Osmotic Blisters

[Brewbeck]

Fellow Members:

Good Morning!

The Endeavor gets lifted for hull and running gear inspections on Friday. I spoke to the marina mechanics yesterday and they confirmed my suspicion that there are, forgive my bad language, osmotic blisters. Don't know the extent but i'm prepared to deal with the issue. Seller had been previously advised but didn't want to put the $ into repair. I have been luck so far with other boats, but with a boat from this era I am not alarmed, yet.

I'm faced with blister repair or walking away from this boat. Opinions?

Also, what do you think about barrier coating? Worth it and does it fix the problem?

[Viper]

One thing you need to consider about blisters is that repairing what you currently see doesn't guaranty other blisters won't show up later. Having said that, blisters for the most part are simply a cosmetic issue, not a structural one. The problem however is that there is a public perception about them which may affect you later should you decide to sell.

The repair is labour intensive if the correct practices are exercised, and the right materials are expensive so it's generally a pricey remedy if it's to be done right.

[Brewbeck]

Got it. I've had blisters repaired in previous boats, and, thank heaven, never owned a Uniflite! Great boat but the blisters on the superstructure gel coat were really cosmetically awful.

I'm considering a barrier coat, and had it done on a 25 Sea Ray, but have no experience whether it works over time. Have you heard any of the members discuss this process? Barrier coat at $115 (US) per ft. (including 3 coats bottom paint).

Wife says, "Walk away." I'm saying, "Let's look at them first."

[bud37]

A question....what would the procedure include for that $115 a ft ??

[Hugo]

Grind them down with 60 grit or so, let it all dry out, fill them with vinyl ester resin and barrier coat over top. Newer boats have vinyl ester resin first spray in the mold to prevent blisters. Polyester resin will blister if boat is in the water long enough...

Good luck.

[hausherrs]

Blisters are not a reason to walk away. Just fix them. I have a quote for 7 to be repaired for $350. I have not had them fixed yet though because I want to do several things. Remove and replace boot stripe, fix blisters, zincs, and clean and recoat the bottom. I may do that after the summer during downtime.

[Viper]

A barrier coat is the way to go but if all they're applying is one coat of it, you're wasting your money. You should be applying a few coats to achieve a decent mil thickness. I usually do about 4 coats then apply the anti-fouling paint who's number of coats will depend on the type the customer wants. I alternate barrier coat colours of white and grey. That way you can tell/ensure you haven't missed any spots. If I'm applying a dark finish coat, my last barrier coat will be grey (Interprotect 2000)

How big are the blisters and what's the extent of their presence; a few, many, they cover the entire bottom?

[Brewbeck]

I had about a dozen blisters ground out, filled and coated and then barrier coated the entire bottom of my 25' Sea Ray. If memory serves it was two coats of barrier and then anti-fouling paint (3 coats). It passed survey several years later blister free. Cost was around $2500 US.

The mechanic who has worked on the "new" boat says he noted and advised seller of blisters at haul out last year but she decided to take no action. The word he used was "peppered". I decided to have the boat lifted to see what's up, and before having the engines and genny inspected. I'll decide what, if anything, I want to do then. I got a quote of $3800 (US) for barrier coat and anti-fouling paint - boat length 32'. Blister filling extra but I combine lift costs and pressure washing to save a little. Yard master says best to wait until Fall when they aren't as busy and humidity and temperatures are more favorable.

So, Friday I get to see the scope of the problem. I'll pass on my observations. Thank you all for your input. It's always nice when your opinions and observations are consistent with my own!

[Brewbeck]

Well, I had Endeavor lifted and pressure washed. . The hull showed about 100 blisters ranging from pea size to a couple of dinner plate sized.
I'm inclined to have them repaired and barrier coating applied. Yard manager says a SWAG at repair cost is $3500 (US) but no guarantee cause won't know until sanding the bottom is done. But, it's a winter lay-up kind of job so I'm just going to enjoy the boat until haul-out and git 'er done then.
The process involves cleaning, then sanding, then grinding them out, letting them dry, and then filling with vinyl ester; then followed by barrier coatings (3) (barrier coating is added cost.). Last step is anti-fouling paint, the hard surface type. Then wait until Spring! If I didn't love boats so much, it would be so much easier!

[CarverChris]

It is not a technical repair. With a little research and provided you want to spend the time/effort it is something you can do yourself. I did about 67 on my 29'. Size ranging from silver dollars to dinner plates. Just grind them out until you find solid material behind them(you will notice the difference), let me dry really well, clean with alcohol, and then fill back in with epoxy resin(might need cloth in places depending on depth). I like west system epoxy set up because they have filler and fairing additives that make it easy getting a nice final product with minimal finish sanding. I will see if I can dig up some pictures of when I did mine.