When NOT to use full length battens?

[Grant Nelson]

Hi,
My original question was going to be 'when should I consider full length battens' thinking that the answer would be based on some percentage of roach to main sail area, or aspect ratio, or something.

But then I scanned a few sail maker web sites and it seems that full length battens have many advantages, even when you do not have much of a roach. For example holding the sail shape, and perhaps for most of us, increasing the life time of the sail. The only down side seems to be that they tranfer more compression to the luff, and the hardware there, with a chance of jamming, and when running off the wind, you have the chance of a 'step' or V forming near the mast.

In some cases you can use a mix, some full battens up high, and 'normal' down low.

So, now my questions is: when you you not want to use full length battens? Of course you can always answer my origional question if that is eaiser.

Thanks!

Grant

[gonzo]

You don't want to use full length battens when the rig was not designed and built for them.

[Grant Nelson]

I am not sure what I can do with that reply Gonzo.
Does it help to say this is not for a existing boat, but for a new design?
Or, let me ask, what are the particular rig design aspects that are required for full batten sails? I have to admit I never though about it but can only think that you need non-jaming mast track hardware...

[Kaluvic]

You don't want to use full length battens when the rig was not designed and built for them.

Not sure why...is it because of structural considerations?
Not sure I would agree.

[Steve W]

Gonzo, could you please elaborate on what structural differences there would be with a rig "designed to use full battens" vs one that is not ,i for one am not aware of any other than perhaps some retrofit items such as articulating cars.
Steve.

[gonzo]

Clearerance with the backstay, adequate sail slides or bolt rope, batten pockets, sail track,

[Kaluvic]

When I think of going to a full batten....the length of the batten increases toward the mast not the back stay...
Depending on the track you have, batten cars may be added.
I think if you were to go to a full batten its a given that the batten pockets would be modified.
So am I correct that your concerns about the rig are not structural?

[Steve W]

Those are all sail related issues,not anything special relating to rig design,while hardware manufacturers would like us all to have expensive car and track systems i have noticed that the F series trimarans have always had large full battened mains without such hardware,in fact they really cant as they roll the sail around the boom to reef or furl,they must work ok as they have stuck with it for decades.
Steve.

[Kaluvic]

I'm certainly no expert....but I can't think of any time that a full battened main would not be preferential.

[sharpii2]

....in fact they really cant as they roll the sail around the boom to reef or furl,they must work ok as they have stuck with it for decades.
Steve.

That they roll sail around the boom is probably the reason why the batten ends don't get stuck. Both ends of the batten are being pulled down more or less evenly.

It's when they are pulled down unevenly they are most likely to get stuck. That is unless they have some kind of roller or slide.

That just goes to magnify Gonzo's point.

The rig must be originally designed for them.

[Kaluvic]

Why....there are batten cars for a variaty of slides...I still dont get it.

[PAR]

As in everything with yacht design, full length battens have their issues too.

A big one is weight. Once you count up all the cars, additional related hardware and the battens, you've now increased weight aloft substantially.

Next on the list is cost. Price out a retro fit for a full up system, compared to a replacement bolt rope or slide sail with conventional battens. When your ass cools down a bit we can talk.

For a cruiser, full battens may not be as logical a choice as the 'round the cans guys. The cost, the maintenance, the wear and tear, plus the weight just don't seem as conducive to leisurely sailing.

Reefing is another well known problem. So much so they compromise batten position to accommodate roller booms.

Binding and jamming use to be big issues, but has for the most part been engineered out of the new systems, though, don't keep up on the maintenance and you'll wish you had.

[yipster]

first thought up, rulings, rulings like AC dont allow full battens
but offcourse there is much more on battens

[gonzo]

I've known several people that got rid of full battens in cruising boats because of the amount of wear and maintenance of the parts.

[Kaluvic]

That’s interesting...and makes sense...most cruisers I know would sacrifice some performance if there is a big maintenance bullet to bit for having it.
Good stuff...thanks!

[Paul B]

rulings like AC dont allow full battens


The AC has allowed full battens since 1988.

[Paul B]

You don't want to use full length battens when the rig was not designed and built for them.

This is nonsense. Most of the boats out sailing using full battens have rigs that were "not designed and built for them."

I agree with most sailmakers to use two or three full upper battens and normal battens for the remainder of the sail.

On smaller boats, say up to maybe 35 feet, you can use a simple bolt rope luff. The inner ends of the batten pockets have cups, normally with the tensioning device located there.

If your mast is set up for slides there is hardware for that.

When you get to a larger boat you might need to have track and cars for the luff.


I have sailed on many boats with full battens (upper two and all, bolt rope and track/car types) and have never had any of them jam. Listen to your sailmaker's recommendation.


So, to answer the initial question, don't use full battens if you are not planning to use the correct hardware for the application. Of course, this goes for every system on your boat.

[Grant Nelson]

Wow, interesting discussion, and as always with sailers and designers, a lot of different views.

Indeed my original question was based on designing a new rig, so retrofit issues are not relevant for my case.

The main down sides seem to be weight aloft and increased cost.

1. I would be curious, for a new design, what the weight and cost difference would be with a short battened sail.

2. The issue of extra maintenance came up. Is that true? Everythig I read said at least the wear and tear on the sail was significantly less, and so the sails last longer. I assume with the right track and slides, there will also be no additional maintenance. Am I missing anything.

Overall, it looks like, if costs and weight are not a problem, that full lenght battens, certianly in the top 2 or so slots, is always a good idea. Does everyone agree? ;-)

Grnt

[Paul B]

The main down sides seem to be weight aloft and increased cost.

1. I would be curious, for a new design, what the weight and cost difference would be with a short battened sail.

Overall, it looks like, if costs and weight are not a problem, that full lenght battens, certianly in the top 2 or so slots, is always a good idea. Does everyone agree? ;-)

Grnt

I think you will find that the weight difference of having the two top battens full is almost nothing.

The cost should not be a great difference. You are talking about the cost difference of longer battens and the inboard cup/tensioners. Of course this could change based on the size of the boat you are talking about. How large is this boat?

On my new main with 2 full length upper battens the sailmaker quoted it that way to begin with, since it is pretty much the standard way to go now. The other 3 battens are not full. This replaced my previous main that was full battens top-to-bottom, and that full batten sail replaced a main with no full battens at all. All three configurations have fit the same mast with no modifications.

[gonzo]

Paul B. : I know you want to win an argument, but claiming that most boats that have full battten mains were not designed for them is strectching the truth to the point of breaking it.
The problems I've seen in retrofits, are for example the loosening of the forestay each time you tack. Also, a very fast and coordinated crew has to work the backstay.
Another problem is that to keep the main flat downwind so the battens don't wrap aroung the shrouds, the vang needs a lot of tension. Dacron sails get stretched out of shape pretty fast. Also, the compression in the mast and boom can break the mast, specially while jibing.

