Cheap Polyurethane Paint
Like Scott, I have used rustoleum rusty metal primer and rustoleum on several boat projects and been very happy with the results. BTW, ace Hardware brand enamels are made at the same factory as rustoleum.However, there is a cheaper polyurethane paint option that I have used under my v-berth etc...Ace Hardware brand floor paint comes in both an enamel and a polyurethane formula at about half the cost of bilge kote. Any quality enamel or poly will not flake off if you prep the area well. Scott is right, clean really well--then clean with a solvent (I generally use acetone). Make sure the surface is not shiny smooth (roughen with 150 grit sand paper if in doubt). Follow the instructions on the can and put a couple of coats on and you will be good for years.