Blistering Attack

By Tom Neale, 2/19/2009


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Blisters are Gone
She was our brand new pride and joy.  She was a 41 foot long fiberglass ketch, built in 1973. We’d bought her during the Annapolis Sailboat Show.  She hadn’t been in the show because she leaned over a bit, but we had coaxed the reluctant broker into showing her to us where she sat behind a shed in a marina.  Two years later it was time to paint her bottom.

We took her to a workboat yard up the creek. This yard had been building and repairing wooden work boats for generations.  It didn’t have any new fangled sling, only a good ol’ tried and true railway.  They didn’t work on fancy “yacht boats” but they said they figured they could sand her bottom and slap on some paint. We knew there was nothing difficult about this sort of job and we also knew they didn’t charge “yacht boat” prices. We delivered her one evening, said an affectionate farewell, and went to our house.  (We lived in one of those things then.)  At the end of the next afternoon I left the office early (I worked in one of those things then) and rushed to the yard to see how things were going.

The whole crew was standing around my boat looking at it. And gesturing. And talking.  I figured this was probably not a good thing and apprehensively walked up.  I heard one old timer saying, “I jes’ don’t know. I never seen anything like it before.  Strangest thing I ever seen.”

When I got close they noticed me and the boss walked up to meet me.  “Dangest thing we ever seen, son. That boat’s got the pox. Go take a look.”  I walked in close to look at the bottom, and sure enough, it did.  Little bumps all over the place. And some big bumps, too.

The boss said, “I don’t know what to do with that.  I don’t know whether to take a knife and pop ‘em like you do with boils or give ‘er a pill like you do with the measles.”

I didn’t know what to do with it either, because that was the first time I’d ever seen or heard of blisters.  We popped a few with a pocket knife. A few of us got some permanent acidic blister juice on our eye glasses and it didn’t smell like we thought it should, but we still didn’t know what to make of it.  We decided to pop all we could and paint’er over. We didn’t know any better. We probably didn’t need to know any better.  We had a good time in that boat for several more years and then sold her (yes, the guy knew she had the pox) and, from what I’ve heard, that boat and its sister ships are still floating around all over the place.

I know a little better today. I’ve see plenty of blisters and I’ve listened to plenty of “blister experts.” Every time you go to a yard you find at least one boat upon which some poor soul is spending all the money he’d saved to go cruising to fix blisters.  I knew one guy who had a boat with blisters and who knew a surveyor with a moisture meter. He had the yard sand out the blisters and put the boat inside a “climate controlled” shed for a few months to let it dry out. The surveyor recommended this. The eager yard had to wait longer than they expected to finish the job because the moisture meter was reading just as high after those few months. They weren’t too upset, because it was their space in their “climate controlled” shed they were renting to the poor bepoxed owner.  This went on for two years and even then, the moisture meter wasn’t reading low enough to make the resident blister experts happy.  And this owner was “up in his years.” Finally he said, “to hell with this,” and told the yard to “fix those things, paint ‘er and put her in the water where she belongs.”  The boat is still out making her owners happy today.

I knew of another guy a few years back who bought the used trawler of his dreams. He was going to do all those nice cruising things you do with trawlers.  He knew the boat had blisters and got the best yard around to fix them.  They ground and ground until somebody told him they weren’t doing it “right.” So he had the boat towed to another “best yard around” who said they would do it “right.” The first thing they did was to put it in storage to let the hull dry.  I think that was probably also the last thing they did. Several years later we were visiting the yard and saw the same boat sitting in the same place “drying.”  We heard that the owner never went cruising. As the drying years went on, his health failed. Father time is more persistent than hulls drying.

We had another boat some years back which had tons and tons of blisters. She was just over two years old at the time and the builder had absolutely nothing to say except excuses. Mel and I and our two daughters were living aboard and, as has usually been the case with our live aboard lifestyle, we didn’t have a lot of money.  We were always in the Bahamas in the winter, and so one summer we decided to put her up on the hard and go to work—ourselves.  I hired a sand blaster to take the top layers off at first, because I knew I’d need at least that much help and he was inexpensive, sitting in his air conditioned space suit mellowed out with his artwork.  But then came the tough part. I spent about a month under that boat in throw away white suits with a pneumatic grinding gun, grinding and fairing out the blisters. After each job, I’d wipe the spots with Acetone which, I thought, had a tendency to help drying. Each one that I faired back would, within a day or so, begin showing moisture around the perimeters.  So I’d fair some more.  The temperature was in the upper 90s. It was a very hot summer. One day one of the yard owners (a friend) came and begged me to lay off work for the rest of the day. He said that I was sure to have a heat stroke. I looked around through my dust covered goggles and saw that everybody else in the yard had already quit. That was one very bad month.

Tom’s Tips About Blisters

1. Some blisters are so deep that they have structural significance and boats with problems like this should be avoided.

2. Some don’t appear to be deep but are symptomatic of inherent delamination which you can’t readily see unless you do something like cutting a plug out of the hull. Delamination can make a hull fail catastrophically.

Click Here for More Tips

Finally we reached the time where I realized there was always going to be moisture in that hull and so I stopped “fairing” and started filling with glass cloth and West System epoxy and fillers. This took around another month.  Then we covered the entire hull with epoxy and then many coats of an Interlux barrier coat, which we found to be a great product. We splashed her and had no more problems with blisters for the many years we kept her.

I’d never want to do that job again, but I learned something from it, about blisters and other boating problems. There are experts galore out here who will tell you there’s only one way (or no way) to fix something. Often they’re right, but not always. Theory sometimes needs to be tempered with reality. Today, if I bought another boat, I’d probably look for one with blisters (not too severe) because so many owners are terrified of them and I know that they’re usually not a big deal to fix, especially if you don’t mind a little love/sweat equity. And if you fix them, years down the road they may pop up again. But, IT’S A BOAT, DAMMIT! 


Copyright 2004-2009 Tom Neale