[bistros]

From a small performance boat sailor's perspective, full battens emerged as a way to put more sail area up higher into better wind, increasing aspect ratio, while also enabling "automatic" depowering when coupled with a suitably flexible mast and standing rigging.

Backstays, reefing and most cruising considerations were never on the radar of Australian skiff sailors and British high performance designers.

Julian Bethwaite created a high aspect ratio, high horsepower rig for Grand Prix 18 foot skiffs that could automatically depower in gusts by using a highly flexible fiberglass top mast section. A lot of fully battened designs were done as (lack of consistent) roach measurement in development classes allowed much more sail area while still keeping inside the legal specifications of the class.

Using a fully battened design in a multi-purpose keel boat design is something I'd consider carefully, as the performance gained under a few specific conditions may be outstripped by adding more crew sail handling jobs, fewer reefing options and higher expense.

--
Bill

[jmolan]

http://books.google.com/books?id=nOdU3dIbANoC&pg=PA218&lpg=PA218&dq=larry+pardey+mainsail&source=bl&ots=2rgM--MBJ_&sig=xKeGBK_yJ8vFePakc3BTIkynY9g&hl=en&ei=DRdfS4q5MYmCswPSm-nCCw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAoQ6AEwAA#v=onepage&q=larry%20pardey%20mainsail&f=false

See if that link works. It is a chapter on a true cruising mainsail.

Also I recieved this from the designer of my boat. John Marples is no stranger to what make a boat go fast either:

The dimensions for your mainsail are; cloth wt. 7.25 or 8.0 oz., Luff 35.2', foot 12.2', Leech 37.0', area 215. The most critical dimensions are the setback (mast to tack cringle distance) and height of the tack and clew cringles. The roach "plus" should not exceed about 12" to avoid conflict with the backstay. If loose footed ( no boom attachment - always my choice) then have the sailmaker put a "D" ring at the clew. That is a stronger attachment.

Our mainsail for the Pacific cruise was battenless, with a slightly hollow roach. After 2 years and 20K miles, it looked like new - no chafe, no failures. It was loose footed with a D ring and without a headboard. It had a smaller area than the battened main, but it could be dropped on a downwind course, in heavy wind, without hanging up on the spreaders. I prefer battenless mains for that reason.

[Steve W]

Steve Dashews boats always have huge roach of course supported by full battens but unlike multihulls they also have backstays,the interesting thing is that they arrived at it by a mistake by a sailmaker,they put up a new sail and it had way more roach than it was meant to and overlapped the backstay by feet,they decided to give it a try anyway and found it sliped through ok so they just sewed strips of uhmwpe around the leach and then it worked great so he kept using maxi roach.
This is a timely subject as im due for a new main and am looking to do a roller boom so will probably use full battens without any car system.I have just posted a bunch of questions on another forum looking for input from f boat owners as their settup is very simple but i need to know how well it works for them.
Steve.

[Paul B]

Paul B. : I know you want to win an argument, but claiming that most boats that have full battten mains were not designed for them is strectching the truth to the point of breaking it.

I don't want to win, or even participate in an argument. But someone has to step in when someone like you simply makes things up. You seem to do this often. You should learn to sail before calling me a liar.


The problems I've seen in retrofits, are for example the loosening of the forestay each time you tack. Also, a very fast and coordinated crew has to work the backstay.

Most keelboats I have sailed with full battens have NEVER had any issue with loosening of the forestay during a tack (loosening is actually beneficial when it is light and/or lumpy, the reason we make sure not to trim on the runners too quickly in racing boats). The thing you can't seem to understand is in monhull keelboats there are more pinhead mains that fit nicely through the backstay that have a full batten for the upper two battens than there are fully top-to-bottom battened sails. My boat, for example, has a pinhead main with two top full battens and it tacks and gybes through the backstay with no more effort than a sail without any full battens. There are thousands of sails out there just like it, most on boats that started life without any full battens.

What boats have you sailed where the forestay has loosened on each tack?


Another problem is that to keep the main flat downwind so the battens don't wrap aroung the shrouds, the vang needs a lot of tension.

Some of us who know how to sail do actually use the vangs on our boats, regardless of whether our battens are full or not. By the way, the vang's purpose is to control twist.


Dacron sails get stretched out of shape pretty fast.

By battens?


Also, the compression in the mast and boom can break the mast, specially while jibing

Please tell us ONE instance where a mast was broken by the force of battens!

[Paul B]

Using a fully battened design in a multi-purpose keel boat design is something I'd consider carefully, as the performance gained under a few specific conditions may be outstripped by adding more crew sail handling jobs, fewer reefing options and higher expense.

--
Bill

What are the added crew handling jobs?

What do you think there are fewer reefing options? I don't see why a sail with full battens in it can't have just as many reef points in the same places as a sail without full battens.

[gggGuest]

A lot of fully battened designs were done as (lack of consistent) roach measurement in development classes allowed much more sail area while still keeping inside the legal specifications of the class.
I really don't believe that's true.: its certainly not the case in any of the southern hemisphere development classes. Large roaches etc came decades after fully battened rigs. Take this late 50s photo (taken in New Zealand)
http://www.sail-world.com/photos/Alt_Mercury%20GBC.JPG
from sail world as an example. http://www.sail-world.com/photo.cfm?NID=64860&Pid=74857

I'm not prepared to comment on ballasted boats, but I would say (with about 34 years of personal experience behind me) that the quality of information on this thread as regards rigs on dinghy sized boats is not great. I have not owned a boat that retained a short batten main sail in all that time.

[Paul B]

so they just sewed strips of uhmwpe around the leach and then it worked great so he kept using maxi roach.

Steve.

Even 25+ years ago we used to put low friction tape on the batten pockets of Hobie Cats where the batten pocket would touch the shroud when running. This prevented any damage to the sail.

Today you can go to the McMaster-Carr website and order some great teflon tapes with super adhesive for any part of the sail that you want to slide by the backstay, no need to sew in any UHMW strips. The stuff is actually made to line automated production line chutes, so it is made to take a lickin'.

[bistros]

I really don't believe that's true.: its certainly not the case in any of the southern hemisphere development classes. Large roaches etc came decades after fully battened rigs. Take this late 50s photo (taken in New Zealand)
http://www.sail-world.com/photos/Alt_Mercury%20GBC.JPG
from sail world as an example. http://www.sail-world.com/photo.cfm?NID=64860&Pid=74857

I'm not prepared to comment on ballasted boats, but I would say (with about 34 years of personal experience behind me) that the quality of information on this thread as regards rigs on dinghy sized boats is not great. I have not owned a boat that retained a short batten main sail in all that time.

You have to live here to believe it. Snipes, Lightnings and Wayfarers abound and there isn't a B14, Tasar or Cherub to be found. Since you live the southern hemisphere and apparently haven't had to watch 1930's boats drift around the lake as the biggest fleet, your comments only apply locally.

