Hey,
Barrier coat is a good thing, but it's a little more complicated than just "remove old
paint, clean, apply barrier coat."
Depending on the particular barrier product you are using, there are all sorts of restrictions on when you can apply the barrier coat (temperature), how many coats of barrier you need, how much time you need to wait between applying the coats (and how long is too long), and finally, when you MUST apply the antifouling
paint.
Note that most barrier coats are
epoxy based, and
epoxy tends to be slippery. Wait too long for the
epoxy to dry and the antifouling may not stick to it.
Again, I used Pettit Protect and followed the instructions VERY carefully. I applied the bottom
paint when the last barrier coat was still tacky. I had excellent adhesion of bottom
paint. The antifouling didn't work as well as I hoped (a fair amount of growth) so I will try a different type next year, but the paint stuck well to the barrier coat, and I have no blisters.
Barry