Scott Marquardt wrote in message . ..
But hey, and here I'm almost serious again: could a pontoon be made that
would fly well, plane well -- and work *upside down* as a better hull for a
catamaran? As has been pointed out, an aviation pontoon hull would make a
lousy boat hull, and vice versa. But might the *top* of a good aviation
pontoon also be a good hull shape for a cat?

Maybe. But either you sit astride it (using the step as back
support?) or else you cut a hole in the surface that's in the water on
takeoff and landing.

Inflatable boat and a pump, anyone?