WishBone Sailing Rig

[brian eiland]

HELP in finding the owner (or ex-owner) of this vessel.

I just posted in the gallery a photo of an unusual wishbone- shaped sailing rig. There were two vessels built similar to this one.

I am in touch with the owner of the 'shorter variation' of this rig, however we would both like to talk with the present owner of this particular 'taller version' of the rig. It was last spotted in the NW (Oregon I believe) USA, and I received some photos of it. However I am unable to contact the gentleman who sent me the photos ,nor the person(s) who have physically sailed on this vessel.
Thanks for any help.

[brian eiland]

The photo had not been posted when I first wrote this message.

It has now:
http://www.boatdesign.net/gallery/showphoto.php?photo=1075&password=&sort=2&thecat=995

[brian eiland]

http://www.boatdesign.net/gallery/data/500/medium/399WishboneMast.jpg

Still looking for someone who knows a person onboard this vessel............north west USA

http://www.boatdesign.net/gallery/showphoto.php/photo/1075/password//sort/1/cat/500/page/1

[SailDesign]

Ouch! My eyes hurt....

Sorry, Brian - couldn't resist. :)

Steve "North-East and therefore useless"

[brian eiland]

I do understand your observation Steve, but sometimes we have to stay open minded when considerting new ideas.

I'm trying to think back to those days when Olaf Harken was pushing some rather radical ideas with his bi-pod mast design onboard the "Procyon" vessel. I would note that Procyon's rig was aesthetically much more pleasing.

My interest in this other 'wishbone' mast rig is more aligned with the fact that it is an all headsail rig. I was seeking both positive and negative comments from a person who has sailed the vessel.

I was hoping to attach a particular overhead photo shot of Procyon, but I had trouble figuring out how to do that on this forum format, as well as a software problem on my computer that seems to want to keep me captured in their freaking format.

[SailDesign]

Brian,
That was NOT intended as a slight. Really...
I had a couple of sails on Procyon when she was in Newport some years back. An interesting concept, with nothing on board that did not function as desired. The swing keel concept was at the heart of my Black Sea 40 design, and will continue to be my "shifting-ballast-of-choice". The bipod rig was unusual, but functional, and certainly cut down on the amount of wire on the boat. Was it better? Not sure - but I'm not a fan of roller-reefing mains to start with.
You may want to call Gary Hoyt in Newport to discuss mast-aft rigs. He dabbled with those some 16-18 years ago, both on his little Delta, now on the hard in front of the Museum of Yachting, and on various smaller boats. He no longer draws them, but I don't know whether it is from a lack of commercial interest, or from a practicality point of view.
While I don't know Gary very well (read "hardly" - we have talked to each other, but that is about all) he always comes across as someone who would be willing to discuss ideas that he has played with. I don't feel cmfortable just giving out his number, but he is the only "Hoyt, Gary" in the phone book. :)

As far as new ideas go, I am very open. I admit to having reservations about the mast-aft concept, though. In "borderline" weather (as in "borderline survival"), are you going ot be able to get the head off the wind if you need to? All the rigging on the ass end would seem to indicate you'll have to take stuff head-on without resorting to a bow-thruster. Is the moderately higher efficiency of the rig really going to overcome the extra windage of the "aft shrouds"? Most impoortantly, maybe, are the General Public in their infinite wisdom (probably joking there...) going to accept the concept?

Steve

[brian eiland]

Lets see if this works for now


http://attachments.postoffice.net/tpl/Attachment/123TSOXYI/PROCYON.jpg?FileName=PROCYON.jpg&Q=426iFsPGY2576S01&O=1895&ContentLength=104971&DownloadID=DAIB

[brian eiland]

Brian,
You may want to call Gary Hoyt in Newport to discuss mast-aft rigs. He dabbled with those some 16-18 years ago, both on his little Delta, now on the hard in front of the Museum of Yachting, and on various smaller boats. He no longer draws them, but I don't know whether it is from a lack of commercial interest, or from a practicality point of view.
While I don't know Gary very well (read "hardly" - we have talked to each other, but that is about all) he always comes across as someone who would be willing to discuss ideas that he has played with. I don't feel cmfortable just giving out his number, but he is the only "Hoyt, Gary" in the phone book. :)

You might note that I originally published this mast-aft idea in Multihulls and Yachting and Rudder back in 72-73 time frame. It was shortly after this that Gary came to the Annapolis Show with one of his mast-aft vessels.....so we were working on theme concurrently I guest. I talked briefly with him then, and on several other occassions. I always appreciated his willingness to experiment, and his abilities of getting the word out (I think his backgrd was marketing).

Its a real shame that he has apparantly resisted the computer age, and does not participate on the forums etc. he has such a marvelious way with words. I tried to get several of his associates, neighbors, etc to get him involved with the internet, but I guess the call has gone unheeded.

As far as new ideas go, I am very open. I admit to having reservations about the mast-aft concept, though. In "borderline" weather (as in "borderline survival"), are you going ot be able to get the head off the wind if you need to? All the rigging on the ass end would seem to indicate you'll have to take stuff head-on without resorting to a bow-thruster. Is the moderately higher efficiency of the rig really going to overcome the extra windage of the "aft shrouds"? Most impoortantly, maybe, are the General Public in their infinite wisdom (probably joking there...) going to accept the concept?

I guess I'm just not ready to give up on the idea yet. No doubt it has been a struggle to get any recoqonition of the possibilities of this rig. There are little hints here and there from various trials, but almost all (including Hoyt) placed the mast at almost the very stern and thus were unable to maintain good forestay tension.....bad for maintaining headsail shapes over a wind range.

Public acceptance. Boy there's a tough one.....I'm sure Gary could add a lot to this. I really feel I am going to have to go to Europe to arouse any real interest in my project. In general they are much more open to new ideas.

[brian eiland]

Does anyone remember Hoyt's "Manta" vessel? This vessel had an 'A' frame mast (don't think it was leaning forward) with a 'winged' style hull. I believe this vessel preceded his Delta vessel with the mast aft.

Does anyone have an old brochure of this vessel, or any literature/pictures of same?? I would very much like to receive some photo material on this vessel. The Newport library did not send me anything on this vessel design when I inquired of them on Hoyt's designs.

[SailDesign]

Brian - the boat was built by Tillotson-Pearson in Bristol, RI (could be Warren RI, they're right on the border). That MAY be willing to have a look in the archives for you. Sadly, no contact there any more.
Steve

[SeaDrive]

Phil Bolger has also tried this sort of rig. His experience was that it was capable of great bursts of speed but he and his friends were unable to make it perform consistently. Comments in his books 103 Boat Rigs and Boats With An Open Mind.

The rig used on the Prout catamarans is not so very different, but they include a small main just to make everyone think its a ususal sort of sloop.

[mark ashford]

Here's a looking design I've looked over but not sailed in Bristol, UK. Photo under link to delta rig yacht. She carries two big genoas and provision for a fisherman's stays'l (?) in between. The owner is a bit cagey about into wind performance but says she goes well on a reach or run.

www.bristolyachtbrokerage.com

[Steve Clark]

This may be one of those ideas that hasn't worked in the past because of material limitations. I think the masts have ended up being very heavy and loaded with spreaders and wires because there is so much compression in the rig. Driven by the need to set a tight forestay on a very long foretriangle. I think this has resulted in rigs that have more weight aloft and rigging drag per square foot of sail area than more conventional sloop or cat configurations.
Problems that won't go away are the inefficiencies of boomless sails when reaching or running and the balance problems( lee helm) that occurr when shortening sail.
Bipod masts never appealed to me. Once you got the luff wire of the main tight enough, the compression on the spars made them heavy. Annd you still have more windage than you want.
SHC

[brian eiland]

Sorry going to have to be very brief answer this morning;

This may be one of those ideas that hasn't worked in the past because of material limitations. I think the masts have ended up being very heavy and loaded with spreaders and wires because there is so much compression in the rig. Driven by the need to set a tight forestay on a very long foretriangle. I think this has resulted in rigs that have more weight aloft and rigging drag per square foot of sail area than more conventional sloop or cat configurations.

In past experiments this does appear so...excessive heavy rigging, etc. But I don't think you would describe Procyon's rig (http://www.boatdesign.net/gallery/showphoto.php/photo/2094/sort/1/cat/500/page/1) in those terms. The legs of the mast replaced the spreaders and shrouds of the traditional rig. This rig actually turned out lighter in weight to the traditional rig.

I don't understand your reference to a 'very long foretriangle' . Neither Procyon nor my mast-aft rig carries a longer forestay. Note that my masthead is located approx where the traditional sloop rig would place it. I will have more to say on another related issue concerning the superority of some aft-raked mast rigs (and with long forestays) (and from actual full size sailing experiences)

Problems that won't go away are the inefficiencies of boomless sails when reaching or running and the balance problems( lee helm) that occurr when shortening sail.

Where do you derive this conclusion that boomless sails are more inefficient? In fact, very often the boom misforms the ideal shape of the mainsail....in addition to other misgivings. Granted a boomless sails (mainsail) may be more of a challenge to get really sheeted ideally, but the payoffs can be significant. Otherwise just get it close as most 'cruisers' do and be happy about not having to dodge that big heavy swinging boom.

Balance problems?? I assume you are referring to my mast aft design? This is a ketch variation, not a sloop or cutter. I venture to guess this rig will not only balance better, but have a greater range of balance positions, and not be one that will drive your bows down with such force when off the wind.

Bipod masts never appealed to me. Once you got the luff wire of the main tight enough, the compression on the spars made them heavy. And you still have more windage than you want.

Bipod mast didn't necessarily appeal to me either, but Procyon's one is rather elegant. Roller furling mains do require a little more luff tension than std ones. But this load is actually trying to 'spread' both legs of the bi-pod apart. So our 'inner spreaders' (cross spreaders) are only going to have to resist a pulling apart of the two legs (tension load). These inner spreaders can now be made of the newer hi-tech synthetics, and thus smaller in cross section and drag.

Another view of the subject might be that these bi-pod mast sections are pre-disposed to bend in one direction, so restraining them is easier than trying to keep a straight single mast tube in column that wants to bend in either direction when under a compressive load.

So now do we really end up with more rigging drag??

Couple of other points:
Yes because the rigging is more aft than conventional it will induce a weathering effect. But look at where the 'heavy weather' sail is rigged.....on the inner forestay.....balance.

Procyon's extra rigging drag was more forward inducing a lee helm...not a feature one wishes in very heavy air

And at anchor this rig will have less tendency to sail around its mooring as it has its drag center aft of its hull center.

Wing and wing downwind is easily accomplished.

I did not like the fact that Procyon's headsail had to be self tacking and thus non-overlapping. I felt this feature lost much of the extra efficency potential of the headsail.

AO Smith's paper on......sorry have to go

[grob]

If you are going to all the trouble of having a bipod mast why not put a main on each mast?

[SailDesign]

Brian,
I think what Steve Clark is referring to by the "less efficient when reaching and running" is that a boomless sail cannot be let out an keep a good shape as easily as one with a boom. Take a nice big genny, and let it out when broad-reaching. Does the shape look or act efficient? Now stick a reaching pole in there (a loooong one:)) and you will begin to get a better shape. Add a downhaul or two, and you are again improving the shape. The simple way to achieve this is to use a sail with both a boom and a vang :) It's called a mainsail.... <sorry - couldn't resist that lst one...>

Bipod masts must, by their nature, take more compression. The angle to vertical is narrower, so the resultant tension in the windward 'pod caused by the side force will be much higher than in a conventional spar (OK, "Much" may be a bit far) and thus the compression in the other 'pod will be similarly higher. Take a calculator and check it. I did.

Steve

[Steve Clark]

I was refering to the headsail only designs, which have their masts stepped way aft. In order to acheive headstay tension, the backstays have to be set up VERY hard. The difference between the staying base aft and forward works by the old cosine of the angle, so if you have a very long "J" equal to something like 85% of the length of the boat. you arew going to have to wail on the backstays. That turns into compression in the mast, which either grows in diameter or in shrouds and spreaders to take the buckling load.
Mainsails may do many things wrong, but they do hide a mast pretty well from an aerodynamic point of view.
Jibs twist when you ease the sheet. They also camber beyond what is reasonable, so they aren't efficient reaching and running sails without some sort of boom and vang system.
inally, maintaining balance as you shorten sail. As a jib gets smaller it moves further forward. This happens with cat rigs as well, so that once you are well shortened down, the boat has lee helm. In big breeze trying to get to windward, this is very bad and unsafe. One reason to have a little mizzen back there.
I'm not dissing anything, just offering observation based on some experience in the feild.
SHC

[brian eiland]

Jibs twist when you ease the sheet. They also camber beyond what is reasonable, so they aren't efficient reaching and running sails without some sort of boom and vang system.
I think what Steve Clark is referring to by the "less efficient when reaching and running" is that a boomless sail cannot be let out an keep a good shape as easily as one with a boom.

Brian wrote:
Not exactly 'boomless', rather wishboned-boomed mainsail:
Kind of interesting comments on the shape of this alternately boomed mainsail........Tom Wylie's new ketch rigged vessels....
_________________
* From Chuck Hawley (Regarding Fred Roswold's comments on Randy Repass's new boat, Convergence): I think there may be some misunderstanding on the need to reef this powerful cat ketch. I sailed on Convergence several times with Randy and Sally-Christine before they departed for French Polynesia, and we reefed the main on both occasions, although at higher windspeeds than might have been the case with a conventionally-rigged boat. The winds in Santa Cruz in the early summer are generally around 20-25 knots a few miles offshore, and we saw over 30 knots apparent. I think the point is that the unstayed rigs depower with each puff, bending off to leeward without actually flogging the sail, so that the rig appears to select the correct "gear" for the conditions. Owners of Wylie cats have reported this for years; now Wylie ketch owners are experiencing it!

What's really exciting to me is to see how perfectly both sails set without the intrusion of a boom along their feet (foots?) The wishboom booms create a sail which looks efficient from luff to clew, much more like a genoa than a conventional mains'l. We were able to hit 13.6 knots on a broad reach with excellent control, and with a very broad range of downwind angles that could be sailed without risking an accidental gibe. Truly an innovative and powerful boat.
___________________
Notes:
1)This reference is to a wishbone boom rather than the wishbone mast of the original posting subject.

2)Interested parties might also visit the discussions of 'loose footed mains' at
http://www.boatdesign.net/forums/showthread.php?t=2595

3)Have a look at these two vessels sailing on a reach and tell me whether it appears as though their headsails are working in more unisonal (harmonious)manner than the headsails with the mainsail??
RANGER http://www.boatdesign.net/gallery/showphoto.php/photo/2157/sort/1/cat/500/page/1
WINDROSE http://www.boatdesign.net/gallery/showphoto.php/photo/2158/sort/1/cat/500/page/1

I'll have more to add to this discussion of these photos and this boomed-main subject at a later date, and probably under a different forum subject heading.

[SeaDrive]

I think the point is that the unstayed rigs depower with each puff, bending off to leeward without actually flogging the sail,...


I remember a review of a Hunter Vision in one of the glossy magazines. They complained that the sagging of the unstayed mast in a puff contributed to weather helm.

They also went out of their way, as I thought, to slam the boat as a 'bay sailor'. Hard to believe they approached the review of an unstayed cat-sloop with an open mind. Hunter responded with a vigorous defense of their rig engineering, as might be expected. No one spoke to my question which was which berth would be suitable for use at sea.

[Suede]

Hi, just popped into this site: http://www.barefootsworld.net/windwalker/voyagephotos.html
one of yours Brian ?
rgds O

[brian eiland]

....one of yours Brian ?

It is not. This fellow picked up on my idea and built one....all the more power to him for being that resourceful. I wish him the best, althought I have some concerns about his rigging arrangement, particularly at the point where the 'aft spreader' pushes forward on the mast.

I have written the fellow asking that he keeps us informed of his trials. I was a bit disappointed that earlier on he copied portions of my website text onto his website without giving me any credits at all. And I have some concerns about his sea experience, and particularly with a 'new' rig.

Lets hope all goes well. I think he plans a transatlantic soon.

[Suede]

You´re right, North Atlanic crossin aug/sept might not be the best way to test a new design/boat...not much abot any handeling problems in the log so far. Should be interesting to follow.
Sailing near cost with a lot of tacking and changing winds, how is this rigg to handle compared to a Bertmuda type? "It doesn´t look like a self-tacking type..."

rgds Olle

[brian eiland]

....
Sailing near cost with a lot of tacking and changing winds, how is this rigg to handle compared to a Bertmuda type? "It doesn´t look like a self-tacking type..."

Are you asking about mine or his??

On mine,the mainstaysail and the mizzen on my rig can both be self-tacking. And the mainstaysail can be a battened, hanked on sail as well.

From my discussion on the website;

8) A rig that can be operated without leaving the cockpit. One single person could sail this fairly large rig from anchor up to anchor down. All the sails roller-furl, and the mainstaysail & the mizzen both can self-tack. Only the genoa needs to be tacked over, and this could be delayed until the boat has come about. Even motorsailer folks should appreciate this rig.

....just let the genoa lay against the mainstaysail during the tack, then pull it around upon completion.

....and if you anticipate a lot of tacking and you don't wish to handle 3 sails, just roll up either the mainstaysail or the mizzen.

[Suede]

Yes, I asked for yours....thanks for the reply. I´ll check this out further.
rgds
Olle

[Suede]

Brian, ´maybe you already looked into this, the documentation from Paasch Marine on "Diomeda Exulans"...the other mans boat....
http://www.bgsu.edu/colleges/library/hcgl/glms0045.html

rgds
Olle

[MikeJohns]

I would hate to try helming this running under bare poles. Keep it out of the southern ocean, wouldnt survive.

[brian eiland]

I would hate to try helming this running under bare poles. Keep it out of the southern ocean, wouldnt survive.
Brian ask:
What specifically are your problems with this rig under bare poles?
And why wouldn't survive?
(Regrettably I may not be able to respond again until I return from Thailand in two weeks)

[MikeJohns]

What specifically are your problems with this rig under bare poles? And why wouldn't survive?

If you were unable to carry sail the windage would be right aft, control would be lost very quickly, the boat would sail backwards pointing into the oncoming seas with no rudder control. Scary thought

[manta clipper]

Does anyone remember Hoyt's "Manta" vessel? This vessel had an 'A' frame mast (don't think it was leaning forward) with a 'winged' style hull. I believe this vessel preceded his Delta vessel with the mast aft.

Does anyone have an old brochure of this vessel, or any literature/pictures of same?? I would very much like to receive some photo material on this vessel. The Newport library did not send me anything on this vessel design when I inquired of them on Hoyt's designs.
We have a Manta, Hull #2, in Narragansett Bay. Also have some printed info on the vessel. But, would like to have more info.

[JimCooper]

Brian Eiland

I met a yacht at sea of the azores with a bipod mast it was in the normal ,mast position for a cutter , fabricated from carbon fibre wing section about 300mm wide, italian designer the main was on a luff wire two headsails the mast was canted back by around 15 degrees. We were both becalmed at the time I took photos but the camera was wonky sorry. Designer I think was a gentleman called Sobrero, if this helps.

The crew were delivery crew mostly spanish and french so my interview was shouted and patchy.
Probably not the design you wanted reading back but interesting all the same.

Cheers
Jim

[brian eiland]

I have recently received some Emails that reference a couple other examples of 'wishbone', or 'bi-pod', or 'A-frame' shaped masts. So I thought I would post them here for reference to the discussions.

1)The Valkyrie catamaran
http://www.stevproj.com/Carz/XBoats2.html (http://www.stevproj.com/Carz/XBoats2.html)
...excerpt, The rig was a bipod of 36' aluminum tubes which could be raised or lowered in 15 minutes (we had a lot of practice by the end of the project). There were four sails: two jibs on Harken roller-fouling (which worked nicely), a staysail on a central catwalk between the cabin and the front crossbar, and a loose-foot, fully-battened main flying on a luff-wire from the cabin.

2)Kolika monohull motorsailer
http://sail-works.com/KOLIKA/html/kolika_10.html (http://sail-works.com/KOLIKA/html/kolika_10.html)
...have a look thru the picture gallery, http://sail-works.com/KOLIKA/html/picture_gallery.html
...excerpt, Pros and Cons of an A- Frame Mast-System
Analyzing the compression loads on a mast, you will find that an A- Frame Mast will only see half the compressive load compared to a single mast. That allowed us to build lighter masts than a single wooden mast, which would weigh about 600 lbs. - ours being only 200 lbs. each. The extra windage is greatly reduced by foil shaping the mast. An A-Frame with the genoa overlapping the mast, has an another benefit: we can sheet in the genoa closer than on a conventional rig where the protruding spreader usually prevents it. The A-Frame mast rather conforms to the angle of the sail. The ease of unfurling both sails made us take advantage of almost every puff of wind. Even when motoring the mainsail is controlled by a light weight wishbone boom that is completely out of the way. The only disadvantage may be, that you can not control sail shape with as many adjustments as on a conventional mast. You can tighten the stay by hand wheel right below the Harken Furler for flattening the sail or tighten the outhaul via a double Pulley tackle from the clue to the end of the Boom. No other adjustments needed. The 2 short whisker poles can be pre-rigged in special chokes on the bow Pulpit so that you can even single hand a spinnaker with Sock or fly 2 same size genoas.

...this rig certainly reminds me of the original Procyon rig configuration
http://boatdesign.net/forums/showthread.php?t=10771 (http://boatdesign.net/forums/showthread.php?t=10771)
and particularly this illustration, http://boatdesign.net/forums/showpost.php?p=79362&postcount=3 (http://boatdesign.net/forums/showpost.php?p=79362&postcount=3)

[Pericles]

Brian,

Reading the Steve Clark comments July 2004 about the difficulty of maintaining sufficient headstay tension with a forward raked mast, what about something like a flying buttress to prop up the mast. A lopsided "A" frame mounted longitudinally is one image or a fishing rod rest type of support with the feet located on the gunnels.

With reference to your wishbone boom mizzen sail, if the luff stay could be raked further aft, would the lift generated be beneficial to boat handling? As for down wind sailing when crossing oceans, would you consider a Kiteship traction sail? http://www.kiteship.com/outleader.php

Kiteship also had a link to the Bat Ship.
http://www.dcss.org/PopSci_May_06.pdf

Your articles are always worth reading and I look forward to seeing many more. You will have read the latest copy of PBB, I wonder if the Paraglass advertisment caught your eye. Their 3D fabrics could be applied to internally reinforce stitch and glue Epoxy/Marine Ply Composite monocoque hulls. The ParaGlass 22 infused with epoxy resin, scales in at 12 ozs per square foot and UK prices for the fabric are the equivalent of $5 per square foot. Greatly increased strength for very little weight and not too much money. http://www.parabeam.nl/

Regards,

Pericles

[brian eiland]

With reference to your wishbone boom mizzen sail, if the luff stay could be raked further aft, would the lift generated be beneficial to boat handling?
Negative, there would be virtually no lift generated this far aft.

