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Discussion Starter #1
Blistering seems to be a big issue, and a serious problem, with many sailboats.
And because I have no knowledge, training or experience in the subject matter, any explanations, simple or scientific, will be wasted on me.
This brief survey, however, will help me greatly.
Thank you in advance for your help. This could be a teachable moment for me.
Would all boat owners who have had their boat sink due to blistering as the original causal factor simply list here the:

Length - Year Keel Laid - Manufacturer - Date Of Loss
 

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SaltwaterSuzi/CapnLarry
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I'm going to answer this one with the risk of getting my head chewed off because there are differing opinions. I work in a marina. I thought I had a blister problem on my boat. (Turned out it was just some blisters in the bottom paint - no big deal.) But I was concerned.

I asked some of the pro's who have worked here for 20 or 30 years. No one had ever heard of a boat sinking because of blisters.

If it's a problem that you want to address, pull the boat, pressure wash as usual, have it blocked on tripods. Pop the blisters and let them dry out for a couple of days, inject some epoxy in to them and let them dry. Sand any rough spots. Apply bottom paint. Launch. Go sailing. If anyone mentions blisters again, drink rum until they can't be heard anymore.

Or spend lots and lots of money and have the bottom ground out and redone. Screw that, I say.
 

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Consider your head chewed off. :D

FROM ZAHNISERS CRAIG BUMGARNER

"In real life, we are starting to see failures in hull bottoms we think are directly related to hydrolysis damage to laminate resin. In six separate cases, we have seen serious, though the hull fractures at the keel roots on fin keeled sail boats. In each case, the laminate resin was severely hydrolyzed. We have seen two cases of laminate fracture across bulkhead hard spots in two powerboats which we thought were related to hydrolysis of the laminate resin. The good news is that eight boats is not a lot of boats, but consider that these are only the ones that we have seen. Surely there are more out there and surely there have been boats lost for these reasons as well. Accident investigation on sunk boats is not like aircraft crash investigation. Unless the boat is in the way, it is usually not raised and the cause of sinking investigated."
Source: Blister & Laminate Hydrolysis in Fiberglass Boat Hulls
2003.

********
And that is evidence from ONE yard on the Chesapeake...a very good yard.
 

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Discussion Starter #4
Thank you for the replies

Thanks for the replies.
I actually wanted to see responses from real owners who had lost their vessel(s) due to this specific cause. The world seems to be full of "reports" and sightings but I have always viewed them with suspicion, while owners would, I believe, tend to be objective and certainly less prone to bias.
 

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I dont think anyone will post that they actually had a hull loss due to blisters. Mostly because it would force a boat owner to admit that they made a bad choice in selection of their vessel...
 

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You might try calling or writing to Craig at Zahnheisers to ask for more detailed and or up to date info CKH.
I don't think owners are gonna come forward voluntarily. I also think some sinkings where hull failures are involved could easily be blister related since it reduces hull strength particularly at stress/flexion point.
I think about the abandoned Vagabond42 recently at sea and wonder if the bulkhead separation due to hull flex may have been caused by an underlying delam weakness due to hyrolysis that allowed the hull to flex too much. Knowing how heavily the bots were initially built, this seems to be a cause worth considering.
Maybe some of the boats lost at sea to keel loss, rudder loss etc. may actuallybe arributed to blister damage but we'll never know.
 

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Discussion Starter #8
Vagabond not sunk

"1969, July 12: yacht Vagabond found derelict on edge of Sargasso Sea."
They may have abandoned ship due to distaste for blisters, but she apparently didn't sink because of them.
My concern is that all these reports seem to be third party, and there are far too many vested interests in selling fixes, cures and treatments.
Hence the question for owners stands.
 

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hull blisters cause sinking.

After more than thirty years in the marine coatings industry and most of that dealing with Bottom issues it is fair to say that i have never seen a GRP boat (Eeven a poorly built one) sink from osmosis.

even the earliest examples of 60's American patrol boats built of polyester GRP laminates that had been immersed for years with no epoxy "barrier coat" or any "anti osmosis" barrier had never suffered osmosis blisters to and extend as to compromise hull integrity and enabel them to sink via water ingress.

Are you sure you are not confusing osmosis blistering with lamination or poor layup issues or maybe stress related cracking.

How old is the boat and what make is it?
 

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After more than thirty years in the marine coatings industry and most of that dealing with Bottom issues it is fair to say that i have never seen a GRP boat (Eeven a poorly built one) sink from osmosis.

even the earliest examples of 60's American patrol boats built of polyester GRP laminates that had been immersed for years with no epoxy "barrier coat" or any "anti osmosis" barrier had never suffered osmosis blisters to and extend as to compromise hull integrity and enabel them to sink via water ingress.

Are you sure you are not confusing osmosis blistering with lamination or poor layup issues or maybe stress related cracking.

How old is the boat and what make is it?
 

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I have never ever heard of a boat sinking due to blister problems. I have made many repairs to blistered bottoms though. It's really not very tough to repair just can be labor intensive depending on the severity of the blisters. Most of the time they were all repaired by grinding them out, alowing them to dry and filling with west system epoxy with a microfiber type filler (peanut butter consistency) and then faired smooth with a sander. Wiped down with mineral spirits? and then another coat of epoxy over the top. Sanded again lightly, wiped clean again and then we applied an epoxy type primer over the top of that and then repainted with a quality bottom paint. In the most extreme conditions an electric stripper was used (very labor intensive, time consuming = $$$) Then again this was almost 2 decades ago so the process may have changed since I was doing this type of work.
 

