blisters and moisture

We just had an early 90's Albin hauled out during a survey. Mechanically, it could not have performed better. We were very pleased with the Cummins 6BTA's. Things seemed to be going well.

Then we pulled it out of the water and I was pretty disappointed. Blisters.... and I mean blisters. As in no way to count them all. I'll try to attach pictures.
A moisture meter also showed some moisture in the stringers, but they tapped out well and seemed solid. They also appeared solid on a back down test where they were shifting the transmissions from forward to reverse and then adding pretty significant throttle to try to detect movement around mounts/stringers with that pressure. All seemed good there. Still, though, some moisture in the stringers per the moisture meter.

Aside from the things we already knew and expected would need attention, the condition of the bottom (all of those blisters) and the moisture were real disappointments.

It's a 25+year old boat -- so we do not expect perfection. Far from it! However, am I overreacting or am I right to be extremely concerned with this level of blistering and some concern over the stringers? Thanks for any thoughts.

My 1988 Albin had severe blistering and hydrolysis.

I ground off all the paint, gel coat, matt layer and in one spot alone, a 6 by 6 foot area half way through the hull. Reglassed with epoxy and barrier coated....has been perfect for 6 years now, coming out next week and hoping for the same.

People will tell you blisters are no big deal, and most of the time they arent.... but when they are......its a big deal. The only real way to tell is by coring the hull in various spots. Starting where the blistering looks the worst or looks unusual compated to the rest.

Just grinding a few blisters out usually tells you nothing.

Again, beware of the "never heard blisters being a structural problem" answers as research will tell you more and more boats are being discovered with very bad hydrolysis and the hulls being declared unseaworthy.

I have repaired blisters on previous boats, but never on a boat that had that many. In my opinion the boat in the photos needs planing and rebuilding the fiberglass. That is a very expensive deal. I would have a good glass shop look at it and see what it will cost to repair and provide a warranty on the repairs. Good luck.

I’ve also done a full blister job before, myself. It was a ton of work at a time when I was willing to sacrifice my time. Totally worth it as a learning experience, but the boat was “only” 23 feet long. As a buyer in a market full of alternate opportunities, nah, I’d not take the risk. Let the seller invest n a full bottom job and see if it worked in a couple years. I just don’t like risks as a purchaser. I’m happy to accept imperfection that I can accurately assign a value to, but this, this is something else. It wouldn’t be for me and I’m of the sort that would accept a certain amount of even blistering.

Blisters are cosmetic. Not structural. Get a repair quote, give it to the buyer, and he may give you the quote as a discount. Essentially it is a result of poor wetting of the mat layer. Really no good way to fix it other than a lot of sanding. (and I mean a lot.) They do have methods of planing the gel coat off but that may not fix the problem. I think the impact on your future resale value is the real question.

I'm not convinced a moisture meter is 100% accurate in detecting moisture in stringers. I would drill some holes for conclusive evidence. If moisture is present, I would take remedial action.

Pic 1 looks like paint blistering,but pic 2 looks like typical osmosis,very widespread. I understand you raise this as a buyer, not a seller.
Osmosis blisters come in various forms. Yours don`t look too deep,grinding some would be an idea, but I`m guessing the boat is back in the water.
With larger blisters, I`d worry about them joining up, that suggests repair.I doubt "doing nothing" is an option with them.
I disagree with the "only cosmetic" view. A shipwright told me that to remove blisters, he has on occasion ground through the hull, necessitating forming up on the inside.
What did your surveyor say about the blisters and stringers?
Appreciate that your reluctance to buy will be replicated in buyers if you buy and resell later. It looks like a whole hull job. Grinding a few areas would show the depth of the problem.Is there any evidence of prior repairs?
This can`t have been unknown to the seller, and maybe the broker. In my opinion,it should have been disclosed,that it was not is a concern.

Having inspected close to a hundred bots with severe blisters and having the good fortune to see them opened up afterwards. My bet on that boat is a serious hydrolysis and very likely significant delamination.

