I am attaching plywood bulkheads to the hull of my boat to provide
support for fuel tanks on a Morgan OI41. Best info I have been able
to assemble says to put foam under the plywood before tabbing them to
hull. Question is: What sort of foam? Thickness of foam? Seems to
md that this application would require something denser than the
standard sheet foam available in home supply stores. Any suggestions?

When I rebuilt my Columbia Sabre, I bought airconditioning line
insulators.
http://www.acehardware.com/product/i...ductId=2126067
I slit them lengthwise, and got 4 strips per insulator. hot glue or
spray adhesive to hull or bulkhead edge. Doesn't really matter which.
All you are trying to do is to create a pocket between the edge of the
bulkhead and the hull, to prevent.....that's right....a hard spot. The
fillet and tape will supply the strength.
Larry Wilson
Columbia 8.7
Columbia Sabre
Urbanna,Va.