If you guys are using a roughed surface to gain speed it is not water on water, rather is is air on water. The ridges act like the dimples on a golf ball, forming air pockets on the surface of the hull between the hull and the water. Other examples are sharkskin, step hull( talk to Chris Selph about those!) WIG craft(which leave the water completely), and outright dimpling, as done on some waterskis, wakeboards, and kneeboards. Heck, if you really want to go fast on the water, use wheels. Yes, wheels. Speed record on water ( close to the speed of sound) was set on wheels. after a certain speed, the water is as hard as any road, so use wheels. Keeps the hull from being ripped to shreds ( again, water is pretty hard at those speeds). This is why the drops of water bounce on the surface - very hard water(speed) and the air pocket between the drop and the water surface ( a WIG effect )