Bottom Paint

[Penns Beach]

2003 2700 SCR Purchase this boat four years ago. It was boattel kept and had no bottom paint. Had the bottom professionally painted immediately. Every spring since then I have painted the bottom with West Marine "ablative antifouling black paint". This year for some reason in a few spots (mainly on the sides) the paint flakes off when I apply fresh paint over it. We boat in the upper Susquehanna area in Maryland which is fresh water. When the painted dried I sanded the flaking spots. Applied fresh paint and the edges flaked off again. What is happening? What should I do?

[rens914]

did you use appropriate epoxy primer before you put on the antifouling
without it will come off again
best thing you can do is get everything off.
put it in 1 or 2 coates of primer and apply antifouling after that
you'll need to do that every 2 years
rens

[shrew]

^^Ditto^^ Ablative paint should wear from the outside in. If the paint is flaking in large chips all the way down to fiberglass, then it is an issue with the paint properly bonding to the hull. Painting over it will not help as it is the base that is loosing the bond. When this occurs the old paint releases from the hull along with the new paint on top of it. The newly painted areas continue to chip for the same reason the previous layers chipped.

This is due to hull preparation prior to the first coat of paint being applied. It could be residual wax, residual bond release from the factory, or the hull was not properly or completely sanded in that area, or the area was not completely cleaned of gelcoat dust between the sanding and the application of bottom paint. And finally, a barrier coat of proper thickness prior to painting will not only help prevent water intrusion, but also aid in the paint in bonding. If you were to apply a barrier coat, you would need to completely strip the hull down to fiberglass.

I had the bottom of my boat soda blasted. I then applied a couple of coats of barrier coat, then a couple of coats of bottom paint.