Join Date: Feb 2010
Location: Toronto, Ontario, Canada
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I'm not trying to prove anyone wrong, nor that I am right.
...speaking of lemmings.... that's how all design trends have evolved over the last 25-35 years. Racers try out a new technology or a new gimmick, it sticks and manufacturers start putting it in left, right, and center.
I am not disputing there are additions to the sail or rig that can make it more or less efficient on any particular course.
However, I disagree that battens add so much to sail shape for on and off wind performance that you so-absolutely-have-to-have-them or you'd be going nowhere without them.
Yes they add a little bit more shape control and give a nudge to improve performance upwind.
I tried to point out earlier that my opinion is based on pure, long-distance, hardcore, off the beaten path cruising. An environment where anything that adds maintenance (cost) or a potential for failure is a detraction from your cruising and could send you home much earlier.
Yes, all RACERS use battens whether full or partial, but they don't care about maintenance or cost - someone else pays the bills.
You can start a discussion about autofurlers and say the same things, it adds performance or not on a particular course blah blah, then take the racers that pay 10-15k on their furling gear, yet after more than a few transpacs and fastnets - only 1 out of 10 on average comes through without failing or jamming.
As for efficient shapes, that's a whole other discussion.
Saying that a roach (making the luff of the sail oval, from a 2D perspective) adds to aerodynamic performance is a misnomer.
It adds to sail area when off the wind - an advantage.
However you can argue that it detracts performance upwind; how? well there's more lift generated at the top of the sail then without the roach increasing the heel and thus reducing the amount of undisturbed air that the sail can transform into power. Conversely, if you add ballast to counteract the increased heel you've just made your boat heavier and therefore slower - again, detracting "performance".
An efficient sail shape (from a 3D perspective) is controlled by the cut of the individual parts and how they are assembled. Talking about an efficient 3D sail shape has to do with laminar airflow on both sides of the sail and including the effects of the slot effect when using headsails.
Basically, if you have additional luff (roach) - you have to use battens to control the shape of it (since its unsupported by the basic geometric shape of the sail) otherwise it would disturb the laminar flow and create too much induced drag thus slowing you down, and again reducing "performance".
Toronto, (Lake) Ontario, Canada
Currently sailing an Albacore but looking around for my next big boat.
Last edited by Talyn; 02-12-2010 at 12:23 PM.