As for down wind sailing when crossing oceans, would you consider a Kiteship traction sail? http://www.kiteship.com/outleader.php
Don't see a problem with these if you wish

[brian eiland]

By now many of you readers are aware of my affinity for the mast aft or aft mast (http://www.boatdesign.net/forums/showthread.php?t=623) sailing rig concept. For the most part I am content with this being a singular mast column, stepped a little further aft on the vessel, and canted forward approx 10 degrees.

However, I’ve had more than a few people interested in alternative rigs ask about my rig and bi-podded rigs in the same questioning. Now, I was always enamored with bi-pod mast rig aboard Olaf Harken’s ‘Procyon’ vessel (http://www.boatdesign.net/forums/showthread.php?t=10771). And this wishbone shaped mast rig (http://www.boatdesign.net/gallery/showphoto.php/photo/1075/cat/500/ppuser/399) in my photo gallery also intrigued me.

So here I present some variations of the mast-aft rig configured with a wishbone/bipod mast column. There is a wide based version, and a narrow based one. And with each of these there are two different spreader arrangements that affect the very important cap shroud angle. Modern mast and rigging materials could very well make these unusual rigs a viable entity

[yipster]

Brian, are these the pics mentioned in your gallery?
i more than agree on your filosofie and see planty of possebillity's.
for a power-sailer-cat (http://www.boatdesign.net/gallery/showgallery.php/cat/500/ppuser/690) i like to learn more on carbon tubes, pricing, perhaps a top bracket, forces, construction, paralel sails, drag, and much more

[brian eiland]

Brian, are these the pics mentioned in your gallery?
No, they are not. Somewhere on one of my computers there are some other photographs of that tall wishbone rig sent to me by a fellow out on the west coast several years ago...I just can't find them at this very moment

I also was contacted by the gentleman who purchased the shorter rigged version of this design not long ago, and I tried to encourage his participation on this subject forum apparently without success. When I get a little more time I will try to find him again.

I like to learn more on carbon tubes, pricing, perhaps a top bracket, forces, construction, paralel sails, drag, and much more
Sorry, never got into this detail on the subject as there was not a paying or buying client to do the work for.

[yipster]

thanks for the reply, take your time but remember i'm interested
like to work out my version of a perfect cruiser one of these day's
and it makes sence to be a bit more precise eventho its only for fun

[brian eiland]

The Valkyrie catamaran
http://www.stevproj.com/Carz/XBoats2.html (http://www.stevproj.com/Carz/XBoats2.html)
Don't know if anyone happened to have noticed their claim as to the pointing capability of their vessel?..."Ullman Sails had a hard time figuring out how to run full battens without a mast to push against, but they figured it out. The main really pulled well without a mast in front to screw up the airflow. The Valkyrie could outpoint any boat it came up against"

[brian eiland]

No, they are not. Somewhere on one of my computers there are some other photographs of that tall wishbone rig sent to me by a fellow out on the west coast several years ago...I just can't find them at this very moment

I also was contacted by the gentleman who purchased the shorter rigged version of this design not long ago, and I tried to encourage his participation on this subject forum apparently without success. When I get a little more time I will try to find him again.
Well he found me. I received a couple of eMails from him and most recently a couple of photos under sail.

[yipster]

thanks for the photo's, looks like a pure sailing machine
still wonder bout wishbone vs bipod, is that a boom on the second sail
is that a canvas cabin, like to hear more if possible
have to read up on matches on a valkyrie search (http://www.messing-about.com/forum/search.php?mode=results) first
did consider asking stevenson some things, i'm just not that far -yet-

[brian eiland]

Somewhere on one of my computers there are some other photographs of that tall wishbone rig sent to me by a fellow out on the west coast several years ago...I just can't find them at this very moment
Bonanza!! I found the photos of the tall rig version (http://www.boatdesign.net/gallery/showphoto.php?photo=1075), a whole bunch of them in fact. I'm going to think about the best way to display some of them rather than posting them all. Turns out they are the original photos themselves rather than images on my computer that were taken by, and so kindly supplied to me by Dennis Pickard.

And in the same paper file I found a lot more info on the bi-pod masted vessel Procyon (http://www.boatdesign.net/forums/showthread.php?t=10771) that I will also post once I scan the info

[brian eiland]

...And in the same paper file I found a lot more info on the bi-pod masted vessel Procyon (http://www.boatdesign.net/forums/showthread.php?t=10771) that I will also post once I scan the info
I posted this additional info and sent a letter to Olaf Harken. You can see his reply here: http://boatdesign.net/forums/showpost.php?p=112067&postcount=33 (http://boatdesign.net/forums/showpost.php?p=112067&postcount=33)

[brian eiland]

Well he found me. I received a couple of eMails from him and most recently a couple of photos under sail.
The new owner of the shorter version of these two wishbone rigs recently sent me this note:
message: I noted your thread on rigging loads (http://boatdesign.net/forums/showthread.php?t=2293). Enlightening in a candle in the wind sort of way. Thanks.

The designer of the Orca and Relentless Wishbone rigs was a Boeing engineer. I have not been able to find any of his published writings and did not know if you have a way to search the lit that I cannot.
Fred Greenway was his name. Died last year. Built this in 90 so should have been active in 60's and through maybe the 70's.

On occasion it seems to be more like an aircraft than a ship, but at times these forms are very much in sync Fair dinkum, Kojii Bangs

[brian eiland]

Sails very well in light air. Not had it over 15 kts of wind yet due to various refitting . Very responsive, tender only at the dock. Underway very comfortable ride. Cuts through 4-5 foot waves as advertised.

Windshield (1/2"acrylic bulb) disperses deck water over sides.

This hung at 22k - 11k in teh keel - 3/4 cutaway very Amerca Cup-like from 80's I guess.

Wishbone rig flex is a little difficult to get used to for a Bermuda rig sailor... about 2" to leeward mid wishbone (between 2 crossmenbers) at 20 degress of heel in 10-15 kts of wind. All sails out. Sorting that out before any venture into higher winds. Scary to some people. Not familiar enough with carbon yet to know myself what to expect in terms of how far it can flex before the big blow I hear so much about.

Yarns along luff of genoa were pointing up about 30 degrees as advertised. Bow hardly moves at all. Amazingly even ride.

Wing and wing was a bit of a challenge but works. Staysail tended to fly away with the boom.

Hydraulic steering takes a little getting used to but very sweet once you do.

This rig (vessel) is not for everyone due to long snug quarters below, but very fun to drive. Head room very good for me. I am 6' 4".

Sister ship is Relentless documented out of Klamath Falls - also Oregon.

More later. Still trying to get photos to work -

[Guillermo]

Brian,
Did you know this?:
http://www.barefootsworld.net/windwalker/aftmastsailingcalc.html
What's your opinion?
I've just found it.
Cheers

[yipster]

very good find Guilermo !
informative and handy, thanks for sharing

[brian eiland]

Brian,
Did you know this?:
http://www.barefootsworld.net/windwalker/aftmastsailingcalc.html
What's your opinion?
I've just found it.
Cheers
Yes Guillermo, this was brought to my attention a couple of years ago. Reference posting #20 & #21 of this thread:
http://www.boatdesign.net/forums/showpost.php?p=25602&postcount=20
http://www.boatdesign.net/forums/showpost.php?p=25653&postcount=21

[hk996]

Guilermo, how did you find that information? thanks for sharing it!

[Guillermo]

Be careful about the trustability of that calculator. The guy dismasted. Have a look at:
http://www.boatdesign.net/forums/showpost.php?p=113491&postcount=34
and, in general, to thread 113491
Cheers.

[brian eiland]

As I mentioned before I felt this discussion belong under the AftMast subect thread rather than here. But I felt I needed to defend the posting in both subject threads in case someone should not be aware of the other discussion

Did you find that in his logs? I've not read them as there appears to be almost no mention of the sailing capabilities of the vessel.

Yes, he says that somewhere, but it's difficult to find among the very long logs. The general feeling I got is that the boat as a whole was a complete disaster (And I have my doubts about the mental sanity of the man....)

As I wrote you in a private email, I also questioned the sanity of this gentleman, but that’s all another subject.

When I was first made aware of his original website and his rig calculator, I was very surprised at the exact wording on his site that copied the wording right out of my website verbatim. Here is a gentleman who never once had contacted me about this subject he had such a great interest in, nor ask any permission of me, nor given any references on his site back to mine. I wrote him a letter about these matters, which he chose to ignore answering, and instead took down some of his web pages from his site.

In that letter I also expressed some concerns about his interpretation of my design. I was particularly concerned about his lack of a resistance element to the forward force that will be generated by the upper aft facing jumper strut over which the masthead backstay passes. In contrast I have provided a triangulated (diamond) jumper strut arrangement to help counter this forward pressing force. I have also provided two additional backstays at this point to counter forestay loads.

…photo of vessel under discussion: http://www.boatdesign.net/gallery/showphoto.php/photo/6863/cat/500/ppuser/399 (http://www.boatdesign.net/gallery/showphoto.php/photo/6863/cat/500/ppuser/399)

In other words I was concerned about his variation of my design. But since he had chose not to communicate with me about my concerns, and since he had already built it, there was not much left to do but wish him the best. Maybe his mast section would stand up to the loads, but I seriously doubted it. I was also concerned about his disproportionably long, lower mast panel.

Another of my concerns was his use of three headsails. To my way of thinking this placed the headsails too close together to be practical. We know from past cutter arrangements that should we have the headsail and the staysail too close to one another it became difficult to maintain the trim on both such that they were always fully engaged. Plus, it became more problematic in a tacking situation. And he obviously had not sailed enough to recognize the balance that can be had with a jib-mizzen combination.

Your reference to the rig being replaced with a conventional one was rather brief, leaving the impression that this mast aft experiment was a total failure.

quotes: The guy wrecked close to Malaga…..He rerigged later with a conventional bermudan rig……Be careful about the trust ability of that calculator. The guy dismasted….The general feeling I got is that the boat as a whole was a complete disaster

I don’t think we can assume this just yet with the VERY limited information we have. All I see so far is a failure of a piece of ordinary rigging, “a Norseman backstay fitting failed, crystallized in the threads." That could happen with any rig. Certainly it appears to be a backstay component, and if he had only a single backstay with this 3-headsail arrangement that would be a real problem. But lets not condemn the mast aft concept in general based upon this flawed design experiment.

And finally I might even have to give some credit to this fellow. At least he went out there AND DID IT, more than can be said for many dreamers

[brian eiland]

The new owner of the shorter version of these two wishbone rigs recently sent me this note:
message: I noted your thread on rigging loads (http://boatdesign.net/forums/showthread.php?t=2293). Enlightening in a candle in the wind sort of way. Thanks.

The designer of the Orca and Relentless Wishbone rigs was a Boeing engineer. I have not been able to find any of his published writings and did not know if you have a way to search the lit that I cannot.
Fred Greenway was his name. Died last year. Built this in 90 so should have been active in 60's and through maybe the 70's.

On occasion it seems to be more like an aircraft than a ship, but at times these forms are very much in sync Fair dinkum, Kojii Bangs
Just today there were some photos of the taller of these two rigs posted by Mike Johns at this other subject thread.
http://www.boatdesign.net/forums/showpost.php?p=146456&postcount=27

...short rig under sail (on this subject thread)
http://www.boatdesign.net/forums/showpost.php?p=110510&postcount=39

A gentleman from Calif recently contacted me about his potential purchase of this taller rigged version. I put both gentlemen in touch with one another. We will see if we get future contributions from either of the two?

Opps, turns out Mike did not post the photos but rather a reference to a 'for sale' listing. Since these can disappear in short order, I'll extract some of the photos and post them here.

[brian eiland]

Just happened across this new vessel proposal by the folks who did the Dynarig. Look, it has two bi-pod masts

Rainbow Warrior III
http://www.gdnp.nl/project/index.php?cat=miscboot&boot=4

[yipster]

thanks for sharing and very interesting study, with such a rig and a heli who will suggest rainbow warior III may perhaps be a cat :P

[RHP]

mispost

[Squidly-Diddly]

http://sfbay.craigslist.org/eby/boa/425155864.html

[RHP]

Thats was my mispost...

http://www.yachtworld.com/core/listing/boatDetails.jsp?currency=USD&units=Feet&currencyid=100&boat_id=1699447&checked_boats=1699447&back=%2Fcore%2Flisting%2Fcache%2FsearchResults.jsp%3Fsm%3D3%26cit%3Dtrue%26currencyid%3D100%26luom%3D126%26man%3DNorth%2BPacific%2B%26slim%3Dquick&searchtype=

[kevin murphy]

Just today there were some photos of the taller of these two rigs posted by Mike Johns at this other subject thread.
http://www.boatdesign.net/forums/showpost.php?p=146456&postcount=27

...short rig under sail (on this subject thread)
http://www.boatdesign.net/forums/showpost.php?p=110510&postcount=39

A gentleman from Calif recently contacted me about his potential purchase of this taller rigged version. I put both gentlemen in touch with one another. We will see if we get future contributions from either of the two?

Opps, turns out Mike did not post the photos but rather a reference to a 'for sale' listing. Since these can disappear in short order, I'll extract some of the photos and post them here.

This wishbone design sailboat is now anchored at Marina Bay, in Richmond CA. It was not there in October, it has been there since I returned to Richmond a couple of weeks ago. I am a newbie to sailing, except for small boats on middle sized lakes in MN, so what do I know? But I saw this boat anchored at Marina Bay, and it is amazing. So I Googled "wishbone mast" (lucky guess) and ended up here.

The boat is very racy looking, looks like a totally custom design to this untrained eye, and it looks like it is built for speed. Performance? I have no clue. But I'm happy to see it here, not as a sailor but as someone who appreciates good design. The boat is beautiful.

I have no idea who owns it, but the Harbormaster at Marina Bay in Richmond CA could maybe help you out.

Someone put some serious money into this boat, by all appearances, so if you are really interested in this design, a follow-up would probably be rewarding.

[brian eiland]

There is a new owner of the tall rig version who only recently contacted me a few days ago (11/28/07). Hopefully he will visit this site and make some contributions to the discussion...I told him of this site

[multihullsailor]

Still looking for someone who knows a person onboard this vessel............north west USA

http://www.boatdesign.net/gallery/showphoto.php/photo/1075/password//sort/1/cat/500/page/1

Brian,

She was offered for sale recently on Yachtworld as a North Pacific 47 called "Relentless" lying outside of San Francisco, $ asking price equivalent of €47,000. I was / am interested in her, but never had any feedback from the broker and she is not offeed on Yachtworld any more. Have seven pictures from her, exterior and interior, if you are interested I could email them ;)

Best regards from sunny Cape Town
Roger

[brian eiland]

Hi Roger,
She has been purchased by this gentleman:

Hello Brian... My name is Art Lane. I recently purchased Relentless
which is the tall mast version of your 47' wishbone design, a North
Pacific 47. I live and sail around San Francisco Bay and will be
moving myself and the boat to port Townsend, WA this
Spring. Thank you for designing this fabulous craft. I am outfitting
it as a durable cruiser. Can you provide info on the builder, specs,
schema, history or specific wisdom? I'm particularly eager for a
comparison to the short mast version. Strictly for your amusement
I'll send you some photos of an over the mast flip tacking rig I
designed and use routinely, based on the crab claw sail.
Regards... Art

I made him aware of this subject posting, and hopefully he will contribute later on. I also corrected his misinterpetation that I designed this vessel, but rather it was a gentleman who worked for Boeing Aircraft

[brian eiland]

...latest email from owner of Orca (short rigged one)

Sorry for not posting directly, running out of time today. I am naturally intersted in talking with new owner of Relentless. We are now locate in Port Angeles after sailing Orca up coast and poking around inside waters this summer and fall. Shakedown went well, at least better than last ship I was on...an icebreaker with a shaft bearing problem in the Arctic - not a lot of fun.

Anyway I found out some interesting things and have had some "experts" on board to help me along and got it into some serious wind with all sails up (force 7-8), paced a few dozen classic yachts at the Port Townsend Wooden Boat Festival races, and from what we could see outpaced them all with just the Genoa up.

Boat is an amazing piece of work. All I can say is my wife would never give it up. She loves it more than I do. And I think congratulations are in order to you. Happy trails and passages. More later. May have a lead on who Fred Greenway was from some locals around here who knew him

[Kojii]

I have reviewed a lot of the observations and precepts/opinions and most everyone is "correct". Paradoxically, the boat sails well mainly because the hull is a racing hull. So this will never be a popular boat. Slack bilges, close quarters below, and tight deck space - but what a beauty in the slings....
The wishbone legs are bowed (cleverly), and require pre-loading, if you will, by the shrouds at the mid-arc to keep them from springing (they are afterall bows of carbon/kevlar/plastic). The wires do the trick as designed. As such the bowlegs of this mast act as shroudmasts with the wires performing the role of the string on a bow, only this string is attached in the mid-arc.
Shortening sail does result in lee helm but not a lot. I have not yet been able to get it to heave to. Still working on it. Fore reaches fine.
Tension loading is "extreme" I suppose. I have bent the upper mast back a few inches to get high tension of the forestay. Replaced some turnbuckles on aft stays but they were not badly worn. Rig is heavier than I would have liked, but necessarily so for strength. Still not much different from standard Marconi with same sail area and probably a little less weight depending or reefing of the Marconi reefing system. This is all anecdotal from my yard experiments, mainly involving my back, which has been a reliable tool thus far.
Aero-hydrodynamically speaking, the thing works well. I did hang it in the yard but the scale was broken...
Very comfortable ride to wind and on a reach she goes. Ran into the harbor last week with 20 knots of wind doing 8 knots without much fuss. Keeping the staysail boom down is a problem. I like sharpieII's ideas and observations.
Many of the observations of the individuals are right on and I appreciate the spirit of the discussion, unlike so many forums on the web, this one seems to keep it neat and respectful. I appreciate that more the older I get.
This will not likely ever be a "popular" rig for many reasons but primarily because it requires a very lean hull to take advantage. Most people just want real estate below and on deck. I do feel safer on it than on the vintage open 60 however. I know this one will come back up...

[brian eiland]

Does anyone remember Hoyt's "Manta" vessel? This vessel had an 'A' frame mast (don't think it was leaning forward) with a 'winged' style hull. I believe this vessel preceded his Delta vessel with the mast aft.

Does anyone have an old brochure of this vessel, or any literature/pictures of same?? I would very much like to receive some photo material on this vessel. The Newport library did not send me anything on this vessel design when I inquired of them on Hoyt's designs.

Over in a another subject tread Deepsix found this reference photo site with some pics of Hoyt's Manta

http://www.geocities.com/starcrew2000/photos/alibi/

...subject thread "Main-less Rig'
http://www.boatdesign.net/forums/showthread.php?t=21274

[deepsix]

I stumbled onto those pictures while searching for something else. They came from a thread called Performance cats 30-40ft, on Sailing Anarchys' Cruising Anarchy forum. There was only a little discuccion on the Manta, now called Alibi, so I doubt you will learn much more. I have included a link to the first post where the boat was mentioned, there seems to be a few people that know about the boat maybe you can find some info there.

http://forums.sailinganarchy.com/index.php?showtopic=55997&view=findpost&p=1521003

[brian eiland]

In going thru some older postings related to 'A framed' mast there was a refernce to some photos on a website that had only been recently taken down. I found the reference forum and ask of the poster if he still had the photos he had posted.

He just recently responded. Here are two photos of a vessel that crossed his path.

[Pericles]

Brian,

Can you see any benefit in moving the tack and luff of a mainsail to either port or starboard (on a deck mounted track), within the confines of an A frame mast fitted to a catamaran? The John Hitch catamaran has three individual head stays, rather than a track, for use as conditions dictate and I wondered about having the a similar facility for the mainsail.
http://boatdesign.net/forums/attachment.php?attachmentid=18787&d=1202813284

Granted the luff of the mainsail is vertical, whilst the luffs on the head sails are angled aft, but how much would this change in the angle of attack of the sails, within the dimensions of a catamaran, improve the upwind working, that is, if it does? Would such an alteration also remove the need for a boom as the mainsail would need not to be sheeted out so far, when broad reaching. This in turn would permit better site placement for the back stays. Just ideas! :D :D

Regards,

Pericles

[brian eiland]

Brian, Can you see any benefit in moving the tack and luff of a mainsail to either port or starboard (on a deck mounted track)..... Pericles
Sounds a bit like this tilting rig concept from Chris White:
http://www.wingo.com/chriswhite/tiltrig.html

Actually I can not see the benefit of moving the tack, nor luff of the main (Wait a minute, I take that back. There could be some benefits, but it complicates things even more).

If anything the Aero-Rig was pretty efficient at keeping a constant relationship between the jib and main.

[Kojii]

I could not help but notice a resemblance between Gary Hoyt's Manta and the ferry Damen "wave-piercing" hull design but called a Catamaran. Based on recent experiences of traditional catamaran ferrys here in Puget Sound the lean monohull sandwiched between fast cat hulls seems close to what Gary was doing with his Manta. Had the Washington State Ferry that dove into a "rogue" wave recently with poor results had this configuration it would have come out much better. They travel and the same speed - 30 knots. The one in Kuwait is the Ameer Alkoulous. The best of both worlds - a wave-piercing monohull that lifts out of the water when seas allow for it.

[Pericles]

In #66 I asked Brian about what might be the result by moving the foot of a mainsail ( either with or without a wishbone boom) to port or starboard on a catamaran. Here is my simply dreadful illustration of what I have in mind. The mainsail is difficult to identify and the ***king scanner is giving gype, so I cannot improve the image. Sorry about that!

If the sails run diagonally across the two hulls rather than down the centre line, could the hulls move through the water and edge more upwind?

It seems possible, but surely someone else has already tried this? All comments gratefully received.

Pericles

[Kojii]

Mike Johns posed a very interesting scenario early on in the discussion.
Disclaimer - I am not an engineer of any sort...

Control being the key...I know that many a standard Marconi sloop, ketch, catamaran, and trimaran have flipped in the southern ocean, and that many of them, if not all, were built by engineers who attested to their seaworthiness. None of them had single aftmasts that I know of. Why did they go over? Why did others just like them not go over? Did the bow drive and trip under the force of the pole driving it down? Did the lack of balance result in yawing and eventual broaching? Did the stern lift and the beamy slow boat fail to speed away from it?

Would the windage "right aft" (actually more like 25%) be sufficient to overcome the series drogue, the rudder, and 3/4 keel and deep narrow hull?
If the location of the stick is the primary directional actor in these conditions it might explain why so many boats with the mast 70% forward of the stern broach as they swing wildly about it. It would seem the only safe place to put the stick in such an environment is precisely in the middle where there is no turning force? And even better might be to get rid of the mast altogether, as some boats seem to do for themselves, clearing the decks with a rollover, surviving as a result.

By the assumptions about the location of the mast I guess the Wylie Cats would be good boats to go under bare poles in. Is that the case?

