Full battens. What is the reason.

[Craig Weis]

Since I'm too lazy to look this up.

JUST WHAT IS THE REASON FOR FULL BATTENS?
To kick the head [top] of the sail out for more area?
I see Charley  Klein

[ www.DorsalSailsandCanvas.com | Dorsal LLC, 61 Michigan Street, Sturgeon Bay, WI 54235 | Phone: 920-743-4126 | Fax: 920-743-4139 | E-mail: Charlie@dorsalsailsandcanvas.com ]

made the sails for his [green on green schooner rig sail boat on his web page]. Charley built this boat when he lived down in FL. using full battens, but his boat is pretty slippery through the water.
skip.

[Potcake boy]

Skip,

There are a number of advantages especially combined with a loose foot including the following:

1. Easy adjustment of chord depth using outhaul alone without stretching the foot and luff.  With tapered battens the max chord depth will remain forward for best shape, though cut of sail can also determine this.

2. Consistent elliptical shape to chord - no sharp angles like at the forward end of conventional battens.  The key to efficiency is laminar bonded air flow.

3. Eliminates flogging - the battens won't allow the sail to whip around in the wind like a bed sheet when not drawing.  Makes reefing/furling easier and reduces wear and tear on the seams.

4. Sail flakes down nicely on boom with sail folded opposite side of boom at each batten - battens resting on top of boom.

5. I would also speculate from my experience that accidental jibes are less likely, as the sail remains nicely under control.

Note: Although full battens are commonly used to support a bigger roach at the head of a sail (square top), that is for the most part limited by the backstay.  You would need running backstays on a monohull. 

Some sailmakers are advocating to use full battens only in the top two positions. Don't know how that plays out in race rules, but the obvious purpose is to increase the roach. You don't get the full benefit of the advantages listed above.

With a loose foot, you should use a means of keeping the clew at the boom.  Some use a strap through the clew cringle and around the boom.  I mounted a stainless steel genoa track on the boom via the slot and use a car with plastic slide surfaces controlled by the outhaul. It has a hook like a reef hook and is used for the full sail and moved forward to the position of the cringle for a reef.  No reef line to crush the excess foot when reefed - I roll and tie it.  Remember, the sail isn't flogging like crazy while you do the reef so getting the hook into the cringle is not difficult, and once you adjust the outhaul it won't come loose.

One thing of note however is that when you get into bigger sails say over 200 sq. ft, the compression of the the battens can cause slides to bind in the slot so raising and lowering the sail will become more difficult.  Racers often use bolt rope luffs which help this problem, or you can use track cars.  The latter is the better solution for the typical cruiser.  I used Tides Marine strong track on a previous boat with excellent results.  Some other marine hardware companies sell systems that incorporate their roller ball stuff and the cost is IMHO extortionate.  I would say that anything smaller than the Compac 35 shouldn't need a track system, the loads on our modest barges (yachts) just aren't that great.

Ron

[LConrad]

Interesting. For whatever it is worth, I asked my dealer for a quote on full batten, loose foot for my 23. Both Com-Pac and another sailmaker advised against this approach and declined to quote.

[Potcake boy]

Lconrad - did you question their reason - did they make any justifying remarks, or were they just not familiar with this type of sail?

It has been working exceptionally well on my 19.

If you are interested in giving it a try, Dirk at National Sails can provide well built sails of this description for a modest price.

Ron

[LConrad]

I think they were familiar with it. I did not talk directly with either supplier so I did not pursue in detail. I made reference to your post as well.

[Potcake boy]

LConrad, 
Well I don't know what they are thinking, but I am kind of cynical and usually figure business people often just don't want to deviate from what they know.

I first got experience with this set up from a Dragonfly trimaran that I purchased.  This was the same model Dragonfly 25 that exploded on the race courses of Europe and put trimarans on the map so to speak.  Look up the sailor/racer Elvstrom and you'll find an interesting history of the success of the Quorning trimaran.  The full battened loose footed main worked quite well on that boat, and is why I decided to use the same design on my CP19.  For what it is, my CP19 sails damn nice with this main, even surprising me at times.  I can easily go from a very flat shape to a very full shape with a quick outhaul adjustment.  I never use luff tension to control draft because the full battens provide the correct depth of chord based on outhaul tension.  Along with a bridgedeck mounted traveler and a vang I always have complete control of the shape and power of the main.

I am still a big believer in a main as the primary sail.  I use a 110% jib cut to set flat (no twist) using the factory mounted fairleads.  If I need to reduce the power of the jib I just furl it in a bit.  When the air is light, I hoist my G3 spinnaker, and away we go.  I don't agree with big headsails on these boats of ours because you can't sheet them that close and even if you do, you loose so much to leeway because of the stubby keel.  You have to fall of a bit in light air to maintain speed, so why not just use a flat spinnaker and give her some juice.  Last week sailing with a friend in Charlotte Harbor, the wind was very light so I hoisted the G3 and sheeted in to a close reach, we blew by a 40 something Beneteau with his main and genoa out.  Now I am not suggesting that a CP 19 is even close to that boat in speed potential, and the skipper was not pushing the boat, but it did illustrate the potential of the spinnaker compared to a traditional genoa.  He was pushing closer to windward than we but our speed difference was obvious.

If you have some Corsair guys up there and can hitch a ride sometime, they can show you how this sail design works.  Or if it gets too cold up there this winter, jump on a $49.00 flight to Ft. Myers and I'll show you how this sail works on a CP19.

Ron

[jimyoung]

I got used to full batten mains back when I was racing Hobie Cats and would not have anything else on my CP 27. Easy to set and drop, and ease in reefing are but two reasons alone that make them worthwhile.