On his ship, he hand made the ribs and stuff. I remember us cramming weights to get the ship right. I think he went with the weight concentrated towards the middle like a sailboat keel and low. That keeps the ship bobbing and tends to right itself. The decks were made out of foam, Nothing else, just foam with maybe a thin piece of wood on the bottom, very light. There is two outside ones and he used the center as the drag one