William R. Watt wrote:
The foam boatbuilding I've seen described requires a building frame to which
a special boatbuilder's foam is attached. It's then covered on the outside
with lots of fibreglass for strength. Then it's femoved from the bulding
frame, turned over, and covered on the inside with more fibreglass. All
that fibreglass makes it heavy.

That's an odd thing to say. Fiberglass/foam core or sandwich
construction is usually described as very light & strong.

However, it's not cheap. The cheapest type of foam insulation is not
suitable for core material as it does not have a good bonding surface
and it's shear strength is comparable to lumpy oatmeal.

Luan underlayment is probably the cheapest per square foot for boat
building material that has a chance of success. It will probably have
durability & longevity issues unless it's given very careful work during
building & good maintenance during use.

Here's a thought- has anybody tried building a stitch-n-glue boat out of
OSB?

Fresh Breezes- Doug King