No reason for the 16in other then trying to keep the height down and scale size close, the idea is that if it works well to build a real 1 or 2seat version. I will try to put up a pic, but to get a good idea check out the "the wig page". I am building a lippsich style one. It seems most people start from a plane background and not a marine back ground. The result is craft that can't take the punishment of rough seas and have too narrow a pop orating range as far as wave height goes.
I am approching from a speed boat mind set, In that it should survive high speed wave impacts.......