Blisters

[syjos]

https://www.powerandmotoryacht.com/maintenance/eliminate-osmotic-blisters-your-hull

https://www.yachtsurvey.com/BlisterRepairFail.htm

This is some interesting reading. Some members of the forum think Pascoe is over rated and some think he is the man. Nothing you read is going to change the reality of there being a big project ahead that may not address fully your needs.

I would never use WEST Epoxy for blister repair and certainly not "hot coat" the bottom paint before the epoxy cures like in the yachtsurvey.com piece.

WEST epoxy is thin so applying a thick coat will take several days to build sufficient epoxy thickness. WEST epoxy takes too long to dry between coats, require washing the amin blush away and sanding between coats. WEST epoxy has nothing in it to reduce water intrusion.

Hot coating over WEST Epoxy is not recommended because the bottom paint will inhibit solvent gassing of the epoxy and the amin blush can not be good between the paint and epoxy.

Interlux System 2000 epoxy is thick, easy to apply, dry quickly and has a long overcoat time, eliminating sanding between coats. It's formulated with micro plates that create a water barrier. Rolling Sytem 2000 is similar to rolling latex paint. It was formulated to not blush and hot coating is recommended to tie the first coat of bottom paint to the epoxy. Four coats and bottom paint can be applied in one long day.

The article did not mention the drying of the hull or measuring the amount of moisture in the laminate prior to epoxy coating. Drying the laminate is the most important element of a barrier coat. I tent the hull and run heaters and dehumidifiers inside the boat and under the hull until the laminate is bone dry.

During the drying process, moisture with unknown compounds in it will leech out of the laminate, coating the surface. That hull needs a good washing with solvents prior to the first coat. The hull should be warm prior to the first coat with heat turned off before the first coat is applied. The cooling laminate will contract and draw the epoxy into the voids in the surface and reduce air bubbles from gassing to form.

Blisters never reappeared on any boat that we repaired properly with Interlux System 2000. Some are nearing 30 years since application.

 

[soin2la]

Be interesting to hear from BoatPoker and Pau Hannah (sp?)

 

[moparharn]

I was not advocating anything other than some interesting reading for Ducatti to learn more about blistering. Also the second article specifically addresses drying. This is back breaking work that must be done correctly as can plainly be seen by the many posts regarding the subject. I think a first time boater should avoid this in his first boat. Bill

 

[BandB]

Worst blistering I ever saw was on a couple of brand new builds delivered to a dealer. You could touch all along the bottom and find soft spots. All returned to the builder who ended up with a stack of about 12 hulls all due to one bad batch of resin.

Then saw a new sailboat when I was a kid. It was in a dealers shop and the builder had told the dealer to circle all the blisters and send a photo. So, the boat had at least 1000 circles on the hull in black magic marker. The builder did agree to take it back.

No one here can possibly tell the OP how serious the problem is, only a range of minor to extreme. We can say it's a cause of concern and additional work or worry. Worth it? Can't tell you.

I knew one guy who waited for hail storms to buy new cars. Always showed up and made offers the next day. The damage could easily and fairly cheaply be repaired, but the loss of value was much greater. Oh and the dealers weren't all that upset over hail. Insurance paid and hail sales were extremely successful. Insurance paid for loss of value and consumer bought at reduced price.

 

[sbman]

I would not buy this boat, much easier to find a boat that doesn't have the blister issue. I have a blister boat, but I didn't pay much for it and don't expect it to ever be worth much either.

 

[Art]

I only read posts on the first page... so... I may have missed some important items.

However, I will ask - WHY purchase a boat with that much of a problem???

There are many boats on the market. Some with little to no problem.

Good luck!!

 

[Ducatihottie]

Thanks the owner took off $20,000 the asking price.

 

[Slider70]

OK. There are lots of boats on the market. You decide which one you buy based on many things. This hull has more blisters than I would tackle.

But, I bought one with 60 blisters on haul out after a very high pressure bottom wash. It was the second bottom wash as I had the boat lift for the survey in a different yard where they had a lower pressure power washer. Only a few blisters showed. If I had the yard with the higher pressure washer on the survey I would likely have walked from the deal? It would have been my loss.

The guy doing the survey recommended I walk from this boat, not because of blisters, but from other concerns. Those other concerns did not scare me as I felt I could handle those repairs myself. Getting the vessel at the right price was my goal. I got a good price reduction resulting from the survey results, and this from an initial good starting ask price.

Blister repairs. I let the boat sit on the hard for a couple of months. Sanded out all the blisters I could find. Over 60. Yes, used the West System (as not recommended by an earlier member) to patch the blisters. Only filled a few that were deeper than most. Let this kick off well, sanded and painted her and back in.

