Preventing below-the-water-line blisters, 1972 Katama

[hermit]

There is at least one area of small blisters along the water line of our 1972 Katama (16' 7"). The Katama is trailered now, but I would like the option of leaving it in the water for up to a month between haulouts during the boating season, roughly June - October. The waters involved are Lake Ontario and the Erie Canal. The hull has never been painted, and the original gelcoat is still mostly blemish-free.

I want to prevent further blistering, but I prefer to avoid bottom painting.

I thought a coat of clear epoxy might work, and I read that barrier coating prevents blistering. Is there such thing as clear barrier coat? That seems ideal. Other suggestions are welcome. I would hire the work done by someone who does fiberglass hull work for a living and knows what they are about.

[L78steve]

Leaving the boat in for up to a month is not a problem. I wouldn't coat the bottom. Most blistering problems Iv'e seen on Whalers is water on the inside.