Friend has a 19' with outboard and it has been painted with reg. boat paint. It has blisters into the hull not deep though. He is sanding them out (50-100 of them) and repairing them with epoxy and is removing all the bottom paint. The resulting surface will be a combination of old gelcoat(30 yrs old) and the epoxy patches. We are curious what he should use to reseal the exterior of the hull.(Water line and below) I have rebuilt several boats and always just regelcoated. He doesnt have the skill to do that. I mentioned two part epoxy or two part urethane. Any suggestions?