Hull Blisters

CKH · #1 (**permalink**) 08-02-2009

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

LarryandSusanMacDonald · #2 (**permalink**) 08-02-2009

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.

camaraderie · #3 (**permalink**) 08-02-2009

Consider your head chewed off.

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.

CKH · #4 (**permalink**) 08-02-2009

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.

night0wl · #5 (**permalink**) 08-02-2009

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...

CKH · #6 (**permalink**) 08-02-2009

Or, no boats have been sunk or lost due to blister condition.

camaraderie · #7 (**permalink**) 08-02-2009

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.

CKH · #8 (**permalink**) 08-02-2009

"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.

slippery · #9 (**permalink**) 08-03-2009

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?

slippery · #10 (**permalink**) 08-03-2009

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?