Batten Pocket Designs

[Toxophilite]

I need to ask a question of those in the know regarding batten pockets

I bought a sailrite kit for my Gartside 130. It's a kind of expensive way of finding out if a new sail will work better on my boat and for fun I got tanbark.

Looking at the batten pockets in the plans it has the type where the aft end of the pocket fans out with the bottom being sewn shut. One slips the batten in the open top section , it drops down and is contained by the sewn up bottom


However sailrite has another type in a video that is just a long narrow pocket with an elastic sewn into the forward end and a little separate cap at the aft edge of the sail. One slides the batten in, pushes against the elastic till the batten will slide into the cap and then lets go, the elastic keeps it snug in the end cap

Is either better?
Does it matter?
Does the elastic tend to wear out after a while as elastic does?

[John hartmann]

Waxwing’s lug is fully battened, with a set up closer to the second you described, but with the aft end of the batten projecting beyond the leach; a light line anchored to a small grommet at the after end of the pocket allows some tension adjustment of the batten:
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The sail was made by the late Stuart Hopkins, of Dabbler Sails. Umami’s gaff main is also fully battened, with two velcro secured tabs one over the other to secure the batten in place, that sail is from the folks a Gambell & Hunter; don’t know if I have a close up of that detail, but will look.

[John hartmann]

Here are a couple of Umami’s sail, depowered with the head scandalized. The second shows the reinforcements that Grant Gambell worked into the sail similar to the Dabbler, and the arrangement of the reef nettles along and just below the batten, which makes for a very neat bunt when reefed. Both the Dabbler tension line and the Velcro flaps work very well to keep the batten secure.
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[wizbang 13]

Putting battens in a traditional sail is a bit over the top .
Chinese lug being an exception of course

[John hartmann]

Oh, I dunno, Bruce. The recreational cruising ancestors like George Holmes and Albert Strange used fully battened lugs in their designs often. Why do you think they’re overmuch?

[JimConlin]

Don’t feed the troll. He’ll be arguing against dacron soon.

One of our boats’ mainsails has the type where the back end is open and the batten is held in by a bit of webbing and Velcro. About once per season, a batten sneaks past the webbing and goes overboard. A genuine PITA.

I’ve had other sails where the end of the pocket is stitched closed and the batten enters from the top side. These work better.

[wizbang 13]

Me argue against Dacron? Na ah . I’ve had my fill of cotton sails.
I’m saying , for a cruising boat, battens and batten pockets are a pita. To make, to maintain, to replace when they fail.
Full battens are another whole thing, I can appreciate them .

[Todd Bradshaw]

Both types of leech batten pockets that you mention will usually work fine. It is sometimes possible for them to shake out if you let the sail flog in the wind, but that's not the only, or most important reason that letting the sail flog is a really bad idea and is to be avoided. Batten pocket elastic does eventually wear out, but so does the forward end of a lot of pockets unless they have really good battens with soft forward ends, so fixing problems up there is a good time to renew the elastic.

My favorite leech batten has a piece of thin webbing hanging off the aft end about 3" long. The webbing has velcro sewn to one side. The batten is inserted into the pocket and then the velcro/webbing is stuffed in there. The aft end of the pocket also has velcro which mates with that on the webbing to lock the batten in place. They're a pain to make, but work well and are very secure.

Bruce is correct that leech battens are a pain to make, a pain to fix and the number one source of chafe needing repairs. Whether or not a sail needs leech battens depends on the design and specifically whether or not there is some leech roach present. A dead straight leech will eventually flap as the cloth ages if it doesn't already when new, so it needs leech battens. A sail that has some leech roach needs battens about three times as long as the amount of local roach to keep it from flapping or from hinging at the forward end of the battens. The alternative is to slightly hollow the leech (1" per 6' of leech length or so) which can allow you to sail with no battens and with a slight leech broadseam or two (straight and tapered with no flare at the ends), no flapping for the life of the sail. The amount of speed or efficiency that most cruising boats gain from having a modest leech roach isn't really worth much, and it is questionable whether or not the eventual durability/repair problems make leech roach and battens worth having.

Batens 3X the amount of local roach. These are the elastic type. There is just enough extra length to push the batten in, stretching the elastic and allowing the aft end to clear about a 1" hem at the sail's leech and lock in. The top batten needs to have a really soft forward end to keep it from making a hard spot in the sail and distorting the chord shape up there.

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The place leech battens wear out first and are a pain to fix is at the forward end. To combat this, the first thing to do is to add an extra patch of fabric under the pocket's forward end (a circle, diamond, square, etc) and the second thing is to make sure that the forward batten ends are both as smooth and as flexible as possible. When it comes to repair costs and effort, cheap battens are no bargain.

