I have a 23' sailboat and the smooth topsides (especially aroung cockpit) have what appears to be pin size black speckling. I have been told that this is the gelcoat wearing thin and the fiberglass underneath showing through , however; if i put boat scrub soap to it, it noticably improves and washes away but is still there. It seems to be almost a mildew or mold look, but cannot get rid of it completely. Was I informed correctly or is there a product to solve this?
What you seem to have here is mold forming on dirt that's collected in the porous gelcoat. Any good deck cleaner should get it out. Soak the area and scrub with a soft brush.To prevent it, compound the area smooth and seal it with a good marine wax twice per season.This worked on my 1986 Regal, which had the same problem when I bought it after it sat on dry land for 2 years.