: Last summer I designed and build my own skin on frame kayak. It turned out to
: be very, very tippy. It is 12' X 20" with a hard chine bottom. I sit
: about 4" inches off the bottom, so I know that if I close that gap it
: would be less tippy.
: Anyway, I want to build another one this summer. What design changes should I
: make to make it less tippy? Thanks for your help! Clint

Since the seat issue has already been addressed, the next thing to look at is the dimensions. If you want the boat to be a close fit on the sides (a good thing), yet still be stable, you need to make it longer. Adding length to the boat will increase stability substantially. Try making the next one 17' long with the same width.