How do you apply antifoul?

In most cases, you'll need to power wash the bottom to remove the dried on marine life and to remove any scale from the old surface. As a good rule, you should rough up the old surface with a power sander and 80 grit sanding paper, so that the new paint can stick well and not have bubbles. Most people use a roller to apply the new paint. Just stir the paint regularly. Follow the instructions on the can to the letter.