Hull blisters

I picked up an '82 H16 that has been sitting for several years outside in pieces. The hulls were laying flat (on their sides) on the ground and now have some small pock marks and blisters in the gel coat, each about the diameter of a dime. The area of about 24 sq in. total around midships in the outer hulls. Can I sand these out and touch them up with something or do I have a major repair to worry about before I put the boat in the water?

There is no way to just sand them down, as you do, you'll find a small amount of water behind each one. When I bought a 79 loaded with blisters, that's what I found. The blisters start in the fiberglass when uncured resin pockets mix with water and then push the softened gel coat up.
I see it 3 ways. If it doesn't take on water, you could sail it as is. You can treat each blister separately, opening it up down to the fiberglass and filling it with epoxy and painting it but other blisters will show up. Or sand the whole area down and epoxy it.
I took all of the gel coat and matted layer of fiberglass off the sides of my hulls from bow to stern. I then used West Systems Epoxy to refinish each hull the then painted them. It was a long process but now I have a nice boat that looks good.

Buxton

I took a Dremel tool with a sanding wheel and opened up 15 to 20 blisters. They are all quite small, the largest about the size of a dime. Only two oozed moisture. I think I'll just dab on with gel coat and touch them up. Then I may do a fine sand and roll on some acrylic paint. Can anyone recommend a hull paint?

Please post your progress. I have to do the same thing this spring.

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Division 10, Fleet 185
Hobie 17 and Hobie 14

My sister had a 30 ft monohull. It had several layers (lots) of bottom paint on it. She had it sandblasted. Millions of large pin head size bubbles were opened up. She let it dry over the winter and used Interlux products to fill and barrier coat the bottom. She then painted it. She gained a knot of speed by that alone.

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1989 Hobie 18 Worlds Boat, Magnum Wings & Spinnaker
1987 Hobie Holder 20 #273

dale.vanlopik"at"att"dot"net

perhaps this will help... just on a larger scale....
http://www.capsante.com/Articles/osmotic.htm

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•Present boat -1998 Hobie 16 Solana Sails furling jib[/size]

As I said I opened the blisters up with a dremel tool and medium grit sanding wheel. Only two out of several dozen had water. I then filled them with Marine Tex using a plastic putty knife. This turned out real well and was easy to sand and finish. Some of the larger blisters required a second application of Marine tex as the product becomes a little soupy after adding the hardener and tends to sag out of the larger depressions. Not sure what the working time is for Marine Tex but had I to do it over I would have waited a few minutes for the paste to thicken up. (A friend of mine with a Nacra 5.0 uses vinylester filler and said he gets similar results except the stuff he uses is light green.) Marine Tex comes in white and gray except the white still dries somewhat light gray but I'm going to paint the hulls anyway with West Marine Sea Gloss Pro polyurethane.