Questions on Blisters

A forum for discussing boat or trailer repairs or modifications that you have made or are considering.
Post Reply
macowneril2015
Engineer
Posts: 189
Joined: Tue Nov 10, 2015 5:51 pm
Sailboat: MacGregor 26X
Location: Downtown Chicago, 2001 26X, 2001 50 Hp Nissan (NS50D2)

Questions on Blisters

Post by macowneril2015 »

So I have dug through here and noted others have had a bunch of small blisters all over the hull of my :macx: when I pull out at the end of the season. I have noted they do not get worse and go away within a couple hours of being out of the water. I need to reapply bottom paint and was considering getting it sanded/ blasted and getting a barrier coat and bottom paint put on. My concern is when the boat is sanded that these legacy blisters will open up resulting in additional cost and work. Any guidance is appreciated as I can just get anti fouling reapplied and just enjoy the boat but I have wanted to try and get it done right.
User avatar
NiceAft
Admiral
Posts: 6192
Joined: Tue Feb 01, 2005 7:28 pm
Sailboat: MacGregor 26M
Location: Upper Dublin,PA, USA: 2005M 50hp.Honda4strk.,1979 Phantom Sport Sailboat, 9'Achilles 6HP Merc 4strk

Re: Questions on Blisters

Post by NiceAft »

I don't believe bottom paint is good protection against blisters. That's what the barrier coat is for.

I had my Mac at a slip for three seasons with only a barrier coat. because I only sailed in fresh water, I only had to deal with algae at the end of the season. I took care of that with Slimy Grimy powder. In twenty years I have never had blisters, and have never replaced the original barrier coat.

Blisters coming and going is new to me. Someone else may enlighten both of us.
Ray ~~_/)~~
User avatar
Be Free
Admiral
Posts: 1366
Joined: Fri Nov 23, 2012 6:08 pm
Sailboat: MacGregor 26X
Location: Steinhatchee, FL

Re: Questions on Blisters

Post by Be Free »

Ray is 100% right. Barrier coat prevents water from soaking into the bottom which is the usual cause of blisters. Bottom paint discourages the growth of marine organisms on the hull.

A blister that goes away that quickly is probably in or under the top layer of your bottom paint. A true hull blister takes a lot longer to shrink and usually requires sanding to remove completely.
Bill
2001 26X Simple Interest
Honda BF40D
"If I were in a hurry I would not have bought a sailboat." Me
User avatar
Russ
Admiral
Posts: 7565
Joined: Thu Oct 11, 2007 12:01 pm
Sailboat: MacGregor 26M
Location: Bozeman, Montana "Luna Azul" 2008 M 70hp Suzi

Re: Questions on Blisters

Post by Russ »

Yep... barrier coat is what prevents osmosis or whatever it is that causes blisters. I may get flamed for this, but Roger used poor gelcoat and blisters happen. First year I pulled out and had tons of them. Still do. Some have popped. Mine aren't that bad and I haven't seen intrusion into the glass. But they are there.

In retrospect, I wish I did a barrier coat. Fresh water seems to be worse for blisters. Probably because it's not as dense.

I've got 'em. I ignore them. In 11 years they haven't gotten worse so I look the other way and can't see them once the boat is launched and floating.

Should I fix them? Probably. But they simply haven't been bad enough to drive me to do all that work.
--Russ
Post Reply