Enforcing ancient fleet solidarity and killing off new high performance boats is a revered art form and popular social event here in North America. It never fails to amaze me that the most active I-14 fleets in North America are here in Toronto, Ottawa and New England - and the midwesterners are still sailing Flying Scots, Thistles and Buccaneers. I sail out of the largest club in the area, and there is more Dacron here than laminates.

The main sail roach measurement issues I was referring to was particular to the I-14s - they only recently agreed upon roach measurement standards at the last worlds in Sydney if I recall correctly. We've got everything from One Design 14s to B5s at our club and you can quickly see the sail area progression over time as you look at sails laid out on the ground. My thesis about development classes growing sail area & aspect ratio using full battens is pretty well borne out by the range of boats I see here.

Be glad you live in a modern part of the world where skiffs aren't thought of as tools of the devil for crazy folks. You are lucky!

--
Bill

[Steve W]

Paul,while the adhesive backed tapes may last a while on smaller boats before peeling off im thinking that on serious offshore boats like the Deerfoot etc they are using something more like Ski/Snowboard base material which is what we used on my sons boat as the roach overlaps the backstay by over a foot, this as well as a flicker works fine as long as there is breeze, a pita in the light tho.
Steve.

[Zed]

I have full battens on slugs, no issues with binding or wear. I think one hell of a lot is down to how the sail is constructed, angle of battens etc.

In the past I have used a fully batten main on a masthead rig not designed with them in mind, again on slugs and again no issues with durability binding or wear.

They are heavier...

Performance was better, light air was better, better heavy air performance, easier reefing, less flogging, easier handling (with jacks)... all in all there was not much negative to pick on...

The only Caveat is that the sail maker is good & experienced with them.... (should not be an issue these days!)

...but that is JMO.

[Zed]

I'd have thought that if you are sailing a boat that has to drop backstay tension to tack the main it would likely be fractional, then either the caps keep fore stay tension or you have runners... either way you are talking about a racing boat IMO.

[CT 249]

You have to live here to believe it. Snipes, Lightnings and Wayfarers abound and there isn't a B14, Tasar or Cherub to be found. Since you live the southern hemisphere and apparently haven't had to watch 1930's boats drift around the lake as the biggest fleet, your comments only apply locally.

Enforcing ancient fleet solidarity and killing off new high performance boats is a revered art form and popular social event here in North America. It never fails to amaze me that the most active I-14 fleets in North America are here in Toronto, Ottawa and New England - and the midwesterners are still sailing Flying Scots, Thistles and Buccaneers. I sail out of the largest club in the area, and there is more Dacron here than laminates.

The main sail roach measurement issues I was referring to was particular to the I-14s - they only recently agreed upon roach measurement standards at the last worlds in Sydney if I recall correctly. We've got everything from One Design 14s to B5s at our club and you can quickly see the sail area progression over time as you look at sails laid out on the ground. My thesis about development classes growing sail area & aspect ratio using full battens is pretty well borne out by the range of boats I see here.

Be glad you live in a modern part of the world where skiffs aren't thought of as tools of the devil for crazy folks. You are lucky!

--
Bill

Jim's right, there were fully battened mains in development classes and some one designs here in Australia and in Europe for many years before particularly large roaches came along.

I think you'll also find that automatic depowering in bermudan rigs really came to the fore in short-battened classes, namely Stars, Swedish canoes and their descendant, the Finn.

[gonzo]

I don't want to win, or even participate in an argument. But someone has to step in when someone like you simply makes things up. You seem to do this often. You should learn to sail before calling me a liar.
You claim that most boats with full battens were not designed for them. That has nothing to do with me knowing to sail or not. It is just a false claim.



Most keelboats I have sailed with full battens have NEVER had any issue with loosening of the forestay during a tack (loosening is actually beneficial when it is light and/or lumpy, the reason we make sure not to trim on the runners too quickly in racing boats). The thing you can't seem to understand is in monhull keelboats there are more pinhead mains that fit nicely through the backstay that have a full batten for the upper two battens than there are fully top-to-bottom battened sails. My boat, for example, has a pinhead main with two top full battens and it tacks and gybes through the backstay with no more effort than a sail without any full battens. There are thousands of sails out there just like it, most on boats that started life without any full battens.

In any rig where the forestay is at the top of the mast, loosening the backstay will loosen the forestay too. My answer to that would be hundreds of boats.

What boats have you sailed where the forestay has loosened on each tack?

All the boats with masthead rigs if you loosen the backstay


Some of us who know how to sail do actually use the vangs on our boats, regardless of whether our battens are full or not. By the way, the vang's purpose is to control twist.

With extra roach the vang tension has to be higher to control twist


By battens?

?


Please tell us ONE instance where a mast was broken by the force of battens!

Read my post. It is the extra compression on the mast by the boom. That is the main cause of broken masts during jibing.

[Paul B]

Read my post. It is the extra compression on the mast by the boom. That is the main cause of broken masts during jibing.

Your posts get more and more bizarre.

OK, please tell us ONE instance where the load on a boom was increased by adding full battens, so much so that the mast broke in a gybe because of the addition of full battens to the sail.

[kim s]

I am fearfull of saying much here in case I get my head bitten off:eek:
I am a confirmed Expereinced cruising sailor and a keen novice w/e racer (what I lack in ability I make up for in enthusiasem.) I "thought" that one of the problems i have with fully battened is that once the batten tension is sett, then it is difficult to change the camber on the sail unless you have some serious purchases in place. for the average Joe with his solid family long keel boat then the only benifit IMHO is the lack of flogging/sail handling etc, On more racy machine, fractional rig and sett up for it (retro fit or otherwise) then I have seen huge benifits.
I have a fellow club member who fitted a full system at huge expense and was very disapointed that he did not win everything in site.
I did try to help and with the added tackles and more purchase managed to get a bit more out of it , But in relation to the amount of money spent. a good sett of standard sails would have given better performance.
Again this might be just down to ignorance on my part.
If any one could explain if I am wrong, then this forum has once again come up trumps and I will toast everyone when I pick the silverware:D

[powerabout]

full batten mains are harder to depower then ones without full battens
no-one seems to have mentioned that

The posts seem to have ended up taking about full roach sails hitting the backstay but I dont see where he said the type of sail plan or rig he had?
I have a big roach fully battened main on a bolt rope but swept back spreaders so no back stay..easy
Hunter production boats have that as well too think of one.

You could have a split back stay as well?

[powerabout]

Read my post. It is the extra compression on the mast by the boom. That is the main cause of broken masts during jibing.
I see what your saying, vang holding sail twist as main sheet has been released ( no curved track and DDW to boom going out a long way) so vang pulling boom with enourmous force into mast.