Haul out a year later had less than ten knew blisters. Old ones held where patched. Did similar repair without the long dry out. Following year three to do, all new. Last haul zero. All this with extensive use of vessel in the ocean. Cost of repair was minimal though a lot of initial stress on seeing those 60 blisters a few months AFTER purchase.

Now over four years owning this boat I am still happy with the purchase and not looking for the second happiest day in a boaters life any time soon.

 

[psneeld]

If a boat blisters after a major repair... it really wasn't.

My boat was a disaster and I followed only the top advice.

After 9 years not a blister and a surveyor doing an insurance survey was impressed.

The top experts on bottom issues all seem to be uniform on repair and reoccurance.

Now a boat with even a lot of blisters only needs them repaired, and then when more appear .....repair them. No big deal, unless you are starting to get serious hydrolysis......then more intensive testing is needed....but is rarely an issue.

 

[Captain DJ]

Some people dont sweat blisters because the internet slogan is " boats dont sink from blisters".

Of course the knowledgable surveyors, yards and others all talk about hydrolysis and the weakening of laminates.

Now, if someone smacks up a boat, virtually everyone here chimes in make darn sure its repaired properly, but its OK to buy a boat with a weakened bottom that will only get worse with time?

Or not worry about it and yell and scream that the same previous owners were so stupid to use wire nuts....

No....I wouldn't expect most boat owners would tell you...they are betting you will watch you tube and then know how easy it is to repair and forget about them.

PS....Its true that most including me haven't ever heard about a boat sinking from blisters, but how many may have has issues from a weakened hull where the boat is never recovered or investigated? I believe the USCG has not given Certificates Of Inspection to passenger vessels who failed hull tests from delamination most likely caused by hydrolysis.

I found this on hydrolysis in relationship to fiberglass hulls:
Osmosis on fiberglass boats is the process of hydrolysis, which creates the water soluble corrosive products which in turn create the familiar cavities.

Once the cavities have formed, then excess water will enter. This process may normally be slow, but the presence of free acids or alkalis will greatly accelerate it.

The first point to note is that it is the phthallic acid, formed in the process of hydrolysis of polyester resin, which causes the chain reaction and subsequent laminate damage, not the water.

Water will react with PVA binders in the laminate, reducing them to acetic acid. This gives the strong smell of vinegar when blisters are burst.

Osmosis blisters are not only a cosmetic problem. They are the visible sign that the hydrolysis of the polyester has affected at least one laminate layer. By the time the first blister shows, hydrolysed alkali products will have reduced the bond between fiberglass and polyester deep in the laminate below the water line! This in turn, will have caused a high loss of structural strength on your hull which no “dry and shield” treatment can restore. Without a proper treatment large parts of the laminate layers will sooner or later have larger areas of polyester hydrolysed with only soft wet fibreglass left.

From:https://www.almerimarmarine.com/osm...l react with PVA,reducing them to acetic acid.

Maybe this will be helpful to the OP.

 

[psneeld]

Thank you...while phrased a bit different than other writings... it underscores the point that blisters can be just like a rash.....maybe a problem but not serious....or is it really because of something else that might lead to horrific things..

 

[Captain DJ]

Thank you...while phrased a bit different than other writings... it underscores the point that blisters can be just like a rash.....maybe a problem but not serious....or is it really because of something else that might lead to horrific things..

Sorry, I did not get that take away ¨blisters can be just like a rash.....maybe a problem but not serious¨ but quite the contrary.

It states:

¨Osmosis blisters are not only a cosmetic problem.¨

and more importantly:

¨By the time the first blister shows, hydrolysed alkali products will have reduced the bond between fiberglass and polyester deep in the laminate below the water line! This in turn, will have caused a high loss of structural strength on your hull.¨

 

[Ducatihottie]

Thanks again.

 

[psneeld]

Sorry, I did not get that take away ¨blisters can be just like a rash.....maybe a problem but not serious¨ but quite the contrary.

It states:

¨Osmosis blisters are not only a cosmetic problem.¨

and more importantly:

¨By the time the first blister shows, hydrolysed alkali products will have reduced the bond between fiberglass and polyester deep in the laminate below the water line! This in turn, will have caused a high loss of structural strength on your hull.¨

I dont believe their evaluation is universally accepted....somewheres between bilsters can be nothing or bad...but if hydrolysis of laminates is advanced, then yes things are not going well. One thing that does seem in agreement is that minot or no blisters doesnt mean hydrolysis is serious.

 

[Flyguy1967]

I would run. Life is way too short and the right boat without all the work and headache will come along. Don't underestimate the work or cost and having owned 2 ponderosas (42 and 48) these ladies are stout boats but the work never stops.

Take a look at the work involved here:

This guy is in full refit/rebuild mode and has the time to do it. Watch all 5 episodes. I understand why it costs $350-$500 per foot.