My boat has a pressurized alcohol stove. I was not thrilled about it when I bought the boat because they have a bad rap. The previous owners had converted from Propane to Alcohol. I've heard that with Alcohol, you can't see the flame. This is only true if the flames are in bright sunlight. If the flames from your stove are in direct sunlight, I think the battle is probably lost already! Besides, the flames from the burning fiberglass should be highly visible by then
I can get fuel at any hardware store. It may be a little slower to heat than Propane, but I am very happy with the Alcohol stove and oven. I don't think it should be a deal breaker, there are bigger issues when buying a boat. I would certainly try it for a while before replacing it. I think Alcohol is fine.