( My Magic 25 has 2 rigging wires from the goose neck to the deck to prevent that happening. Early boats did break some masts when pumping the vang downwind)

[powerabout]

I'd have thought that if you are sailing a boat that has to drop backstay tension to tack the main it would likely be fractional, then either the caps keep fore stay tension or you have runners... either way you are talking about a racing boat IMO.
I did a regatta on a Swan 80 a few years back and we had to drop the main down a foot on each tack and then back up....nice not!
22 crew no prob.

[Steve W]

Kim B,As Paul B said,having full length top battens is pretty much the norm these days but all full length you see more on cruisers for handling reasons rather than performance.Unfortunatly its those top ones that have the backstay clearance issues.
Steve

[gonzo]

In a sail with no battens, the tension on the vang is minimal. Just enough to keep the boom from kicking up. With full battens, the boom needs to be kept down with more tension, which creates more compression sideways on the mast. The area around the gooseneck is where masts usually break during jibing.
Paul: the battens do not add tension, but to keep them from wrapping around the shrouds it is necessary to tension the vang more. With few exceptions there is no support for the mast at the gooseneck.

[Paul B]

Paul: the battens do not add tension, but to keep them from wrapping around the shrouds it is necessary to tension the vang more. With few exceptions there is no support for the mast at the gooseneck.

Believe it or not, I know how a vang works. I also know that people who know how to sail use their vangs, regardless of the type of mainsail they use. I also know that having the vang on does not break a keelboat's mast at the gooseneck during gybes (unless the mast was deficient in the first place).

In fact, in almost 40 years around the scene and over 10 years actually working in the industry I have never seen a keelboat's mast broken off at the gooseneck due to vang loads. When you consider I started in the industry working for one of the larger spar builders at the time I might add I always take note when I see a broken spar, to deteremine the root cause of the issue.

So you have claimed on this thread that you have seen retrofits where the mast broke because the boat changed to full battens. You've had three opportunities to tell us specifics, and yet you cannot.

[Paul B]

I did a regatta on a Swan 80 a few years back and we had to drop the main down a foot on each tack and then back up....nice not!
22 crew no prob.

Sound like pretty poor sail design there. Normally if a crewed racing keelboat has a huge roach they go with dual backstays, as used on the IACC boats and even the OD48 I have spent time sailing.

Which Swan 80 was it?

[Paul B]

full batten mains are harder to depower then ones without full battens
no-one seems to have mentioned that


Funny, most people find just the opposite is true.

[CT 249]

I am fearfull of saying much here in case I get my head bitten off:eek:
I am a confirmed Expereinced cruising sailor and a keen novice w/e racer (what I lack in ability I make up for in enthusiasem.) I "thought" that one of the problems i have with fully battened is that once the batten tension is sett, then it is difficult to change the camber on the sail unless you have some serious purchases in place. for the average Joe with his solid family long keel boat then the only benifit IMHO is the lack of flogging/sail handling etc, On more racy machine, fractional rig and sett up for it (retro fit or otherwise) then I have seen huge benifits.
I have a fellow club member who fitted a full system at huge expense and was very disapointed that he did not win everything in site.
I did try to help and with the added tackles and more purchase managed to get a bit more out of it , But in relation to the amount of money spent. a good sett of standard sails would have given better performance.
Again this might be just down to ignorance on my part.
If any one could explain if I am wrong, then this forum has once again come up trumps and I will toast everyone when I pick the silverware:D

For my 2 cents worth, you're only 'wrong' in lumping all fully battened sails together. As we all know, they can vary from conventional small-roach sails that have just had lightweight battens retrofitted to reduce flogging and make stowage easier, to high-load squaretops that require immense mainsheet tension when set on stiff masts. As you said, with some designs there can be limits on shifting the draft, but not with all types of fully-battened sail.

I certainly wouldn't say that a good fully-battened sail is harder to depower when sailing (if worst comes to worst you can twist them off without flogging) but the fact that they can power-up even when the sheet is fully eased can be a problem in some craft when coming into start lines and in other very low-speed situations.

[powerabout]

Sound like pretty poor sail design there. Normally if a crewed racing keelboat has a huge roach they go with dual backstays, as used on the IACC boats and even the OD48 I have spent time sailing.

Which Swan 80 was it?
Sayonara

You take a hit on IRC for split backstay I am pretty sure so the config was a rating thing.

Light breeze is when you have a prob, 15kts+ no prob

[Paul B]

You take a hit on IRC for split backstay I am pretty sure so the config was a rating thing.


I think you take a bigger rating whack in IRC for an oversized roach that would require the sail to be dropped in order to tack, not to mention the pain of not powering up properly out of the tack.

Sounds like someone made a large mistake with that sail design if they were planning to buoy race under IRC...

[Zed]

I did a regatta on a Swan 80 a few years back and we had to drop the main down a foot on each tack and then back up....nice not!
22 crew no prob.

I'd be talking to the sail maker...!

[kim s]

For my 2 cents worth, you're only 'wrong' in lumping all fully battened sails together. As we all know, they can vary from conventional small-roach sails that have just had lightweight battens retrofitted to reduce flogging and make stowage easier, to high-load squaretops that require immense mainsheet tension when set on stiff masts. As you said, with some designs there can be limits on shifting the draft, but not with all types of fully-battened sail.

I certainly wouldn't say that a good fully-battened sail is harder to depower when sailing (if worst comes to worst you can twist them off without flogging) but the fact that they can power-up even when the sheet is fully eased can be a problem in some craft when coming into start lines and in other very low-speed situations.

I stand corrected there.
I suppose I do know that there not all the same, but had not thought about in that way.
On the full on big roach boys, they are depowered quite quickly by dumping the sheet rather than the track (trying to grind them back in afterwards when the gun goes off)
As far as this mast breaking bit is concerned, the only real difference I have noticed is that the fully batten rig (especially the big roach) really does power up a lot quicker and I have been on board boats that have broached hard over as they gybe cos people where not concentrating. and I have seen masts go (not sure where they broke) but they are more due to operator incommpitance rather than the fact they where fully battened.

Kim

[gonzo]

http://www.youtube.com/watch?v=fSIe2w-cQ4s
http://en.wikipedia.org/wiki/Jibe
http://www.briontoss.com/spartalk/showthread.php?t=314
http://www.kerchevalave.com/cgi-bin/ubbcgi/postings.cgi?action=reply&forum=Haven+Forum&number=7&topic=000504.cgi&TopicSubject=The+Agony+and+the+Ecstasy&replyto=3

http://www.vidoemo.com/yvideo.php?i=UmJ0Y3BicWuRpNlZzbG8&mast-ing-down

[Paul B]

All this effort and you still cannot tell us the specifics of your claim of firsthand knowledge. Not one of your links even anecdotally proves your point. Every post you make seems to trump your earlier posts in bizarre nature.


http://www.youtube.com/watch?v=fSIe2w-cQ4s

A video of a Laser sailing in heavy air. No full batten sail. No retrofit to full battens. Mast doesn't break at gooseneck.

