I think on this site about 18 months ago, a group set themselves up via a blog site to design and build a F16 which would be made avaialble to all who were interested. I think a number of regular readers of this forum were involved, is that design still kicking about ?

Have a look at the method John Lindahl is campaigning in building his LR2 and LR3 A cats, gives a very strong structure and very light weight hulls plus it quite well documented. Google should find it no problem.

There is also a very good boat design and build section on this cat sailor forum at the bottom of the list of forums and also another good resource is /www.boatdesign.net/forums/

Best of luck but one tip, which is it going to be a single hander or a dual hander, they are quite different designs.