I would tend to agree with the assumption about mast windage and directional control, but I am not sure if it is tautologically correct - other factors being at play. i.e. if a drogue and rudder can keep the yawing to a minimum would the mast aft actually tend to drive a narrow and deep hull with more control than its counterpart with a forward mast? Look forward to other input. K

[brian eiland]

Kojii,
In your posting just above, I'm having trouble discerning what portion of the text applies to Mike John and what portion is yours. I also did not see these 'quotes' from MJ in the previous text of this subject thread, so I would ask to which thread they apply, so I can look at the thread context in which they were made.
Thanks, Brian

...and many thanks for joining the discussions. We all stand to learn something here.

[Kojii]

MJ's #26 in this thread was what I was referring to. I thought at the time it made a lot of sense.
"I would hate to try helming this running under bare poles. Keep it out of the southern ocean, wouldnt survive."
__________________
Mike Johns.

[MikeJohns]

Inherent danger in the aft mast rig?

Sorry Brian, perhaps I could have put that earlier post more eloquently

I think the Achilles heel of this type of rig is that the COE of the bare rig is aft of the CLR of the vessel. I think the designer must consider bare poles as the final shortening of sail and that balance is just as important in this condition (COE relative to CLR) as it is in any other.

Anyone trying to maneuver a sloop in the marina with a strong wind blowing will be aware of the effect of the rig placement.
In severe weather running off under bare poles is a good option, but an aft mast rig may make this option dangerous particularly in conditions such as experienced commonly enough in parts of the world where storms and very large seas can only be safely contended with at certain stages by running and actively helming.

My concern is that with the weather taken on the stern quarter and with the windage aft that it will add significantly to a broaching effect particularly as the vessel rises to the top of the crest as the wave rolls underneath. The vessel meets the breaker if present and also at the same time experiences the full force of the wind. In short I predict a hard time for the helm in the very conditions where astute downwind helming is the only control you have.

I know I’m talking of survival situations where no sail can be carried, but this consideration does not endear me to this rig arrangement. I like your newer rig a lot better.

[Kojii]

Not sure if my last post got through.
Your observations ring true. Tight marina slip approaches in with a beam wind require non-traditional rates of approach. One chance to get these right, but necessary to maintain directional control.
The prayer flags I ran down the aft edge of the wing masts (4-1 aspect) demonstrate clearly their sail-like qualities.
One non-traditional option with this two-foote mast, deck-stepped, with pin hinges would be to drop the mast on the deck before it becomes a greater hazard erect. Not easy to engineer, but possible. I am thinking airbags and explosive turnbuckles ...just kidding. Thanks for input. K

[Pericles]

Mike,

In a situation of running before a storm with bare poles, I would stream a drogue, so as to allow the following waves to slide under the catamaran. In those circumstances I don't think the aft mast will encourage broaching.

http://www.seaanchor.com/deltadrogue.htm

http://www.multihullpages.com/heavy_weather.html

Read Gary Pearce's answers questions about "Zazen", after his voyage from England to Australia. http://www.john-shuttleworth.com/owner.html He mentions a downwind leg.

Regards,

Pericles

[yipster]

thinking of wind, inertia, seaway etc how di or un-desirable would it be to strike a mast altogether, any rough guesses?

[Kojii]

I would have to say this is a drastic measure given the weight involved, wire attachments, etc. My point is simply that with a bipod it does become a real option because of the stance of the mast step - both feet on the deck as it were. So here we are again with the trade-offs. This is simply not an option with keep stepped masts and probably not with most deckstepped mast because they "stand" on one leg. This would only be feasible in a situation where you could get it down before the winds hit. It could not be done in the middle of the blow. One would have to know what was coming well in advance. A good designer could put this together on this rig without much trouble I am sure. Once on deck, strap it down and enjoy the ride....

[brian eiland]

Striking a mast while at sea should NEVER be considered, regardless of its being a single mast tube or bi-pod....besides its near impossible.

Good seamanship is the key to surviving a storm. There have been many different types of vessels that have been taken to sea and survived big storms. Each of these different type vessels have their own 'quirks' that must be accounted for in extreme conditions.

Some vessels may be better off running with a storm, some better off facing it. Look at the multitude of arguments for drogues verses parachute anchors. And look at the multitude of storm sail deployments that have been utilized over the ages. And how about the variety of multi-masted vessels. Or the differences in handling multihull vessels verses single hull ones.

So to condemn one vessel design in favor of another based just on its mast placement is not a fair assessment. If we did this we might have to proclaim that a aft-masted vessel would perform better in a sea-anchor (para-anchor) off the bow attitude than would a fore-masted vessel....probably so, but not necessarily.

I personally much prefer the concept of a bow deployed sea anchor in an extreme storm to that of running off under drogues. Eventually I am going to get real tired, and I much prefer some rest to constantly steering down the face of waves.The key is knowing your vessel and how it best reacts to the conditions of the sea.

Parachute Anchors, Para-Anchor, Sea Anchor (http://boatdesign.net/forums/showthread.php?t=10448)

[brian eiland]

...The wishbone legs are bowed (cleverly), and require pre-loading, if you will, by the shrouds at the mid-arc to keep them from springing (they are afterall bows of carbon/kevlar/plastic). The wires do the trick as designed. As such the bowlegs of this mast act as shroudmasts with the wires performing the role of the string on a bow, only this string is attached in the mid-arc...
Dear Kojii,
You mentioned at one time about the possibility of getting in touch with someone who knew the designer, Mr Greenway from Boeing Corp. I wonder if his widow would have some info? It's often that such papers of the deceased get lost to the world, as no one takes the time to dig them out from obscurity. Have you checked to see if he had a surviving spouse. I'm sure she would be more than willing to see her husbands work go to good use.

I would be very interested to see his observations on why he chose to use a 'bowed frame' for his bi-pod, and the subsequent use of additional shrouds and spreaders?? We might even run across his mast construction details. It would be interesting to see these details, as well as if there are differences between the tall rig and your shorter rig versions?

[rob denney]

thinking of wind, inertia, seaway etc how di or un-desirable would it be to strike a mast altogether, any rough guesses?

G'day,

Extremely desirable. weight and windage would be lowered, the boat would become a whole lot safer. However, getting it down at sea is not to be recommended and there is the problem of what to do if you need the rig in a hurry (ship, man overboard,etc).

My solution to this is a telescoping mast. This allows you to have as much mast as you want, when you want it. In a good breeze you reef the mast at the same time as you reef the sail. Many cruisers do not go upwind with a reef due to the drag of the rest of the rig.

The concept only really works on an unstayed mast, and is perfectly suited for a wing mast, There is a harryproa under construction at the moment that will have such a mast. Should be sailing by Xmas. I will keep you informed.

regards,

Rob

[yipster]

stil wonder how far striking and raising mast(s) stretches and can be really used in various conditions
thanks for speaking out guy's and yes plz do keep me informed on that or any telescopic mast rob
pete gosh is going to write a book on team phillips, guess he will also go into the masts in more detail

[Pericles]

The Lateen rig, when lowered, considerably reduces top hamper, which is why it has withstood the test of time. Dipping lugsails are also good in that respect, but in both cases, crew numbers are important. Short masts are easier to manage and be made freestanding :D

http://en.wikipedia.org/wiki/Lateen

http://en.wikipedia.org/wiki/Lugger

Old forms of sails and rigging systems are easily revived, if implemented using modern materials such as carbon fibre spars and Spectra.

Perry

[MikeJohns]

On a ballasted mono-hull lowering the mast in heavy weather is not a good idea since it will make a knockdown or inversion far more likely.

Some of these comments need to be clarified as to what sort of vessel they refer to mono or multihull.

I'd be interested if anyone has a cruising Cat say 40 to 50 feet Weights and moments. What happens to the radius of gyration with and without the mast? I presume that the loss will not be anything like the reduction for a monohull.

Typically a light 40 foot mono-hull roll period will drop from 4 to closer to 2 seconds without the mast. Even a heavy displacement 60 footer will drop to a 3 second roll period sans masts. Pretty uncomfortable and dangerous. The loss of inertial damping also makes the vessel more prone to violent roll knockdown etc.


As for aft masts, drogues helming running off etc:
Tactics must vary as the storm progresses and the sea conditions change. There’s no hard and fast rule for survival in extreme conditions. Surely every deleterious ‘quirk’ is just that, if the CLR is fwd of the COE for bare poles then the vessel is dangerously unbalanced in that situation IMHO.

Running under bare poles has been shown a very necessary tactic in some storm conditions, . Most vessels survive 'normal' heavy weather, some don’t, analyzing and making sense of the lottery has seen a lot of effort from people like Marchaj and more recently Cloughton et al at the Wolfston unit in the UK and Renilson and Deakin here at the Australinian Maritime college in Tasmania.

There has been some study on drogues in the wave tank here by Deakin I think. They have their time and place but they are not a total panacea.

I'd seriously think about some proper testing. My own opinion is that if the vessel has a strong inclination to swings bow into the wind then it has a very strong disposition to get into irons if bare headed. I don't like that thought since there are conditions that preclude carrying anything.
Solutions? I suppose you could use dagger boards right aft.

The iron topsail would be needed to you back after a broach, what about some high drag device for the forestay to shift the windage fwd in survival situations. Flog resistant and sheetless would be good. Of course you might go too fast then you'll need that drogue :-)


Cheers

[Nordic Cat]

what about some high drag device for the forestay to shift the windage fwd in survival situations. Flog resistant and sheetless would be good. Of course you might go too fast then you'll need that drogue :-)


Cheers

2 or 3 halyards to the bows would give some windage. About 45 N/meter at 40 knots for a ½" wire, so 3 halyards of 20 m each = 60 m x 45 = 2700 N

Maybe add some rode for a bit more?

Same effect as streaming lines:)

Regards

Alan

[Kojii]

Curious about the inertial changes with mast struck. Would the 50 % ballast be an advantage in this case. My seasense was that this vessel will roll badly (9' beam) with or without the mast up, but I can't see it being worse with the mast struck. Please explain. Thanks, K

[MikeJohns]

Kojii
It is a damped oscillatory system The frequency of oscillation depends on the mass moment of inertia. Inertia is the mass times the distance from the roll axis squared consequently the rig has more effect than you might initially consider.
It is also the reason a heavier rig can add considerable comfort by reducing the roll accelerations (designed for not retrofitted).

9 ft beam and 50% ballast then I think your rig is going to be even more important since the vessels GM is going to go through the roof sans mast. In other words it will become not just uncomfortable but even dangerous to be on deck.

In a W&M spreadsheet it’s easy to add the vertical components, calculate and sum the total rotational inertia.
Natural period is then easily calculated but you need to find GM pref from a hydrostatics package and add a hydro damping coeff based on keel area & hull-form.

[Kojii]

Thanks Mike, I suspected it would be something like that;) ...I tried computing the underwater profile once but ran out of steam. I estimated the full rig with furler - the whole - at around 1,100 lbs. I guess from my limited experience with the boat in a sea way I sense it would tend to do as you predicted with the aftmast in big following seas/winds. I always have felt very comfortable driving into the seas/wind so far on this boat because it does none of the pitching and slamming and reverberating that I have felt on most conventional "broadbeam", production boats.
Mast is only 48'. Does the two-footed, gunnel mounted aspect improve or diminish the roll concern? Thanks. Appreciate everyone's input much. K

[MikeJohns]

Kojii
You are welcome.
Gunnels, Bulwarks aren't going to make much difference to this.

[kenJ]

I haven't read the whole thread so this may be a duplicate. The original picture you posted was taken in Bremerton, WA. Hope that helps in the search.

[catsketcher]

Hello,

I remember reading an article in Australian Sailing about masts and roll moment of inertia. It is pretty common supposedly for people to become seasick after breaking masts as the boat then rocks like a motor boat. One quote came from a bloke who found it very hard to keep his footing after the mast broke.

My little folding cat can be rocked really easily when folded with no mast. Put the mast up and the period becomes much longer. Like a long rope on a swing rather than short one.

Think of the high wire trapeze artists. They hold a long pole to increase their roll moment of inertia. They take much longer with the pole to start falling either way and so can react to any unbalancing forces they experience.

cheers

Phil Thompson

[jop]

I own a tanton 43 and wish to change my wishbones for carbon fiber's ones, i have been told that the Nonsuch 354S use to have it, can anyone help me to locate the manufacturer
Many thanks
jop

[Kojii]

We did 35 degree snap rolls up the pacific coast in this boat (shakedown), spending some hours in the trough. I would have to say the effect of the mast inertia would seem a distant third when compared to angle of attack and speed. On a related comment - Davy Jone's Locker is littered with the bones of excellent sailors. I have sailed on an Open 60 of early vintage in enough wind to provide a sensation similar to that of the Laser I learned to sail on Lake Washington. I understand clearly how these big sleds came to be declared "unsafe". However good a sailor's skills, there is no substitute for a sturdy, sea-kindly vessel that can keep a mere mortal afloat, even after we make a tragic error. Slocum survived not simply because of this skill, which is undisputable, but because his vessel, when submerged off the coast of South America, came back up to the surface so he could climb back down out of the rigging.

[brian eiland]

Here's a new concept that combines the bi-pod mast and aero-rig combination.

...more concept sketches here:
http://www.yachtforums.com/forums/future-yachts-concept-boats/9115-future-concept-57m-super-sailing-yacht.html

[Kojii]

Brian, any idea on materials in the legs of that mast/shroud? A la modulus of elasticity. Like the hot tub or did they just fill the cockpit with water? K

[Nordic Cat]

4 "masts" plus 8-10 stays/shrouds, as well as those massive foils at the top has me thinking about the immense weight and windage of the rig.

Maybe the designer never tried calculating the windage. A 12 mm shroud of 1 m length generates around 450 grams of drag at 20 m/s ( about 1 lb of drag at 40 knots).

The cw or wind resistance co-efficient for the projected area of the masts is normally calculated at between 1.0 and 1.1, compare this to a well designed car that is around 0.24 or lower.

He would be better off using a traditional Ballestron type rig with unstayed masts.

Just my 2 cents worth

regards

Alan

[brian eiland]

Brian, any idea on materials in the legs of that mast/shroud? A la modulus of elasticity. Like the hot tub or did they just fill the cockpit with water? K
I think it is just a concept drawing at this time.

[brian eiland]

But here comes another entry to this bi-pod mast idea.

[brian eiland]

The photo had not been posted when I first wrote this message.
It has now:
http://www.boatdesign.net/gallery/showphoto.php?photo=1075&password=&sort=2&thecat=995

Here are some detail photos of the taller rig of these two vessels...I had misplaced them until recently.

Note the use of shrouds along with the bi-pod legs.
And their termination in line with a pivot point of the rig.

The mast appears to be forward canted about 7 degrees

[Kojii]

The new owner of Relentless found the performance in heavy winds to be unbalanced and has shortened the mast (to just above the notch) and canted it aft about the same it was canted forward and put a whole new rig on it (double furler with wishbone boom) after adding the skeg-hung rudder. Initial sail tests in the harbor seem promising - longer foot, lower CE, less compression on mast. More to follow I am sure. The experiment continues...Kojii

[Kojii]

Brian,

Best wishes for the new year. I have made some contact with - of all things - Mr 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. Wooden boat forum has interesting discussion on bendy masts and strength (i.e. resistance to failure). I think Fred was impressed with curves for shock absorbing abilities. My experience so far is that he was right. Not sure if it is catenary. But, as expensive as the curved ones are to build - try replacing a straight one. May eat these words some day, if so I hope with a little honey on them. Cheers, K

[gar37bic]

In going thru some older postings related to 'A framed' mast there was a reference to some photos on a website that had only been recently taken down. I found the reference forum and ask of the poster if he still had the photos he had posted.

He just recently responded. Here are two photos of a vessel that crossed his path.

Brian et al,
I believe this vessel is presently on the hard at Shaw's Boat Yard in Dighton MA - down the hall from mine. I am told the builder/owner sailed it around the world (singlehanded?) at least once. He has died, and his widow has put the boat up for sale.

I am wondering if I should be interested in this, or the Manta Clipper 34, which is also for sale near me. I'm looking for a liveaboard-caribbean boat, in the long run I might want to go farther.

IIRC it is 45 feet long. I was told that the hull is cold-molded wood. It has a shallow draft wing keel - to my untrained eye, something like a newer Catalina. I'm guessing at a six foot draft. It has a number of minor features that I have never seen on another hull - a sawtooth SS strip on the bow at the water line, a small black bulb (sonar?) on a stem hung from the bottom, just ahead of the keel, and a two-part rudder (steel?) - like two foils one after the other, at slightly opposing angles of attack.

[globaldude]

Hello Gar37BIC , hey just looking for any reference to Kolika - yacht in Dighton on hard - and was happy to see your post of her .
I have just placed a contract to purchace her and will fly over on the 5th of May to inspect her :). I remember seeing your towns name on the map while looking for Dighton .
Sounds like you have looked her over yourself . I didn't know about the " saw tooth SS bit on the bow .I think the owner , a Mr Klimmek, was a very clever guy and his attention to detail shows in the photos I've seen .

I've visited these forums for some years now and having a 50' steel hull in my workshop was intending to finish her then go cruising .
Old story , not enough years left to do all the things I'd like to do so, given the present hard times, its meant it's far cheaper to buy than build .

Acording to the map, it looks like it's only 30 odd miles from Boston [ where I fly into ] to Dighton and I imagine I could get a bus to there ??.
I'd appreciate your local knowledge as to the best way to get there ??.
Perhaps you'd like to look her over with me ?, I'm the kinda guy who likes to bounce things off of my friends when venturing out so as to get constructive critisism .
your thoughts please . --- somewhere here I think we are able to mail directly so as to not bore fellow members with non thread talk .
I'd like to say though , that should all go well and we complete the sale, I'd be real happy to give my thoughts and impresions of how this rig behaves in various conditions as we intend sailing her back down the east coast through Panama back to our Pond . pete , New Zealand.

[brian eiland]

Brian et al,
I believe this vessel is presently on the hard at Shaw's Boat Yard in Dighton MA - down the hall from mine. I am told the builder/owner sailed it around the world (singlehanded?) at least once. He has died, and his widow has put the boat up for sale.
Been away from all boating subjects for awhile (sabbatical). The two boats I remember discussing mostly were Orca and Relentless. Both were on the west coast if I remember correctly. So what is this vessel that is in MA?? Any pictures??

I have made some contact with - of all things - Mr 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
Be interesting to hear these stories.

[globaldude]

Hello Brian, we have talked before but it was years ago :) , below is an address for the home page of Kolika .
In looking her over I would be very interested in your opinion on the rudder and it's posible advantages/ disadvantages as I value your opinion having read your posts now for some years --- and Yipster , if you read this :) -- [you guys don't always see eye to eye but it makes for thought provoking reading ]
The late Mr Klimmek was , in my opinion, a very clever man and his attention to detail shows all over the boat ---- Rudder trim tab is able to be linked to wind trim tab [ no obtrusive wind self steering gear at the rear means easy boarding and dive ladder there now] , or GPS plotter . rear edge of pilot house has hand holds right across it [and right throughout the boat for that matter ] .
Yacht with design speed of 7.5knts has cort around prop - should be more eficient right , at least more protected in the waterways I'll be sailing.

Here's a goodie , the saloon table is set higher to allow better view for seated people but also allows big LOW draws under the [ now raised ] sole to stow those heavy goods such as canned foods or perhaps heavy hand tools .She has a shower/bath the lenght of which tucks under a hanging locker [ I think ] .
I see now from another post above that he has a " saw tooth SS edge right on the water line " I imagine for cutting floating lines -- good and real bad there eh !?.
I've no doubt I will find many more interesting features when I fly over to look her over shortly .Kolika was the last of several boats he had built and was , in his opinion, " the best of a lifetime collecting ideas for the ultimate cruiser " .
There's no such thing as the perfect boat - man - woman - horse [ I've owned 9 ] we all have good and average points and we live with our compramises eh .
I look forward to your opinion or that of any other member :)

http://www.sail-works.com/KOLIKA/index.html

[gar37bic]

Hello Brian, we have talked before but it was years ago :) , below is an address for the home page of Kolika .
...
I've no doubt I will find many more interesting features when I fly over to look her over shortly.
There's no such thing as the perfect boat - man - woman - horse [ I've owned 9 ] we all have good and average points and we live with our compromises eh .
I look forward to your opinion or that of any other member :)

http://www.sail-works.com/KOLIKA/index.html
Globaldude, I just now saw that you had posted back in March, and were going to see the boat. I'm sorry I didn't get the message - I will have to check to see if I am getting email notifications. I would have enjoyed seeing the boat with you. I also know (from the boatyard that 'someone from New Zealand came to look at the boat' a while back but didn't buy it. Was that you?

I took a good look at the boat this weekend. It's a very complex boat from a systems perspective - electrics, hydraulics, mechanical, you name it. I think of it as an "engineer's boat". That turns a lot of people off, and rightly so - more systems means more maintenance, more hanging upside down in the bilge in the middle of a gale. But that's OK with me - I'm a geek anyway, more familiar with that stuff than with the boat itself! :) My interest is as a liveaboard sailor, and this boat has capacity and durability - and it's more ocean-capable than I am. So I'm thinking of making an offer. I'd like to know what you didn't like about the boat.

[gar37bic]

PS - You've owned 9 --- what? !?!?! was that women, horses, boats, or all three? :)

[brian eiland]

I'm sure this vessel reference has been posted before, but in looking thur some old postings of mine, I did not see it in these particular discussions

50 SMG Catamaran
http://www.sail-the-difference.com/DESIGN.28.0.html?&L=1

[brian eiland]

I have recently received some Emails that reference a couple other examples of 'wishbone', or 'bi-pod', or 'A-frame' shaped masts. So I thought I would post them here for reference to the discussions.


2)Kolika monohull motorsailer
http://sail-works.com/KOLIKA/html/kolika_10.html (http://sail-works.com/KOLIKA/html/kolika_10.html)
...have a look thru the picture gallery,
I was looking thru the picture gallery again and noted his treatment at the intersection of the mastheads...interesting

[Spiv]

I originally posted this in a different forum, but this is the proper place to discuss my new rig.

Well, it has taken a long time, but my new boat design is nearly complete.
I engaged Richard Woods as my consultant in the design of the hull.
He has patiently guided me while I designed the sailing rig and the accommodation and he has been exceptionally professional in his approach to the hull design.

Brian, you can see a lot of your thinking in this rig with a mixture of other ideas of mine and from pictures. I hope you will give me your blessing, but please feel free to comment on any aspect of it.

Here are the drawing of the rig.
While I know that they will not suit every taste, they are just what I want: a mainless rig that is easy to handle single handed and that I can safely lower in a minute to go under bridges.

The two fore sails will be on 'Stay Furlers', since the forestay are Dyneema rope, they can be bent over the trampoline when I lower the mast. They do not reef, so they will be either in or out according to the wind.
The mizzen is on a conventional Furler that can be reefed.
Lastly there is a storm sail that can be hanked in the unfortunate case I get caught in a gale.

The Genoa has a self tacking track on the roof, close to the mast and the Mizzen has a similar system on a targa bar not drawn yet.

There you go, I reopen the subject for all to participate in the discussion...

