After reading, Mr. MACOJOE's mention of BIX stripper I called the company. The young lady told me that Bix Stripper can be used on gelcoated fiberglass. HOWEVER, it will degloss the gelcoat and should only be used if the boat is going to be repainted. When asked which one of their strippers would be best she suggested BIX Tuff-Job available at Home Depot and Lowes. She also suggested only covering about a two foot area at a time. Takes about 30 minutes to work. Because there is about 140 square feet of bottom paint to remove I will try it as soon as the Georgia weather gets back in the fifties.