When I did a boat years ago I used a 1 part brush on Polyurethane. It worked out great. It looked great and was very durable. A lot of people told me to go with a 2 part polyurethane but I chose the easy way with the one part and had great results. Saw the boat a few years after I sold it and the engine room paint looked great. The poly paint is great the only thing is that cleanup is a *****. Pretty much have to use laquer thinner to clean your brush and any mess. I washed the bilge with Simple Green and water with a scrub brush. Let it dry then right before I painted I wiped everything down with laquer thinner then painted. The first coat looked great but I put a second coat on the next day anyway.