[Pericles]

Returning to this thread this afternoon, I went back to the start to refresh my memory. At #82 in May last year, I suggested a dipping lugger rig as a method of reducing top hamper in a blow. I promptly forgot about this until today, but last November a 37' Mounts Bay lugger set off from Cornwall and sailed to Melbourne with a stop over in SA for Xmas.

http://www.petegoss.com/mystery/blog.php

About 4 days out from Melbourne, they were hit by a freak wave.
http://yachtpals.com/spirit-of-mystery-4102

A dipping lug sail might be a useful rig for a catamaran after all. The Knights of Malta sailed lateen rigged galleys against the Ottoman navy.
http://upload.wikimedia.org/wikipedia/commons/e/e0/Battle_of_Lepanto_1571.jpg

A carbon fibre wing shaped spar and bipod mast with Dyeema cordage would be an interesting experiment, avoiding the bad tack" with the sail pressing against the mast.

A crabclaw sail is another option? In his book Sail Performance, C. A. Marchaj records the results of wind tunnel testing of a number of primitive and modern sailing rigs, including a number of different configurations of crab claw sails. While the upwind performance of the crab claw was less than modern high aspect ratio sails, the reaching and running performance was markedly superior, and Marchaj rated the crab claw sail as the top overall performer.
http://en.wikipedia.org/wiki/Crab_claw_sail

[brian eiland]

...A crabclaw sail is another option? In his book Sail Performance, C. A. Marchaj records the results of wind tunnel testing of a number of primitive and modern sailing rigs, including a number of different configurations of crab claw sails. While the upwind performance of the crab claw was less than modern high aspect ratio sails, the reaching and running performance was markedly superior, and Marchaj rated the crab claw sail as the top overall performer.
http://en.wikipedia.org/wiki/Crab_claw_sail
You bring back up an interesting summation that Marchaj arrived at...other than hard on the wind the tall fractional rigged sloop is definitely less than optimum for all other points of sail....the lower aspect-ratio sail plans being significantly superior.

Yet everytime rig discussions come up, most folks drift into this mind set that 'fractional sloop rigs are THE BEST'

[yipster]

the lower aspect-ratio sail plans being significantly superior.
hi Brian, thats not exactly well put and basicly untrue
this quote from http://proafile.com/view/weblog/comments/rig_options_crab_claw/ explains it better
Marchaj theorized that the crab claw develops lift in a different way than the standard Western Bermudan. It operates in what is called *vortex lift* mode, which creates powerful spinning tornadoes of air off the leading edge. The spinning vortexes are zones of intense low pressure, and thus lift is created.
to get that vortex lift from the delta the aspect ratio has to be small and high stalled
so the lower aspect ratio delta alone is actually bad
yet the extra vortex lift it creates about doubles the sail power
at least thats how i read it...

[brian eiland]

hi Brian, thats not exactly well put and basicly untrue
this quote from http://proafile.com/view/weblog/comments/rig_options_crab_claw/ explains it better...
Nice reference Yipster. I was speaking in generalities. Its been a VERY long time since I read Marchaj's book(s), but I do recall his bringing up the low AR superority in quite a number of cases, not only just the crabclaw rig. Numerous references, charts, diagrams, and test if I remember correctly....almost surprised me

[Pericles]

The John Rowland "Over the top" for coming about, http://proafile.com/view/weblog/comments/rig_options_crab_claw/ suggests a quick trip to a hang gliding shop to purchase a Rogallo wing, might be a good move. http://en.wikipedia.org/wiki/Rogallo_wing

That and a sled kite for down wind might be all the Dacron ever needed. :)
http://www.blueskylark.org/zoo/single/sled/

BTW, Wikipedia also had this. http://en.wikipedia.org/wiki/Abbas_Ibn_Firnas

[yipster]

bang, again an hour -with pleasure- reading up all those links :)
wonder if a hangglider was ever used for sailing a boat
made a rough wavepiercer proa sketch, shunting be easy'r too
than added a swath leg under the bench/house ama for comfort and more
eh, back to Brian's WishBone Sailing Rig

[gar37bic]

I was looking thru the picture gallery again and noted his treatment at the intersection of the mastheads...interesting

Thanks for the pic - I missed that one before, and it saves me climbing the mast! I wondered how it was set up, up there.

I'm presently negotiating to buy this boat. It's been orphaned for a couple of years, and has suffered a bit. However at this point it looks like it is recoverable. It's also a unique boat with a huge complement of systems - electrical, hydraulic, electronic, ... All that affects the marketability of such a boat.

If the deal goes through, I would love to have anyone who is interested come and look at it, and (once it is ready) to come and help me figure out how to sail it! (Not far from Fall River MA)

[gar37bic]

The John Rowland "Over the top" for coming about, http://proafile.com/view/weblog/comments/rig_options_crab_claw/ suggests a quick trip to a hang gliding shop to purchase a Rogallo wing, might be a good move. http://en.wikipedia.org/wiki/Rogallo_wing

That and a sled kite for down wind might be all the Dacron ever needed. :)
http://www.blueskylark.org/zoo/single/sled/

BTW, Wikipedia also had this. http://en.wikipedia.org/wiki/Abbas_Ibn_Firnas

Your second pic of the 'wishbone rig' reminded me of SailRocket for some reason - probably just the sail shape: http://www.sailrocket.com/

[brian eiland]

...wonder if a hangglider was ever used for sailing a boat
made a rough wavepiercer proa sketch, shunting be easy'r too
than added a swath leg under the bench/house ama for comfort and more

Something like this Yipster?
Tilting Rig Design by Chris White (http://www.wingo.com/chriswhite/tiltrig.html)

...or Powerfoil sails (http://www.boatdesign.net/forums/sailboats/anyone-familiar-powerfoil-sails-603.html)

[brian eiland]

The new owner of Relentless found the performance in heavy winds to be unbalanced and has shortened the mast (to just above the notch) and canted it aft about the same it was canted forward and put a whole new rig on it (double furler with wishbone boom) after adding the skeg-hung rudder. Initial sail tests in the harbor seem promising - longer foot, lower CE, less compression on mast. More to follow I am sure. The experiment continues...Kojii
A broker out west just sent me this photo of the new 'shortened rig' .

What a butcher job !!:eek: :rolleyes:

....the new and the old

[Kojii]

Watched Art test it inside Ediz Hook. Went fine. He has some experience with this sort of rig - http://www.holopunicanoes.com/hss.html
The vessel did not tolerate the tall rig in heavy wind, nor needs it to move well. It was just overkill. Designer pared it down himself on hull # 2 (Orca).
Looks odd, but that's what they said about the Marconi rig once upon a time.
He does drastically reduce compression on mast legs, since it is now canted aftward. CE already low, is now lower still. For the experimental and adventurous sailor surely. Which eliminates most sailors...;)

K

[gar37bic]

As it happens, I am proceeding with purchase of Kolika, having gone through her with the surveyor and have done some more research. Globaldude (if you are still around) - your visit to the boat and discovery of some of the problems turned out to set the stage - they lowered the price some more. :) It's not a done deal yet but well along the way.

According to the builder Mr. Klimmek, the bipod mast weighs only 400 lbs. It is hollow wood with fiberglass skin. As he wrote, it weighs about 2/3 what a single mast would weigh. (You can read more at the web site for the boat, http://www.sail-works.com/KOLIKA/

This makes sense to me, as the masts do not have to deal with any significant bending moment - all forces are either tension or compression, and the rigid spreaders (with crossed tension wire) allow the two to act together as a single trust. I think that a single mast has to deal with much higher bending forces.

Also according to the builder, aerodynamically, the masts do not cost as much as might be expected. They are airfoil-shaped, so their windage is lowered. If I recall correctly a round object has the same drag as an airfoil ten times the width.

Perhaps most importantly, a single mast 'dirties' the air flowing across a sail significantly causing loss of lift, especially at high angles of attack. On the Kolika the sail's leading edge is almost completely clean, with only the roller furling to impede the flow.

I finally learned about the unusual prop and rudder design. The rudder has two sections behind the prop that are angled about 10 degrees from straight, in opposite directions. It turns out this has the effect of straightening out the propwash, eliminating prop walk. The circular foil around the prop is called a 'Kort nozzle'. This increases the efficiency of a prop - there is an article in Wikipedia. Overall though I think this arrangement has more drag when sailing than a more typical setup.

The trim tab apparently did not work as expected, and Mr. Klimmek locked it in place at some point.

[edit: One more interesting tidbit. The surveyor discovered that the original painted waterline was incorrect, and a new one applied. The boat evidently rides about six inches lower in the water than planned, which means the boat is heavier than planned. With 320 gallons of water and 180 gallons of diesel, plus 80 additional gallons hot water storage, that amounts to roughly two additional tons to haul around.]

[Norman Brown]

I am glad someone is purchasing this yacht. It opened my mind to bi-pole rigs and started me doing figures for rig loads (a A frame does not need increadible wire loads. Hence it stands 'easy') and chain plates (most disapear). This makes the rig lighter eaven though it looks bigger (hence Pirocon). I will be interested in her sailing characteristics once she is back sailing. I have split my masts again as 4 masts with cross spars in carbon is more ridgid and just as light. Windage is no problem as the sections are smaller and give less windage than the single mast and wires. (search 'Lionhart of Hartlepool').

[nelsonyachts]

Dear Wishbone Enthusiasts,

One of these fine Kevlar vessels is currently for sale at Nelson Yachts in Alameda, CA. The Rig has been cut down to just above the wishbone. The price on this boat is excellent given the effort that went into her. Please contact Chad at Nelson Yachts (http://yachtworld.com/nelsonyachts) to purchase this boat.

HERE IS A LINK (http://www.nelsonyachts.net/images/Boats/sail/47_northwest/47_nw_pdf.pdf)to a .pdf of photos.

[multihullsailor]

Dear Wishbone Enthusiasts,

One of these fine Kevlar vessels is currently for sale at Nelson Yachts in Alameda, CA. The Rig has been cut down to just above the wishbone. The price on this boat is excellent given the effort that went into her. Please contact Chad at Nelson Yachts (http://yachtworld.com/nelsonyachts) to purchase this boat.

HERE IS A LINK (http://www.nelsonyachts.net/images/Boats/sail/47_northwest/47_nw_pdf.pdf)to a .pdf of photos.

Why was the rigg cut down? Are pictures available of the current mast situation?

[yipster]

http://www.yachtworld.com/core/listing/pl_boat_detail.jsp?&units=Feet&id=2083126&lang=en&slim=broker&&hosturl=nelsonyachts&&ywo=nelsonyachts&
http://nelsonyachts.net/images/Boats/sail/47_northwest/47nwpdf.pdf

[nelsonyachts]

Hi all,
Attached are large pictures of the current rig situation on Relentless. A second jib is to be added below the existing one. The double sail on single furler idea has been scrapped in favor of two low aspect headsails on furlers. Contact Chad at Nelson Yachts in Alameda for more info. http://nelsonyachts.net/images/Boats/sail/47_northwest/DSCF2987.JPG<br> http://nelsonyachts.net/images/Boats/sail/47_northwest/47%20Northwest%20Custom%20Kevlar%20Cruising%20Boat%20For%20Sale/DSCF3009.JPG

[ChiefOren]

I am building a 50' sailboat, here in Israel. I have been interested in an A-frame configuration. But I would like opinions on the Idea brought about by www.runningYachts.com for an Aft-Mast configuration. I was thinking of using an Aft-Mast configuration, but with an A-Frame. I would then use 2 jibs for main sails, as was discussed here. A third jib could be used as a Storm Jib. Thus the boom would be eliminated completely. And with an Aft-mast configuration, there would be no loss of sail area.
Any ideas?

[multihullsailor]

I am building a 50' sailboat, here in Israel. I have been interested in an A-frame configuration. But I would like opinions on the Idea brought about by www.runningYachts.com for an Aft-Mast configuration. I was thinking of using an Aft-Mast configuration, but with an A-Frame. I would then use 2 jibs for main sails, as was discussed here. A third jib could be used as a Storm Jib. Thus the boom would be eliminated completely. And with an Aft-mast configuration, there would be no loss of sail area.
Any ideas?

ChiefOren,
check out this website for some more infos and maybe ideas on just such an arrangement:
www.sail-the-difference.com

Roger

[yipster]

some calcs on a A frame from a model RC site http://www.rclandsailing.com/catamaran/mast_forces.htm

[walltar]

Now i could say i am in love with that ship and for that price i would buy it in a minute. Pitty i am in europe and i dont have money right now. :(

[Spiv]

I am building a 50' sailboat, here in Israel. I have been interested in an A-frame configuration. But I would like opinions on the Idea brought about by www.runningYachts.com (http://www.runningYachts.com) for an Aft-Mast configuration. I was thinking of using an Aft-Mast configuration, but with an A-Frame. I would then use 2 jibs for main sails, as was discussed here. A third jib could be used as a Storm Jib. Thus the boom would be eliminated completely. And with an Aft-mast configuration, there would be no loss of sail area.
Any ideas? Hello ChiefOren,

I am about to build a 17 x 8.3m composite cat.
I had the hull designed by Richard Woods and I designed the superstructure and whisbine style CF mast with 3 furling sails two conventionally in front of the mast, one (mizzen) aft.
Mizzen and Genoa are self tacking.

I designed the mast in an oval Carbon Fiber sectio, but still have not obtained detailed engineering calculation.
I'd be happy to share the design with you if you will participate with the engineering costs.

[Kojii]

Another reason for the wishbone rig. Can you find it in the photo taken in very light wind in the harbor. The hook knocked most surface winds down to a breath. Rowed Orca out of the slip using 10 foot carbon fiber sweeps, and got the sail up as we quietly slipped out of the marina.

[gar37bic]

What's the advantage of the catenary vs. straight mast legs? My understanding of the straight mast legs is that the major forces are all in line with the mast - no bending moment, so they do not have to be as large and heavy. On my boat the pair of mast legs only weighs about 400 lbs. - I can pick up one end of a leg (barely) even with full rigging and hardware.

It seems to me that the catenary curve would require more strength in the leg. However, in my case the main sail is rigged on a roller furling at the center, not following the mast leg, so the forces applied to the mast legs are all at the top and bottom. Perhaps that is a difference?

[gar37bic]

I should say, my boat's mast legs are hollow sitka spruce, not lightweight composites. The boat is not build using high tech lightweight composites. According to the builder, a single mast would have been over 600 lbs.

[Kojii]

The observation is not meant to imply that there is only one way to build a wishbone or an a-frame mast or even to compare the two directly. A boat is a synergy of forms and motions. Weights are certainly one concern.
The important thing is - how it works in a seaway. Obviously, your a-frame has been proven, as has the wishbone we sail. They address the mast "problem" differently.
The straight line must be held straight or "in column" as the technicians like to say. Forces tend to induce bending. A-frames (essentially a double mast) are strong, but are they synergistically stronger together. By linking them do you gain twice the strength of a single doubly big stick, or something more.l
A curve, likewise, is not so vulnerable as a single straight stick, being already bent. It needs to be held within the parameters of the modulus and the arcs integrity limits. And two arcs linked together...again speculatively...stronger than a single straight stick of twice the size of a single arc?
I was looking for some considerate thoughts re the arc of the leach in relation to the arc of the mast leg. I have done some experiments on the foil mast and wonder what the experts on aerodynamics think of the reaction between the mast and the sail spilling wind across it specifically re drag.
Cheers,

[yipster]

not wanting to spoil this good conversation but just saw another "radical new concept" (http://www.youtube.com/watch?v=V_-m4ButAHw) at yachtforums (http://www.yachtforums.com/forums/future-yachts-concept-boats/12132-radical-new-sailboat-concept-twin-masted-swing-sail.html) nice renders but i have doubts and thoughts

[Pericles]

Yipster,

This what you mean?

http://www.yachtforums.com/forums/future-yachts-concept-boats/12132-radical-new-sailboat-concept-twin-masted-swing-sail.html

[yipster]

Pericles, yes there is the design i tripped over while i should have looked away
a new tread somewhere would have been better but many rig ideas allready here
with the presentation on yachtforums locked for comments i check what we think
so yes, that concept, and i realy think broadly of concepts, got me confused
Carl of yachtforums and PBB mails members this info and thanks for that
at first sight the text and looks are interesting the next second i sat baffled
why 4 masts, how can sail geometry change moving the straight booms,
why sideboards, why not the lead in the foil instead of the extra bulb etc etc
i like dearing concepts but this sounds to my eye unbelivable, nice pic's tho

[Pericles]

Glad to be of help. Carl also sent this link. It's OT, but droooollll. http://www.yachtforums.com/forums/burger-yacht/12144-review-burger-151-fantail-cruiser-sycara-iv.html

Regards.

[Kojii]

Pericles et al,
Any ideas regarding previous posting on turbulence/drag interaction of sail/catenary mast as in wishbone. Specifically would there be potential advantage on some points of sail? Any ideas appreciated.

[Squidly-Diddly]

They must have done something fancy to hide some heavy duty gear.

I'm sure they don't want that motorboat slamming against the side of the yacht during launching.

The distance from the top deck to the water would increase pendulum.

Any clue how that is addressed?

[brian eiland]

Brian,

Best wishes for the new year. I have made some contact with - of all things - Mr 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 Or ca went around the Horn from West to East and came back through the canal. Heresay at this pt. More as we get it. K
Any updates to report?

I have some interested parties who persist to ask questions about this designer and his reasonings.

[Kojii]

Very little. The bus driver is pulling up distant memories. Did say that the boat performed very well in a blow crossing El Caribe ("as designed" he quotes Mr Greenway as saying). This steady ride in rough water is is our experience as well. It is consistent with Bolger's assessment as a good heavy weather rig and combined with the slender hull you get very good handling in an irregular seas.
Mr Greenway was probably not a Boeing engineer afterall. There is some indication he was involved in the F.L. Wright Foundation. Who knows. He did build a geodesic dome in Northern California, and we are told the New England style boat shop in Port Townsend where the two North Pacifics were built.
Will post the latest photos under sail. As you can see the isn't so much as a rifle on the water. We made 2 knots in this very light air which may have reached 6 knots at the masthead from time to time. Not bad for 11 tons. The sails stayed full as long as there was any wind at all. Sailed it to the dock as the light was waning.

[basilroman]

Wow, I am glad google dug up this long string on A frame rigs. You guys have dug up tons of good info.

I am working on a 36 foot cat design with an A frame rig and am thinking about making solid backstays. I'll admit I kind of like how it looks drawn up and how it flows with the hard top and targa. The negative perspective would be that the four legs look like an oil derrick.

Functionally, I like how it would allow the front legs to slope back more steeply moving the peak aft, and spread the compressive load across most of the leeward hull. It would also serve to lighten up the individual legs substantially and lighten up or even eliminate the forestays. I guess one other functional issue would be more cross cabling between the legs which would increase windage and maybe limit the size/roach of the boomless main, though pre-bending the legs by wishboneing them in to the peak could eliminate some of that.

I'd love to hear your thoughts.

[alan white]

Windage, windage, and windage... The issue of two masts (port and stbd) has been discussed in detail already, and still, looking around, few boats have 'em. But adding two more, the question of windage being excessive, being at least double the amount the A frame rig suffers, it's gotta be a lot of windage aloft.
With the A frame alone, it's easy to stay the rig from at least 3 points by wires, and wires are very light and thin compared to aluminum sections, not to mention wires don't need to be maintained in column! The complication of stiffening tubes that are skinny enough to present a minimum windage (still too much windage) would be prohibitavely expensive anyway.

[basilroman]

I hear you on the windage. However, a comfortable cruising cat already has very high windage, so the percentage increase would be in the single digit percentages for A frame or even double A frame, even considering more air flow aloft. On a mono it looks like it would be well into double digits, so a bigger difference there.

Plus, even though a negative under power or heavy seas, windage can be somewhat compensated for with sail area while sailing.

The bigger cat benefit is how nicely the A frame opens up the cat layout. A double A frame would also take some cost out of the hull structure.

This SMG50 production cat seems to be getting a good reception, pics below.
http://www.newswinch.com/fr/wp-content/uploads/2009/11/mat-bipole-4.jpg
http://www.sailawayyachts.co.za/catamarans/images/CC443_big.jpg
http://www.adrianews.com/images/stories/reports/_a2n7727__large_600750.jpg


Catbird Suite is 60 foot cat for sale, so pics also available.
http://www.damsl.com/postcards/popup.html?img=100_catbir24.jpg

[ChiefOren]

Solid Backstays are dangerous. They can snap, and you cannot redily fix them. It is far better to have lines that can strech a bit and aleviate the stress on the masts. Remember, the masts are working with the wind, and if they are too rigid, the fatigue of the metal struts is much greater. I'm sure George agrees here. I plan to have an A-frame aft-mast rigging, and the back-stays are going to be hefty galvanized lines. Better to go big on lines, but avoid rods. At least with the lines, they don't usually fail at once, but you can see one or two strands that snap, and you have an indication of what's to come. But if the rod, or brace breaks, the intire rigging will go, without notice.
Good luck with your project.

[brian eiland]

I'm sure this vessel reference has been posted before, but in looking thur some old postings of mine, I did not see it in these particular discussions

50 SMG Catamaran
http://www.sail-the-difference.com/DESIGN.28.0.html?&L=1

We are having some discussions over on the aftmast subject thread about an Italian research paper that did some wind tunnel testing on an A-frame mast configuration. Thought it would be timely to bring this 'wishbone mast' discussion up again, and also put some photos with this A-frame catamaran project.


http://www.sail-the-difference.com/home/english/the_features_of_the_easy_to_use_smg_catamaran/smg_50plus/ (http://www.sail-the-difference.com/home/english/the_features_of_the_easy_to_use_smg_catamaran/smg_50plus/)

[dskira]

not wanting to spoil this good conversation but just saw another "radical new concept" (http://www.youtube.com/watch?v=V_-m4ButAHw) at yachtforums (http://www.yachtforums.com/forums/future-yachts-concept-boats/12132-radical-new-sailboat-concept-twin-masted-swing-sail.html) nice renders but i have doubts and thoughts

To much time on the computer not enough time sailing.
It seams that any guy open a "studio" and "design" yacht.
They think it is a "niche" to get rich. They confound the owner wealth and there own position.
What a load of crap.
Daniel

[gar37bic]

We are having some discussions over on the aftmast subject thread about an Italian research paper that did some wind tunnel testing on an A-frame mast configuration. Thought it would be timely to bring this 'wishbone mast' discussion up again, and also put some photos with this A-frame catamaran project.

Maybe I'm not enough of a traditionalist - I like the looks of the a-frame on the cat! Of course, I'm biased, since I bought and am restoring this boat: http://www.sail-works.com/KOLIKA/. ;)

That cat is a nice kittie! As the cat page mentions, the a-frame mast seems to make especially good sense on a catamaran, because the mast base transfers the forces directly to the hulls rather than a big heavy cross beam.

I didn't find your thread where you talked about the italian analysis. Can you post a link, or something?

