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Fins...why symmetrical foil?

Posted: Thu Sep 14, 2006 10:14 pm
by StrangeBrew
So...most production boards come with four fins. Still haven't figured out why all the fins are the same shape and size; obviously, on a twin tip, the heel side fins get far more use.

That aside, they're also symmetrically foiled; same foil on both the inside and outside. If there a reason for this? I can understand on a windsurfing board that the fin needs to be symmetrical; you gybe and ride both sides of the fin. Okay. BUT, if we do spend the bulk of the time on our heels, would it not make more sense to have an assymmetrical foil so that not only is the fin acting as a foil to provide stability, but also providing lift?

Compare, for instance, the side fins of a surfboard versus the centre fin. Side fins; assymetrical foil; provides lift (also drag, but that's more to do with the toe angle) whereas the centre fin, which is the stabilizer, is symmetrical.

Anybody tried/made assymetricals to fit on a kiteboard?

just wondering...thoughts/experiences appreciated.

Posted: Mon Sep 18, 2006 3:55 am
by munteruk
I've used asymetric foiled fins on one of my boards before. I couldn't tell the difference. Compared to windsurfing the fins on a kiteboard do relatively little work so changes to their design have less impact. There may be efficiencies that can be gained by changing the design but I wouldn't expect them to be revolutionary.

Posted: Mon Sep 18, 2006 12:26 pm
by max
the cabarete boardbuilder EH swears by assymetrical fins....his fins are foiled like little airplane wings.....the faster you go the more they hold the rail in the water...they look like they are fitted backwards...