Originally Posted by bayview
years ago I got a piece of foan from a boat builder and submerged in water for six months. It did not absorb any water. try that with balsa.
My boat is cored (with the latest and greatest synthetic at the time, Corecell, as I recall) above the waterline, solid below. I took some of the cores (the ones that are left after a hole saw is used to cut a penetration for a thru-hull, etc.), thoroughly cleaned and weighed each, then sealed each in its own bag of water. Several years later, I opened the bags, dried off each of the samples and compared the weights to determine whether either the fiberglass or the coring had absorbed any water. Happy to report that none had, not even the ones with coring exposed directly to water for years.