I was looking back over this thread prior to replying. WRT windage, according to the original designer of my boat, the windage is similar to or perhaps less than a single mast. There are several reasons:

The individual legs have much less side load, and share the effort so can be much lighter and smaller
They can be designed with a more effective airfoil shape
People are not aware of just how much windage the wire rigging causes. IIRC my old fluid dynamics, a round profile (wire) causes as much drag as an airfoil with 10 X the cross section. If true, then think of each wire in the standing rigging of a typical traditional rig as being an airfoil 30/8" (2.75") across.
The sail can be more efficient (given the inefficiencies of any roller furling), because the mast does not spoil the leading edge
A small thing but possibly significant - the support structure for the two masts is less, as the forces can be passed directly into the hull instead of via a heavy crossbeam - this is true to some extent even for a monohull. In my boat there are a couple of extra frames in the hull, and a big steel bracket that passes the force through the side deck.
Of course this also means no big post in the middle of the boat! :D
But my side deck has a big 'ol mast sticking out of it that gets in the way when trying to go forward :(

[ChiefOren]

As I am building a 50 George Buehler sailboat, I plan to incorporate the A-Frame concept with the Aft-Mast configuration. In this way, I can eliminate altogether the Main Sail, and instead incorporate 2 Gibs that will do the work. I may in the future add a mizzen, but at first I will try without. I am very interested in others that have tried the A-frame, and would also like to know what others think of the Aft-Mast.
Thanks for the update.

[gar37bic]

To much time on the computer not enough time sailing.
Daniel
That is a strange boat - if nothing else, it seems to take 'windage' to new highs. :)

[gar37bic]

As I am building a 50 George Buehler sailboat, I plan to incorporate the A-Frame concept with the Aft-Mast configuration. In this way, I can eliminate altogether the Main Sail, and instead incorporate 2 Gibs that will do the work. I may in the future add a mizzen, but at first I will try without. I am very interested in others that have tried the A-frame, and would also like to know what others think of the Aft-Mast.
Thanks for the update.

Chief, I suggest you take a look at some of the pictures and specs of my boat - I've posted the link above but here is a link to the pictures: http://www.sail-works.com/KOLIKA/html/picture_gallery.html

Here's a good picture of the rig. One thing I don't understand is why he left the bottom of the mainsail so high. It looks to me like I could get the foot of that sail another 'foot' or two longer/lower, improving the sail efficiency. But the builder did put some hardware at the front of the wheelhouse that sticks up a foot or so, so maybe that's why.

http://www.sail-works.com/KOLIKA/assets/images/db_images/db_Sail23.jpg

[ChiefOren]

I have seen this, and was very impressed. The difference though, is I wish to rake the mast forward as per the Aft-mast configuration, and use three stays, which will be used as two gibs and a permanent Storm Sail. I could then in the future also incorporate a ketch, but for starters, I could do without. Thank you for the link to your site. I had it on one of my earlier computers, but it went out with the hard disk that I had to replace. Could you give us some of your thoughts on the A-Frame, and how it worked out?

[gar37bic]

Solid Backstays are dangerous. They can snap, and you cannot redily fix them. It is far better to have lines that can strech a bit and aleviate the stress on the masts. Remember, the masts are working with the wind, and if they are too rigid, the fatigue of the metal struts is much greater. I'm sure George agrees here. I plan to have an A-frame aft-mast rigging, and the back-stays are going to be hefty galvanized lines. Better to go big on lines, but avoid rods. At least with the lines, they don't usually fail at once, but you can see one or two strands that snap, and you have an indication of what's to come. But if the rod, or brace breaks, the intire rigging will go, without notice.
Good luck with your project.
I am reminded of an analysis by Navy scientitsts that I read long ago, about the chinese junks. One of the big differences that was noted was that where USN ships were built strong and stiff to resist the forces of nature, the junks were flexible and stretchy. This made them possibly less efficient, but more adaptable to extreme conditions - like a palm tree vs. a big oak.

[gar37bic]

I have seen this, and was very impressed. The difference though, is I wish to rake the mast forward as per the Aft-mast configuration, and use three stays, which will be used as two gibs and a permanent Storm Sail. I could then in the future also incorporate a ketch, but for starters, I could do without. Thank you for the link to your site. I had it on one of my earlier computers, but it went out with the hard disk that I had to replace. Could you give us some of your thoughts on the A-Frame, and how it worked out?
If you're talking to me, I am no expert, and haven't even sailed my boat yet - I'm still fixing it! So I can't say anything from my own point of view. But the original builder was happier with the overall results than even he anticipated.

I did post a couple of items about the aerodynamics in post #150 a little while ago - you may not have seen it. But I will say that the masts indeed are very light - I think about 200 lbs. each even with the hardware. They have an airfoil shape with an internal cross-membrane - the cross section looks like a figure 8.

I'm unfamiliar with the aft-mast thing you are talking about. How does that work? Is it akin to 'suicide doors' on the old cars?

[gar37bic]

I should mention that the masts are over 52 feet long.

[ChiefOren]

To start, you could look at www.runningtideyachts.com to view the Aft-mast configuration. The Idea is to rake the mast forward about 10% and connect to it two Jibs, eliminating the Main Mast and Boom. I thought, gee, nice, but wouldn't it be more reliable with an A-Frame? So by combining the A-Frame in an Aft-Mast configuration should actually bring a lot of benefits.

[ChiefOren]

Also, with the Aft-mast rigging, the sails would not overlap the masts like what we see in the above picture that you sent. This would allow for closer hauling of the sails, maybe even using sail tracks on the deck for sharper tracking.

[TTS]

Sounds a bit like this tilting rig concept from Chris White:
http://www.wingo.com/chriswhite/tiltrig.html

Actually I can not see the benefit of moving the tack, nor luff of the main (Wait a minute, I take that back. There could be some benefits, but it complicates things even more).

If anything the Aero-Rig was pretty efficient at keeping a constant relationship between the jib and main.

I know that htis is an old thread, but my question about this is, does anyone know what the platform that this rig is on? IE, hulls and are they planing hulls?

[brian eiland]

Any updates to report?

I have some interested parties who persist to ask questions about this designer and his reasonings.
I've recently been contacted by a gentleman who claims to have some blueprints of the taller rigged vessel. He refers to her as 'Nimrod'. We show a photo with the name 'Relentless'.

Possible he will be able to shed some other light on the designer and his work?

Meantime he referenced me to some other photos:
http://www.nahiku33.com/mw.html

[Kojii]

It was Nimrod. The photos shown were taken at Railway Marina, where we are now moored on Puget Sound.
As in my other posting (other thread) Nimrod/Relentless is now at John Wayne Marina and has had it's keel removed (it did not go willingly), mast shortened, power plant upgraded, and a doghouse stuck on the stern. It is not the same boat. Still has a get home bipod rig only.
I have the DWGs for the boat also. Since the boat had long since been sold by the original owners before it got to Railway, I doubt any new light will be shedding, but I'm just a skeptic...
Orca remains intact.

[brian eiland]

I have reviewed a lot of the observations and precepts/opinions and most everyone is "correct". Paradoxically, the boat sails well mainly because the hull is a racing hull. So this will never be a popular boat. Slack bilges, close quarters below, and tight deck space - but what a beauty in the slings....
The wishbone legs are bowed (cleverly), and require pre-loading, if you will, by the shrouds at the mid-arc to keep them from springing (they are afterall bows of carbon/kevlar/plastic). The wires do the trick as designed. As such the bowlegs of this mast act as shroudmasts with the wires performing the role of the string on a bow, only this string is attached in the mid-arc.
Shortening sail does result in lee helm but not a lot. I have not yet been able to get it to heave to. Still working on it. Fore reaches fine.
Tension loading is "extreme" I suppose. I have bent the upper mast back a few inches to get high tension of the forestay. Replaced some turnbuckles on aft stays but they were not badly worn. Rig is heavier than I would have liked, but necessarily so for strength. Still not much different from standard Marconi with same sail area and probably a little less weight depending or reefing of the Marconi reefing system. This is all anecdotal from my yard experiments, mainly involving my back, which has been a reliable tool thus far.
Aero-hydrodynamically speaking, the thing works well. I did hang it in the yard but the scale was broken...
Very comfortable ride to wind and on a reach she goes. Ran into the harbor last week with 20 knots of wind doing 8 knots without much fuss. Keeping the staysail boom down is a problem. I like sharpieII's ideas and observations.
Many of the observations of the individuals are right on and I appreciate the spirit of the discussion, unlike so many forums on the web, this one seems to keep it neat and respectful. I appreciate that more the older I get.
This will not likely ever be a "popular" rig for many reasons but primarily because it requires a very lean hull to take advantage. Most people just want real estate below and on deck. I do feel safer on it than on the vintage open 60 however. I know this one will come back up...
Just ran across this photo on my computer and thought it fit this description pretty well. I don't think it has been posted?...and I'm sure Kojii must have sent it to me.

[Kojii]

Just wanted to add that a few days later we did heave to under staysail only. The boom made itself very useful. Very comfortable ride, well-balanced. Attached another shot from a blustery day some years ago in Oregon.

[brian eiland]

Somehow I missed ever seeing or knowing of this vessel, but here is a gentleman who is not affraid to experiement. Just happened across this vessel this afternoon. Perhaps we'll encourage the owner to add some comments to this forum.

http://www.damsl.com/

"The rig is my idea (tested on a smaller catamaran) with engineering and construction specifications by Malcolm Tennant and Anthony Stanton of New Zealand design team Malcolm Tennant Multihull Design (tennantdesign.co.nz), who designed the boat. Dave Pope, who was a member of the Tennant team, did the original construction drawings of this boat and has contributed a lot to development of the new rig. Dave now has his own design firm and is based in Whangarei (dpd.co.nz).

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........."

.....more discussions, photos, and videos

[Squidly-Diddly]

I bet it would sail OK on just one side's two sails.

Maybe have heavy and light air sails on diff sides?

[upchurchmr]

Does anyone have any information on the performance of this idea, or an idea on why it has never been seen again?

I always thought it would be interesting unless you wanted the new "megahorsepower" rigs with a massive screacher.

Something like this Yipster?
Tilting Rig Design by Chris White (http://www.wingo.com/chriswhite/tiltrig.html)


...or Powerfoil sails (http://www.boatdesign.net/forums/sailboats/anyone-familiar-powerfoil-sails-603.html)

[brian eiland]

Just wanted to add that a few days later we did heave to under staysail only. The boom made itself very useful. Very comfortable ride, well-balanced. Attached another shot from a blustery day some years ago in Oregon.
61093
Got a question for you Kojii. Is that bow of the wishbone section of the mast distorted asymmetric, or is that the camera angle that makes it appear so??

In other words it appears as though the port leg is more exagerated in bow (more compression), and the starboard one is straighter (tension).

[brian eiland]

Mr upchurchmr,
I believe the answer to your inquiry about the Powerfoil sail was covered pretty well by Tom Speer's reply in that other subject thread.

Per Chris White's tilting rig, I'm going to beg off for the moment, but I think you will find some interest in the 'tilted sails' of Catbird Suite that I just recently added a reference to, ...and intend on expanding on that discussion.

[upchurchmr]

Brain,

Thanks for pushing me to the Powerfoil sail discussion, Tom Speers comments are always just beyond my casual reading capabilities.

I really was interested in the Chris White rig in looking for comments.

Thanks again.

Marc

[brian eiland]

Somehow I missed ever seeing or knowing of this vessel, but here is a gentleman who is not affraid to experiement. Just happened across this vessel this afternoon. Perhaps we'll encourage the owner to add some comments to this forum.

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........."[/I]
After I posted this reference to this vessel I made a hard copy of his 'Explaination of the A-frame Rig', and reread it several times. It is quite interesting. He makes a good argument for his configuration:
1) that allows for variable tack (sail) locations across the beam of the vessel
2) that might well be called a cutter arrangement
3) all roller-furling sails with no mast interference with leading edge of sails

I thought it deserved being printed out here,...or you could go to his website and see it along with the photos.
http://www.damsl.com/ (http://www.damsl.com/)

Explanation of the A-frame Rig
The A-frame mast or bipod rig is my idea (tested on a smaller catamaran) with engineering and construction specifications by Malcolm Tennant and Anthony Stanton of New Zealand design team Malcolm Tennant Multihull Design (tennantdesign.co.nz), who designed the boat. Dave Pope, who was a member of the Tennant team, did the original construction drawings of this boat and has contributed a lot to development of the new rig. Dave now has his own design firm and is based in Whangarei (dpd.co.nz).

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.

The boat was built here in Whangarei and originally had a wind turbine rig, a 50ft diameter, 3-bladed windmill, which drove two props. With that rig, the boat could sail straight into the eye of the wind. But there were some engineering problems and construction faults in the turbine, and then I came to realize that I missed the aesthetics and silence of cloth sails. The turbine rig was too mechanical, much like just driving a motorboat, always with some machinery noise and vibration, and I got tired of that.

The new rig, with the A-frame mast, makes perfect use of the boat structure and indeed enhances the strength and integrity.

Catbird Suite has 4 sails, so far, including 2 genoas (one off each bow), a staysail and a mainsail. The staysail and mainsail have 3 positions each, i.e., the tack of the sail can be attached on either side deck or on the centerline of the boat.

For short tacking upwind, staysail and mainsail are both used in their center positions, and are thus vertical, as in a conventional rig. But, unlike a conventional rig, the main, like the staysail, doesn't have a mast in front of it disturbing its wind and therefore is more aerodynamically efficient than on a conventional rig that has the sail running up the backside of a mast, which spoils the airflow onto the sail.

PHOTO
(Mainsail & staysail on centerline of boat, port tack)

PHOTO
(Mainsail & staysail on centerline of boat, starboard tack)

For a long, passage-making tack, I attach staysail and main to fittings on the windward side deck and use one genoa, the genoa attached to the windward bow, so I then have the entire width of the boat for sheeting positions, so no booms or whisker poles are needed as I go from close-hauled to reach. In other words, the sails are sheeted down to the boat itself, and thus the boat is the “boom”.

PHOTO
(Closehauled, starboard tack, using starboard, i.e., windward genoa and staysail and main in starboard sidedeck positions. Port genoa, furled, can be seen at upper left in this picture.)

In that arrangement, I can, with my innovative sheeting system, go from close-hauled right through beam reach and broad reach, with ideal sail shape for every position in between, but no booms, or poles, because the entire width of the boat is available for sheeting positions. The sail plan thus, with sails attached to windward side of boat, looks like a cutter rig that is heeling, even though the boat is not heeling. And she goes to windward very well, like 30 degrees off the apparent wind, and there aren't many cruising boats that can do better than that.

PHOTO
(Reaching, port tack, all sails on port side. Note that, even though the boat is not heeling, the luffs of the sails are “heeling”, i.e., are angled to the right of the vertical, from the port side deck to the masthead which is above the centerline of the boat.)

PHOTO
(Reaching, port tack, sails in same positions as in previous picture taken from different angle.)

The leeward genoa (in the case above, the starboard genoa, which can be seen, furled, at the upper right of the picture) can be added to this sail plan, and, when close-hauled, a whisker pole is not needed, with the clew of the leeward genoa sheeted just outboard of, that is, to leeward of the leeward mast. But easing the sheet to reach, in order to maintain ideal sail shape, requires a whisker pole, because then the clew of the leeward genoa would be out beyond the leeward side of the boat.

My sheeting system does require a lot of rope, but rope is much cheaper and easier to handle, and less dangerous and potentially destructive, and less heavy, than booms. The advantages make handling the rope worthwhile.

Why do they call purchase systems "purchase" systems? Because the more mechanical advantage you want, the more rope you have to purchase.

The geometrical advantage for sheeting of the genoa attached to the windward bow is especially great. Even on a beamy cat, with the genoa in the middle, i.e., between the bows, as in conventional rigs, there's only half the boat for sheeting range and, therefore, with a big genoa, you cannot maintain ideal sail shape for beam reach, and certainly not for broad reach, not without a whisker pole, because the clew of the sail is then out beyond the leeward edge of the boat, so the sail develops too much belly. I have the advantage of the entire width of boat for sheeting of the windward genoa, and one genoa is usually enough on any point of sail except dead downwind in very light winds.

PHOTO
(Broad reach, port tack, mainsail & port genoa)

PHOTO
(View of mainsail on broad reach, port tack)

Whisker poles would be of use dead downwind in very light winds for poling out both genoas at the same time, and covering the gap in the middle with the main and staysail. That arrangement would capture a tremendous cross-section of wind.

But my boat is so easily driven and my genoas are so big, that most of the time around here, one genoa is enough, and it's handy to sheet across the entire width of boat and maintain ideal sail shape with no need for a pole, and to be able to alter course drastically without having to worry about a pole, or having to fuss with it in the first place. Indeed, downwind with a good breeze, one genoa, sheeted right across the bows, moves the boat along very well, and it's quite amazing how much you can alter course, almost 180 degrees, that is, almost from beam to beam, without jibing. In other words, you can sail “by the lee” on one tack, with the leach of the sail becoming the luff.

I've provided for addition of whisker poles, with fittings on both masts, topping lifts, etc., but have not added poles yet.

The staysail is my storm sail and has very good sailing balance, being directly above the keels, whether in a side position or on the centerline.

PHOTO
(Staysail in starboard side position)

The A-frame mast structure is incredibly strong and simple in comparison to conventional masts with all their necessary complications. With sails on wires, which are the most efficient kind (no mast in front, spoiling the airflow), and you want to be able to furl ALL sails quickly and easily (so they have to be on wires), the big problem is that sails on wires, which wires must be very taut, create a lot of compression on a mast, so the mast must be very strong and MUST be kept in column, i.e., not allowed to bend, which requires spreaders and more wires, stays, adding more compression, and, on conventional masts in the middle of the boat, the stays are at angles that add even more compression, and thus more stress on the boat, and, on a catamaran, right in the middle of the boat, trying to break the two hulls apart.

The larger the angle between stay and mast, the less compression on the mast and the less stress on the boat. That's why big single masts have lots of spreaders, to increase the size of the angles of wires to mast, but at the cost of lots of wires and fittings and complications, increased windage, wear and tear on sails, etc., etc.

My stays, in this geometry, have very advantageous angles, with therefore less compression on the mast structure, and a lot of the existing tension and compression forces, especially the side loadings, which are the greatest on any boat, are contained within the A-frame structure. There are fewer wires and the wires are smaller, lighter, less expensive than would be required in most conventional rigs. Altogether, there is less material involved in this rig, and thus less weight as well as less expense.

Thus the essence of this rig is in its geometry. Just look at the size of the angles between wires and masts. There are no really acute angles as there are in most rigs. And with respect to strength to weight ratio, and strength to cost ratio, I dare say that few rigs could compete.

The compression load on the boat is not only shared by the two hulls at their strongest points, the load is not trying to break the two hulls apart, as it is in a conventional rig. On big cats, it has never made sense to me to have a huge mast in the middle of the boat, trying to break the boat in half. A cat is two boats in one, so why not have two masts stepped right down to the keels through the parts of the structure best able to take the compression, as well as dividing the load by two, and increasing the side-loading angles to the fullest extent possible.

There are a few cats around with so-called bipod rigs, a mast stepped in each hull, but vertical, the masts not connected at the top. That's not nearly as strong a rig as an A-frame, which is a triangle, actually, or a system of triangles. A cat with vertical bi-pod rig is simply two monohulls connected at the hulls. My goofy analogy is two one-legged men side-by-side with one water ski each, with the skis connected but no other connections, not as stable as one two-legged man on water skis.

As you may or may not know, a much stronger rig, than on a monohull, is necessary on a big cat, because big catamarans are very unforgiving, in that they don't heel, so you don't get the shock-absorber effect of heeling like a monohull, not only heeling and absorbing some of the force, but also spilling wind, when you get a big gust. That is, a catamaran with vertical sails does not have the shock absorbing heeling effect, but my sails, when the tack of each sail is attached to the windward side deck, the sails themselves are "heeling" from the start, and thus spill wind a bit when you get a gust. That's a significant safety factor.

You don't "fly a hull" in a cat of this size, rather, you'd better reduce sail long before that, and a conventional rig would not be strong enough to lever the boat over. The rig, or the boat, would break first. However, my rig is much stronger than a conventional rig, maybe even strong enough to lever the boat, but if she ever did start to heel a bit, let alone fly a hull, the spilling effect of my already tilted, or "heeling" sails would increase very quickly.

A catamaran with a conventional vertical rig, in a gust, accelerates much more than a monohull, because none of the energy is absorbed in heeling or lost in spilling. So with my "heeled" sails, yeah, I may sacrifice a bit of abrupt speed, but my boat has speed to spare, indeed, goes TOO fast at times, so I can afford to sacrifice a bit of speed in the interests of less shock loading, more safety, and not having to be so constantly on the alert and ready to slack off in the gusts.

On the other end of the wind scale, in very light winds, my sails have an advantage over the sails on conventional, vertically rigged boats, in that their sails require a certain amount of wind just to lift the sails away from the vertical enough to set them into their proper aerodynamic shape for sailing to windward at all, and in winds of less than the required amount for setting, which is considerable on a big boat with heavy sails, the sails are worse than useless, they are all drag. That's why you move yourself over to leeward in a little sailing dinghy in very light winds, to heel the boat a bit and thus get your sails to hang and set properly by gravity. It would take a lot of heavy crew to accomplish the same effect on a big cruising monohull, and would be impossible on a catamaran.

My sails, attached to the windward side, because they are "heeled" to start with, as soon as I unfurl them, they assume their proper shapes by the effect of gravity and I'm away with the gentlest puff of wind, rather than with sails drooping like laundry and the boat going backwards.

There is nothing "radical" about the rig. All the components of the mast structure, and the sails and rigging, are standard off-the-shelf, tried and true and available world-wide; it's only the geometry and the sheeting system that are different and yield several advantages and built-in safety factors, in comparison to most rigs.

The A-frame mast structure is not experimental, except in a relative sense in its rare use on boats. It has been used in various pylon structures for ages now, is tried and true, and indeed less complicated, requiring fewer and smaller wires, and is much stronger than the typical yacht rigs, especially on catamarans, with far less stress on the boat and the mast and fittings. The geometry takes full advantage of the beam of a cat, in the standing rigging as well as in the geometry of the sail plan and the sheeting.

This geometry is 3-dimensional, whereas the standard, vertical, monohull rig is 2-dimensional, up and down and fore and aft, and then you have to complicate things in order to hold the sails out to the side (in the 3rd dimension of the real world) at the proper angles, with booms or poles, and then hold those down with vangs. Why encumber your boat with all that gear when you can move the sails over to one side of the boat, and then, with some extra rope and a few tracks and padeyes strategically placed, sheet right down to the boat which itself becomes the "boom"? And why limit a cat to a monohull rig in the first place?

...just a couple of photos to give an overall picture of the arragement

[upchurchmr]

Very impressive boat and actual realization of the theory's.

