vagaries of wind and wave action and is built expertly enough you should see it moving within the limits of the material/construction and that is actually a sign of it's ability to absorb and/or distribute stress. Like the overstressed and therefore rigid sail that blows out in the storm, the rigid mast breaks at weak points. One logical approach therefore is to reduce the number of stress points to zero (impossible) or increase the number of stress points infinitely and in so doing reduce the "weakness" value of each point along the arch below the critical threshold.
Spendy, hand laid, time-consuming project. Ours is carbon/kevlar co-fab triaxial with a glass wrapper for protection using Cargill Hi-performance resin. It is 20 years old this year and so far...no outward signs of failure/overstress, and we have been tough on it. I have said this all before in this forum, but like Brian I figure someone might be willing to step out of the box for a minute. Hope this is fruitful for you.

pbmaise

01-22-2011, 04:32 AM

Aloha Brian and Kojii
Thank you for your replies. Essentially I am engineering a solution by eliminating items from the previous design which led to over compression. My thoughts are a curved mast that is curved in line with hull and not the beam. I've done a lot of web searching and sure enough found others that have had thoughts along my line. The photo below of Wear Bridge shows a curved structure that first leans backwards before curving around to lean forward. This type of configuration would eliminate the backspar. Digging digging I found a very interesting design by David Estabrook. Photo attached.

He even has a patent on it.
http://www.freepatentsonline.com/6662738.html

Notice it is an aftmast design and as of yet we have not mentioned his name anywhere in this forum. Has anyone seen a working rig of his?

One thing I like about this curved mast idea is the possibility of adjusting the CE ratio. I envision a track at the top of the mast which I can move to change the horizontal location of the halyard attachment point. Moving the CE ratio forward on my boat is important for downwind performance.

Phil

brian eiland

01-22-2011, 08:07 AM

Perhaps you've seen this?
http://www.boatdesign.net/forums/sailboats/futuristic-mast-aft-design-10120.html (http:/http://www.boatdesign.net/forums/sailboats/futuristic-mast-aft-design-10120.html/)

I googled David Estabrook and found nothing else

brian eiland

01-22-2011, 08:14 AM

...or perhaps these stylish renderings I posted earlier in this subject thread:
http://www.boatdesign.net/forums/sailboats/aftmast-rigs-623-3.html#post120157 (http:/http://www.boatdesign.net/forums/sailboats/aftmast-rigs-623-3.html#post120157/)

Kojii

01-22-2011, 04:39 PM

Materials had to be invented to make Montgomery & Bolger's vision come to fruition in the aft mast designs of the last few decades. What materials are available to make an aft mast that hangs out over the deck and does not flex from the weight of the wind in the sails? Boeing just built a new airliner with carbon spars in the wings. We watched it's shakedown flights over the Straits. Considerable flex in those wing spars. If it did not flex it would snap or have to be so heavy as to lose it's raison d'etre - economy. Incorporate flex into your design. The one recurrent (and spot on) criticism of the aftmast rig is the increased tension needed in the forestay due to the angle (not the length) of the stays. Our rig has a flexible spar on top of the arch. We can crank back on the big back stays to bend the spar to get the proper forestay tension because the materials allow such bending. This is more similar to a longbow (the sail would be the arrow). Racers have this bend successfully of course many decades. Bending the mast forward seems to be predisposing it to sag forward and poor performance. Without proper tension the rig sails poorly. With proper tension it snaps to attention and scoots. Brian worked out the tensions in a previous postings I am sure you have read. I was impressed by the marginality of increased tension required and that has been my observation. Small increments of increased tension have large refunds in performance. With the curved stick it does not all go into compression. With a longer foot and shorter stick you can accomplish a lot in light air without wasting a lot of sailcloth aloft. Experimentum periculosum.

brian eiland

01-23-2011, 01:13 PM

You've experienced it, I've experienced it, and a number of other folks....that upwards lift from the sails. Perhaps it more of a phenomena aboard multihuuls that are not heeling over and are unballasted.

I brought this up long ago back in posting #__. where I also referenced Herresoff's same observations:

Just happened across this very recent reference to a 'lifting' situation.