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[Marty J]

Bruce is correct that leech battens are a pain to make, a pain to fix and the number one source of chafe needing repairs. Whether or not a sail needs leech battens depends on the design and specifically whether or not there is some leech roach present. A dead straight leech will eventually flap as the cloth ages if it doesn't already when new, so it needs leech battens. A sail that has some leech roach needs battens about three times as long as the amount of local roach to keep it from flapping or from hinging at the forward end of the battens. The alternative is to slightly hollow the leech (1" per 6' of leech length or so) which can allow you to sail with no battens and with a slight leech broadseam or two (straight and tapered with no flare at the ends), no flapping for the life of the sail. The amount of speed or efficiency that most cruising boats gain from having a modest leech roach isn't really worth much, and it is questionable whether or not the eventual durability/repair problems make leech roach and battens worth having.

This bears repeating. If you're not racing, I really don't see the value in battens (junk rigs excepted). Just take the 5% hit on sail area in exchange for a sail that's cheaper, easier to flake, and longer lasting.

[Woxbox]

One of our boats’ mainsails has the type where the back end is open and the batten is held in by a bit of webbing and Velcro. About once per season, a batten sneaks past the webbing and goes overboard. A genuine PITA.

I’ve had other sails where the end of the pocket is stitched closed and the batten enters from the top side. These work better.

My experience exactly. I've also had the type Todd mentions, where you push the velcro back into the pocket with a stick, and those proved reliable, too.

Battens do create localized wear points, no question. But I've had fully battened sails that are a pleasure -- they create a really good, powerful airfoil shape and the sail just doesn't flog. Worth the hassle.

[Todd Bradshaw]

I eventually came to the point on fully battened lugsails where I eliminated closing the forward end of the batten pockets. Normally they would be closed by either being sewn shut or have some sort of riveted-on plastic cap. Instead, i made them with both the luff and leech ends open and equipped with small grommets so that the battens could be tied in at both ends, eliminating the potential for chafe in that area, or pocket cap problems. Since lugsails are not attached along the mast this could be done and worked great.

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The grommets above the pockets below are reef lines - required by the event rules for the race. The tie-in grommets are smaller and hidden behind the batten tips in this photo.

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[Toxophilite]

Lots of great information, thanks very much.

Frankly I prefer the look of a lugsail without battens but the sail plan I have for my boat calls for battens and I just don't have enough knowledge to ask Sailrite to build it without, as it ended up being rather a large expenditure after exchange rate, taxes, shipping UPS etc. As such I was ill inclined to gamble with the design. This is a 74 sq foot lugsai though the sailplan incorrectly describes it as a 68sq ft sail. Maybe that should've been an indicator... I guess I could cut the leech straight, or slightly hollowed..yikes. I did get it vertically cut because I like the look So the aft panel is one long piece

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[wizbang 13]

Oh don’t get me going on vertical cut sails .
Yes yes… Todd has some beauties right there, but he actually knows what he’s doin.

[Todd Bradshaw]

Vertically cut with a roach and battens is a very strange combination. It leaves you no means to tighten the leech to prevent flapping as the sail ages, which would normally be accomplished by the hollow on a vertical cut or by a couple of very small leech broadseams on a cross-cut sail. That job will need to be done by the battens alone, so don't leave them out. Cutting the leech straight would eventually flap, so if you were to cut off the roach you would want to hollow that edge about two inches, which would also work fine and look like this.

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[Toxophilite]

Well, it wont be the first foolish $$ decision I've made. I thought these sails were intended to be made that way (vertically cut) and it was my decision.
I though the dotted lines on the plan were reef points. Are they actually indicative of the sail panels?

Heck. I had a sub optimal sail and then spent, what was for me, a bundle, to buy another!!

A discouraging revelation.

[Todd Bradshaw]

No, those are reef lines. The panel layout for a sail which has a roach and battens is pretty much automatically assumed to be cross-cut. If I had such a kit, I'd just ditch the battens, hollow the leech panel a couple of inches and be done with it. Remember that you need 3/4"-1" for a leech hem and your corner patches should be recessed along the leech edge to allow for it. I will usually lay down two rows of seam tape tight together and following a curve dawn on the cloth with a pencil and a lofting batten. Then you can slide the scissors along the outside edge of the tape and get a nice clean cut. Fold it over, taping it down as you crease it with something hard, sew it and you're done. On the first sail I ever made, I used the handle of that little screwdriver to crease Dacron. I have used it for that job on every Dacron sail that I have ever made and the handle is worn down to show it.

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[Toxophilite]

Thanks for that. I guess I would probably use a few feet of sail area.
Is the hollow in the leech symmetricall, with the deepest part of the curve in the center of the leech?

[Todd Bradshaw]

Yep. Just a fair curve with nothing fancy. You probably won't notice the difference in sail area. Roach only really produces much power when sailing off the wind with a big roach. Most of the time, a moderate leech roach is just along for the ride and not big enough to add much.