If you knew about Laser sailing you would know about this failure mode. It is quite common.

This has nothing to do with your false claims. FAIL.


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

I wonder what the point is of posting the Wiki definiion of a gybe?

This has nothing to do with your false claims. FAIL.


http://www.briontoss.com/spartalk/showthread.php?t=314

No mention of how this mast was broken. No mention of full battens. No mention of any retrofit.

This has nothing to do with your false claims. FAIL.


http://www.kerchevalave.com/cgi-bin/ubbcgi/postings.cgi?action=reply&forum=Haven+Forum&number=7&topic=000504.cgi&TopicSubject=The+Agony+and+the+Ecstasy&replyto=3

No mention of use of full battens. No mention of retrofit to a full batten sail. Mast is not broken by gooseneck. Admits incorrect build method, causing scarf joint glue to let go.

This has nothing to do with your false claims. FAIL.


http://www.vidoemo.com/yvideo.php?i=UmJ0Y3BicWuRpNlZzbG8&mast-ing-down

Not during a gybe. No mention of a retrofit to full battens. Obvious rigging failure, mast breaks at hounds first, does not break at gooseneck.

This has nothing to do with your false claims. FAIL.

[gonzo]

The Sharpie 500 class was designed for full battened mains. The wear and tear on the mast track and sail lead owners to change to short battens. These were cotton sails and wooden masts. The groove for the bolt rope would wear and split. The forward section of the pocket would wear and the battens poked through. The battens would also snap if flogging in strong winds. They were made of ash or oak.

[Paul B]

The Sharpie 500 class was designed for full battened mains. The wear and tear on the mast track and sail lead owners to change to short battens. These were cotton sails and wooden masts. The groove for the bolt rope would wear and split. The forward section of the pocket would wear and the battens poked through. The battens would also snap if flogging in strong winds. They were made of ash or oak.

So your point is people should not use a sail type because it didn't work well in a class if you used 1950s technology to support it?

Yes, this post of yours does trump your last one in the bizarre factor. At least you are consistent.

By the way, you have yet to tell us the specifics of the retrofits to full battens that you have seen that caused masts to break. Why are you avoiding this?

[gonzo]

I'm afraid you will make me cry again Paul B. I can't sleep because of you being so mean to me.

[TeddyDiver]

I did a regatta on a Swan 80 a few years back and we had to drop the main down a foot on each tack and then back up..
Don't know if it's done or not, but imagine if, instead of a single backstay, there were twin stays attached to a spreader at the top of the mast...

[gonzo]

Some boats have a fiberglass batten that keeps the slack of the backstay from getting hooked on the sail. However, you need to loosen the backstay and tighten it when you tack. The tension on the backstay keeps tension on the forestay and also controls mast bend.

[Paul B]

Some boats have a fiberglass batten that keeps the slack of the backstay from getting hooked on the sail. However, you need to loosen the backstay and tighten it when you tack. The tension on the backstay keeps tension on the forestay and also controls mast bend.

You have obviously never sailed on a boat with a backstay flicker.

You obviously don't understand the basics of how that type of rig is set up and works.

[gonzo]

Paul B has a little problem. I can send some cheese to go along with your whine. Post something relevant to these threads.

[Zed]

A big crane can work sometimes.

[tamkvaitis]

ukhalsey - a realy respected sailmaker states this abut full lenght battens

We use the term Batmain to describe a mainsail with full-length battens, meaning the battens extend all the way across the sail from leech to luff. Full-length battens have many virtues for cruising sailors including better shape holding ability, longer life and easier handling. The sails last longer because the full-length battens prevent flogging — the violent snapping back and forth that happens when you're tacking, reefing, hoisting or lowering your sail. As conventional sails flog, the sailcloth breaks down, especially at the front end of the battens where the leech of the sail “hinges” back and forth. Flogging is the prime culprit in sail wear-and-tear. The full-length battens induce a smooth airfoil shape to the sail, which improves performance in all conditions. In light air the Batmain holds a smooth airfoil shape instead of sagging like a wrinkled bed sheet.
Also, the Batmain won’t slat as the boat rolls in the waves. In heavy air the Batmain doesn’t flog when the sheet is eased out to reduce heeling. The Batmain does not flail and snap when depowered, the silence is a pleasant surprise. Full-length battens also restrict the draft of the sail from moving aft in heavy air when sailing upwind. Downwind, the full-length battens hold out the leech of the main giving you more pro-jected sail area.

And this is their sugestion about racing mainsails.

The Powerhead main is our long-life racing design. Whether you are buying a Tape-Drive, Tri-Radial or Cross-Cut main, the Powerhead’s full-length top batten gives you many of the durability benefits of a full-batten main (UK’s Batmain), while offering performance benefits. The Powerhead gives you more control over the shape of your main, especially the draft's depth and fore-and-aft positioning because the full length battens prevent the sail from changing shape much. The Powerhead is easier to trim than a full-batten main since the leading edge of the sail is free to luff. And the Powerhead is a lighter sail than a Batmain since it uses shorter battens and no special luff hardware.
The long top batten stabilizes the highly loaded head area, and stabilizes the leech allowing UK to build a maximum-roach sail that gives you more sail area. The full-length top batten also increases longevity by dampening the damaging effects of luffing and by preventing the draft of the sail from moving aft over the years.
Along with the full-length top batten, Powerheads feature the new longer-length battens in the lower positions. The longer battens support the leech better and eliminate a hard ridge that sometimes develops at the inboard end of the battens as sails age. Powerheads that are used with lazy jacks or the Dutchman ® flaking system can have the bottom batten full-length to help catch the sail better as it comes down.

Sailed both types of sail and don't realy liked the full battened version. These sails are very nice If you get the right batens with right tightness and right wind speed. Othervise it is a headache

[powerabout]

Don't know if it's done or not, but imagine if, instead of a single backstay, there were twin stays attached to a spreader at the top of the mast...
Yes i have raced on previous gen TP52 with split backstay, its a pain in the arse as exrea crew needed and in IRC ( as this was racing) you pay for it so the boat was converted to single backstay which is much easier and safer as you are not dropping it in each tack.
The sail plan also modified to suit.

No big deal if the're all hired guns but otherwise...

[powerabout]

[QUOTE=Paul B;339629]You have obviously never sailed on a boat with a backstay flicker.
Ok for small boats..like a Mumm 30
where you pull on the backstay but by the time you get to 40' its hydraulic so you cant deal with the slack or it s a big winch station which doesnt really fit on a 40 footer.

[CT 249]

http://www.youtube.com/watch?v=fSIe2w-cQ4s
http://en.wikipedia.org/wiki/Jibe
http://www.briontoss.com/spartalk/showthread.php?t=314
http://www.kerchevalave.com/cgi-bin/ubbcgi/postings.cgi?action=reply&forum=Haven+Forum&number=7&topic=000504.cgi&TopicSubject=The+Agony+and+the+Ecstasy&replyto=3

http://www.vidoemo.com/yvideo.php?i=UmJ0Y3BicWuRpNlZzbG8&mast-ing-down

I have to admit, Gonzo, the relevance of those links escapes me.

