If no one has tried Mildew Stain Remover from Star Brite give it a shot.....the best stuff I have ever used. My boat has been sitting for about 4 months without being washed and had mildew pretty much everywhere....followed the directions and sprayed it on, let it sit and rinsed it off and all the mildew was gone, couldn't believe the results....give it a try you won't be dissappointed.
I had to store my boat for a few months due to engine problems. When I took the cover off, I had quite a bit of black mold\mildew on the fiberglass. I first tried using a bleach based cleaner, followed by soap and water, but had no results. Then I used Star Brite Mildew remover with the yellow label, and the stuff did an AMAZING job. Sprayed it on, agitated with a brush and let it sit for a few minutes. Rinsed it off, and it was sparkling white, and I have had no regrowth. Next, i will be buying the deck cleaner to scrub my decks. if it works as good as the mildew remover, my boat should end up looking fantastic:obscene