Let me start off with the problem. I have a 16ft Gheenoe clone that I have been using for a few years with a 6hp Evinrude. No problems, but it was not enough to get her up on plane. It was moving around like a displacement hull at about 6mph. it looks just like this one but in much better shape: http://www.microskiff.com/cgi-bin/yabb2/YaBB.pl?num=1303763440/0 Now I have a 15p Johnson and she get up on plane just fine! about 20mph now. Here is the problem. The whole floor area between the 2 seats flexes with the chop. as much as 2 or 3 inches!!! It is very disconcerting to watch! It has also cracked the corners of the floor on the coffinbox style livewell. I am fairly adept at fiberglassing and woodwork, so here is what I plan to do. I would like to carefully cut out the coffinbox, place some 1/2 to 1 inch tall ribs and stringers on the hull, fill empty areas with flotation foam. Then cover the stringer system with 3/8 ply and glass it in. then place the coffinbox back on top. The foam is for two reasons. To provide some floatation (the boat has none) and provide support for the thin floor. I don't want to add much weight and the floor does not get walked on much, just when boarding and disembarking the vessel. Anyone see a problem with the plan so far? Also, does anyone have a clever way to make sure all of the stringers/ribs are level on top? They are all going to have to be individually hand cut. The hull has curve and some bow to it in this area.