There are a lot of ways to clean the deck of a boat but our suggestion is to go for a product that’s made especially to clean this part of the boat. A product that was made to clean the fiberglass surface of a boat deck ensures that the toughest stains come off while the paint and gel coat of the deck remain intact. While there are lots of solutions recommended for the job all over the internet, not all of them are gentle on fiberglass, and you’re better off going for a specially formulated and proven product for the sake of your boat.