Could you explain how those links relate to the claim that fully battened rigs cause masts to be lost during gybes?

[Grant Nelson]

CT, not just break, but break at the gooseneck...

I have to admit that Gonzo and Paul do add some flavor to this post... you never know, something useful might surface.

That aside, I want to thank everyone for their input, as it has been a good education, both from the theory side as well as the practical experience side.

My overall feeling is, at least for my new design 17 footer, which is not an all out racer, that I can best go for having the top one or two battens as full length, and the lower one or two shorter.

I read somewhere that the right length is "two times the roach plus a bit" which, incidently, with my sail, makes the top two battens full length.

Key hardware aspect is to have the right track... I saw a number of types mentioned, but would like to get some links to pictures and manufactures of the best to use..

Thanks,

Grant

[Paul B]

I have to admit that Gonzo and Paul do add some flavor to this post... you never know, something useful might surface.

My overall feeling is, at least for my new design 17 footer, which is not an all out racer, that I can best go for having the top one or two battens as full length, and the lower one or two shorter.

Thanks,

Grant

Looks like something useful DID surface.

If the crazy claims by Gonzo were not contradicted by people who have actual knowledge you might have concluded that using two top full battens would break your mast. Sadly your project would have suffered for it.

[gonzo]

Paul B: I made a post just for you. Where are you when we need you?

[Koch]

I am a sail maker and designer at Banks Sails Tampa. About 90% of the cruising mainsails we make are full battened. Sometimes we add a little roach, sometimes the same roach, occassionally we reduce the roach... it depends on the boat and how the customer uses it. We have even made fully battened sails with NO roach (for reduced flogging and easier stowing). 100% satisfaction, no one has broken their mast during a jibe, and not a single instance of a forestay loosening during a tack... :confused: The only times we have advised against full battens is with the old-style external metal track... then the slides do tend to stick and jam with full length battens.

[Typhoon]

I agree with Koch. I've made dozens of cruising and cruiser/racing mains (as well as many laminate racing roachy mains) and we've never had a customer complain.
We'd always ensure the lower full battens in a cruising main ran parallel to a reef and also if we could, we'd land the ends of the batten on luff and leech reef patches to help distribute the load and also to make the sail super easy to reef.
We'd also extend the head patch reinforcements down into the top batten at the leech at the very least as well.
You'd be amazed how much simpler putting in a reef is when the reef slab has a batten constraining it near the reef points, it settles the whole sail down really nicely when the luff and leech are under reduced or no tension.
If you have a batten in the loose sail you are trying to flake up on the boom when reefing, it is even better again, grab batten and pull it up over the boom, instant flake! If you have lazyjacks, loosen halyard and watch it do it for itself.
We also made the vast majority of cruising fully battened mains with slugs or slides, no failures there either. Decent reinforcing patches at the luff and leech end, plus a good batten pocket end (through bolted in design) eliminated any issues. A slug or slide sewn right into the batten end and one immediately above it eliminated any issues with any wear. We favoured flat battens in cruising sails rather than rod or tubular battens, they last a lot longer and are very forgiving with regards wrapping around shrouds etc, plus they are flexible enough to deflect if caught under say a reef line.
As with any sail with slugs or slides, nice tight webbing holding the hardware on is far more important in eliminating sticking than what that hardware is sewn to....
Put a fully battened main on a boom with a simple two point lazyjack system and you have a ridiculously easy to handle, very hard to damage sail.
As for exorbitant cost, adding full battens typically added around 10% to teh cost of a sail, hardly a hefty premium....
So, as with anything, if you use the technology and materials appropriately, you can have an excellent sail. If you get a cheapo hack job done by someone who has no clue, it will suck.

Regards, Andrew.

[Grant Nelson]

Wow, Koch, Typhoon, thank you for those replies... very useful, detailed, but practical info I and other can use... just what this forum is all about!
Grant

[gonzo]

So you've had no problems with extra wear on the track of wooden masts?

[Koch]

Anyone in Florida with a wooden mast has a lot more to worry about than battens. Varnishing 3 or 4 times a year due to intense UV, and checking for rot, keeps them too busy to sail. Only wooden masts we see are on small sailing craft. We either use no battens or sewn in battens on small craft to keep the weight down and make the rig and sail easy to drop and stow into a bag.

[gonzo]

That doesn't answer my question.

[Koch]

If you're referring to external metal tracks, I answered that above. We don't recommend full length battens be used with external metal track and slides. They often jam when raising and lowering the sail, this is even a bit of problem without full length battens. Best results from metal track is reusing the customer's old slides on the new sail and having regular battens. With internal tracks we generally use Allslip slides on bigger sails (over 30' LOA) and Delrin slides on smaller boats. Nylon doesn't last long in the sun here. And webbing on the slides is the only way to go, as Typhoon said. Occasionally we do a strong track system (Tides Marine) installation. This is a tough plastic track (teflon?) that sides up the slot in mast, and uses HD metal slides. Very low friction, and much cheaper and easier to install than Harken, etc.

[Typhoon]

Agree with plastic slides. You'd be amazed what is available in plastic (nylon) slides these days. Personally, I would replace slides on any sail every couple of years as maintenence, full batten or not.
Stainless steel slides are also good on larger battens as far as strength goes, but do tend to hang up more often that nylon.
You can also buy some really nice, long alloy slugs from Bainbridge that work very well at batten ends, their length and rigidity make them very useful in this area.
As for timber masts, well, as Koch said, it depends on the track.External tracks would depend very much on how they were fastened to the mast, how close the fastenings were etc. I've seen some pretty rugged stainless and brass tracks on masts and they wouldn't worry me. Even some of the alloy tracks are tough.
If you follow correct hoisting procedures, the battens should not force themselves into the track at all, Once hoisted and drawing, the battens cause no additional loads to a track that a fully set conventional main doesn't cause, this assumes a typical very mild roach, which is what you'd find on a traditional yacht or cruiser. The battens used are very important here and they shouldn't be stiff at all, just stiff enough to support the roach.
The flat fibreglass battens we used ranged from 30 to 50mm wide and 3-4mm thick. They'd form around stays etc downwind fairly well, no chance of breaking and definitely no chance of loading up a mast track.
To give you an example of how flexible these battens are, they would arrive to us when shipped, a 15m length coiled to around 1.3m diameter.

Regards, Andrew.

[gggGuest]

My overall feeling is, at least for my new design 17 footer, which is not an all out racer, that I can best go for having the top one or two battens as full length, and the lower one or two shorter.
So hang on, 17 foot boat... How big is this rig? It sounds as if all you should just have ordinary plastic end caps and the sail with a conventional luff rope like 99% of the rest of the many thousands of rigs of that sort of size in the world. Also at that sort of size I wouldn't consider anything other than full length battens, if for no other reason then the simple ease of rolling the main round the battens for storage at the end of the day.

