Could possibly float boat

[shaunjohnson]

what i know about foam...
polyester foams have to be fiberglassed over with epoxy resin only.
urethane foam can be fiberglassed with normal resin.
high density foams are great for boat building but if you fiberglass it it will be punctured, it is designed to crush under loads.

takes AGES to rot in water.

umm....that's about it...
i used to be a member of the RC airboat clan and we built 1/4th scale gassers out of the stuff. layered it up then glassed it over.
i made 2 gassers like that and one gasser out of plywood.