SW: How does she perform downwind, is it a matter of sheeting in and hanging on?

Murry Jones: It was actually easier with the gennaker up than with the wing alone, because we had more lift in the bow. We are pushing the bow down a little when we are wingsail alone. Not that it is dangerously at all. But when the gennaker was up, it was really comfortable. It feels very good in that respect.

http://www.sail-world.com/USA/index.cfm?SEID=2&Nid=79491&SRCID=0&ntid=118&tickeruid=0&tickerCID=0 (http:/http://www.sail-world.com/USA/index.cfm?SEID=2&Nid=79491&SRCID=0&ntid=118&tickeruid=0&tickerCID=0/)

brian eiland

02-01-2011, 05:27 PM

Sodebo almost pitchpoles at start of singlehanded race. Thank goodness she didn't have her full mainsail up.

I particularly like this photo of her with her rig set well back on the boat, and sailing under a three sail combination.

...more photos and a video of the wild ride here:
http://www.sail-world.com/index.cfm?Nid=79811&refre=y&ntid=118&rid=4 (http:/http://www.sail-world.com/index.cfm?Nid=79811&refre=y&ntid=118&rid=4/)

brian eiland

03-21-2011, 10:52 AM

I was just informed today that a potential client has acquired two Stiletto 23's that he wants utilize to perform some experimental testing of a number of alternative rigs, including one on the aft mast configuration. He'll use one boat as the 'control boat' I believe and make mods to the other.

This should be interesting....and VERY challenging for my rig as this vessel would NOT be high on my list to place my rig on....total lack of deceit boat structure locations.

Personally I have a great interest in putting this rig on a Lightning class boat. I think this would make a fairly easy adaptation as a base structure, and there are lots of 'control boats' out there to sail-off against. Anyone have a good source of a Lightning at a real good price??

I thought I had posted this rough sketch of a suggestion for a temp frame structure for this fellow's Stiletto 23 experiment...but apparently I had not...so here it is.

I had another fellow asking about such an experiment using a Hobie 16...NOT a good candidate for such an mast aft experiment....even worst than Stiletto 23.

Pericles

03-21-2011, 12:31 PM

Brian,

Last known address for David Allen Estabrooks.

50, Water Street,
PO Box 519,
Newburyport. MA 01950

http://www.freepatentsonline.com/20030000441.pdf

He seems to have a wide range of interests.

http://www.freepatentsonline.com/6633740.pdf

I hope you can make contact with him.

Regards,

Perry

upchurchmr

04-10-2011, 01:40 PM

Brian,

Does this mean that I could go faster in my old Tornado catamaran with a raked mast?

Marc

brian eiland

04-10-2011, 06:28 PM

Brian,

Does this mean that I could go faster in my old Tornado catamaran with a raked mast?

Marc
NO, I would not recommend this rig for a vessel like that....not in style, nor size vessel. Besides what I am speaking to is a 'cruising rig' for easy handling....it's a single masted ketch...not a hi-aspect performace sloop...

Timothy

04-10-2011, 07:07 PM

Brian There is an aft mast cat about 40' long that has been anchored of the beech near my windsurfing club in Na Jontiem Thailand for the last six months or so. Is it one of your designs?

brian eiland

04-12-2011, 11:34 PM

Brian There is an aft mast cat about 40' long that has been anchored of the beech near my windsurfing club in Na Jontiem Thailand for the last six months or so. Is it one of your designs?
Hi Timothy,... none of my specific designs have been built. However I'm guessing it might be one of these from a Thai builder??

http://tinyurl.com/catamaran-power-sailing-HK40 (http://tinyurl.com/catamaran-power-sailing-HK40)

...or posting #425
http://www.boatdesign.net/forums/sailboats/aftmast-rigs-623-29.html#post426517

Timothy

04-13-2011, 01:12 AM

Thats the one

glyphics

06-30-2011, 03:45 PM

brian eiland

07-02-2011, 09:50 AM

Brian: I'm not new to this thread but I have not posted before.

There is an interesting sailboat concept called the Universal Hull that uses an aft-mast rig and a single staysail. I wonder if you have seen it. This site has a reprint of an article the July issue of the British magazine, "Seahorse" (alas, without the referenced diagrams), but the YouTube video shows good performance from a small rig.