[gonzo]

Ok, so that agrees with my initial statement that full size battens do not work as a retrofit on all rigs.

[Koch]

Ok, so that agrees with my initial statement that full size battens do not work as a retrofit on all rigs.True, only about 99% :rolleyes: .

[Zed]

I have never been disappointed with a retro fit of full battens! That is all I can say and anecdotally I am convinced that they deliver better life, at least in the dacron sails I have used.

[Koch]

I'm sure it makes your job a bit more difficult when your customers read some of the stuff written on bulletin boards, then see your products don't match what the internet "experts" said was the right way.

Must make for some interesting conversations.Most of the time it's the opposite problem... customer reads about some wacked idea on the internet and wants us to build it. About half the time we talk them out of it, the other half we charge double, make them sign a waiver, and build it. Crazy thing is, no matter how poorly it performs, the customer is always thrilled. :confused:

[Zappi]

I've had numerous sails built with full battens for a rig not necessarily "designed for it". All worked great and I will positively go that route with my next sailboat. I will say feeding the bolt rope into the mast on a 29' could be more of a challenge than standard batten. It still does not change my opinion.

[Munter]

We retrofitted full length battens to the mainsail on our Cole 43. It worked a treat even though we didn't change the track sliders. The rig was masthead and had no runners. The battens helped remove some hooking from the leech, quitened the main down when hoisting/dropping and did not cause any issues with the existing rigging. They did add a bit of weight but I think the trade off was worth it. Our next main (replaced the original due to installation of a longer boom) was also fully battened and worked even better.

[gonzo]

I understand that with slides the retrofit is more straightforward. How does it work with boltrope?

[Steve W]

I am building a roller reefing/furling boom for my Lindenberg 26 and will be having a full batten sail made,obviously the battens need to be paralell to the boom rather than right angle to the leech but i also cant use slides as i need to go the bolt rope route. My understanding is that when dropping the sail with full battens as the batten drops at the outer end it torques the mast end when using standard end fittings and this causes friction which makes the sail hard to drop bu im thinking that this will not be the case with my settup as i will be standing at the mast keeping tension on the halyard with one hand and rolling the boom with the other so it should come down smooth,does this sound reasonable?
As far as hoisting goes,i will have a shaft through the mast with a crank on the front so the tack will be as close as poss to the mast,i will enter the bolt rope into the track a lot higher than normal to minimise the entry angle and use a prefeeder in between,maybe a floating one like on a headfoil so i can adjust it until it feed right and of course regular doses of Mclube,sound ok?
Steve.

[gonzo]

With roller reefing in general you need at least a good topping lift. Vangs that have the boom holding feature work better.

[Crag Cay]

Most roller boom furlers have the 'luff groove' on the mast extended away from the aft face of the mast, either by using a riveted extrusion or a 'soft', fabric based extension piece on smaller boats.

This ensures the luff bolt rope furls and unfurls directly under the luff groove No change of angle.

I use the Danish Sailtainer system which works well complete with full battens.

http://www.boatdesign.net/forums/attachment.php?attachmentid=40329&stc=1&d=1265212456

[gonzo]

The rigid vang furls more evenly than a topping lift.

[Paul B]

The rigid vang furls more evenly than a topping lift.

How does the sail know the difference?

[gonzo]

With a topping lift the tension is changing with the movement of the boat.

[Paul B]

I use the Danish Sailtainer system which works well complete with full battens.


I've never used this system. Heck, I have never even seen one.

Can you tell us if the boom needs to be on CL for it to work well?

[Paul B]

With a topping lift the tension is changing with the movement of the boat.

How?

And why would that impact the sail-to-boom interface?


Have you used this furling system with both a topper and a rigid vang?

[gonzo]

Yes, I have used roller furler with different setups. Even sheeting hard, the boom moves up and down which makes the tension on the sail uneven. This ends up in wrinkles.

[Paul B]

Yes, I have used roller furler with different setups. Even sheeting hard, the boom moves up and down which makes the tension on the sail uneven. This ends up in wrinkles.

How can the boom move up and down if the Topper is set and the (non-rigid) vang is set up to counter the Topper?

Topper keeps the boom from moving down. Vang keeps the boom from moving up.

[gonzo]

You asked about the topping lift

[Crag Cay]

Can you tell us if the boom needs to be on CL for it to work well?
No, it doesn't need to be on the centre line but it's easier if it's luffing to reduce the drag on the bolt rope.

The rigid vang is physically constrained to it can't lift the boom beyond the optimum furling position. This is the setting where the sail rolls without gravitating to one end of the boom or the other as you roll it down.

The reef positions are best when there is a ful length batten 300mm or so above the boom.

The only downside of the system is that you can't ease the clew off in light airs.

They sold about 2500 units in Europe but I think the full batten / lazy jack / stack pack set up has eaten into their market more recently. But our Sailtainer is 20 years old and has been faultless.

[Paul B]

No, it doesn't need to be on the centre line but it's easier if it's luffing to reduce the drag on the bolt rope..

Thanks. I am assuming the added mast track is rigidly held on CL. I'm guessing there is a pretty nice pre-feeder?


The reef positions are best when there is a ful length batten 300mm or so above the boom.


When reefing, what holds the new "outhaul" tension? Is it simply the tension on the rolled sail?

[Crag Cay]

Yes the added mast track is both rigid and on the centre line, but the gooseneck has also been brought aft to coincide exactly.

Yes the reefed 'out haul' is partly the quality of the roll (which is very good) and the sail tension imposed by the compression in the full length batten.

[Paul B]

You asked about the topping lift

Not exactly.

You stated the TL was not as good as a rigid vang. When asked why you said in your experience the boom supported by a TL moves up and down and caused the sail to have wrinkles.

So why didn't you simply use the vang to stop this problem? Seems like a pretty logical thing to do.


So what you are saying is, the rigid vang functions better for people who can't figure out how to use a normal vang to keep a boom from rising.

[gonzo]

Paul B: you are starting to hijack another thread to start a fight.

[Paul B]

Yes the added mast track is both rigid and on the centre line, but the gooseneck has also been brought aft to coincide exactly.


OK, so at any angle the feeding sail is (reasonably) under the track?

When furling, does the bolt rope lay on top of itself, or is there a mechanism that offsets the roll in some increment? I am thinking if the luff all rolls on itself that would be a big bulk compared to the rest of the furled sail.

