Don't call me a "senior"!
I was thinking of painting the inside of the lockers (mostly under seats/bunks) on my boat. It struck me that garage floor 1-part epoxy "paint" might be just the ticket. I saw some stuff at the local HomeDepot that was solid gray (no contrasting flakes, such as those found in many similar products), and thought that it would make pretty good "bilge paint". It should wear well, since it's made to take being walked and driven on. The only question might be how well it would stick to fiberglass.