General Info: Gel Coat Blisters Above the Water Line

[Cheechako]

I had a boat that had them creeping up to 6" above the boot once. I soon discovered blisters on the inside of the hull in the bilge! (1.25" thick)Ouch... peel that!

[Dragon Lady]

I've heard of 6 month old Mahe's with osmosis and I've been told by the charter operator that I bought my boat off that Salinas are the worst of the lot.

I have also heard that Lagoons have the same problem but have managed to keep it quite, that really is hear say so please don't crucify me for saying it, it was just what a delivery skipper who delivers a lot of new lagoons told me.
I have three theories and I and I am happy to be proven wrong.
I would be even happier to hear what FP really believe the answer is.

Theory one, the infusion method uses resin which is highly hygroscopic which sucks the water into the laminate from where ever it can.

Theory two, the infusion process produces dry spots or areas of low resin content which again sucks the water into the laminate from where ever it can.

Theory three, during layup the ambient conditions are very humid and there is residual moisture trapped in the cloth during infusion.

All a bit out there I admit, and I'm sure people can dismiss them and perhaps come up with a more plausible answer.

One thing I am pretty certain of and that is that they haven't fixed the problem yet.

[Dragon Lady]

Originally Posted by Cheechako

I had a boat that had them creeping up to 6" above the boot once. I soon discovered blisters on the inside of the hull in the bilge! (1.25" thick)Ouch... peel that!

I don't know if peeling is the answer, I've just bought a battery powered die grinder to grind out the blisters if it ever stops raining here.

[muskoka]

The problem is that they keep using polyester resins because they're marginally cheaper. Perhaps as DL suggests, the infusion process makes the layup even more prone to this type of failure - but who knows? Vinylester would eliminate the problem, but it appears that the market is so price sensitive that no one will pay the added premium?

I do know that I'll never again buy a polyester boat.

[Dragon Lady]

I was told that Vinylester is a about 5 times the price of polyester and that why it isn't used except as a barrier coat on most boats.

[muskoka]

Barrier coats are epoxy, which is much more expensive than Vinylester.

I don't know the exact cost difference between Polyester and Vinylester, but I've been told that it probably adds about 10% to the cost of a new boat. I'd pay that difference!

[neilpride]

Dragon Lady, i know this sound hard, but, grinding blister by blister above the waterline is just a temporary fix, take the moisture meter and peel that gelcoat, dry it and regelcoat or paint the whole thing , im sure you dont want to spend $$$ to see after few months another bastard showing up in the topsides.
Cheers.

[muskoka]

I disagree - a full peel of the topsides is outrageously expensive. Peeling, glassing, fairing and painting topsides is a major amount of work. The finish has to be far better than what you can get away with below the waterline. It's throwing good money after bad.

Our boat has a couple of areas where the blisters are localized (each area about 1 square meter). Most are tiny, with very few being 6-8 mm. We did the whole lot in one go, and we get one or two showing up each year. I have the gelcoat applicator fix dings during the annual haul out anyway, so there's little additional cost to fix a couple of blisters.

I think you're far better off not worrying about it and accepting that your fiberglass boat will require a little more work and money to keep her looking good.

[muskoka]

BTW, my 1982 Hatteras has not a blister on her entire hull. The layup is massive and the resin would have been polyester. Then again, in 1982 oil was dirt cheap so they probably used liberal amounts of whatever they needed and let the thing sit in the mold to cure properly. I actually think she'll be seaworthy virtually indefinitely if properly maintained!

Oh, for the good old days.....

[Dragon Lady]

Thanks guys,

my boat has had the full peel under the water and it's not the smoothest even for an FP which always seem to have a bit of a raspberry ripple effect.
I think I'll go the grind out and see how it goes.
Neil it may only be temporary like you say but I think it's worth a go.
That's what FP suggested.

[neilpride]

Originally Posted by Dragon Lady

Thanks guys,

my boat has had the full peel under the water and it's not the smoothest even for an FP which always seem to have a bit of a raspberry ripple effect.
I think I'll go the grind out and see how it goes.
Neil it may only be temporary like you say but I think it's worth a go.
That's what FP suggested.

In any case , localized blister gelcoat repairs is way more cheaper V painting the whole hull, if a blister pop up grinding and regelcoat,
now spraying a expensive stuff like awlgrip in a badly moisture surface is just wasting time and money, and most of the LPU topcoats cant be repaired in the blisters scenario, haa btw seems to me you dont found a real profesional in this isues, im not talking about peel the entire topsides, im talking reading with the moisture meter and found the culprit areas, peel and dry and macht color regelcoat a 5x5 ft section in topsides is a piece of cake for most profesionals, here in the boatyard we have a Lagoon who crash in Hurricane Earl when he broke free from their mooring leaving a big crash hole rupture in the starboard side aft, the guys recore the section , laminate and regelcoat the area, this days the boat is here around and you dont see any diference or flaw to discover by visual inspection the repaired area, but hey is a money isue and a personal choice, Good luck!

[minaret]

Originally Posted by muskoka

I disagree - a full peel of the topsides is outrageously expensive. Peeling, glassing, fairing and painting topsides is a major amount of work. The finish has to be far better than what you can get away with below the waterline. It's throwing good money after bad.

Our boat has a couple of areas where the blisters are localized (each area about 1 square meter). Most are tiny, with very few being 6-8 mm. We did the whole lot in one go, and we get one or two showing up each year. I have the gelcoat applicator fix dings during the annual haul out anyway, so there's little additional cost to fix a couple of blisters.

I think you're far better off not worrying about it and accepting that your fiberglass boat will require a little more work and money to keep her looking good.

This is the sort of thinking which leads to severe hydrolysis problems. The blisters are a symptom of a problem (osmosis), but that problem will eventually have other symptoms as well (hydrolysis). If the layup is wet enough to blister, it will eventually hydrolyze as well. This is a structural issue. Whoever peeled and dried your bottom really screwed up by not taking it above the waterline high enough to solve the issue. It doesn't cost that much extra if it's all done at the same time.

[Ozbullwinkle]

This may have been mentioned elsewhere but what is FP doing to resolve this widespread manufacturing problem resulting in osmosis across their model range which has been ongoing for many years now & what is their official comment to the marketplace about this?

This has got to be doing some serious damage to their reputation in the marketplace although their new boats still continue to sell however it must be having some impact on their sales with it's effect on consumer confidence.

Surely it is not that hard for them to resolve as it is not widespread among a myriad of other manufacturers & it is certainly in their best interests to resolve this issue once & for all.

[Gordon]

Hi All, FP are addressing this problem in their new build technique and as to the issue with the blisters, it has become a court case over in France, and the company, I am told will make a public announcement in due course.

Cheers Gordon.

[Dragon Lady]

Yeah sure Gordon I believe you.
FP have been saying this for some time now.
Which particular court case are you referring to?
They said the multi million dollar payout in the states a couple of years ago was going to change everything.
Do they even have such a thing as law suits in France?
Anyway you have nothing to worry about, you change boats so often you probably don't even have to redo the antifoul let along worry about osmosis.