Thoughts on Blisters

[Peter B]

There is nothing that makes me reach for a bottle of red and a corkscrew faster, than talk of blisters.

Sarawana has blisters, always has had from what I can gather. She is 33 years old & not in danger of sinking, or from what I can gather, ever likely to be in the next 33 years.

You can buy an awful lot of nice shiraz for the cost of a blister bottom job.

I'm with you on that one Andy. My boat's 39 yrs old, with scattered modest blisters here and there, which have not changed in the 12 years I've owned her. A series of surveyors have all commented they are cosmetic only, and even when the insurance company suggested I have a peel job done, just after I had an insurance survey done while out, and new anti-foul applied. When I advised him of those opinions, showed him close up photos, and advised I had no such intention, he said, "that's ok, you clearly have assessed the situation well, so we are ok with that also. No problem…"

I wish it was going to be as easy to get around the 'new' and recent regulation which says when you sell your boat and need a new gas certificate, gas stoves with no flame out device no longer pass. So even though our stove has been fine for 20 plus years, with never an issue, and I have a remote solenoid activated cylinder shut-off, that is no longer acceptable, so we are up for a totally new stove...

 

[psneeld]

True...blisters can be simple or bad.

Laminates suffering from hydrolysis is never good.

Blisters may or may not be associated with resin hydrolysis.

If you have resin hydrolysis and delamination...blisters are the least of your worries.

But if you HAVE blisters....unless you are the type who doesn't care that large sections of your hull may be compromised...you may want to look further.

here's an excerpt from people who may know a bit more than your local marina or glass shop guy and from my experience most surveyors.....and it echoes the dozens of tech articles I have read/researched and confirmed with well known (bottom expert" boat yards.

by New Hampshire Materials Laboratory

Hydrolysis Failures of Fiberglass: delamination, blistering & bleeding.
Hardly a week goes by without our being asked to do a failure analysis of something made of fiberglass. The failure may be an industrial tank, piping, a yacht hull, a swimming pool, or a water tank in an RV. This issue of Nuts and Bolts addresses the failure called "hydrolysis", as well as a very different kind of failure due to leaching of a constituent in the fiberglass' resin. We hope neither of these happens to you, especially since the insurance industry usually classifies these as "wear and tear" failures so they are not often covered.

Hydrolysis of Fiberglass

 

[Art]

Luckily, and I don't mean to brag, Tollycraft build-outs were accomplished using very good resins hand-forced into fabric that was well saturated and very thick in alternating direction plies. So far no blisters on our 34' 1977 Tolly tri cabin. I've only heard of one Tolly that had blisters... not sure how severe they were nor what type water that boat experienced.

Uniflite boats were another story. Mid 1974 onward that builder used a resin with extra fire retardant (mandated by govt due to contract for 1000's of Vietnam Delta Patrol Boats). Uni began using the new resin in all its boats. Results were: It took a few years after boat was built... but... on too many of the post mid 1974 Uniflites blisters developed everywhere on every surface of boat. Eventually that circumstance bankrupted Uniflite. The rest is history!

I owned a 31’ convertible, with FB and twins, 1973 pre blister Uni. Very nice boat. I’d fully researched Uniflite blister problem and that boat before purchase.

Happy Boating Daze! - Art

 

[FF]

Uniflite boats were another story. Mid 1974 onward that builder used a resin with extra fire retardant (mandated by govt due to contract for 1000's of Vietnam Delta Patrol Boats). Uni began using the new resin in all its boats. Results were: It took a few years after boat was built... but... on too many of the post mid 1974 Uniflites blisters developed everywhere on every surface of boat. Eventually that circumstance bankrupted Uniflite. The rest is history!

Great story , but the problem came after the price of resin went from 17c a pound to about 75c a pound .

The resin had more sytrene that has to evaporate to NOT be trapped between layers.

This timing was bad for Quality builders as usually the faster the hull is laid up the stronger it becomes.

For USN builds the hull technique required woven roving and no CSM (mat) and the hull to be laid up cont from start to finish.Highest glass to resin ratio with no hassles.

Weather FR (fire retardant) resin was used or not most of Uniflites problems were from being a Quality builder not adapting to garbage resin.

