I gave up on the bottom paint removal project on my v20 last year and sanded it as best as I could and put a good coat of west marine black bottom paint with a red line between the black and white and it looks great..I had about a 2 foot area clean but it just would not buff out and looked stained..They rough up the surface before applying bottom paint and damage the gel coat in the process so it will never look right..in my opinion..plus it was first put on in 83 and who knows how many coats after that...Its one of those things that looks easier than it is..Frank