In your library or used bookstore, you may be able to find a book called "Foam Sandwich Boatbuilding" published in the '70s. He details a method of boatbuilding using a wooden mold, putting sheets of building foam on the mold and fiberglassing the outside, then popping them off the mold and fiberglassing the inside. The book describes the method for very large craft such as 40 to 60 foot trimarans. The method should be applicable to smaller craft. He does mentin specific brands of foam that can be used, but they are English brands and probably not available 20 years later. I was thinking of using insulating foam blocks to reinforce the bottom of my fiberglass motorboat, if I do, I'll let you know how it works.

> If styrofoam is unsuitable, what kind of foam strips will be nice for such
> work?

> The following products are not suggestions, i have no knowlege, but these
> names come to mind: Nomex, Divinycell, Airex.

> Ray Jardin did use 3/8" Airex as core material, description o his
> method to be found at

>
> http://www.transport.com/~ray316/kayak_construction/kayak_construction.html
> But he did put the Airex on a male plug, so I guess this kind of Airex
> would be much too soft for strips on a strip-built.

> Jan Gunnar