This sailboat calculator is great fun to noodle with! http://www.image-ination.com/sailcalc.html I think the results should be taken with a large grain of salt, however. The calculation makes no effort to locate the center of gravity or determine freeboard. If this were a physics problem from my college days, I think I'd get a tongue lashing for trying to make this approach float! According to the calculator, a P-15 with a 400# payload is more stable than an M-15 with the same...I think not! I guess there's no substitute for turning boats over and seeing what happens. My friend Scott pointed out that floatation run up the mast can make a great difference in these situations-good point made. So, any intrepid volunteers willing to turn their pride and joy over in the interests of science? I would, naturally, except the lake's mighty cold now and the water level is down... Tongue firmly in cheek Steve Tyree, P-15 #2098 "Amy Ann"