For upwind work (lowest possible angle to the wind, more appropriate to a racing catamaran) would there be any reason that both Genoas could not be used? The windward one sheeted to the bridgedeck/ cabin area and the leeward one sheeted to a whisker pole? Given the wide separation of the tack of the sails, the apparent "blanking" of the leeward sail would not actually be a penalty, similar to boats with two independent masts. As you turned away to a reach an angle would be reached where there was inteference and you would need to return to the operation shown above.

Just wondering if there is an obvious reason this would not work to achieve the best tacking angles (at the highest speed).

Marc

[brian eiland]

I have recently received some Emails that reference a couple other examples of 'wishbone', or 'bi-pod', or 'A-frame' shaped masts. So I thought I would post them here for reference to the discussions.

1)The Valkyrie catamaran
http://www.stevproj.com/Carz/XBoats2.html (http://www.stevproj.com/Carz/XBoats2.html)
...excerpt, The rig was a bipod of 36' aluminum tubes which could be raised or lowered in 15 minutes (we had a lot of practice by the end of the project). There were four sails: two jibs on Harken roller-fouling (which worked nicely), a staysail on a central catwalk between the cabin and the front crossbar, and a loose-foot, fully-battened main flying on a luff-wire from the cabin.
Interestingly this Catbird vessel is somewhat similar to this Valkyrie project I added to this subject thread back in 2006 (I believe I knew of this project long before, but had never added it to these discussions). Valkyrie never got to the movable tacks for the inner sails, and never really had a 'mainsail'.

[brian eiland]

In #66 I asked Brian about what might be the result by moving the foot of a mainsail ( either with or without a wishbone boom) to port or starboard on a catamaran. Here is my simply dreadful illustration of what I have in mind. The mainsail is difficult to identify and the ***king scanner is giving gype, so I cannot improve the image. Sorry about that!

If the sails run diagonally across the two hulls rather than down the centre line, could the hulls move through the water and edge more upwind?

It seems possible, but surely someone else has already tried this? All comments gratefully received.

Pericles
Hey Pericles, your thoughts realized on this Catbird vessel. :D

[brian eiland]

If we take another look at this illustration I posted back in #97, and then imagine moving that tack of the genoa to the windward hull (per Catbird), I just don't see how she points higher. If it were moved to the leeward hull, then maybe so, even though the aft sheeting of that 'leeward' genoa is 'off the vessel'.

This is going to be one of my questions to the owner of Catbird once he finds the time to join in our conversation (he has indicated a desire to do so after he finishes with some personal time).

[brian eiland]

If we take another look at this illustration I posted back in #97, and then imagine moving that tack of the genoa to the windward hull (per Catbird), I just don't see how she points higher.
Perhaps the better pointing ability comes from being able to concurrently move the mainsail's tack to windward?

Maybe that is why the SMG 50' cat incorporated a movable tack for their mainsail.
http://www.sail-the-difference.com/home/english/the_features_of_the_easy_to_use_smg_catamaran/smg_50plus/

[brian eiland]

...I was looking for some considerate thoughts re the arc of the leach in relation to the arc of the mast leg. I have done some experiments on the foil mast and wonder what the experts on aerodynamics think of the reaction between the mast and the sail spilling wind across it specifically re drag.
We might see some of this data surface from the wind tunnel test on the new Creenpeace 'Rainbow Warrior' vessel that utilizes an A-frame mast. Originally mentioned back HERE in #52 (http://www.boatdesign.net/forums/boat-design/wishbone-sailing-rig-1999-4.html#post161178), and now getting ready to launch, New Warrior Rig (http://www.damsl.com/), and HERE (http://www.superyachttimes.com/editorial/13/article/id/3960)

...more on this vessel to come...

[brian eiland]

I was looking for photos of another catamaran that utilized twin genoas on the bows and had some trouble remembering where they were. Finally found them over here in a few different postings on that subject thread.

61113

61114

61115

I also found a number of other A-frame mast discussions that I felt should be cross referenced to this thread.
http://www.boatdesign.net/forums/multihulls/main-less-rig-21274.html

Here was an interesting one on a monohull:
A-Frame Etchells (http://www.boatdesign.net/forums/multihulls/main-less-rig-21274-6.html#post211677)

[pool]

Perhaps the better pointing ability comes from being able to concurrently move the mainsail's tack to windward?

Maybe that is why the SMG 50' cat incorporated a movable tack for their mainsail.
http://www.sail-the-difference.com/home/english/the_features_of_the_easy_to_use_smg_catamaran/smg_50plus/

The mainsail tack is fixed on the SMG 50 - the track you see on the photo is for the selftacking staysail. Found that out from a larger resolution photo on their webpage.

While still keeping with a fixed conventional rollerfurling / forestay setup midships on the longeron, one could easily move the tack of a light air upwind sail, on a flying rollerfurler, to the bow. Like taking the tack of an asymmetric spi out to the bow when going downwind. No need for twin forestays, to both bows, with the associated weight and resistance.
Technically not much of an issue, but I'm not sure if that would significantly improve upwing performance in light air.

[brian eiland]

We might see some of this data surface from the wind tunnel test on the new Creenpeace 'Rainbow Warrior' vessel that utilizes an A-frame mast. Originally mentioned back HERE in #52 (http://www.boatdesign.net/forums/boat-design/wishbone-sailing-rig-1999-4.html#post161178), and now getting ready to launch, New Warrior Rig (http://www.damsl.com/), and HERE (http://www.superyachttimes.com/editorial/13/article/id/3960)

...more on this vessel to come...
They were stepping the two A-frame mast on this new vessel this past weekend:
http://www.greenpeace.org/usa/en/news-and-blogs/campaign-blog/raising-the-masts-on-the-rainbow-warrior-iii/blog/35681/

[brian eiland]

The mainsail tack is fixed on the SMG 50 - the track you see on the photo is for the selftacking staysail. Found that out from a larger resolution photo on their webpage.
You are correct, I misinterpeded that photo when I looked at it too quickly.

[brian eiland]

While still keeping with a fixed conventional rollerfurling / forestay setup midships on the longeron, one could easily move the tack of a light air upwind sail, on a flying rollerfurler, to the bow. Like taking the tack of an asymmetric spi out to the bow when going downwind. No need for twin forestays, to both bows, with the associated weight and resistance.
His justification for those twin forestays is twofold;
1) to rig to the stronger bow locations and not have a front crossbeam
2) to have 'heeling sails' on his upright very stable multihull.

For Heavy Air
As you may or may not know, a much stronger rig, than on a monohull, is necessary on a big cat, because big catamarans are very unforgiving, in that they don't heel, so you don't get the shock-absorber effect of heeling like a monohull, not only heeling and absorbing some of the force, but also spilling wind, when you get a big gust. That is, a catamaran with vertical sails does not have the shock absorbing heeling effect, but my sails, when the tack of each sail is attached to the windward side deck, the sails themselves are "heeling" from the start, and thus spill wind a bit when you get a gust. That's a significant safety factor.

You don't "fly a hull" in a cat of this size, rather, you'd better reduce sail long before that, and a conventional rig would not be strong enough to lever the boat over. The rig, or the boat, would break first. However, my rig is much stronger than a conventional rig, maybe even strong enough to lever the boat, but if she ever did start to heel a bit, let alone fly a hull, the spilling effect of my already tilted, or "heeling" sails would increase very quickly

A catamaran with a conventional vertical rig, in a gust, accelerates much more than a monohull, because none of the energy is absorbed in heeling or lost in spilling. So with my "heeled" sails, yeah, I may sacrifice a bit of abrupt speed, but my boat has speed to spare, indeed, goes TOO fast at times, so I can afford to sacrifice a bit of speed in the interests of less shock loading, more safety, and not having to be so constantly on the alert and ready to slack off in the gusts.


For Very Light Airs
On the other end of the wind scale, in very light winds, my sails have an advantage over the sails on conventional, vertically rigged boats, in that their sails require a certain amount of wind just to lift the sails away from the vertical enough to set them into their proper aerodynamic shape for sailing to windward at all, and in winds of less than the required amount for setting, which is considerable on a big boat with heavy sails, the sails are worse than useless, they are all drag. That's why you move yourself over to leeward in a little sailing dinghy in very light winds, to heel the boat a bit and thus get your sails to hang and set properly by gravity. It would take a lot of heavy crew to accomplish the same effect on a big cruising monohull, and would be impossible on a catamaran.

My sails, attached to the windward side, because they are "heeled" to start with, as soon as I unfurl them, they assume their proper shapes by the effect of gravity and I'm away with the gentlest puff of wind, rather than with sails drooping like laundry and the boat going backwards.

[brian eiland]

Technically not much of an issue, but I'm not sure if that would significantly improve upwing performance in light air.
I'm hoping to ask the owner about his upwind performance in light airs while using that 'windward genoa'. I believe this would only work if he repositions the tacks of his other sails (staysail and/or mainsail) also to windward. Otherwise I believe his pointing capabilities would deminish.

Or perhaps he could make use of his leeward genoa (if there is enough air to keep it full, and he could sheet it properly) to point higher. In other words the vessel so configured with the mainsail tacked down to the centerline, and the geona tacked down to leeward would effectively have the vessel headed up higher than a vessel with the conventional arrangement of the genoa and mainsail tacked down to the centerline of the vessel.

[philSweet]

The usual explanation for this geometry (inward leaning biplane geometry) is to reduce the heeling moment experienced. The downforce on the windward side and the upforce on the leeward side counters the heeling force to a substantial degree. In this case it would also tend to decrease the racking moment as well.

[philSweet]

In this case it would also tend to decrease the racking moment as well.

Only if sails were set on both stays. If only set to windward, racking would increase.

[pool]

His justification for those twin forestays is twofold;
1) to rig to the stronger bow locations and not have a front crossbeam
2) to have 'heeling sails' on his upright very stable multihull.

For Heavy Air

For Very Light Airs

All I see is a lot of complication, weight and windage in that rig, for doubtful improvements in performance.

You can easily stay with the simple, strong and proven longeron / fwd crossbeam setup and a selftacking rollerfurling jib on centerline - then add any type of heavy or light air sail(s) you feel the need for, set flying on a furler and attached to the bow(s).

[Kojii]

Got a question for you Kojii. Is that bow of the wishbone section of the mast distorted asymmetric, or is that the camera angle that makes it appear so??

In other words it appears as though the port leg is more exaggerated in bow (more compression), and the starboard one is straighter (tension).

Both are true, as usual. The bow legs of the arch are the same material as helicopter rotor wings. They flex. Tied together as they are with the inner struts, one pulls the other, and gravity, sail force, heeling angles, all play their part. It gets really interesting when you change the wires.
Move the bow string (shrouds) to the deck tabernacles (they were absent on this day of sailing) and tension them up carefully maintaining balance then tension the fore and aft stays again incrementally to keep the arch symetrical or close and voila she sails in same wind with same heel and the rig remains symetrical.
More interesting (to me anyway) dress the archmast to port or to starboard and then tension up to keep that bend. The mast top is fully a foot over to port or to starboard (keeping in mind the boat is 9 feet wide). Why you ask? The wing (sail) is now in a different orientation to the centerline of the vessel, is it not? This changes the angle of attack to the wind without changing the vessel heading. We saw a good deal of wind on our last outing to Juan de Fuca and much of it on the nose. Results of the experiment are not conclusive to me as yet, but it was very interesting to be sailing as close as we were to the wind. Very strange indeed. I am sure a lot of engineers can fully explain the experience to me.
All this experimentation is only possible because the old mystery man Fred built a carbon/kevlar catenary wing archmast with an integrated spire that has (so far) withstood all the bending and "distorting" that we have thrown at it. Remarkable.
Experimentum periculosum...

[brian eiland]

Both are true, as usual. The bow legs of the arch are the same material as helicopter rotor wings. They flex. Tied together as they are with the inner struts, one pulls the other, and gravity, sail force, heeling angles, all play their part. It gets really interesting when you change the wires.

Move the bow string (shrouds) to the deck tabernacles (they were absent on this day of sailing) and tension them up carefully maintaining balance then tension the fore and aft stays again incrementally to keep the arch symetrical or close and voila she sails in same wind with same heel and the rig remains symetrical.

Brian replied: I assume your vessel is rigged near the same as the photos of Relentless I posted back in HERE in#98 (http://www.boatdesign.net/forums/boat-design/wishbone-sailing-rig-1999-7.html#post209976) ?? These are the deck tabernacles and shroud attachments you are speaking of??

More interesting (to me anyway) dress the archmast to port or to starboard and then tension up to keep that bend. The mast top is fully a foot over to port or to starboard (keeping in mind the boat is 9 feet wide). Why you ask? The wing (sail) is now in a different orientation to the centerline of the vessel, is it not? This changes the angle of attack to the wind without changing the vessel heading.

Brian replied: Interesting experiment, but not a practical adjustment underway.

We saw a good deal of wind on our last outing to Juan de Fuca and much of it on the nose. Results of the experiment are not conclusive to me as yet, but it was very interesting to be sailing as close as we were to the wind. Very strange indeed. I am sure a lot of engineers can fully explain the experience to me.

Experimentum periculosum...
Kojii, do you have some photos of the details of your rigging?

[brian eiland]

Chief, I suggest you take a look at some of the pictures and specs of my boat - I've posted the link above but here is a link to the pictures: http://www.sail-works.com/KOLIKA/html/picture_gallery.html
I just looked thru your gallery of photos again, and I can not determind how the masts tubes are mounted on deck (how rigid or flexible). Nor can I determine how rigid or flexible that masthead is (joining of the two at the top)??

I'm particularly interested in the top joint as it has been expressed that Procyon experienced some problems here. And of course this could be more problematic with twin tubes mounted on a wide beamed 'individual' hulls of a big catamaran.

[Kojii]

Kojii, do you have some photos of the details of your rigging?

I suppose all this is quite troubling to the straight stick "keep it in column" extruded aluminum crowd...fair dinkum.

Orca's rig represents a simplification of the rig from the photos of the old Relent you mention.

Simply put the shrouds go from top of the mast to the deck tabernacles outboard attachments (cast aluminum). These tabernacles are through bolded to the inner frames which conform to the hull and are bolted through the hull down to about the waterline. This inner frame transfers the stresses to the hull/deck near maximum beam.
On their way they pass two critical points. First, the distal spreaders are aluminum rounds (very stout) articulated at just the below the articulation of the legs at pelvic joint and angled upward slightly from the mast. The shrouds then pass close enough to the arch legs at the knees (where the interior spreader is located) that I have placed UHMW guides. The shrouds rest against these pads, which also guide the shrouds. I have yet to determine the extent these points of contact play in the maintenance of the catenary under loads, but it is obvious they are keeping the flex of the bow "limited" shall we say?

The shrouds originally (when we first sailed it) went from this arch knee (point of the lower inner spreader) to the mast top without any wires going to the tabernacles. That also resulted in a lot of flex under heavier loads (15 knots and up). This was a modification by someone after the initial redesign of the rig from the tall to the medium height it is now (39').

Surprisingly, I have no photos of this that would help you much at this point. Will be going up mast soon and get some at that point. The photo attached may help some - it shows the inner spreader (Radar mount) and you may be able to make out the UHMW knee caps. Regards, K

[brian eiland]

I'm sure this vessel reference has been posted before, but in looking thur some old postings of mine, I did not see it in these particular discussions

50 SMG Catamaran
http://www.sail-the-difference.com/DESIGN.28.0.html?&L=1
Here is another reference to some good windward performance by the SMG catamaran;
http://www.sail-the-difference.com/fileadmin/users/9/news/2009-05-05-Kornati_cup_results.pdf

[brian eiland]

Just happened across this interesting A-frame rig making use of a lateen sail up front,.....and a mizzen sail as well. Some good photos over HERE:
http://www.boatdesign.net/forums/boat-design/frame-mast-25696.html#post449122

http://www.puremagma.com/page5.html

[High Tacker]

Hello to all, especially Brian Eiland and philSweet,

I'm a newcomer to the Boat Design Forum and first of all want to thank Brian for his references here to my A-frame rigged boat Catbird Suite and her website www.damsl.com. And it's good to see that quite a few members recognize some of the benefits of an A-frame rig with all sails on furlers.

In particular, the reference above to the good upwind performance of the SMG-50 catamaran is informative because usually the first question sailors ask is whether she goes well to windward. I can say yes for Catbird Suite and am glad to hear about SMG-50. But there are many other benefits in an A-frame rig, especially with furling sails whose tacks are movable.

With respect to philSweet's comments re the geometry of some of my sail configurations, it is correct that the heeling moment is reduced when the tacks of the sails are attached to the windward side of the boat, effectively "heeling" the sails, re-directing the heeling moment downward and also allowing for some spilling of wind in gusts. And, heeling moment is further reduced if sails are attached to both sides of the boat.

With respect to the racking moment, I want to point out that with main, staysail and genoa all tacked down to the windward side, every sail (and on all points of sail) in its entirety is over the boat and within the cage of the rig, i.e., everything is inboard, as opposed to the conventional configuration in which, during reaching and running, substantial portions of a mainsail and a big jib are outboard, exerting leverage on the boat. In my sails-tacked-down-to-windward configuration, on a beam reach or broad reach, the luffs and leeches of the sails effectively amount to a rig within a rig, almost doubling the strength of the standing rigging, and without a boom putting a bending load on the mast in addition to racking the rig.

Most of the time, there's no need for sails on both sides of the boat. Mainsail, staysail and one genoa total some 2100 sq. ft. of sail, and having those three sails attached to the windward side of the boat allows the entire 30-ft. width of the boat for sheeting, eliminating the need for booms, and thus that old bugbear the accidental jibe becomes a non-event. And having the total sail area directly above the boat greatly reduces the tendency to broach.

See www.damsl.com for more details on the advantages of unusual sail configurations accommodated on a catamaran with A-frame rig and furling sails whose tacks are movable. The rig of course also allows for the straight up and down, fore and aft conventional configuration. Uh, perhaps we should call that the square configuration.

I would also like to answer some comments about weight and windage. It is a fallacy to assume that two legs of an A amount to two times everything, far from it. If designed properly, an A-frame rig, in comparison to a single-masted rig that would support the same total area of furling sails, has superior ratios of strength to weight, strength to complexity, strength to cost, and strength to windage.

Again, see www.damsl.com for detailed explanations. See the photos and notice how slender the mast sections are on Catbird Suite.

Cheers, Tom Bradshaw

[downunder]

Tom,

I was wondering who designed and built your A-frame rig and the cost versus a standard rig.

I would have thought it would have been more expensive.

I am looking at having 46 ft cat built in 2013 and if not more expensive would be a consideration.

i yust noticed some of the info on your website. very interesting.

best regards

John

[High Tacker]

Hello John

To answer your questions about design and cost of the A-frame rig:

Malcolm Tennant, world-renowned New Zealand multihull designer, designed the rig. It was our Plan B in the original design of the boat, in case the wind turbine rig turned out not to be completely satisfactory, which is indeed what happened. In the meantime, I did very extensive testing of the A-frame concept with a much smaller version (on a 14-ft. cat) and my boating partner did some testing on one of Malcolm's Great Barrier Express cats of about 30-ft. But what the hell, what's to test? The furling sail is one of the simplest and is indeed the greatest invention in sailing in the last couple of centuries. And A-frames have been known as among the strongest of load-bearing structures for thousands of years.

The final version of the rig on Catbird Suite, including hard furlers for the genoas and solf furlers for the main and staysail, plus the sails, but not including winches, cost about NZ$144,000. That's from memory and from files I have on my laptop with me (am traveling now). Malcolm had told me that a conventional rig and sails would have cost at least NZ$200,000. My mainsail is not very big, but then I have two genoas, so my sail area would total quite a bit more than on a conventional rig. Of course, a big genoa is much cheaper than a big and complicated, fully-battened main. (And there's less likely to go wrong with it, a lot less to maintain!)

Have a close look at the pics on www.damsl.com and you will see that the masts are very slender and of the simplest kind of aluminium section, no tracks, no open slots to spoil the integrity of the tube, and only fittings for stays and sheaves for halyards and topping lifts for whisker poles.

You will see that the design is very simple and elegant, so the result is lower cost, less maintenance, and replacements over time will be cheaper and easier. Everything is very standard, off-the-shelf available worldwide. Furling sails are very simple and very light in comparison to a complicated monster main, and of course far easier to handle.

The builder of the rig, Silhouette Spars, sold the firm, now Whangarei Spars & Rigging, and the main guy who built my rig is no longer there, but he might be available. However, you might not be able to get quite as good a price, because he and my former boat partner were good friends and had done a lot of boatbuilding together.

My best bit of advice is DON'T BUILD A BOAT, AND DON'T HAVE A BOAT BUILT FOR YOU. You would be much better off, and get much, much more for your money, and a tried and true boat, and rig, if you simply bought my boat! She is like new and in today's market I am forced to offer her at less than one-quarter of her replacement cost. You will never find a better deal. She was built by some of New Zealand's finest boatbuilders, closely supervised by my partner and me. She is THE brick shithouse of catamarans.

You're in Australia, right?

Cheers, Tom

[High Tacker]

Sea trials of a real superyacht with A-frame sailing rig

Just heard from the designer(s) of Greenpeace's 840-ton Rainbow Warrior III, with two 50-meter A-frame masts, five sails all on furlers. She was launched a couple months ago, is in sea trials now and so far has sailed in winds of 10-25 knots, all has gone well, everything is working fine, no problems, no real surprises, according to Gerard Dykstra of Dykstra & Partners, who also said, "Working the rig is safe, though the individual sails are rather huge." No kidding!

Dykstra & Partners did extensive wind tunnel testing and chose the A-frame rig for efficiency and practicality. The design of their A-frame structure is identical to that of the 20-meter A-frame on Catbird Suite. Uh, well, Catbird Suite doesn't have any need for all that spyware, antennae, etc., on the outboard sides of the mast(s).

Below are some pics of Rainbow Warrior III sailing. See www.damsl.com for more on A-frame sailing rigs.

[High Tacker]

SOME OF THE BENEFITS OF FURLING SAILS WITH MOVABLE TACKS

Here is a pic of Catbird Suite (looking aft) on a reach, port tack. Tacks of mainsail, staysail and genoa are attached on port side. Everything is inboard for easy handling in contrast to a conventional rig in which substantial portions of mainsail and genoa would be outboard to starboard, levering the boat around, increasing likelihood of broaching. Entire width of boat is available for sheeting down to, maintaining ideal shape on all sails with no booms necessary. Accidental jibe has become a non-event.

See www.damsl.com for more pics and detailed explanations.

[Kojii]

Sea trials of a real superyacht with A-frame sailing rig

Just heard from the designer(s) of Greenpeace's 840-ton Rainbow Warrior III, with two 50-meter A-frame masts, five sails all on furlers. She was launched a couple months ago, is in sea trials now and so far has sailed in winds of 10-25 knots, all has gone well, everything is working fine, no problems, no real surprises, according to Gerard Dykstra of Dykstra & Partners, who also said, "Working the rig is safe, though the individual sails are rather huge." No kidding!

Dykstra & Partners did extensive wind tunnel testing and chose the A-frame rig for efficiency and practicality. The design of their A-frame structure is identical to that of the 20-meter A-frame on Catbird Suite. Uh, well, Catbird Suite doesn't have any need for all that spyware, antennae, etc., on the outboard sides of the mast(s).