Ask Psneeld to post some photos of the nightmare he went through.
I'll bet that boat is facing the exact same thing.

boatpoker said:

Having inspected close to a hundred bots with severe blisters and having the good fortune to see them opened up afterwards. My bet on that boat is a serious hydrolysis and very likely significant delamination.

Ask Psneeld to post some photos of the nightmare he went through.
I'll bet that boat is facing the exact same thing.

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Blisters are cosmetic......yeah.....maybe that all that's going on.....

psneeld said:

Blisters are cosmetic......yeah.....maybe that all that's going on.....

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Never heard of a boat sinking due to blisters. They are a result of using junk resin or poor wet out of the mat. I just finished repairing thousands of them. In many blisters the mat was completely delaminated and showed evidence of insufficient resin. I did not discover any defects in the roving and did not need to grind past the mat.

The mat layer is purely cosmetic. It does not add any strength to the hull.

SoWhat said:

Never heard of a boat sinking due to blisters. They are a result of using junk resin or poor wet out of the mat. I just finished repairing thousands of them. In many blisters the mat was completely delaminated and showed evidence of insufficient resin. I did not discover any defects in the roving and did not need to grind past the mat.

The mat layer is purely cosmetic. It does not add any strength to the hull.

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That may well have been the case on your boat. Not sure that is relevant to any other boat.

SoWhat said:

Never heard of a boat sinking due to blisters. They are a result of using junk resin or poor wet out of the mat. I just finished repairing thousands of them. In many blisters the mat was completely delaminated and showed evidence of insufficient resin. I did not discover any defects in the roving and did not need to grind past the mat.

The mat layer is purely cosmetic. It does not add any strength to the hull.

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Guessing this was on your IG30,commiserations. But why repair them if purely cosmetic and only seen on rare haulout occasions.Were you concerned they could become more than cosmetic?

BruceK said:

Guessing this was on your IG30,commiserations. But why repair them if purely cosmetic and only seen on rare haulout occasions.Were you concerned they could become more than cosmetic?

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Now that is a darn good question Bruce.

BruceK said:

Guessing this was on your IG30,commiserations. But why repair them if purely cosmetic and only seen on rare haulout occasions.Were you concerned they could become more than cosmetic?

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1) OCD
2) Mat was showing in many places so it wasn't osmosis, more like a flood, and I was concerned about continued water ingress
3) Bottom was severely crazed in addition to blisters
4) Seemed like an opportune time to barrier coat

I seriously underestimated time it would take but it's done. Don't think I'd do it again. Was not at all concerned about any structural impact. Not unusual to hit very rough conditions so I pay attention to boat structure.

IG is light on transverse stringers and that concerned me more. PO never repaired a wide crack in the transom causing a lot of rot in one layer of plywood. There are 3 1/2" layers of FRP and 2 1/2" layers of plywood so I just drilled a lot of holes in the lazarette side to dry it out. Then filled it with epoxy. I don't think the transom will fall off.

I haul out every fall. Usually when the first hurricane heads up the coast. Would not surprise me to have more blisters appear. I think the whole mat layer is suspect.

boatpoker said:

Having inspected close to a hundred bots with severe blisters and having the good fortune to see them opened up afterwards. My bet on that boat is a serious hydrolysis and very likely significant delamination.

Ask Psneeld to post some photos of the nightmare he went through.
I'll bet that boat is facing the exact same thing.

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That is indeed my concern. The boat is back in the water now, so my opportunity to grind away is not an option.
boatpoker, let's assume worst case and there is significant delamination. Would the repair process involve something like the gel planer in the attached video below, or are we talking about a deeper peel process into additional layers of the construction?

If it matters, I think the hull is all fiberglass and is not cored on these boats.

One more hint. In 2011 the boat was hauled out and I think there were some blisters repaired then (but we are taking just a few -- not a big concern then). As far as I can tell, that was the last time the boat was out of the water. So that is 7 years, sitting idle with hardly any hours, in a slip on the TN river. The blister issue you see in the pictures developed in that 7 year period.

Thanks for additional thoughts to anyone who cares to chime in.

