Blister/ osmosis repair successes? Failures?

[groundtackle]

I’m interested in knowing if anyone can report their successes or failures with large scale osmosis repair. I’m not talking about a few individual blisters but rather large numbers of small blisters of varying depth covering the entire hull.
I have read about pealing, drying, delaminating and or barrier coating etc but I have also heard of folks spending the big $$$$ on this type of fix only to be disappointed a few years later with recurrence of the problem.
If you had success and you’re in the PNW, maybe let us know who did the work.
Thank you

[Cheechako]

If you are talking real small blisters: I had one boat years ago with hundreds/thousands of small BB size blisters. They were not deep. Removing the Gel coat by grinding to expose them, then letting it dry for a 3-4 weeks and epoxy resin coating seemed successful. The gel was thick on that boat, I ground the tops off the 'BB's' essentially. All gel was not removed except in some areas. It dried out well.

I had another boat earlier that had severe blisters, up to 3/16" or so deep. A couple patches were 4" long x 1.5" wide! I ground all of them out and let dry for weeks. Filled and epoxied. I'm not sure that boat would have lasted too long with the repair but it lasted a couple of years after and I sold it.

Both these were like 30 years ago though.

I have seen boats in the post peeled condition in the big yard in Anacortes. It looked like it would surely fix the problem, but looks like a ton of cost and work. Not sure how much glass was added after it dried. Looked dry when I saw it and the glass surface was a bit rough which would have been great to bind new glass onto.
But we're talking a major expense there and many hours.

Drying and filling blisters works pretty well really on boats that aren't saturated... If you have to do that every 3-4 years it's a lot less money.

[El Pinguino]

I'm not in the PNW but sorted mine in New Zealand with Osmosis Solutions, Gulf Harbour.
Full peel, HotVac treatment, and then Vinyl Ester.
https://www.osmosis.co.nz/gallery/sa...de/page_1.html
That was 2014, still going good.

https://www.hotvac.com/default.aspx
Seems there is a HotVac operation in Oregon.
Not cheap.

[LouK]

A few years back I had a boat that looked like it had been a backstop at a Turkey shoot. Soda blast, dry out, West System epoxy, sand until your arms ache, sand some more, barrier coat 3 layers, sand some more, bottom paint. Worked great, almost killed me.

[stormalong]

Similar to Cheechako I bought my boat with hundreds of blisters. They were mostly between the gelcoat and the laminate. A few were into the laminate. They were all gouged out. The entire bottom was hand sanded by me and my brothers and left to dry over the winter in Chicago. In the spring it was sanded again, spot epoxied, faired and got five coats of Interprotect 2000. Seventeen years later a few blisters appeared. It was done all over again on a much smaller scale. No blisters back since. Still have the same boat almost 33 years later.

[Fore and Aft]

Groundtackle I survey plenty of boats that have had major osmosis repairs. The failures I have seen have been when the hull was never dried before new fibreglass was laminated back on the hull. If the hulls been dried, fibreglassed and faired properly there should never be an issue again.
Cheers