On Mon, 29 Oct 2007 15:43:06 -0400, HK wrote:

the few cored hulls I have seen with holes in
them seem to have very thin fiberglass on each side of the coring material.

That's the whole idea of course, cut down on the amount of heavy
fiberglass by substituting a lightweight core, a good concept as long
as the skins stay glued on and the core is undamaged. It is sort of
like a cardboard box however, surprisingly strong right up until the
core gives way, then it's junk.