Below are some pics of Rainbow Warrior III sailing. See www.damsl.com for more on A-frame sailing rigs.

Good luck selling your boat.

It looks like there is bow or arc to those legs in the bi-pod. I wonder if that is so and why would the designer do that?

[High Tacker]

Hello Kojii,

Them legs do look kinda bowy. Maybe the designers are Dutch cowboys, but that seems kinda unlikely. Hey, maybe they subscribe to that ol' Southern stoic philosophy from way down yonder in Ms Slippi, to wit: Bow up an' take it, boy...iudicium difficile...but do you yourself not tend to tension up, like, go into a state of isometric tension when you sense that a load is about to come on?

[High Tacker]

Kojii

I think you can see the bow more clearly here.

[High Tacker]

Kojii

One more bowy pic:

[Kojii]

http://www.youtube.com/watch?v=h--n62JSQPQ
Den Haag cowboys.

[yipster]

lol:D:D:D

[sharpii2]

Good luck selling your boat.

It looks like there is bow or arc to those legs in the bi-pod. I wonder if that is so and why would the designer do that?

The legs have bow outward probably to keep them from buckling inward. Also, that gives them a bit of 'spring', so the inward leg of the mast can bend a bit, relieving shock loads on the hull substantially, in the event of a sudden squall or a sharp roll.

[sharpii2]

This is an interesting look at the future. I imagine smaller ships will start sporting sailing rigs by the 2nd quarter of this century, as fuel extraction gets ever more costly and precarious. The rigs will be everything from sail assist to primary propulsion.

I wonder about the main tri-sail on this rig. I see it is boomless and can only be sheeted to one leg or the other of the mast. From what I've read from Mr. Bolger, this is very poor sheeting, even for upwind sailing (he calls for a 10 deg. offset for this). For reaching or running, this must be even worse.

My guess is that this sail, along, to a lesser extent, with the others, is cut flat or nearly so. This way it will furl easier and bag less with poor sheeting angles.

[upchurchmr]

Doom and gloom.

The last 30 years of reading the same story that fuel will begone tomorrow, and everyone will have sails has proven to be a colossal joke.

There are fewer sailboats sold now than in 1980, before the gas crisis.
People will just get use to paying more for their fun.

Most enthusiasts who get on the eco kick produce boats that fail, cause enthusiam does not equal commonsense and knowledge.

[Kojii]

Doom and gloom.

The last 30 years of reading the same story that fuel will begone tomorrow, and everyone will have sails has proven to be a colossal joke.

There are fewer sailboats sold now than in 1980, before the gas crisis.
People will just get use to paying more for their fun.

Most enthusiasts who get on the eco kick produce boats that fail, cause enthusiam does not equal commonsense and knowledge.

For centuries the ignorant had the people convinced the Earth was the center of the Universe, long after it was widely known by the intelligentsia not to be true. The status quo continued to burn people for thinking and speaking the truth.

The conventional assertion is that sailing is just too slow and will never become accepted over the faster petro-fueled vessels.

I know a lot of power boaters, professional and recreational. Good people, smart, qualified. The cost of fuel is the primary reason their vessels sit at the dock week after week, month after month, year after year. The cost of oil varies from well to well, refinery to pump, but at some point the cost rises above the benefit. The tide turns and it becomes a bad deal "economically". Some people have just reached that conclusion sooner than others.

For future reference:
http://www.theflatearthsociety.org/forum/index.php?topic=13876.0

[upchurchmr]

Most people don't use their boats no mater what.
Most people over buy what they can afford.
Most people loose enthusiam when some little thing goes wrong with their expectations.

Its easy to ascribe global calamity to those circumstances.

I understand and agree that petroleum is a dwindeling resource in a world of increasing population.

The reason boats become too costly to use is the insistance on too much - power, speed, refrigeration, A/C. While I also dislike miniscule "yachts", there is some reasonable level at which you can use your boat. How many have seen 30 to 50' yachts sitting in a marina with crud on the bottom and ropes rotting and 10 years of dirt on the deck. And by that I mean sail boats, which are not necessarily dependent upon any significant cost of fuel.

Except for liveaboards and actual cruisers, how much of the cost of a boat is fuel? How much does it have to be?

I might believe you if the size of cars has not steadily grown in parallel with the cost of gas. Most of them carrying one person.

Gas prices for boats sitting in a marina is a red herring.

Respectfully in complete disagreement, mostly.

Marc

PS I'm sorry this has nothing to do with Wishbone-sailing-rigs, a thread which interests me. I quit on this off track subject.

[Kojii]

Will row the boat out past the breakwater. Sweat - the other green fuel....
:cool:

[High Tacker]

A note on boomless sails and sheeting, also re motorsailing with boomless sails

Rainbow Warrior III tri-sail

sharpii2 above questioned the sheeting of the tri-sail on Rainbow Warrior III to either leg of the A-frame near the top, and that somehow reminded me that I've seen other comments on this forum questioning motorsailing with a boomless sail.

By the way, sharpii2, on this Youtube video of RW III motoring with all 5 sails furled, they look to me to be pretty neatly furled, so I think they are all flat cut. She's a purpose-built ship, the purpose being to chase environmental miscreants, so methinks she'll be doing a lot of motorsailing with her diesel electric power, and flat-cut sails are better for motorsailing, as per my argument here below.

See http://www.youtube.com/watch?v=IjncCTnpPSc

If you search Youtube for Rainbow Warrior III, there are lots of videos, and some with brief bits of her sailing, but I didn't think to single those out. There'll be more, I'm sure. She just went out for a bout of sea trials about a month ago.

Re sheeting of that tri-sail, sharpii2 has a good question, and I intend to ask the designers. I just got a reply to my 2nd pestering email to them asking for more news. They are going out this next week for the second round of sea trials, so there should be more soon. But re that tri-sail, first of all my guess is that with so much overall sail area, the tri-sail is probably used only in light air and then more often motorsailing than not, and in either case it would be sheeted in much tighter than 10 degrees, say, at about 7 degrees when just sailing close hauled, and even tighter for motorsailing. See:

http://sailmagazine.com/headsail_sheeting/

I agree that it looks like a pretty narrow range of sheeting up there to the A-frame legs and not good for reaching, but maybe they have another way of doing it. At any rate, all the sails on that rig are on furlers, and in any thing more than light air, they'd probably just furl that sail and still have plenty of sail area. And when running, maybe the narrow sheeting range doesn't really matter much. Way up there, there would often be enough wind to keep that sail at least part way out to one side or the other, and shape doesn't matter much when running as long as it doesn't just keep flopping down in the lulls, and if it's that dead calm then all of the sails would be useless and they do have motor power. At any rate, the tri-sail would be about as effective running as would a big jib on a narrow monohull without a whisker pole...well, maybe a bit more effective because it's up so high.

Motorsailing with boomless sails

I've seen it said in this forum that a boom is necessary, which is absolutely mistaken, by somebody, I imagine, who had only ever motorsailed with a mainsail on a boom, because his jib sheeting arrangement didn't allow the jib to be sheeted flat enough. If he had simply taken both jib sheets to blocks on pad eyes at points farther aft (and closer to the centerline on an arc drawn between the existing sheeting extremes but farther aft than the track for a self-tacking jib) and then sheeted it tight, say to considerably less than 7 degrees, flattening the jib, then he immediately would have seen some effective motorsailing close to the wind with the jib alone...uh, well, it is certainly very effective on a catamaran with the leeward motor balancing the jib, indeed with two big jibs, one on each bow, flat-cut furling jibs. A jib with built in camber would be another story, but most jibs nowadays are flat-cut furling ones.

Another way of looking at it is that many mainsails have too much camber for motorsailing. A flatter sail is better. Even if the clew can be moved farther back on the boom, still there is usually too much camber built into mainsails, that is, too much for motorsailing, when what you need quite often is a smaller angle of attack of wind on sail, and the more camber the sooner the sail will luff. It's counter-productive to try to fight that by pulling the boom on the traveler too much to windward. You add drag that way, and lose power. It's better to have a sail that can be flattened.

Thus a boomless, furling, flat-cut mainsail properly sheeted can be better for motorsailing than the typical mainsail with a boom. And with the beam of a catamaran and enough sheeting points scattered around the deck, tracks, pad eyes, etc., and using two sheets simultaneously, a boomless sail can be just as good as a boomed sail for any point of sail.

See the photo below of my Catbird Suite on a reach using the genoa attached to the windward bow. Note that there are two blocks on the clew of that sail, so that there are two double sheets, i.e., four ends of rope that can be easily moved around and attached at different points on deck so that I can put the clew of that sail anywhere it needs to be and with the ideal sheeting angle in the vertical as well as the horizontal, all of the sail and gear inboard, nothing outboard and inaccessible and levering the boat around, no tendency to broach. The same for the mainsail and staysail whose tacks are attached on the windward side deck so that the entire width of the boat is available for sheeting down to. No booms needed.

This of course won't work on a narrow monohull, in which case a boom or a whisker pole is absolutely needed when the clew of the sail is outboard of the boat. Of course, a monohull is only half a boat, so the answer in the monohull case is to sell the monohull and get yourself a catamaran. See the following link for all the things you can do when you have a boat wide enough to sheet down to the deck on all points of sail.

www.damsl.com

With a flat sail, you can add camber when you need it simply by moving the clew in along the chord of the sail, i.e., making the chord shorter.

A boom is NOT necessary for sailing to windward

I've also come to realize that many sailors think that booms are necessary for sailing to windward, because so many have questioned the fact that my boat is boomless. And somewhere, in my early days of sailing, I read an explanation of sailing to windward which said that the force of the boom pushing forward against the mast was the actual force that pushed the boat forward into the wind, and hence the necessity of the boom. I don't remember what book that was, not Bolger, I think, but a book purported to be an expert rendering of the physics of sailing. Jibs were relegated to creating the much touted slot effect. I remember wondering then why all jibs didn't have booms, making for both some slot effect and more push??? Of course, with a boom on a jib, you can't have it overlapping the main.

Anyhow, it was a borrowed book, and much later the boom broke on my little boat, which had a loose-footed main attached to the boom only at the clew. I was able to get home by attaching two sheets to the clew and sheeting to two blocks attached near the corners of the stern, flattening the main somewhat in the process, which was good because there was a pretty fresh wind.

Lo and behold, she went better to windward than with the boom. And I realized that when you sheet down to the boat, the boat becomes the boom!

Later on I read about and saw pictures of Arab dhows with lateen rigs, which were the first craft to sail to windward, and without booms, around 800 or 900 A.D., long before European sailors learned to do it.

The one and only GOOD thing that a boom does is to maintain the chord of the sail, i.e., to keep the clew from riding up and moving in toward the tack of the sail, or toward the luff, i.e., to keep the sail from developing too much belly. And if you've got a wide enough boat, you don't need a boom for that one thing.

The force of the boom against the mast serves only to put a bending load on the mast.

I never borrowed that book again, but probably should have, just to see what else could be disproved, so that I might have tried other things sooner. Like, I'm quite sure the book said that it was impossible to sail straight into the eye of the wind. They all said that.

BTW, many of YOU all on this forum have said that. How do you like the taste of crow?

As a little aside here, but apropos to being careful with use of the word "impossible" or always insisting that, if an unheard of way is really better, then it would long since have been thought of and everybody would be doing it already:

see www.damsl.com and on the welcome page look to your left and click on Wind Turbine Rig.

And on this forum, see:

http://www.boatdesign.net/forums/boat-design/sailing-directly-windward-27000-4.html

Back to the subject of boomless motorsailing:

Here's a quote from another thread on this forum,

http://www.boatdesign.net/forums/sailboats/aftmast-rigs-623-32.html#post476746

according to the owner of the boat Lyra in the photo below, the yellow boat with aftmast rig,

"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."

[High Tacker]

Oops! Forgot to attach the photos to that last post. Here:

[High Tacker]

Here's another video of Rainbow Warrior III. There are some sailing scenes about one minute into it:

http://www.youtube.com/watch?v=hhuSpD81FOQ

[sharpii2]

Doom and gloom.

The last 30 years of reading the same story that fuel will begone tomorrow, and everyone will have sails has proven to be a colossal joke.

There are fewer sailboats sold now than in 1980, before the gas crisis.
People will just get use to paying more for their fun.

Most enthusiasts who get on the eco kick produce boats that fail, cause enthusiam does not equal commonsense and knowledge.

You are right.

There will always be fuel and there will always be people able and willing to pay for it.

But that is not what I was discussing.

I was discussing transporting goods over water for profit.

As fuel gets more expensive, either ever larger vessels must be built to lower the gallon/ton/mile ratio, or, failing that, alternatives to straight fuel driven vessels will most likely be used.

When I say this, I'm talking about smaller vessels which must be small to get to out of the way places.

Some day, some shipper, using such a vessel is going to discover that equipping such with sails (which will be used along with the engine most of the time and used exclusively only during the most favorable conditions) will lower his costs enough to make purchasing and installing such a rig a worth while business proposition.

There are any number of reasons sail boats aren't popular these days.

Power boats are more convenient and more versatile than sailboats which are either designed to get around cans the fastest or sail across the ocean blue.

It will take an astronomical hike in fuel prices to rule out straight power boats.

Until that happens (not likely in my life time), straight power boats will continue to rule the recreational boating market.

There are just too many alternatives to chose from.

Planing, semi-planing, power multihulls, and, finally, displacement monhulls.

[upchurchmr]

Sharpi2,

I understand your point about commercial delivery. Its just that there have been several attempts I remember in the last 30 years and they were all disastorous (I sure wish there was a spell checker on this forum, like everywhere else in digital land) failures.

A recent development in my career at an aircraft factory, is my working in a "Affordability" team. Generally it is not too hard to construct an economic model for a change, against which you can check reality and unexpected problems.

Vague predictions just don't provide any way forward. I just wish the forum focused on what could be done, with some concrete way forward - even if it ends up being wrong and has to be changed.

Brave words, but I don't have "concrete" suggestions in this case - I don't understand commercial delivery economics.

[brian eiland]

Please...lets not get into a discussion of sail verse power, ...and where the state of future oil supplies will be. There are other subject threads on this forum that deal with those subjects.

We are interested in alternative sailing rigs here.

Thanks, Brian

[upchurchmr]

My appologies, I really am also interested in the sail rigs.

Actually the cruiser boat information is interesting, but I want to understand a practical way to do something similar on my Tornado catamaran (20') for day sailing. Suggestions would be appreciated.

Of course, I still want the performance. Something about having cake and eating it too.

Marc

[sharpii2]

Hi, upchurchmr.

IMHO, the three main reasons for failure in sail assisted ships during the last thirty years are:

1.) Fuel prices are still too low for them to be competitive. A vessel is a large assortment of compromises. More of one thing usually means less of another. A sail rig structure is bound to get in the way of cargo loading and unloading operations. There is also the issue of speed. A vessel with a 300 ft waterline can easily loaf along at 8 or 9 kts, barely breaking a sweat. Under sail, it would take an exceptional amount of wind to produce the same speed. Now, it is cheaper to go faster and ignore the wind.

2.) Attempts that I have heard of went too far in the name of purity. The only purity a working vessel is permitted is purity of purpose. That is why commercial fishing boats look so ugly. Elaborate rigs with experimental technology have no place on a vessel that must earn its keep. Better to go with something modest and relatively cheap. Like a pair of gaff sails, made as big as possible, but small enough to be out of the way when not used. An S/D of maybe 5 to 7 comes to mind. A rig that small belays any pretense of being a sailing vessel. But the twin gaffs will probably pay for themselves in a remarkably short time. Even at today's prices. Such vessels have existed before, back in the time engines weighed hundreds of pounds per horsepower and had voracious appetites for coal, circa the 1870's.

3.) The vessels with which such attempts have been made on were too large. Even 300 ft is pretty large for a sailing vessel. This is because, as the vessel gets longer, the wave train it produces gets longer too. The longert the wave train, the lower the percentage of hull speed (1.34 * the length of the waterline in feet for knots) it must attain to reach a reasonable speed. Back in the 1980's, the Maldive fishing fleet started installing engines on there lateen rigged double enders. Cy Hamlin, one of my instructors, was involved in the project. There were many problems, all of which had to be worked out in the most affordable way possible. I only bring this up because the Maldive fishermen did not dispense with their sailing rigs. They merely cut them down to a slightly more manageable size. These boats were around forty to fifty feet in length. For even the fifty footer to reach 7 kts, it has to go 75% of hull speed, where a typical cargo vessel has to go only about 50%. So, to get a reasonable speed, the Maldive fisherman has to run his engine at a higher throttle. But a sailing speed of 7 kts is possible well within most wind conditions.

Institutional vessels, such as 'Rainbow Warrior', may well lead the way. This is because they really don't have to compete with other commercial vessels, but are not pure affectations either. Operating costs must be considered. The 'Maltese Falcon' and other super yachts may well end up becoming institutional vessels.

Sorry about the continued segue, Brian. I already had my comments written before I saw yours.

[upchurchmr]

Sharpie2

Thanks for the answer. I'm done, perhaps you could start another thread?

I'm feeling bad about what we did to Brians Thread.

But what about my Tornado?

Marc

[High Tacker]

Hello upchurchmr,

Apparently you are interested in trying an A-frame rig or something similar on your Tornado 20 cat? Daysailing, you say, still high performance, but maybe something safer, easier to handle, more like a cruiser?

If you already have the gear, the beam, etc., for carrying a jib at the center between the bows, probably cheapest and easiest would be an A-frame with just a jib and a mainsail on the centerline, both on furlers, no booms, like the SMG 50 mentioned several times in this thread,

http://www.sail-the-difference.com/home/english/the_features_of_the_easy_to_use_smg_catamaran/smg_50plus/

and Gary Hoyt's Manta Clipper is very similar (see first 2 photos below) although it has a boom on the mainsail.

Or, if you want to play around with a lot of different sail configurations, check out my Catbird Suite at

www.damsl.com

But I would suggest the PYRAMID RIG

It might LOOK more complicated, but another rig that I've experimented with is what I call the Pyramid Rig. It amounts to 3 windsurfer rigs pinned together at the top to form a 3-legged pyramid. All 3 masts rotate 360 degrees. Wishbone booms maintain sail shape on all points of sail. If you get in trouble, you just let the sheets go, and everything weathercocks. You can leave her sitting on the beach with all sails up, or at a dock or a jetty or tethered behind your big boat.

Construction is easy. 3 aluminum tubes of 1 inch circular section, attached to the boat, on hinges if you like so that the rig can be lowered easily, and a bolt at the top through the 3 tube ends all in a row with the jib tube in the middle between the 2 side mast tubes. Every couple of feet along these tubes there is a plastic bushing-type of bearing made of the same kind of stuff that you make prop shaft stern tubes of. These tubes are inner masts and then there is an outer sleeve for each of them and the outer sleeves are 2-inch luff spar sections that slide on over the plastic bearings. So then you have rotating masts which are very strong and can take a lot of bending from the wishbone booms and still rotate around those plastic bearings. The booms are hinged onto pins on the outer mast sleeves.

See the photos below. That tiny jib was ridiculous and I later got a big jib that filled up the foretriangle between the jib mast and the two side masts. I had the little jib made before deciding to go with 1 jib mast in the center instead of 2 jib masts, 1 to each bow. That would have made a 4-legged pyramid. This little cat was actually built as a powercat meant to be driven by an outboard or two, and so it's narrow in comparison to sailing cats, hence a small jib if it had to swing between 2 masts at the bows.

I don't have photos of the big jib, but it was made of dacron. The plastic sails were on the advice of the sailmaker, because a lot of windsurfers had plastic sails. But that was a mistake and I much prefer cloth sails for a number of reasons, not the least of which is that stupid birds will accidentally collide, beak first of course, with see-through sails. Who wants leaky sails?! And they are a pain in the ass to hoist up the groove of the luff spar and to take down, because they have to be rolled up, not folded at all. Dacron will take a lot of punishment.

If I did this rig again, I think I would go with the 4-legged version on a beamier cat, but shouldn't get too long-winded about that here.

You can imagine the advantages of such a rig. You can make it as tall as you want for performance. Yes, there is of course a weight consideration, although I think it could be built of much smaller and thus lighter sections than what I used. I don't think it would be all that much heavier than the conventional rig on a Tornado. And the weight is balanced by the smaller, or re-directed, heeling moment that you get from slanted sails in such a biplane rig, that is, the 2 side masts form a biplane, one side of which is pushing the windward hull down, and the other side is lifting the leeward hull. And since the sails can rotate, you just let them go when heeling gets critical, and they just weathercock. With the wishbone booms, they don't flog like with a conventional boom.

It's very safe downwind, because you let the sails rotate beyond 90 degrees to the wind, so that they are always taking the wind on the proper leading edges and there is no danger of jibing. And do you have trouble reefing your big conventional main downwind, or getting it down? This rig eliminates all that bother. You just let the sheet go, and the sail weathercocks and there's no shrouds in the way.

Anyhow, have a look at the pics below. Note that in some, I was experimenting by using one of the mainsails as a bigger jib, before I got a big cloth jib, and in that makeshift arrangement, the forward end of the boom, where it is attached to the mast, was not high enough, hence the sail shape is not right. Also, the cloth jib was much bigger, its boom much longer.

Note that when the little cat was tethered behind the big cat, with no wind, all the sails fall toward the center, but when the wind got up, they would just weather cock. So I just detached the sheets and left her with sails up. As I said, the plastic sails were a pain in the ass to get on and off.

I sometimes wish I'd done this rig on Catbird Suite, but it would have been much more expensive than the A-frame, because I would have wanted to do it of carbon fiber. Also, the A-frame leaves lots of room for experimentation.

Note that this pyramid rig is very strong. There is very little compression on those masts. And, unlike the vertical bipole rigs on a few cats, which do not have the masts connected at the top, there is no big complication of strength and rotating gear at the base in the pyramid rig, because there is no big bending load at the base, indeed, the masts can be mounted on simple hinges for lowering. Note, too, that there is no great tension involved either, as in conventional rigs, so no need for chain plates.

There is some bending load on the masts from the wishbone booms. It's amazing how much bending the masts can take when there is very little compression. And when bent, they can still rotate when you tighten the sheets, albeit with a little groaning from the plastic bearings. Of course, when you slack the sheet, the bending load is relieved and the mast rotates without complaining. All in all, there is no danger with these booms. They're over your head and there's nothing else for them to bash. But you can dispense with booms if you want, and just not use the leeward mainsail when reaching. Just like with the A-frame, you can sheet down to the boat.

Oops, I somehow managed to delete the first two photos, of Gary Hoyt's Manta Clipper, will attach them to next post.

[High Tacker]

Here are the pics of Gary Hoyt's Manta Clipper, which may actually have been mentioned and shown already on this thread, sorry if this is repetitious.

