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blisters on hull


rich185
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Hi, i got to grips with removing the old antifoul a week or so ago on the boat only to find thousands of tiny blisters on the gelcoat all over the hull below the water line. They are very small only about 2-7mm wide.

i spoke to shetland boats to see what they recommend me to do and i was just told not to worry about it and to 80 grit sand the hull and then antifoul the boat and use it, i wasnt really happy with just doing that so iv now brought 3 tubs of hempels high protect osmosis protection and i was going to sand the hull up and put 3 or 4 coats of that on followed by some underwater primer and then the antifoul.

Gutted that iv been able to buy a boat that is not very old but with this problem.

Anyone got experience or any ideas as the best way to go about treating the hull?

 

Any help much appreciated

Rich

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Hi Rich,

There's lots written on the subject of fibreglass osmosis, and a professional treatment could cost you a few thousand. If you have an option of getting your money back from supplier or surveyor, it might be worth doing.

 

A full professional treatment involves removal of the affected gelcoat, followed by heat treatment to dry the hull totally over several weeks, and then replacement of the gel with an underwater, waterproof epoxy filler to the same thickness.

 

You can treat blisters locally by removing them, grinding back, drying them out, filling each individually with underwater epoxy, then making it smooth with an orbital sander etc. It can take many days, and might need doing again and again in future years, but will progressively achieve a similar job.

 

If you sand back the surface of the blisters, treat and re-antifoul, you'll make the gel very thin, and puncture it in a few places (filling as necessary with underwater epoxy), then cover it with a few layers of treatment, you should significantly reduce water ingress between the gel and laminate, but existing moisture in the hull can keep causing problems. There is a risk that next season, the blistering will either be back, or be worse. You'll also have the risk that when you come to sell the boat, few buyers will be keen if they know it has had osmosis, or can see the blisters themselves, and you might have to reduce the price accordingly.

 

Another option is to just accept if for this season, and plan your campaign for next winter, armed with tools, techniques, treatments and research. It probably won't look a lot worse.

 

A marine surveyor for osmosis work might charge a few hundred pounds, but might save you money in the long run.

 

If you check your insurance policy, it might also give guidance on if you can claim or not, or what your insurers recommend.

 

I wish you the best of luck.

 

Mike

PS Also Google the subject, and you might find someone with a similar model, who has found a cost-effective treatment.

PPS If you decide to commence the drying out work now, and get cabin fever, let me know, and am sure I can drag you and Emma out when Frisky is back in commission

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I have been recommended to a glass fibre expert by our revered vice chairman who trades in Hamworthy. He is reputedly very helpful and I feel sure he would give you the benefit of his advice if you dragged your boat down there before you start cutting things about. I'm sure the name will appear shortly.

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If and its a big if, you have osmosis then don't underestimate the time to dry the hull out.

 

My yacht had this and it was hauled out in Jan and dried until July to get the moisture readings down to acceptable levels. Then ground down and re gelcoated with phenyl resin that is less inclined to water ingress.

 

We didn't get the boat back until the end of August.....

 

That said no boat has sunk because of osmosis!

 

Hope that yours is not so bad. If it is young and it sounds as if it is you shouldn't have a real problem as a modern layup avoids the worst of the problems and modern resins are not so prone to the problem.

 

Best of luck.

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Hello Rich

 

This happened to my first fishing boat I bought from new. After the third year exactly the same happened to mine. The manufacturer honoured the three year hull warranty and the boat was taken back to the factory and repaired. It took four months to be returned.

 

How old is your boat? check to see if the hull still under warrantee.?

 

Greg

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Thanks for the advice guys, and thanks for the offer mike, might take you up on that offer.

 

Greg, the boat was built in 2001 and sold in 2002, i doubt there will be any warranty left on the hull.

 

 Will let you know how it goes.

 

Rich.

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  • 4 weeks later...

Hi all, well iv had 2 osmosis pros looking at my hull and theyve both told me that there is nothing to worry about and use the boat, at the most it could be a very early sign of osmosis but nothing more than that, which was better news than i was expecting.

So i have now spent about 30 hours scraping poor antifoul off the hull (never again!!!) and have lightly keyed up the hull for the new paint which also ended up smoothning out the blisters as they were so small.

Hull looking great and have now given it 3 layers of hempel underwater primer followed by 2 layers of hempel tiger xtra.

Engine is now back on the boat after iv serviced it aand running sweet.

Now the best bit, ill be putting her in on f pontoon at cobbs for the summer season on Saturday providing saturdays weather doesn't get any worse, which will be just in time for the bream comp. Cant wait.

 

Rich.

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Do you want to borrow some more Mike?

I've yet to fill all of the 26 rod holders on Wishin Too

 

 

26 ?

 

I've only got 7 on the Tiddler ! :mellow:

 

Mind you . . . . . . that's 6 for me and only 1 for Jacqui . . . . . . . :D

And she still catches more than I do !  :wacko:

 

Ah well  . . . . . . . hope to get out again soon.  ;)

 

Jim

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Cheers for the great comments guys.

i hope to do the bream comp tony but will have to see how things go tomorrow first, but i will put our names down on the list. Just excited to finally get the boat in the water and catch some fish. Me and emma haven't been fishing since mid October last year!

 

Rich

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Cheers for the great comments guys.

i hope to do the bream comp tony but will have to see how things go tomorrow first, but i will put our names down on the list. Just excited to finally get the boat in the water and catch some fish. Me and emma haven't been fishing since mid October last year!

 

Rich

 

That's the problem when you get married!!!!!!!!!!! :lol:  :lol: :lol:  :lol:  :lol:  :lol:  :lol:  :lol:  

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