I have a 25 year old fiberglass sailboat,recently acquired, that has an area in the deck of the cockpit that "gives" when you step on it. It feels spongy. Looking at the underside of the deck there doesn't seem to be anything that looks different. The soft area is just forward of the wheel and is about 18 inches in diameter. I'd like to be able to repair it , but don't have a clue. hcmcs@sbcglobal.com