ALL commercial boats (bigger than 6 pack) that are inspected vessels by the USCG must use FR resin ., then and now.

FR resin is only about 1% more costly than roaring flame resin , I am always surprised the big buck buyer dont demand it , or that their more knowlegeble insurabce carriers dont demand it.

 

[Capt Kangeroo]

I'm in Andy & Peter's camp, I bought my boat with blisters, knew they were there when I bought it and I have no intention of fixing them. My surveyor's opinion (for what little it's worth) was if they bothered me, fix them. If they don't, go boating & forget them. My insurance company couldn't care less about them either and neither could I. When I sell the boat I'll pass along the price concession I got because of them. However, if I bought the boat paying full value and blisters developed later, I would be somewhat concerned and give serious thought to fixing them, but it would be purely a monetary based decision.

One thing I have always wondered however, is it better to pop them or leave them alone? Seems to me popping them and letting off the pressure would keep them from getting bigger as well as allowing for the acids to be flushed out.

 

[psneeld]

I relate blisters to bubbles of rust in the paint job of a car.

Now imagine that you are unable to see underneath the car at all...all you can see is the rust bubbles in the paint.

I would be wondering....is it just a handful of pinholes in the paint that the rust has grown under???? .....or could it be rust coming up from below because the entire frame and much of the panels have finally rusted through from underneath.

Boat blisters are much in the same if you read my link I posted earlier.

The blisters could be self contained little problems or a picture of a much more serious problem that you will only know if you do some destructive testing/coring.

Even if you DON'T have blisters...your hull can be hydrolyzing to serious proportions....granted not many hulls go there...but those that live in the water all year round in warm water are the most at risk.

I ran my boat from Ft Lauderdale to Jersey with a large portion of my hull damaged at least 1/2 way though it's thickness. No issues and it probably could have survived a storm...the damaged portion of the hull may have outlived the rest of the boat in terms of usefulness as we all know the average TT was overbuilt when it comes to hull thickness.

So do you do something or not????? Only your desires can dictate what you think is right or wrong when it come to hull integrity...I like to know what I have....just ignoring blisters doesn't tell you a thing.

It cracks me up when members talk about an extra seacock jeopardizing the safety of their boat yet when I have personally found major flaws within a boat that other "experts" missed...and could be affecting many more hulls out there....it's doomsaying.....

 

[Art]

Uniflite boats were another story. Mid 1974 onward that builder used a resin with extra fire retardant (mandated by govt due to contract for 1000's of Vietnam Delta Patrol Boats). Uni began using the new resin in all its boats. Results were: It took a few years after boat was built... but... on too many of the post mid 1974 Uniflites blisters developed everywhere on every surface of boat. Eventually that circumstance bankrupted Uniflite. The rest is history!

Great story , but the problem came after the price of resin went from 17c a pound to about 75c a pound .

The resin had more sytrene that has to evaporate to NOT be trapped between layers.

This timing was bad for Quality builders as usually the faster the hull is laid up the stronger it becomes.

For USN builds the hull technique required woven roving and no CSM (mat) and the hull to be laid up cont from start to finish.Highest glass to resin ratio with no hassles.

Weather FR (fire retardant) resin was used or not most of Uniflites problems were from being a Quality builder not adapting to garbage resin.

ALL commercial boats (bigger than 6 pack) that are inspected vessels by the USCG must use FR resin ., then and now.

FR resin is only about 1% more costly than roaring flame resin , I am always surprised the big buck buyer dont demand it , or that their more knowlegeble insurabce carriers dont demand it.

Fred

You may be correct regarding other boat builders’ resin problems, but you are incorrect... regarding the reality of Uniflite’s blister problems being specifically due to fire retardant in resin.

Mine is not a “story” as you say, but, rather it is “straight from the horse’s mouth”. While I owned a Uni I spoke for over 15 minutes with Art Nordtvedt, the originator of Uniflite. He's heck of a nice guy!

If you’d like added info about the fire retardant in resin causing the blisters/bubbles in fiberglass that eventually broke Uniflite Builder’s financial back read this link... especially the bottom portion.

http://www.unifliteworld.com/Uni2011/Models.html

Happy Boat History Daze! - Art

 

[judojim]

Uniflite blisters and other issues...

