WRINKLY SAILS
Q: When I see photographs of raceboats, I notice all kinds of wrinkles in their mainsails. This is true even of small boats like Lasers at the Olympic level. How is it that these wrinkles don’t affect the aerodynamics of the sail? Surely it must slow them down, especially going to windward.
Kenneth Jenkins, Horicon, WI
BRIAN HANCOCK REPLIES
I presume you mean those horizontal wrinkles and not the vertical ones. (The vertical ones are bad and are caused by too much bend in the mast or too much halyard tension.) The horizontal wrinkles, on the other hand, are not as bad as they look. Granted, all things being equal, it’s probably better to take up on the halyard or cunningham to remove them, but not if that comes at a cost to sail shape. Understand that a sail is designed to a certain shape, and you have a limited number of tools with which to manipulate it. In light winds you want more draft, which means keeping the mast a bit straighter. In heavier winds you want a flat shape, so you bend your mast more and take up on the outhaul. Also, understand that the main has to operate in winds from zero to 30 knots. The sail may be optimized for certain wind speeds and not for others, so what you may be seeing is the result of a compromise on the part of the sailmaker. A few wrinkles along the luff in the area just behind the mast is also experiencing a certain amount of turbulence from the mast anyway, so the issue is not a critical one.
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June 2017