SoWhat said:

Never heard of a boat sinking due to blisters. They are a result of using junk resin or poor wet out of the mat. I just finished repairing thousands of them. In many blisters the mat was completely delaminated and showed evidence of insufficient resin. I did not discover any defects in the roving and did not need to grind past the mat.

The mat layer is purely cosmetic. It does not add any strength to the hull.

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Boats havent sunk because of blisters most likely, but we don't know how many may have from compromised hulls from hydrolysis.

Dry mat all over the boat under gel coat isnt from insufficient resin, its from hydrolysis and if you keep getting blisters....its an almost definite sign of hydrolysis. You can only tell for sure with coring or deep grinding....unless obvious from other indicators.

You can in fact have pretty bad hydrolysis without blisters even.

I used to think I knew a lot from repairing several personsl boats and several commercial hulls showing blisters and delamination.

Till my trawler, with the extent of blisters it had, I thought I understood their relationship in boating.....

Wrong.......

I did 6 months worth of research calling yards, surveyors, fiberglass shops, and researching the underground fiberglass storage tank and pipeline industry struggling with the same issues. Only about one in 10 marinas, surveyors, glass shops, etc...etc....had nearly enough of a clue.....let alone stuff on the net from other boaters.

The tank industry has much better research because the EPA is on their butts all the time....I learned a lot more than casual reading of the net and boating rags.

AZ2Loop said:

That is indeed my concern. The boat is back in the water now, so my opportunity to grind away is not an option.
boatpoker, let's assume worst case and there is significant delamination. Would the repair process involve something like the gel planer in the attached video below, or are we talking about a deeper peel process into additional layers of the construction?

If it matters, I think the hull is all fiberglass and is not cored on these boats.

One more hint. In 2011 the boat was hauled out and I think there were some blisters repaired then (but we are taking just a few -- not a big concern then). As far as I can tell, that was the last time the boat was out of the water. So that is 7 years, sitting idle with hardly any hours, in a slip on the TN river. The blister issue you see in the pictures developed in that 7 year period.

Thanks for additional thoughts to anyone who cares to chime in.

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Psneeld has all the right answers. I strongly suspect your issue is much deeper than gelcoat.

Another thought..... Is a hull in that condition insurable? Or would an insurance company require a repair if they saw that on a survey?

AZ2Loop said:

Would the repair process involve something like the gel planer in the attached video below, or are we talking about a deeper peel process into additional layers of the construction?

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The planer can be set to whatever depth is required to peel off both gel coat and delaminated mat. It's not an inexpensive process. It is also highly dependent upon the expertise of the operators who reapply the resin at the correct mixture, at the right thickness, with the right cure, etc. It is probably the only way to actually fix the problem.

Simply grinding out existing blisters will just fix the existing blisters. The osmotic process will still be at work creating a new crop of blisters to be discovered at next haul out. I opted for the grinding approach with my eyes open. The boat isn't going to sink, hopefully the number of new blisters will be manageable, and peeling would cost more than the boat is worth.

If you have any remote distant thoughts about selling the boat someday then pass unless the owner will discount the full cost of a peel. Buyers don't want to deal with known defects

AZ2Loop said:

Another thought..... Is a hull in that condition insurable? Or would an insurance company require a repair if they saw that on a survey?

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Depends on what they see....

They are just as ignorant much of the time because of what isn't put in a survey..... because of the surveyors ignorance of this topic. So most of the time they insure with a "blister fix"...but at some point they won,'t and every year seems to show more and more cases of delamination from hydrolysis.

We are talking about a subject that is relatively misunderstood...an it is because it is not a widespread issue.

But if your boat falls into a certain life of constant immersion, warm water and faulty building practices....you could have a failure issue sometime in it's lifetime.

Had my boat lived in colder water and been pulled every year for 5 months or so....it may have had little or no issues. That's why it isn't an issue that has grabbed a lot of SERIOUS attention.

Grinding is preferred over peeling for repair of severe hydrolysis. That's because hydrolysis isn't of consistent depth all over the hull. Peeling just makes the repair easier rather than better because of the new, smooth surface over something that resembles the Moon's surface.