[Steve W]

I guess i didnt state that i am doing a simple boom that rolls the sail around it just like the Corsair Trimarans use and have been for years,so i will,of course use a topping lift and end of boom sheeting,by using a through the mast shaft to rotate the boom to keep the tack close to the mast so i dont need to set the track back.I have in the past installed a profurl in boom system on a customers boat but to be honest,i see no advantage over the Corsair system which is just the old fashioned system from way back but the full battens make it work.The in boom systems to me remind me of a saying we had 35+years ago when i first got into boatbuilding which went something like "an elephant is a mouse built to marine department specifications" in other words an extremly complex(expensive)way of doing a simple job.There may be some validity on really large boats but overkill on boats under 40ft or so imho.
Steve.

[Koch]

I made a bunch of sails for the sailtainer system a number of years ago while working at another loft. They worked well. IIRC, the tack angle was pretty critical... something like 87 degrees, plus or minus a half degree or so. As I recall, the bolt rope offset just a bit each roll, kind of like a cable on a large winch does. My memory may be faulty, though.

Question about the tack angle: It seems like no problem on a mast with normal rake, but on a boat that carries a lot of rake it would seem that the boom would droop if the proper tack angle is to be maintained?

[Koch]

I guess i didnt state that i am doing a simple boom that rolls the sail around it just like the Corsair Trimarans use and have been for years,so i will,of course use a topping lift and end of boom sheeting,by using a through the mast shaft to rotate the boom to keep the tack close to the mast so i dont need to set the track back.I have in the past installed a profurl in boom system on a customers boat but to be honest,i see no advantage over the Corsair system which is just the old fashioned system from way back but the full battens make it work.The in boom systems to me remind me of a saying we had 35+years ago when i first got into boatbuilding which went something like "an elephant is a mouse built to marine department specifications" in other words an extremly complex(expensive)way of doing a simple job.There may be some validity on really large boats but overkill on boats under 40ft or so imho.
Steve.I've sailed Corsairs a bit, and made a few mains for them. That system works fine. Only problem I can see with using it on a Lindenburg 26 is not having the boom vang fitting accessible while reefed. Perhaps something can be rigged up with one of the oldfashioned boom claws. I guess the vang isn't an issue with Corsairs b/c they seldom ease the main much past the end of the traveller... but I don't recall ever having reefed on a Corsair. One slight problem with the Corsair that won't be a problem on the Lindenburg - the top couple of battens on the Corsair flat top main have to be removed to roll the last few feet... I assume the Lindenburg sail will have a normal monohull type roach.

[Paul B]

As I recall, the bolt rope offset just a bit each roll, kind of like a cable on a large winch does.

That's what I was getting at. It seems the offsetting would make for a better roll, but with no mechanism to force it does it do it naturally?

Back in the old days the in-mast furling systems could really have issues if the foot wasn't cut correctly and too much sail rolled onto itself. I suspect the same can be true for in-boom systems.

[gonzo]

Are you having a tapered boom to take the extra fabric in the center of the sail?

[Koch]

That's what I was getting at. It seems the offsetting would make for a better roll, but with no mechanism to force it does it do it naturally?

Back in the old days the in-mast furling systems could really have issues if the foot wasn't cut correctly and too much sail rolled onto itself. I suspect the same can be true for in-boom systems.Yes, that's why the tack angle was critical. If too close to 90 degrees, the sail would bunch up at the front. If the angle was too close to 85 degrees, then the luff would start creeping too far aft on the roll which created problems where the bolt rope exited the mast groove. When the tack angle was at the specified angle the system worked very well.
With the in mast furlers, the issue wasn't that the sail wouldn't roll up; it was that the sail would get too bulky and start rubbing against the interior of the mast. Even with a slightly raised clew, care must be taken not to make the head and tack patches too bulky or use too heavy a cloth.

[Zed]

Mast furlers scare me! I was always impressed with the Hood boom system, from memory it had a padded leech and the wedge in the track to accommodate what I assume was a flatter cut main for rolling. It seemed to me to be an excellent cross between ease of use and performance.

[Koch]

In-mast furlers are far better than the old behind the mast furlers... but that is damning by faint praise. If you are doing a furler, a boom furler is best.

[Steve W]

Koch,its great to have a sailmakers insight,thanks. What im planning to do re the vang is have dedicated reef points with luff and leech cringles just like with slab reefing but no intermediate lacing grommets,the reefs will be just above a batten and i will use a line through the luff cringle at 45 Degrees down so i will be holding the new tack down and fwd,i will have an internal outhaul which will attatch to the clew with a snap shackle,so when i have a reef rolled in i will disconect the outhaul and hook it onto the reef cringle and if necessary tie it down also,although having a batten just rolled on to the boom may be enough(most of the Corsair guys tie the reef in)
Ok,now the vang,since i will have dedicated reef locations i am going to attatch the vang to the boom with a webbing strop,it is going to be a double vang/preventer arrangement which will be 4:1 each side with a single line running back to the cockpit,the bottom end of the tackle will go to a strongpoint at the toerail each side so there will not be the strong foreward component pushing the boom foreward at the gooseneck or trying to pull the strop fwd,so i will have reinforced patches sewn on the sail at each reef point with a hot knife cut slit just like we used to have in the foot for reef line before loose footed sails,so that when you roll a reef you unsnap the tackle from the strop and dump it on the deck,roll the reef and then thread the strop through the slit and rehook the vang,i see no reason this approach wont work fine,i should point out that my sole reason for roller furling is ease of putting the sail away,the reason for the double vang is to get rid of the traveller in the cockpit,i dont want it.
Steve.

[Koch]

Sounds like it might work, Steve. Make sure the slit in the sail for the strop is well reinforced, just in case it takes an unexpected load on some occasion. Another option is using a boom claw, like this:
http://www.boatcatalog.biz/prods2/5237.htm

[gggGuest]

Best system I've used had luff and clew cringles and a zip fastener to tidy up the slap. With full length battens to roll the slab round it was quick and neat. This was for a dinghy where you put the slab in on shore and the mast reefed along with the sail.

[Steve W]

Koch, boy i havnt seen one of those boom claws for decades, your right that would work well actually, i may start looking for a suitable one online,my boom tube is 3.5" diameter. i have a sailmking question for you,my boat came(from e bay sight unseen) with a bunch of sails,mostly old but i got pretty excited when i opened the mainsail bag and im seeing crisp dacron,shiny cringles ballpoint pen marks and no blackmarks on the bolt rope and i said to my son,this thing is new but as i spread it out on the lawn my exitement waned as i saw that although the luff lenth was about right at 28ft 8" but the foot which should have been 9ft was 14ft, 5ft too long, its a nice sail but what odd proportions (maybe a fu?) ,anyway now that i have decided to lengthen the boom it is now (only) 3ft too long so is it possible to recut this sail to 11ft on the foot and add full length battens? It would be a shame to waste it.
Steve.

[Koch]

That's a lot to cut down. It can be done, but don't expect the result to be perfect. Generally, a 10% reduction is about the most you want to cut.

[Steve W]

Thanks Koch,i thought it was a lot but i may try it as i dont think i can sell it because of the extremely low aspect.
Steve.