the problem starts with the steel and the fact that we dont have time to do things properly anymore.
years ago boats were put outside to allow the mill scale to come off that is the coating on the steel when new, this hard scale comes off with time and when you have blacked over it your black comes of with it, usually at the water line,
were water meets the air, so shot blasting removes the mill scale, and within an hour a Zinga coat is applied to stop it rusting because over night you will have a coat of rust on your boat. Zinga is very easy to apply, a 5lt can is heavy, the Zinga black is not as black as bitumen but a nice dark grey and a real nice finish, the Zinga rep will give advise .