Two Different Purposes
Chuck, As long as they build fiberglas boats with gel coating there will always be a need for a barrier coat. Newer boats with newer materials, and equally important, newer construction process controls, greatly extends the time before you could possiby experiance blisters. The bottom paint you are talking about helps in reducing the buildup of algae and/or facilitates the removal when time to clean the bottom. It really does nothing in blocking water migrating over time into the gelcoat and eventually the fiberglas. The barrier coat is the best insurance you can buy in reducing water transfer to the hull. Believe me, when you go to eventually sell your boat, nothing will turn off a prospective buyer quicker than blisters. Barrier coat the boat, it's well worth it, even with todays newer boats.
