Has anyone had blisters on their hull after leaving it in fresh water for an extended length of time ( lets say 3 months or longer). Have certain hulls been more susceptible to this. What causes blisters on the bottom of a hull? Has anyone ( or know of anyone) specifically from Lake Winnipesaukee in NH. that has had a problem with this.

Thank You, Kirk

Just looked at a boat with blisters.Blisters are from the fiberglass absorbing water,a lot of people don't realize that fiberglass is very porous,that is why you put bottom paint on anything that sits in the water for any length of time.The gel lets the water seep through and it will start to form blisters between the gel and the skin coat of the fiberglass,most of the time it will not hurt anything it will just look like hell,but if it spreads and gets to be like chicken pox (boat pox) you'll have to grind the gel off and have it redone,this boat I was looking at would have cost about 9 grand to do,and a lot of times hull warranties won't cover them

KN: I worked at a marina on Lake Winnipesaukee for several years.

I saw many boats with little blisters in the gel-coat (below the waterline).

I guess I never learned a concrete scientific explanation for it, but it was fairly common.

The best explanation I had heard was that, over time, the water can actually penetrate through the gel-coat, through tiny "pores", if you will, where micro-organisms in the water actually get in there and live, which eventually forms the blisters.

The fresh water blisters I had seen there are substantially smaller than some salt-water blistering I have seen, where the long-term blisters go way beyond the gel coat, and can get up to several inches in diameter. I'm told these are caused by a similar phenomenon.

There may not be any easy solution, other than to dremel-grind them out, fill 'em with thickened West System epoxy (that's what I'd use, anyway), and then barrier-coat it.

My .02.

Good luck.

I've never had blisters in my hull bottom as it is the original gelcoat and is in good shape. I did however get some blisters in the sides of my boat below the water line. That is because I painted it with cheap paint. I just wanted to get it in the boat in the water. I'm repainting this year with the good stuff.

If you go to boatered.com you can do a search and read for days about blisters. It also has a lot to do with the layup when built. Years ago I had a wellcraft (85) that one side of the hull blistered like crazy and the other side was fine. I think it was much more prevalent in the 80's hulls before they started using vinylester resin.

Everything you didn't want to know about blisters.
http://yachtsurvey.com/blisters.htm

Beat me to it cuda - that is good reading...

Yes Dockrocker, a lot of his stuff makes a lot of sense. I've read all his articles.

Pascoe is the man!
I've spent days on end on his sight. Great reading.

Yep, he definitely has his biases, but he obviously knows a heck of a lot about how boats are screwed together (when they should be through-bolted! )