Drill a test hole
Drill a hole down into the deck in the suspect area. If it brings up clean wood, you are OK. Fill gthe hole with epoxy, sand it flat and breath a sigh of relief.If it brings up nothing, or wet/rotted wood, you need to go right to work lifting the top layer of the deck, getting the rotted wood out, and replacing it. Check the archives for my description of this job at the mast step on Lady Lillie, a '77 h27. It's not a bad job to do yourself if you have the time and inclination. Otherwise, it is a normal job for any good fiberglass repair operation.By the way, another symptom of the problem is if the ceiling liner is forced down around the forward bulkhead of the main cabin, or the door in that bulkhead sticks when you try to move it. Both of these symptoms will probably go away if you unstep the mast. If so you know it is the mast step.DavidLady Lillie