I have a fiberglass tri-hull boat and when I pulled the plug after some fishing the other day water drained out which pointed to a leak. I put some water in the boat and low and behold there is a hairline crack on the bottom about 8 inches long with about 2 inches leaking out the water that I put in. The crack is in the gelcoat and apparently let water into the fiberglass which weakened and now leaks. The bad spot is about a 1"x3" area. What would be the best way to fix this. Epoxy Fiberglass resin or polyester resin. Will the epoxy bind to the gelcoat if the gelcoat is roughed up some before application? I don't care how the repair looks as long as it's strong. It's below the waterline and an ugly spot would just give it some more character.