We pressure wash, sand and break/grind the blisters as we come across them. Most of the blisters are small dime size and a few quarter which are surface blisters. Pettit Trinidad is epoxy based so it dries hard to form a protective barrier. However, if left to thick the bottom paint will blister. That is why we lightly sand the hull. Same idea as sand between coats when varnishing/painting so the paint sticks.
.....clearly the mad raving of an "internet heckler".