Remember, at some point, severe blistering and pockmarking of the gel coat says look deeper than just "blistering"....that's where the uninformed usually stop.

Warm water and in particular fresh water seems to accelerate the formation of blisters. So, even if you buy a boat without blisters you might get a nasty surprise if you store it in fresh water. Resins used since the mid 90’s seem to have helped a lot.

https://www.youtube.com/user/madsdahlke

I hope this is the right link. There is a YouTube channel called Sail Life the guy just did a complete peel and restoration of his whole he did a great and meticulous job it’s a great visual for what’s involved in this process

Did he do a peel or just sand off the antifouling and gel coat?..... That's what it looked like to me....and he mentioned voids in the laminate but was waiting for an answer...what was it?

He did sound more educated on the process than the novice "blisters aren't a problem" type....

So like him, lots of research pays back huge dividends.... Not rrkying on the average forum post or boating rag....

psneeld said:

Did he do a peel or just sand off the antifouling and gel coat?..... That's what it looked like to me....and he mentioned voids in the laminate but was waiting for an answer...what was it?

He did sound more educated on the process than the novice "blisters aren't a problem" type....

So like him, lots of research pays back huge dividends.... Not rrkying on the average forum post or boating rag....

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He applied a layer of mat all over and several in areas he took down farther. I got the feeling he had a few blisters and made sure he would not have to worry about them anymore. He puts a lot of research into it and gets sponsored as a result.

This is the only way:

Anything else is wasting time and money.

Greatlaker221 said:

He applied a layer of mat all over and several in areas he took down farther. I got the feeling he had a few blisters and made sure he would not have to worry about them anymore. He puts a lot of research into it and gets sponsored as a result.

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Mat is actually the worst thing to put on....but at least it was saturated with epoxy....at least I hope it was saturated for his sake.

Sealife said:

This is the only way:

Anything else is wasting time and money.

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Actualoy the experts prefer grinding to ensure you get all the moisture and dekamination...peeling just makes reoairs eadier.

Blister repair

In 1986 I bought a 1974 Ericson 32 sailboat. At the time everyone was talking about blisters so I bought a boat on the cheap because it had blisters like you are seeing. There was not one square foot without a blister. We bought her in September of that year, sailed her till January then pulled her after the super bowl. We ground off the gelcoat, ground out the blisters, rinsed then bagged the boat in plastic with dehumidifiers inside. Very hard work. There was a river of water that came out of that boat. Late April it was dry enough to do our epoxy repairs. Eight coats of West System epoxy and she was ready to float again. It took about 15 years for some blisters to appear. One or two on each haul out were handled easily. Would I do it again; no, not at my age. Would I pay someone to do it if I loved the boat. Yes for sure.

A river of water suggests hydrolysis, not just blistering. Why the whole subject is misunderstood by so many.

Good job to get 15 years till the next blister.

psneeld said:

A river of water suggests hydrolysis, not just blistering. Why the whole subject is misunderstood by so many.

Good job to get 15 years till the next blister.

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When we put her back in the water, she rode about 4" higher in the water.

Also, on a side note. The yard called me and asked if we could put her in the water as they needed my spot for another boat. I told them ok. They put her in the water without putting the knot meter plug back in. She almost sank to the bottom. Luckily my wife was there and started screaming. They came back and pumped the water out after we had floated oil our of the engine. Ugh. What a black ugly mess after having just fixed up the boat. I did get the engine cleaned out and it lasted another 12 or 14 years.

The guy on sail life did a pretty comprehensive repair. He started by removing all the bottom paint. After that he used a heated vacuum mat to dry the hull. Next he peeled the hull and then reglassed as needed. All his glass work involved putting on at least one layer of 1708. In some places he put more on depending on the depth of his peel. All of his glass work was done with West System epoxy and he was careful to get full saturation and to remove all bubbles. Finally he faired the entire hull then applied six layers of west system with their barrier coat additive. Probably the best bottom job I have seen done, but it pales in comparison to the deck repair he did.