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SaltwaterSuzi/CapnLarry
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Larry again here, operating without benefit of head, (having had it chewed off:chainsaw)

I have to agree with DOCRN who supplied a much better and detailed description of the easy (DIY) method of repairing blisters.

I repeat, I and many others have never heard of a boat sunk by blisters. I'm not denying that it's possible. Just that it cannot be demonstrated to have occurred.

As a hardened skeptic, I usually look at the reasons someone may be saying something. In the case of ZAHNISERS, I'd bet that they are making a ton of money repairing bli$ter$. Of course, they're not going to tell you that they are not dangerous. They also tell you, if I read it right, that the repair will only last for 2 to 5 years (longer if the boat is stored out of water). Good for repeat business.

Is it possible to get my head chewed back on? This is darned uncomfortable. :rolleyes:
 

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Discussion Starter #13
Thankk you

Thank you for the information. I am planning to buy something that is pleasing to the eye and comfortable to spend a lot of time aboard. And, since “blistering” always results in the lowest sales price, I want to hear from owners who have lost a vessel due to this condition alone. I seem to have a hard time finding any. And that is very informative in itself.
 

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I have never ever heard of a boat sinking due to blister problems. I have made many repairs to blistered bottoms though. It's really not very tough to repair just can be labor intensive depending on the severity of the blisters. Most of the time they were all repaired by grinding them out, alowing them to dry and filling with west system epoxy with a microfiber type filler (peanut butter consistency) and then faired smooth with a sander. Wiped down with mineral spirits? and then another coat of epoxy over the top. Sanded again lightly, wiped clean again and then we applied an epoxy type primer over the top of that and then repainted with a quality bottom paint. In the most extreme conditions an electric stripper was used (very labor intensive, time consuming = $$$) Then again this was almost 2 decades ago so the process may have changed since I was doing this type of work.
Other key points...

System still the same but epoxy's have improved.

Very important to flush every cleaned out blister with water until all salts is removed and alkalinity is below 5.

Every cleaned out area has to be completely dry. vaccum bag method or tape black polythene onto the affected area (sealed) and open up every day until no moisture appears on polythene.

Filling with a pure epoxy filler needs to be done with a mixture that is not over mixed with Microfibre and thus become underbound and lose 100 % adhesion (wet out of surface) with substrate.

Priming or any "anti osmosis" coating system that is applied to the repaired areas or the entire hull (if totally stripped) need to be qualified by the supplier as being FIT for PURPOPSE and then applied to Spec. this means the Epoxy primer needs to be made from a high quality Epoxy and recommended for "Anti Osmosis" protection. It also needs to be applied at the correct Dry FILM Build (DFT), Typically 300 plus microns.

lastley, one tip!...when the priming system is applied and the product is print free and solvent free (moderate push with thumb reveals no paint on said thumb) the Antifoul can be applied direct to the primer with no sanding. (unless you want a super smooth racing finish). this is what professional spray painters do all the time because sanding entire boats creates no advantage (for ablative A/fouls) but introduces extra costs and contanination issues.
 

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Vinylester is now the preferred finish coat once the laminate has been peeled/prepared/rebuilt with epoxy and laminate as needed. Then the vinylester gets epoxy barrier coats.
Beg to disagree. the years of testing for durability of repair / product, water migration...etc... shows that a good quality epoxy is best followed by Vinylester.

Vinylesters only advantage over epoxy is drying time and price with some ease of use and processing advantages and properties.

There is reams of test data to support Epoxies. however Vinylester will do the job for less cost but is less durable long term.

it has to be remebered that companies that supply anti osmosis systems give better physical and technical backing of epoxies over vinylesters. but the Vinylester supporters will push this product because it will meet a new build Ltd warrantee at a cheaper price.
 

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Slippery...I guess people will differ but Zimmerman's and Steve D'antonio have a different perspective and are NOT concerned with promoting one over the other...only effective and long lasting repairs which they can stand behind. Check out pages 16/17 though the whole artivle is quite good:
http://www.zimmermanmarine.com/docs/blisters 1.pdf
 

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Slippery...I guess people will differ but Zimmerman's and Steve D'antonio have a different perspective and are NOT concerned with promoting one over the other...only effective and long lasting repairs which they can stand behind. Check out pages 16/17 though the whole artivle is quite good:
http://www.zimmermanmarine.com/docs/blisters 1.pdf
Agree totally. What i am saying is that they both will do the job in terms of acceptable life span but all the testing (immersion, pressure /boiling...) show epoxies are slightly better.

I personally would use Vinylester for processing speed, cure speed, curing conditions, cost and considering the boat i have. but some prefer epoxy for workability etc.. .
 

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Great article, thanks for posting it.

Has anyone actually had their hull peeled in the US or Mexico? How were the results and what, roughly, does it cost?
 

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Great article, thanks for posting it.

Has anyone actually had their hull peeled in the US or Mexico? How were the results and what, roughly, does it cost?
Noa fan of peeling unless the hull is in very poor condition and has vast amounts of issues / numerous blisters and or is structurely unsound.
 
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