> The unique feature offered with two large rudders on a proa is the potential advantage of using asymetric sections for the rudders.
what a brilliant idea! by "potential", do you mean to say this is NOT customary on modern proas? if so, why not!?
so upwind the more curved surface faces upwind. lift is generated even when the angle of attack is zero. so less leeway and drag. course is more upwind even though heading is the same.
but what about downwind? you maximize VMG by sailing on a broad reach re. true wind, which on a boat that can sail windspeed is a beam reach re. apparent. you don't want to prevent leeway (correct?), so do you flip the asymmetric rudders around so that the more curved surfaces point downwind? this would then generate more leeway, which when trying to go downwind is good. am i getting this right?
new member by the way. just bought a weta trimaran, and am dreaming about retiring on a larger boat. maybe a harryproa!
ben arthur
weta #358, "gray matter"
ithaca, new york