If you have a blister problem, and your boat has some value, then you can consider the expense of eliminating the blisters by sand blasting or the other methods of gel coat removal and then you must let the hull dry before you apply epoxy. You don't want to apply epoxy over a wet hull - that is a waste of money. If you are just wanting to protect your hull from blistering, then you must remove any existing antifouling paint before applying the 2000. VC17 is a single season paint with a biocide of cuprous oxide. It is excellent if you apply it at the beginning of the season and leave the boat in. But, like any cuprous (copper) oxide coating, if you pull the boat and let the hull dry, then a chemical reaction takes place and renders the antifouling properties useless. Therefore, if you intend to launch and relaunch your boat several times over a season, VC17 is not a good paint as each time it dries, it won't be so effective. If you are leaving the boat in the water, then I recommend you sand the 2000 down to a very smooth surface, because one of the beauties of VC17 is it's smooth and fast surface (racers love it). It seems futile to apply it over a stippling from a roller. That sort of defeats the paint's purpose. But, do it if you don't care about maximizing the potential of the paints contribution to boat speed. If you are going to launch and retrieve the boat many times during the summer, you'd be better off using an ablative paint that has multi-season characteristics. These paints don't suffer from a chemical reaction rendering it useless when the hull dries. As long as you see paint, even after a period of winter storage, you can assume that the paint will work. Copper paints work by the biocide sluffing away from the paint surface, leaving the paint behind. With VC17, you don't need to worry about paint build up, but with most other copper/single season paints, the paint will continue to build up so that at some point you have to sand it down or smooth. With multi-season paints, the paint and the toxicants sluff away at the same rate. The biocide is sort of like a cold pill that keeps supplying protection over a period of time. As long as you see paint, you know it is working for you. Maybe a bar of soap is a better example. It keeps cleaning as the bar gets smaller until it is gone. When the multi-season paint is gone, then you have to repaint. Therefore, with a single season paint, you could be looking at paint on the hull, but if it is an older application, there might not be any toxicant left.
