When we bought the boat last year we started with Ajax cleanser with bleach to kill all the black spots on the deck. The deck glass was like a chalkboard! Finally, this season, after wet sanding with 1500 grit and lots of water, polishing with a makita buffer and wool pad with 3m fiberglass cleaner and wax, THEN a coat of Collonite buffed off BEFORE it dries as per the directions, Calypso absolutley shines! Try this procedure as S2 does have nice gelcoat. Water beads up and I find myself walking by it at the dock and catching the reflections. Looks like new glass. This pic shows a little of it.
