Antifouling: Everything you need to know - Practical Boat ...
If you’ve taken the existing antifouling back to the yacht’s gel coat or epoxy coating, it’s recommended that you paint the hull with primer to ensure good adhesion. If your existing paint is flaking, you need to prime any bare or flaky patches. Scrape away until all the flaky paint has come off, then feather the edges by wet sanding them.