Wow! Talk about the triumph of implementation over design! There are a number of proven hull designs that could have been used, why would he use one that wasn't proven? 700 hp and no go. It is painful to watch the water test videos.
The cockpit instruments and controls are pure eye candy. The wiring is what I wish my boat looked like.
I think that the Hickman Sea Sled could be adapted to amphibious use, and have often thought about building one with retractable wheels. The idea of lowering sponsons never occurred to me, and it seems that one would have to be very careful raising them: if you are still in the water, you won't float, if you are on land, you have already dinged them up.
1975 32' Flybridge Sedan, twin Perkins 6-354 diesels, 1:1.53 velvetdrives, 16 X 19 props. Merritt Island, Florida