<http://woodenboat.com/boat/?paged=2>

That was an interesting posting. I had not seen it. I've made a copy and reread it several times. It has more to do with hull design, but it was interesting that he used that mast-aft rig with the single foresail as a beginning,....and maybe more interesting once he experiments with a more std rig, as he mentions doing.

Fanie should find that quite interesting.

By the way, if you wish to include a web link in your posting there is a little icon at the top that looks like a 'globe' with a link symbol.

Your link:
http://woodenboat.com/boat/?paged=2

I also enjoyed this little quote from the article,
"For the purposes of the article, I submit that the best type of research science has no fear of being wrong, because we often learn as much from a theory which is proved wrong as from one which is proved to be right. Instead, we make progress when we make bold and clear predictions which are sufficiently explicit to be tested to destruction."

Youtube videos of aft mast sailing
http://www.youtube.com/watch?v=OUQHQmmdSZc (http://www.youtube.com/watch?v=OUQHQmmdSZchttp://)

http://www.youtube.com/watch?v=R_TEDjFCKJM
Even though the breeze was light, you can also see a little of the explosive acceleration when the boat heels and the chine touches the water....towards end of video

brian eiland

07-28-2011, 09:24 PM

I was just recently sent a link to this aft-mast article that appeared in an Australian publication called “The Coastal Passage (http://www.thecoastalpassage.com.au/)”. Here is the PDF article (see pages 36,37) (http://www.thecoastalpassage.com.au/papers/tcp49special.pdf) they made available on-line, but seeing as how the print size is very small (for us older guys), I've reproduced some of the 'rig related' portion of the article in a larger print style for this forum discussion.

I've included this material here as it is another aft-mast vessel that exist in real life, and that is the subject matter of this forum thread. The gentleman has some interesting observations about the sailing capabilities, particularly with reference to its basic single-sail configuration. I can't help but think that even his rig's capabilities could be improved with just a few modifications I'll outline in this posting. Meantime here is his observations:

By Ian Campbell, SC Lyra
I see quite a few cats using the “staysail sloop” rig now, and in a recent Multihull Magazine there were two new designs using a mainsail-less rig. Lyra has been in the water for a year and a half now and has 7000 miles under her keel including a Coral Sea crossing so we have had quite a lot of experience travelling without a mainsail and I think it may be time to give an honest evaluation of it.

The rig is not perfect; if it was every boat would have one. It does have a flaw that is inherent in the concept and it comes about this way. In order to get good balance the mast has to be stepped right aft and to have a rake aft. In order to get a similar sail area as a conventional rig the mast has to be higher. And the big staysails have to be made from heavier cloth. We wind up with a tall mast stepped far aft with two long foresails and with a short rigging base aft it is the very devil to get enough tension into the cap shrouds to stop luff sag. You wind on shroud tension until the hull starts to flex and still there is more sag than you would like.

Those two heavy sails on the sagging foresails flog from side to side in a big seaway so much that the masthead can sometimes flex forward as much as 5 inches. One reason for doing away with the mainsail was to get away from the annoying boom slatting to and fro – that drives me mad in a seaway, and here we have our own boomless equivalent. It's not dangerous or noisy, just annoying.

The cure is to rake the mast much further aft to open up the rigging angles at the masthead, and to build a stiffer glass beam athwartships under the mast compression post. From the point of view of performance I don't think this rig can be beaten for a cruising cat. The contention that the rig won't go to windward is codswallop. We travel at a hull speed equal to the true wind speed at 30 degrees apparent under auto pilot and down to 28 degrees hand steering, and the rig still pulls well down to 23 degrees when motor sailing.

Sailing against a Seawind in the Brisbane to Gladstone race we were pretty much neck and neck he was faster in light wind; we went better when the wind got up. We saw 18 knots a time or two, 12 a lot of the time though I must say we do a lot of traveling stooging along at 7 knots. We have done quite a lot of sailing in winds of 35 knots, gusting to 40 knots with seas to 4 meters and found the boat as rigged handles well with a few turns in the furler and no tendency to slide off a wave. No panic, no heart stopping moments. We only had a bit of water in the back of the cockpit twice from big breaking waves. In light winds the big outer staysail sits well and is always well balanced.

