I'm going to disagree with you simply because I've seen the result of gelcoat sprayed over a painted fiberglass surface.

A guy I knew had a perfect 69 Camaro with a fiberglass hood. A buddy of his had one he was fixing up. Well he who had was willing to help the buddy who didn't have make a glass hood for his car. Now these guys worked in the fiberglass shop at a boatbuilding place I also worked at. It was suggested to him that he would have to strip the entire hood before he could use his hood for the plug for the mold. Well he didn't agree. He felt as long as he put enough coats of mold release wax on, the paint would be protected. <img src="http://www.catsailor.com/forums/images/graemlins/smirk.gif" alt="" /> Well he was wrong. In fact not only did it ruin the paint but extensive damage was done to gel surface and in some areas it seemed to burn down into the glass. so needless to say they both were without hoods.

Lesson learned.

Also I can't find where Dirk said heat was applied to the area that had problems. Just guessing?

In the 27 years I've been around boatbuilding and automotive finishes I've seen some really strange things happen. When you apply gelcoat over something that has been painted with the possibilty of a laminate repair anything can happen. I don't see the boatyard as culprits in bad work. They could not have known what they were getting into until they did. I would have been more suprised to hear that there was no reaction knowing what the facts are at this point.