"Bart" wrote in message

My understanding is balsa has far superior adhesion because
the end grain is rougher. Foam can suffer from extensive
delamination due to freezing--as water continues to propagate
in the layer between the laminates. Does anyone have
any experience with this?

My experience: There are four C&Cs in our marina, all of which have
end-grain balsa above the waterline and in the decks. And all are quite
wet. As for structural integrity, all the owners have remarked that they
aren't going to do anything about it, as the hull and deck stiffness is
still pretty good. I do worry about the freeze/thaw issue, however. And
weight.

My sloop has Airex foam. No delamination anywhere, and I can't find any
water in the hull or deck at all. I've been over the entire boat with a
moisture meter several times in subsequent years. Of course that is just
one man's experience, but I'm happy.

Max