It's commonly believed that those Uniflights could have blisters that can penetrate the hull. This is thought to be due to the fire resistant resin Uniflights used in those years. I think blisters are for the most part cosmetic and repairable one at a time at your convenience. I don't think months of drying out are needed or stripping the hull for that matter. A die grinder and epoxy filler after a couple of days are all that are needed.

Not only are there plenty of blisters on my 1976 Uniflite 42ftsportfisher, most of which seem harmless, but a few of them go to the bone and are under pressure such that you will get a face full of smelly "vinegar smelling" liquid sprayed in your face.so,wear a face shield when grinding them.


I have one blister that opened up to a coring material (yellowish in color, and soft like styrofoam). Now I have a large gap tofill, which I will use Quickfair, a bondo like product. Then I'll glass over with glass weaving and west systems with 404 filler.
How do I attach photos?

 

[CPseudonym]

How do I attach photos?

http://www.trawlerforum.com/forums/s22/set-up-your-account-|-help-tips-etc-5739.html

Post #6 answers your specific question but most new folks will find the whole thread quite helpful.

 

[RT Firefly]

Greetings,
Mr. jj. Welcome aboard.

 

[bfloyd4445]

Not only are there plenty of blisters on my 1976 Uniflite 42ftsportfisher, most of which seem harmless, but a few of them go to the bone and are under pressure such that you will get a face full of smelly "vinegar smelling" liquid sprayed in your face.so,wear a face shield when grinding them.


I have one blister that opened up to a coring material (yellowish in color, and soft like styrofoam). Now I have a large gap tofill, which I will use Quickfair, a bondo like product. Then I'll glass over with glass weaving and west systems with 404 filler.
How do I attach photos?

In my opinion Uniflite made fine boats and like most others of that vintage had their blister issues. When you are done with your boat provided you dry the hull properly and make the repairs properly that hull be be good for decades to come. Back in 1989 i used the interlux 2000 epoxy system covering the whole bottom of my new sea ray sundancer and never saw a blister. That stuff was difficult to apply because of the low solvent content. Most people thinned it down which is a mistake cause its the thinners that cause the issue in the first place.

 

[what_barnacles]

got under my boat today, it's sat in the water for at least 8 years. I was fully expecting to come up all teary eyed and consumed with total dread.

I found 1 possible blister on the rear transom. The rest of the hull was smooth and solid. The PO said he had 4 coats of epoxy barrier put on when he had the last bottom job done in the Caribbean before they came back to the states. I suspect he also had them use tin based bottom paint because it was amazingly clean. The leading edges of the the keel and the chines and the rudder and prop et al had barnacles but the rest of the boat was clear with just a slight layer of slime.

I am flabbergasted to say the least.

 

[bfloyd4445]

got under my boat today, it's sat in the water for at least 8 years. I was fully expecting to come up all teary eyed and consumed with total dread.

I found 1 possible blister on the rear transom. The rest of the hull was smooth and solid. The PO said he had 4 coats of epoxy barrier put on when he had the last bottom job done in the Caribbean before they came back to the states. I suspect he also had them use tin based bottom paint because it was amazingly clean. The leading edges of the the keel and the chines and the rudder and prop et al had barnacles but the rest of the boat was clear with just a slight layer of slime.

I am flabbergasted to say the least.

I'm surprised you found any blisters. My guess is that one was missed eight years ago. If the hull is properly dries and all suspect areas are ground out and thourghly dried then filled and epoxyed it should be good for a long long time. Or, the guy doing the epoxy added solvent to make a smother finish

 

[psneeld]

Hulls can get blisters from water inside the hull also.

Having barrier coat on the outside and a wet bilge can still cause blisters.

 

[bfloyd4445]

Hulls can get blisters from water inside the hull also.

Having barrier coat on the outside and a wet bilge can still cause blisters.

Only if the inside of the hull wasn't properly dried and sealed with epoxy. I asw a hull once that looked fine but the surveyer put his probe through it from in the bilge near a thru hull fitting. Was like mush but looked fine outside. Money well spent for that survey

 

[psneeld]

true...many forget the bilge and voids that can hold water and saturate a hull from the inside..