I bought a 1975 18' fiberform trihull last fall knowing very little about boats, was told by the prior owner that the motor just needed a tune up. took motor off rebuilt carbs and tuned up and motor runs good now but started looking over the hull and found that under the splash well there is a long angle iron bolted through the transom for support and the wood in there is mush on the bottom of the center of the hull(the keel i believe it is called) it appears that the boat hit something as it is scraped about three feet long and 6 inches wide can see the actual fiberglass and water appears to have gotten into the fiberglass and it just wont dry up. at first thought maybe spreading marine tex over it and sanding smooth but with all that moisture would probably be a waste of time. any thoughts would be great.