[brian eiland]

Actually the 'Manta' subject came up several times before. This gentleman even offered that he had some old brochure material....but he never posted it to my knowledge
http://www.boatdesign.net/forums/boat-design/wishbone-sailing-rig-1999-2.html#post26593 (httphttp://www.boatdesign.net/forums/boat-design/wishbone-sailing-rig-1999-2.html#post26593://)

Thanks for those pics...don't find them that often.

[upchurchmr]

High Tacker,

How much sail area did you carry on Lagoon Hopper? What was the mast height? What was the boat length? Did you have a back stay to the peak of the 3 masts?

I assume that when you were on a broad reach the leeward main was badly shadowed and developing no power. It also seems that hard into the wind the jib would shadow the leeward main. Please comment.

You might not be aware, but there was a Pyramid rig discussed by AYRS in the 70's, but it had a central mast with 2 jibs that rotated around the mast. In that case nothing was shadowed until you went directly down wind. I never hear of a real report of the practical aspects.

Marc

[High Tacker]

Hello upchurchmr,

This pyramid rig was very quickly put together and tried, because I had already pretty well decided to go with the A-frame for the big boat, with all furling and boomless sails. But I wanted to give the pyramid a try, and I'd like to see somebody carry on with it.

Sorry I don't remember the exact numbers you asked for, but a lot has gone in and out of my old noggin since then. Am pretty sure that the aluminum tubes used for the inner masts came in 5 meter lengths, so the side masts would be exactly that, with the heads of the sails about a foot below the peak and the foot of the sail about 3 ft off the deck, or enough for sitting head room. The jib mast is longer, so some tube was added to the 5-meter length.

By rough estimate, the rig is just over 15 ft. tall and mainsail area would be considerably less than 40 sq. ft., maybe closer to 30. Sorry, was dealing in sq. meters then and don't remember that either. The jib we finally got was somewhat bigger than the mainsails. Boat length is 14 ft, and as I remember, beam was less than half that. The boat, with rig, is still sitting on the beach in New Zealand, with weeds growing up, through, around and over it, so it ain't goin' nowhere, and I'll be back there in November, and the sails are stowed away there. If you're really interested in exact numbers, I'll get them for you then. But you would want a much taller rig anyhow. This one was very conservative.

There are two backstays, to the stern of each hull, or, rather to the corners of that stainless frame, which then has posts in the same lines to the sterns. The mainsails are sheeted to that frame. The jib mast is stepped on just a 1-inch aluminum tube across the bows and I thought that backstays were necessary to prevent too much downloading on that. So the side masts take a bit of compression, but not much because the sails are all on masts, not wires.

You're right about the jib blanketing the leeward mainsail when hard on the wind. We were able to go to about 35 degrees apparent, with the jib sheeted right to the base of the leeward main mast, in other words, just to the leading edge of the leeward mainsail, so they were sort of acting as one sail. But it was possible to go quite a bit closer to the wind by pulling the jib in tighter, but that de-powered the leeward main. I forgot to mention it, and the post was already getting long-winded, but one way to solve that, or at least improve it, is to have the two side masts closer together. The mains would then be narrower, but you could make the rig taller, have very high aspect ratio mains. Note on the SMG 50 that the masts are stepped apparently on the inboard gunwales of the hulls. But I don't know the beam of your boat. Actually, there's so little compression on the pyramid masts that they could be stepped anywhere on deck, on the bridgedeck, where ever.

This pyramid rig may appear to be heavier than the A-frames, but I don't think that has to be so. There is not nearly as much compression loading, almost negligible in comparison. And the tube within a tube structure, with bearings between the two tubes, is very strong. The outer tube is reinforcing the inner tube. There is a very precise formula for calculating how close together the bearings should be in terms of compression. I've forgotten the formula, but if you don't know it, a good designer could do the calculations for you, or you could look it up. But I think you could go a lot taller with the same diameter and wall thickness of tubes. Compression can be carried around a curve, the trick is just to have those bushing type bearings as close together as necessary. And with the wishbone booms, the masts WILL be bent. How much you can bend the masts is the question. We did add some short sleeves onto which the booms are hinged, to spread that rather than have point loading. You might want to spread the boom load even more.

Another way to deal with the jib and leeward main relationship would be to have a curved track at the base of the jib mast, so that the tack of the jib could swing to leeward, say, almost to the leeward bow. I had thought of doing that, but after deciding to go with the A-frame, I never got around to trying it. If you read some of my long-winded explanation at
www.damsl.com, you'll see what I mean by advantages in moving tacks of sails around.

What I had in mind for a track was to take a length of that 1-inch aluminum tube and bend it to the arc that the base of the jib mast would transcribe in swinging from one bow to the other. The jib mast could be stepped to a ring that would slide along that tube, with a stop at each end of the arc.

Then the tacks of the jib and the leeward main would be more or less in line, fore and aft, and you could get little a slot effect between them, although they would not overlap, of course. I think more important than that, the jib, as well as the leeward main, would be canted into the wind, so that the leeward side of the boat, especially the bow, would get some lift, help keep her from tripping over the leeward bow.

Also, for downwind, you could pull the tack of the jib to one bow or the other, so that the jib would fill the gap between the mains, which you would wing out on either side.

There's actually less interference than you would think between the two mains, except for a small range beginning with the wind just forward of the beam. Once the wind is abaft the beam, everything seems OK, although I found it difficult to judge sometimes with those thick plastic sails. I think what's needed is experimentation using very light cloth sails.

[High Tacker]

upchurchmr,

I think I know of that other pyramid rig you mentioned, or, rather, one that I know of, also called "pyramid" had 2 jibs (or triangular mainsails) which formed opposite sides of a 4-sided pyramid, so the 2 sails formed a biplane canted together at the top in the same way the mainsails on my pyramid do when they are sheeted so that they are parallel to each other, as when pointing. Yes, on that rig, the sails were always parallel to each other, the mast in the center rotated and the sails rotated with it, then one sail would blanket the other when the boat was headed downwind. A friend of mine, a Brit in New Zealand, Neville Skit (not sure of spelling, so long ago) did that rig on a cat, the Golden Kophai, in the 80s. It had some practical advantages. The pyramid was in the center of the boat and he had a big genoa that he would move from one bow to the other, with a wire between the bows as traveler. My girlfriend and I sailed around Fiji with Neville and his wife Sheila on that boat for a couple weeks, in the early 90s, and then again for about a week down the east coast of New Zealand's North Island.

[upchurchmr]

High Tacker,

Thanks for all the information. It should be enough, just knowing the height of the masts gives me a good understanding, along with the length of the boat. My goal would be to put more sail up than the normal Tornado, on a shorter mast height. The old classic Tornado was limited to 235 sq ft. on a 31' mast. Of course it doesn't really work if one of the mains is blanketed.

Thanks,

Marc

[sharpii2]

Sharpie2

Thanks for the answer. I'm done, perhaps you could start another thread?

I'm feeling bad about what we did to Brians Thread.

But what about my Tornado?

Marc

I don't completely understand what your goals are.

Are they to get the mast off the cross beam? End up with a giant jib?
Or something else?

IIRC, a Tornado has a 3/4 fractional sloop rig. Such imposes very little stress on the hull structure for its performance capability. The main issue is holding the mast upright and maintaining adequate tension on the jib luff.

With an 'A' frame mast, you can have a clean luff on the main as well as the jib and, perhaps get better performance. But the long main luff needs to be to be held tight as well as the jib (with much greater tension, due to its longer length). This may end up putting more stress on hull structure rather than less, even with the elimination of shrouds.

A compromise would be to put ladder rung like spreaders between the two legs and run a much narrower spar up across them, between the two legs.
To this, the mainsail could be attached.

Now you have eliminated the long, unsupported, main luff and replaced it with a spar with a much smaller cross section than the original mast. This might provide some performance improvement at the expense of greater top hamper.

A third approach is to go with a tripod mast, with the main, sail carrying portion, running up from the very bow and canting aft so the mast head is even with the transoms of the boat. Two shorter legs come up from each side of the boat to meet the main leg somewhere near its mid point.

To the long center leg, the roller furling sail is attached. Viewed from the side, this looks like a very tall lateen sail.

Now you have eliminated the very tall 'A' frame, the spreaders, the narrow spar between them, and the jib stay. You have replaced them with a thicker spar in front of the sail, giving up some performance, but have reduced top hamper and have all but eliminated sailing stresses on the cross beams.

Now you have a single sail, which may make up for some of the loss of efficiency.

The biggest advantage of this rig will be raising it. A block and tackle could be placed at the apex of the two shorter legs to raise the longer center one. These two shorter legs could be set up to pivot fore and aft. Pulling on the block and tackle will cause the two shorter legs to pivot upward and raise the long center leg as well.

This would be a revelation in simplicity compared to raising the more conventional rig. It could be done safely even in a strong cross wind.

Most likely, a more conventionally rigged Tornado will beat you in any kind of a race, though.

I don't think what Brian did would work with your boat. Going with the bipod mast eliminated the need for heavy shrouds very long spreaders, not to mention the downward loads they would put on the wing deck. But he still has back stays and back spreaders to hold the jib mainsail luff tight. No doubt, the wing deck and hulls were designed and built in anticipation of the loads these would impose. Not so with your boat.

[High Tacker]

Just want to point out another advantage of A-frame rig: there's no mast stuffing up the view from cockpit or saloon (see below), and on Catbird Suite, there's no boom either. See

www.damsl.com

Barbara likes that at the wheel.

[High Tacker]

And there's no danger of bashing by boom when you poke your head out for an even better view:

[brian eiland]

High Tacker, you certainly make a good case for alternative rigs.

And thanks for all those great photos and explainations. I've been a little busy with other matters to keep up with everything lately.

[brian eiland]

One question comes to mind concerning such a rig. Have you experienced any problems with the integrity of the junction at the masthead??

Those are long lever arms that can excert lots of conflictng forces at the masthead, depending upon the individual movements of their bases at each hull.

The single-hulled Procyon (http://www.boatdesign.net/forums/sailboats/procyon-project-bold-experiment-10771.html) even experienced some such problems.

[High Tacker]

Re: masthead detail photos below

Hello Brian,

Not very much ever escaped ol' Malcolm Tennant's attention. See pics below for his solution to stresses at the masthead. Each leg of the A has a sizable plate welded to it at the top, and these two plates are then bolted together. Note that the bolts have advantage of being scattered over some considerable area. I forget exactly how long the plates are, something like 1.5 m. Note that they are quite long relative to mast fore and aft section length. Note also the outline of black, which is the edge of a thick rubber gasket between the two plates to allow flexibility for some motion. Also, the boltholes are slightly bigger than the bolts. Malcolm said that if there was no such allowance for motion, then there would be a problem, stress cracks developing and so on. I think Procyon's problem was that there was a rigid connection at the top.

Also, for flexibility at the other two corners of the triangle formed by A-frame and boat, the two legs of mast are stepped on pedestals, each pedestal on the corner of two very strong interior bulkheads (one fore and aft, one across). The masts actually are sitting in collars on stainless steel plates that are sitting on the pedestals with thick rubber gaskets providing flex between the plates and the pedestals, and the plates are through-bolted to chainplates on the interior bulkheads (that spreads the compression load, and can also take tension because theoretically one mast or the other could at times be in tension).

Another allowance for movement is that the bases of the masts have rocker, in other words, the base of each mast tube is cut in a slight curve, so that the masts can actually rock, tilting fore and aft within stainless collars welded onto the base plates and through which collars the masts are pinned athwart ship. Sorry I don't have photos of the mast bases handy, am still traveling. To sum up, there is flexibility at the top and at the bottom(s) of the A-frame.

To shape the plates at the masthead in the form of a bird, a profile of a catbird, was my idea. The catbird builds its nest in the highest tree around, is a predator who then swoops down on its prey. Hence the expression, to be "in the catbird seat" is to have a very big advantage, like, on top of the world. It is an American bird, and there is a famous James Thurber short story, "In the Catbird Seat". I took some liberties with its profile, gave it more of a hawk's curved beak, whereas a catbird actually has a straight beak. The boat herself has a suite of cabins and a suite of sails (all with pics of Catbirds on them), and she is my symphony, hence the name "Catbird Suite".

More at www.damsl.com

[Bendigonian]

Guys,

One major advantage of the 'A Frame' has to be the possibility of mast lowering and possibly even folding in sections for motoring along rivers. Somewhere or other I found images of an 'A Frame' cat with, what looks like, the rig mounted on raised pedestals to keep it above head height after lowering.
It's a bit hard to tell, the image is small and low-def, but it does look like there are hinges about 5' up.
Does anyone know of this cat? My only info is the image name..'Dinghy trip 039.jpg and that it was seen on the St Lawrence.
It also has what looks like an entrance in the front of the cabin to the foredeck, similar to the South African SMG-50+; another advantage when you don't have a big stick stuck in the middle of the deck.
Update. I had a note from Phil who took this pic and put it up on BD a while ago, but he doesn't have any more info. Anyone else?
http://sandhurstpublications.com/AFrame039.jpg

[High Tacker]

Bendigonian,

I searched my files and have only that same pic, labeled the same. It was sent to me by one of the guys at Dykstra & Partners, the designers of Rainbow Warrior III, along with some other examples of boats with A-frame rigs. I'm waiting to hear back from him about the second round of sea trials with RWIII, so will ask him then if he has more pics of the cat that you're interested in. You mention the SMG-50 and its forward cockpit with no big stick obstructing. In the pics below, it looks like the legs of the A-frame on the SMG-50 may be hinged at the very bottom. If I remember correctly, Procyon's A-frame also was hinged. And I'm pretty sure that Brian Eiland has posted pics of Procyon on this forum, probably on this thread.

You've probably seen the SMG-50 website, but just in case, here's the link to the photo gallery there:

http://www.sail-the-difference.com/home/english/gallery/number_one/

[High Tacker]

When we were designing the A-frame rig for my boat, Catbird Suite, the idea of hinging the legs of the A-frame for lowering did occur, but I was put off by the added complication, and cost, of doing it without weakening the rig. Besides, for cruising inland waterways, I'd choose a long, skinny canal boat covered in solar panels, a small wind turbine or two, and electric drive, instead of a big and beamy catamaran with sails. Horses for courses.

Of course, to be able to lower the mast is an advantage, if that's what you want. Some of the A-frame-rigged boat designers have done that, but I think they've mainly chosen the A-frame for strength to support several furling sails, and the advantage of not having a mast in front of the mainsail, spoiling the air flow. And the catamaran designers among them were clued up enough to realize that with the beam of a cat you don't need booms. But, to my knowledge, all the other A-frame boats still adhere to the conventional, vertical, fore and aft, sail configuration.

My main consideration in choosing the A-frame was for strength, stepped down through the hulls, to withstand the compression loading of lots of sails on furlers, since I consider roller furling (and reliable roller reefing) to be the single greatest development in sailing in the past couple of centuries. Second only to that was the idea that if some of the sails were on what I call soft furlers (no luff spars), that would open up many possibilities for experimentation.

Not only does Catbird Suite have a very strong A-frame rig with 4 furling sails (and plenty of room for more), the deck layout allows for a number of unusual and advantageous sail configurations, in addition to the usual vertical, fore-and-aft configuration. I think of her as two proas leaning together. The mention of canted sails, as on a proa, usually brings to mind the boats that are out to break speed records. (See for example, the thread on Sailrocket on this forum.)

Catbird Suite has a good turn of speed, but she is a big and luxurious cruising boat. And since cruisers typically are more interested in safety and good performance in light winds than they are in setting high speed records, I'd like to point out some of those particular advantages of proa canted sail geometry on a catamaran.

The mainsail and staysail on Catbird Suite are on soft furlers so that they can be easily moved around and the tacks of the sails attached to different positions on deck, not just on the centerline of the boat as with conventional, vertical rigs. I use them on the centerline for short tacking. But they can be moved and their tacks attached to either side deck so that the sails can be canted into the wind for speed and lift, or canted away from the wind for ease of handling, peace of mind, ideal sail shape with no booms or poles, and good performance in very light airs without the nuisance and wear and tear of the sails continually flopping down in the lulls.

On a long, passage-making tack, for convenience, safety in high wind speeds, and efficiency in very light winds, I attach the tacks of the mainsail and staysail to the windward side deck, so that, in combination with the genoa attached to the windward bow, there are then 3 sails, all canted away from the wind. The entire width of the boat is then available for sheeting, so that no booms or poles are needed in order to maintain ideal sail shape, all the way from close hauled through reaching to running.

Cat sailors know that big cats are very unforgiving, i.e., the rig and sails suffer a lot of shock loading in gusts because there isn't the shock absorbing effect of heeling and spilling of wind as with a monohull. With the sails canted away from the wind as described above, the sails are already heeled even though the boat is not heeled, so that there is some spilling of wind in gusts. Of course, with a cat of this size, you don't fly a hull, indeed something would probably break first, but if she ever did start to heel, the spilling from the already heeled sails would be dramatically increased.

See www.damsl.com and on the welcome page look to your left and click on A-frame Rig and you'll get my longwinded explanation of all the advantages.

It is also advantageous in very light airs to have the tacks of the sails attached to the windward side and thus the sails are leaning away from the wind so that they set into proper aerodynamic shape by the effect of gravity, whereas, if the sails were vertical there would often not be enough wind to lift them into shape.

You remember when sailing a little dinghy, when there is very little wind and your sail is just hanging there and flopping, you move your butt over to leeward to heel the boat a bit so that the sail will fall into shape. So in very light wind, as soon as I unfurl a sail, I'm away, while all those vertically rigged boats have sails hanging like so much laundry, all drag, and so are going backwards. Also, my sails don't come flopping down in the lulls; they're already "down" but are hanging in proper shape, and so maintain their shape, ready for the first breath of wind to come back. See the pics below for ideal sail shape in very light airs.

[Spiv]

The mainsail and staysail on Catbird Suite are on soft furlers so that they can be easily moved around and the tacks of the sails attached to different positions on deck, not just on the centerline of the boat ...

A really good idea; how did you solve the sheeting for so many different tack positions?

[High Tacker]

A really good idea; how did you solve the sheeting for so many different tack positions?

In the first photo in my last post above, you can see that the genoa has two blocks on its clew with a sheet around each block, so, 2 double sheets, 4 ends of rope that can be moved around to various pad eyes and tracks on deck, which are bolted through to beams and chainplates on interior bulkheads, as are various tangs for attachment of tacks of the sails, and the tangs also serve as sheeting points.

All of the sails are rigged with 2 blocks at the clew. Sometimes one of the double sheets is slack when not needed, as in the photo above. Other times, both are used, with one end of each sheet led back to a winch on either side of the cockpit, and the other ends attached to appropriate points on deck. In general, with 4 ends of rope, 4 angles, 4 vectors, to shift around, you can put the clew of the sail anywhere you want in the space above the boat. That is, when the tacks are attached to the windward side so that the sails are always over the boat. If you want to cant the sails INTO the wind, i.e., attach them to the leeward side, it works close hauled without poles, but for reaching, then whisker poles are needed in order to maintain ideal sail shape, because, of course, the clews are then outboard.

On a long tack, as I said, for convenience, ideal sail shape without booms or poles, safety, and performance in light airs, I usually cant the sails away from the wind by attaching the tacks on the windward side of the boat. An additional safety factor is that with all of the sail area directly over the boat, on a beam reach, for example, there is no sail area way outboard and levering the boat around and tending to broach. Also, all of the gear is reachable from deck, inside my big, trusty handrails. I'm too old to be crawling out on booms.

It's amazing to me that some sailors still think that booms are necessary, even on a cat. Of course, a monohull needs a boom because it's only half a boat and thus not wide enough. I'll never forget reading somewhere, in my youth, that the force of the boom pushing against the mast is the force that propels the boat to windward. What sheer nonsense! I discovered otherwise when the boom on my little boat, attached to the sail only at the clew, broke. I was able to get home because I had two blocks that I attached to cleats at the corners of the stern, and sheeted to them. So the boat itself became the boom and actually pointed better. That was a borrowed book that I had read, that claimed to be about the "physics" of sailing, and I never bothered to borrow it again.

And I remember reading somewhere in one of these forums that, when motorsailing, a boom is necessary because you need to pull it to windward on the traveler. Which is also nonsense. No booms needed when motorsailing. Indeed, the flat cut of a furling boomless sail works better than a cambered main for motorsailing, IF you sheet it properly. Some motorsailors think otherwise simply because their jibs don't have proper sheeting points for motorsailing and it hasn't dawned on them that that can easily be remedied.

[Spiv]

In general, with 4 ends of rope, 4 angles, 4 vectors, to shift around, you can put the clew of the sail anywhere you want in the space above the boat.

When reaching I have been using a second sheet attached to a block on my spring cleat and adjusting the clew to the optimal position; your system allows even more flexibility.
Thank you for sharing your knowledge.

Incidentally, I have seen some interesting boomless rigs in Turkey and posted some pics on the mainless thread. (http://www.boatdesign.net/forums/multihulls/main-less-rig-21274-3.html) (I hope this link works...)

[Angélique]

http://www.boatdesign.net/gallery/data/500/medium/399WishboneMast.jpg
click pic to enlarge (http://www.boatdesign.net/gallery/data/500/399WishboneMast.jpg)

Still looking for someone who knows a person onboard this vessel............north west USA

http://www.boatdesign.net/gallery/showphoto.php/photo/1075/password//sort/1/cat/500/page/1

It's been 8½ years Brian, but here she is for sale / sail . . . . .



http://sfbay.craigslist.org/eby/boa/2780025525.html

What is that thing? Would it sail? ... I don't even know what to ask!

Sleek Apocalyptic Survival Sailboat/Motorboat - $27000 (Bodega Bay)

Date: 2012-01-02, 2:49PM PST

Reply to: sale-burvs-2780025525@craigslist.org (mailto:sale-burvs-2780025525@craigslist.org?subject=Sleek%20Apocalyptic%20Survival%20Sailboat%2FMotorboat%20-%20%2427000%20(Bodega%20Bay)&body=%0A%0Ahttp%3A%2F%2Fsfbay.craigslist.org%2Feby%2Fboa%2F2780025525.html%0A)

47'x9.5'x5.0' long, narrow, shallow draft Kevlar, carbon fiber, epoxy, solidly constructed, high hull speed, extra long range expedition vessel. Massive tankage, radar, plotter, forward looking sonar, hydronic heater, hydraulic steering, Lavac head. 12 tons loaded, 4 tons internal lead ballast.
6'4" headroom throughout. Brand new out of the carton Cummins diesel and drive train now with 100 hours.
CALL Max at 310.991.4202

Location: Bodega Bay

65687 65688 65686
click thumbs to enlarge (a bit)See the thread - OK... would someone explain this to me? ... (http://www.boatdesign.net/forums/boat-design/ok-would-someone-explain-me-41200.html)

Cheers,
Angel

[Guillermo]

It's been 8½ years Brian, but here she is for sale / sail . . . . .

See the thread - OK... would someone explain this to me? ... (http://www.boatdesign.net/forums/boat-design/ok-would-someone-explain-me-41200.html)

Cheers,
Angel
$27000....???
Perhaps an additional "0" ? ;)

Cheers!