The true benefits are ease of sailing. Up wind in a narrow channel you just steer from side to side and
let the self tacker do its thing while the other boats go by under motor, and downwind with the wind dead aft accidental jibes are a ho-hum event, the sail just goes to the other side. Whatever the angle of sailing If the wind gets too hard you just pull the furling line in on the electric winch and if the wind is light and variable it is no big deal to pull the other string and get a furled sail out. The result of all this is we sail a lot more than we did on any other boat I have owned.

The effect on the fuel bill is lovely. We spent a month traveling from Gladstone to Cairns and used 160 litres of diesel. We motored through the narrows and around the Hinchinbrook creeks to Ramsey Beach landing and through the channel in a dead calm. We used the engines to anchor and to maneuver into the marinas in Townsville and Cairns and we charged the batteries every two or three days. I don't think we could have done that journey over that length of time with a conventional rig and used so little fuel. We just would not have sailed that much.

So for the next boat definitely use the same rig, no contest. Rake the mast further aft and plan to move the shroud chain plates further aft. Spend some of the money saved in not having batten cars, boom, lazy jacks, sail covers, vangs, topping lifts, main halliards, main sheets, battens, reefing winches etc, etc, etc, on light weight headsails. Fatten the hull sections forward. Rake the bow a lot. Lift the run aft a couple of inches at station number 9. Design for a little more displacement...stiffen the main beam......build the bottom step at the transom higher............

Modifications (I would suggest)
I've hi-lighted those portions of his article that caught my attention, both positive and negative.

In general I have to believe that some improvements to his sail shapes would have to improve the wind propulsive efforts. After all the sail is acting like airfoil, and we all know the shape of an airfoils very important for its efficiency. Furling headsails, particularly “sagging” ones can produce awful sail shapes.

1) Modifying the leading edge of these foresails should be a high priority. Something as simple as providing a foam pad insert of varying dimension sewn into the luff of the headsail can flatten that partially furled sail needed for increased wind strengths. Here are relatively simply modifications to the leading edge of these roller furling/reefing headsails presented by noted designer Dick Newick back in 1980 (attached PDF patent).

2) Provide for a better backstaying arrangement. His angled backstays (the cap shrouds) is just not a very good means to provide for good forestay tensioning. He is placing all of the loads onto the windward side of the vessel, and asking this shroud to act as both a shroud and a backstay! Traditional shrouds on 3-point multihull rigs are already coping with big loads from the increased stability of the multihull form....now you want to add backstaying loads to that shroud....and ask it to operate at a much slimmer angle with masthead!!

I believe you have to get a little more creative about providing decent backstaying, that will in turn provide more acceptable forestay sagging, thus better sail shape.

One key to this better aft staying has to be looking at the situation somewhat analogous to what we already do with athwartships staying....the use of some spreader(s) arrangement. I call one of my 'aft spreaders' an 'aft jumper strut' . The arrangement I use on my forward leaning aftmast rig could also be adapted to a straight standing aftmast.

3) Another fault I find with the 'Lyra's Rig' is there appears to be a lack of a proper 'staying base structure' for the rig to attach to. Nothing is stayed back to the primary bulkhead that the mast sets on? There is no athwartships, nor longitudinal rigid frame structures to the vessel. It's an 'open cavern' vessel that depends upon its skins to support its rig....as such there must be a lot of sagging in the rigging as “the hull starts to flex” as he says. A little more attention needs to be paid to the 'hull structure' to properly engineer a boat for an aftmast arrangement.....in fact this could be said for a conventional rig on most multihulls as well.

On a positive note I did find these comments by the owner interesting....quote:
1) the contention that the rig won't go to weather is codswallop.
2) accidental jibes are a ho hum event.
3) the result of all of this is we sail a lot more than we did on any other boat I have owned.
4) I don't think we could have done that journey over that length of time with a conventional rig and used so little fuel. We just would not have sailed that much.

