Daggerboard

[bevan]

does anyone know how to calaculate the area needed for daggerboards on a catamaran?
Thankyou!!!!!

[tspeer]

1.5% - 2% of the upwind sail area is a reasonable rule of thumb.

Tom, would that be total area of both boards or the area of the board in each hull?

[tspeer]

Yes ;-)

I think one would want to look at a number of successful designs of similar boats and use their boards as a starting point. I find Kurt Hughes' catalog to be especially valuable for this, because he has such a wide range of types, all the way from beach boats to world cruisers.