I think I was that suggested the belt sander. I used one on the stern of my 6.0 - previous owner had abused the boat such that the stern had some pretty serious structural cracking (looooong, but funny, story!). It still took a bit of work to get through the gel coat. However, it would be difficult to sand and NOT get through the gel coat using the belt sander. I would only do this if you plan on refinishing this area later.