Mick@itc

07-30-2011, 08:08 AM

brian eiland

08-02-2011, 08:14 AM

...just happened across a few comments by this gentleman 'Southern Star' over on another forum.
Brian

Sandy, I agree with your assessment of the earlier Prout 34's. As to what is commonly called the 'Prout' rig (cutter rig with mast stepped well aft by the companionway bulkhead), there have already been discussions of the relative merits of the rig in another thread on this site - I suspect it was in relation to some of the new Broadblue cats where there was a choice of rigs.

My Solaris Sunstream has an identical rig and I firmly believe that, for the following reasons, it has serious merit in an offshore cat:

1. It steps the mast at the strongest point of the bridgedeck - over the companionway bulkhead.

2. All lines are automatically led to the cockpit without various turning blocks for the halyards, reefing lines etc.

3. It allows sail area to be maintained, but breaks it up into smaller, and hence easier to handle sails. This is particularly important with respect to the mainsail, which will not require electric winches etc. to facilitate hoisting.

4. It has a dedicated stay for a staysail/storm jib, which brings the center of effort both down and back in precisely the wind conditions which favour the same (witness the number of offshore monohulls that now have 'solent rigs', with a detachable inner forestay for the staysail/storm jib).

5. The additional stays provide additional strength to the rig.

6. A furling staysail/storm jib permits the use of much heavier weight dacron than would be appropriate for a genoa, and therefore ensures that the lighter genoa is not used (abused) in excessive wind conditions. Furthermore, sail shape is easier to maintain if one is only reefing a furling sail to about 30 percent of its overall size. Finally, it is easier and safer to unfurl/reef a dedicated staysail/stormsail from the comfort of the cockpit than having to go forward to raise a sleeved storm jib ( eg. galerider) over the furled genoa, or to remove the genoa from the slot in the extrusion and raise a dedicated storm sail in its place. (On the negative side, I will agree that higher aspect-ratio sails tend to peform better and, in particular, the new huge mainsails with significant roach and flat-tops provide much more sail area up higher, where the winds tend to be stronger).

7. Since the Prout rig spreads the sail area more fore and aft than the typical fractional sloop rig, it will tend to have a lower mast. This in turn lowers both the center of effort and center of gravity, important in a catamaran in terms of reducing the risk of capsize. Furthermore, the lack of a mainsail with significant roach allows much better sail shape when reefed, and permits the use of backstays - further strengthening the rig.

Although direct comparisons are impossible without sailing the same hull with each type of rig, I have found that the larger foretriangle aids in tacking; I do not, for example, need to depower the main, as is sometimes necessary with huge flat - top mains in order to come about cleanly.

Once again, different horses for different courses - but for offshore sailing with its greater potential of being caught out in heavy conditions, the 'Prout rig' made and continues to make a good deal of sense.

Brad
http://www.cruisersforum.com/forums/f48/affect-of-mast-location-on-a-catamaran-21229.html

*************************************************

Clawing off a lee shore? If what you say is true, one would have expected the seas to be littered with the wreckage of Prouts that were forced onto a lee shore. While they are not demons to windward, the ability to fly a dedicated staysail/storm jib from a proper location (further inboard) and with proper sheeting angles; and, the very low freeboard/windage make them quite capable of sailing off a lee shore.
http://www.cruisersforum.com/forums/f48/opinions-on-a-1983-prout-37-a-61437.html#post697983

Mick@itc

08-24-2011, 06:22 AM

Hi
The Scrumble project is going with a mast further aft than "normal". Have a look on their blog.

Mick

upchurchmr

08-26-2011, 03:51 PM

Would you happen to have an address for the blog? Somehow I can rarely find things that are jus "on the Internet". This shouldn't take but a minute if you really think people should look at the blog.

Hi
The Scrumble project is going with a mast further aft than "normal". Have a look on their blog.

Mick

Mick@itc

08-27-2011, 01:41 AM

Would you happen to have an address for the blog? Somehow I can rarely find things that are jus "on the Internet". This shouldn't take but a minute if you really think people should look at the blog.

