On Mon, 6 Dec 2004 22:25:47 -0500, "cc0080793" wrote:
I was told when we first put it in the water to watch for "blisters" in the
fiberglass hull a few years down the road. Well... here I am a few years
down the road (3 years to be exact), and I DO see some half-dollar sized
places on the hull that must be the aforementioned blisters (3 or 4 down
each catamaran). Nice, smooth bulges about 1.5" in diameter that protrude
about 1/8" off the surface of the hull, almost looks as if there was a
carriage bold head under there that was glassed over.

Is this "blisters"?

Might be. Are they below the waterline or above? If below they are
probably classic gel coat blisters. Yours are moderate in size and
few in number so no cause for panic yet. In small numbers like yours
the most cost effective remedy is individual spot repair. Grind out
the blistered material with something like a die grinder or Dremel
tool, fill with thickened epoxy and sand smooth. The generally
accepted prevention is several barrier coats of epoxy over the entire
hull below the waterline. Antifouling bottom paint is not a water
barrier.

If the blisters are above the waterline they may be "hard spots" where
some structural member inside the hull is trying to poke through.
That should definitely be investigated by a professional. Do you have
a hull warranty from the builder? If so dig it out and give it a
close read.

What to do? Is this something I could fix myself, or does it need
"professional" work?

If you're handy with epoxy work you could probably do it yourself.

Some have said painting the glass hull with an anti-fouling paint will help
prevent this, but I didn't think painting a glass hull was a common
practice.

It's common in many areas to prevent fouling buildup. It will not
prevent blisters however.