Here you go... http://scrumbleproject.wordpress.com/

brian eiland

09-23-2011, 07:55 AM

I guess since I've touted a 'different' sailing rig for such a long time, people find me to ask if I've seen this one, or that one. I've become a magnet for 'different rigs' considerations ;):D

Here is one of those I just received recently . I'm posting it here because it does make primary use of headsails to drive the vessel, AND it was conceived by its 70+ year old owner for easy handling.

By the way, check out the text in the lower jpeg image

_________________________________________________
Hi Brian...
You may have already seen this rig, but just in case you haven't ...
here is a link and some pics in attachment for you.

http://thecoastalpassage.com/xit.html

I don't know this fellow personally (John Hitch of Hitch-hiker cat
designs) ...But about 3 years ago I saw his boat 'X-IT' (60 footer),
parked here in the estuary at Laurieton NSW Australia... I thought
that Earth had just been invaded... so I rowed my boat around this
beautiful monster to see what sort of critter piloted such a craft...
and there was a solid older gentleman (human) sitting on the back deck
sipping on a cup of tea. (John Hitch), and because I didn't want to
disturb him, I did not say hello. (which I now regret because from
what I hear he is extremely knowledgeable and easy to talk to)
From all reports this cat can easily do 20+... with only fore-sails
(as you can see)

Originally Posted by brian eiland
http://www.boatdesign.net/forums/boat-design/wishbone-sailing-rig-1999-12.html#post485560

Somehow I missed ever seeing or knowing of this vessel, but here is a gentleman who is not affraid to experiement:

63' Catbird Suite .... http://www.damsl.com/
"The rig was completed in December, 2006. It works very well, is quite efficient upwind, is especially good reaching and running, and is easy to handle because all sails furl and there are other advantages as well........."

Interesting detail...he can vary the sail's tack (down) positions across the beam of the vessel, and in some instances get a 'heeling effect' on a non-heeling multihull. :cool:

brian eiland

11-19-2011, 03:46 PM

How very interesting. The design I am working on is a polycore aft mast design. I believe Lyra is polycore too. I need to share a cup of coffee with Ian!

The more I look at the aft mast set-up the more sense it makes for a cruiser.

Mick
Hey Mick, would a nice Polycore 40 footer in kit form do you?

I'm working on a modification of the Solitary Island 12m design for an aft-mast rig. I think its going to work out real nice. I think this vessel design has lots of potential. I'll post some sketches soon.

Solitary Island 12m (http://www.australiancompositepanels.com.au/Solitary%20Island%2012.htm)

bearflag

11-21-2011, 03:51 PM

Chris White Atlantic 47, MastFoil (http://www.boatdesign.net/forums/multihulls/chris-white-atlantic-47-mastfoil-40670.html#post502801)

Pretty cool design, from Chris White.

http://www.chriswhitedesigns.com/assets/images/banner_mastfoil_text3.jpg

brian eiland

12-12-2011, 04:08 PM

Originally Posted by Mick@itc
How very interesting. The design I am working on is a polycore aft mast design. I believe Lyra is polycore too. I need to share a cup of coffee with Ian!

The more I look at the aft mast set-up the more sense it makes for a cruiser.

Mick

Hey Mick, would a nice Polycore 40 footer in kit form do you?

I'm working on a modification of the Solitary Island 12m design for an aft-mast rig. I think its going to work out real nice. I think this vessel design has lots of potential. I'll post some sketches soon.

Solitary Island 12m (http://www.australiancompositepanels.com.au/Solitary%20Island%2012.htm)
Here are a few rough sketches for a general idea....(NOTE: forestays are not correct, backstays aren't there, etc...just rough idea)

Bruce Woods

12-13-2011, 01:03 AM

Here are a few rough sketches for a general idea....(NOTE: forestays are not correct, backstays aren't there, etc...just rough idea)

Ok Brian, I've lurked here for a while wondering what the attraction is too the aft mast no main sail rig.

Obviously you have many thousands of blue water miles up with one of these rig types , and have seen its many virtues in action.

Can you post some pictures of your boat, maybe in exotic locations, so that we can all see it in action on different points of sail, or direct me to some pictures already posted of your boat.

As a long time cruiser I can see the virtues of the Prout style rig with a fully battened main. A fully battened main is very close winded when motor sailing and doesn't flog when luffed, and most importantly doesn't get fuller in the puffs through forestay sag. I have found large headsails on roller furlers to be very inefficient when partially furled irrespective of how much money one throws at luff foam etc. The flogging sheets of a headsail can do a fair bit of damage when released to furl. The small main, single line reefing and full length battens , contrary to what is written on wikipedia is a very manageable sail.

Surely the extremes of cruising rigs , either no main and large headsails, or large main and no headsails is exactly that, extreme. For the life of me I can not see the positives out weighing the negatives for either extreme. Surely the right mix for cruising lies in the middle somewhere.

With no fully battened main the motorsailer is missing out on the stabilizing effect and/or drive from sail power over probably around 100 to 120 degees of the compass rose going to windward depending on wind strength, and around 20 degrees each side of dead square unless using a pole and preventers down wind. Having read the anti boom garbage on wikipedia I can't believe you recomend a pole and preventers for your headsail rig, or do you?
Regards

Spiv

12-14-2011, 07:44 AM

Having read the anti boom garbage on wikipedia I can't believe you recomend a pole and preventers for your headsail rig, or do you?
Regards

Hi Bruce, I have not read the Wikipedia article you refer to (nor have intention to) but you can read a lot of interesting and thought provoking ideas here: http://www.boatdesign.net/forums/multihulls/main-less-rig-21274-4.html

brian eiland

01-28-2012, 02:00 AM

I just wanted to add a link to this discussion that could offer some interesting possibilities for the roller furling mizzen sail on my aftmast design

http://www.boatdesign.net/forums/sailboats/square-top-mains-9668-5.html

brian eiland

01-28-2012, 02:09 AM

I was looking thru some older material on one of my computers and found this photo that someone sent to me in the past. It was their experiment with my rig design.

But I can't find the correspondence that came with that photo? Any help out there to ID this project?? ....I think it was a steel monohull

Silver Raven

01-28-2012, 05:17 PM

Ok Brian, I've lurked here for a while wondering what the attraction is too the aft mast no main sail rig.

Obviously you have many thousands of blue water miles up with one of these rig types , and have seen its many virtues in action.

Can you post some pictures of your boat, maybe in exotic locations, so that we can all see it in action on different points of sail, or direct me to some pictures already posted of your boat.

As a long time cruiser I can see the virtues of the Prout style rig with a fully battened main. A fully battened main is very close winded when motor sailing and doesn't flog when luffed, and most importantly doesn't get fuller in the puffs through forestay sag. I have found large headsails on roller furlers to be very inefficient when partially furled irrespective of how much money one throws at luff foam etc. The flogging sheets of a headsail can do a fair bit of damage when released to furl. The small main, single line reefing and full length battens , contrary to what is written on wikipedia is a very manageable sail.

Surely the extremes of cruising rigs , either no main and large headsails, or large main and no headsails is exactly that, extreme. For the life of me I can not see the positives out weighing the negatives for either extreme. Surely the right mix for cruising lies in the middle somewhere.

With no fully battened main the motorsailer is missing out on the stabilizing effect and/or drive from sail power over probably around 100 to 120 degees of the compass rose going to windward depending on wind strength, and around 20 degrees each side of dead square unless using a pole and preventers down wind. Having read the anti boom garbage on wikipedia I can't believe you recomend a pole and preventers for your headsail rig, or do you?
Regards

G'day cobber. In all your searching - Bruce - have you come across anyone who has costed these rig 'improvements'?

Brian that pic - is not good advertising - looks like a junk boat in a junk slip-yard. No offence ment!

Notice the Atlantic 47 - that someone says is 'nice' - yeah RIGHT but has anyone costed it & can they show that 'said' cost is justified. They all look extremely expensive to me & rather 'over' complicated.

I thought the idea of cruising was to 'keep it super simple' & cost effective & easy to use - or have I missed something here?

What we need in here it a qualified sailmaker - to properly explain the cost effectiveness of all the various sail combinations over a 15 year period of time for the general cruising people. Yes? - No? Ideas people? Ciao, james