Blisters, wicking or bubbles?

[SaltedEgg]

Recently, I looked at '88 Fulmar 32 that was in the water and noticed bubbles on the hull above the waterline. There were also smaller bubbles throughout the cockpit. The bubbles were spread evenly above the waterline. The owner said the bubbles were caused by paint being applied in a humid environment and the moisture became trapped inside the bubbles which, when popped, releases a brownish liquid. He assured me that there were no bubbles/blisters below the waterline.

From the research I have done, it sounds like the problem could be as the owner has stated, or caused from wicking in which case there would most likely be blisters down below.

I'm not expecting a definitive answer from the pictures, just some information or advice. All is appreciated.

[coopec43]

Apparently the problem is not isolated. I'd be worried if the bubbles were under the waterline.

Here are are a few links which may help understanding the problem

https://international-yachtpaint.com...ering-bubbling

bubbling paint [Archive] - Ausfish fishing Australia, Australian Angling Forums

QUOTE: "
Why would paint blister?
Interior Painting Problems: Blistering. Paint bubbles can form long after the paint has dried. ... Paint blisters or bubbles occur when the paint film lifts from the underlying surface. The loss of adhesion between the paint film and surface is usually caused by heat, moisture or a combination of both."


Clive

[MartinR]

Looks like paint lifting. Probably paint applied over too high moisture content in layup. Nothing to do with Osmosis and normal blistering. That said, no guarantee that there are no blisters below the waterline. Why not just check below the waterline, easy to do. If you do not want to dive, use a GoPro on a stick.

[SaltedEgg]

Originally Posted by MartinR

Looks like paint lifting. Probably paint applied over too high moisture content in layup. Nothing to do with Osmosis and normal blistering. That said, no guarantee that there are no blisters below the waterline. Why not just check below the waterline, easy to do. If you do not want to dive, use a GoPro on a stick.

Exactly! Can’t gaurentee and definitely need to have a look below. The concentration of bubbles increases slightly closer to the water line. That might mean something.

Thanks for your reply!

[timeout2]

The more immediate question is how do you repair the existing bubbles above the WL. You can sand down a bubble at location X=A,Y=B, but a month later another bubble may appear at location X=A+1, Y=B+1. In other words, the whole hull should be stripped above the WL. Not a trivial task.

Below the WL probably has antifouling paint that may have been put on at a different time so it may not suffer from the same problem.

[boatpoker]

No argument about any comment or advice offered so far .... but ..... "brown liquid" could be a concern. I have difficulty seeing that as a by product of paint & moisture. Brown liquid from a blister is commonly associated with hydrolysis of the resin.

[GordMay]

Originally Posted by boatpoker

... Brown liquid from a blister is commonly associated with hydrolysis of the resin.

Particularly if it smells like vinegar.

[Copacabana]

Originally Posted by boatpoker

No argument about any comment or advice offered so far .... but ..... "brown liquid" could be a concern. I have difficulty seeing that as a by product of paint & moisture. Brown liquid from a blister is commonly associated with hydrolysis of the resin.

Is there anything that can be done to fix this? I have a few spots that have brown liquid oozing (styrene?) from a laminated toerail. There is no wood anywhere in the construction, so I have ruled out rotting wood. (Sorry to hijack the thread...)

[Suijin]

The owner is both right and wrong. Yes it’s moisture that got under the paint, and no, there is an excellent chance that the blisters now go down below the level of the paint.

I painted the topsides of my boat with Awlcraft five years ago and neglected to raise the waterline. This past year a lot of blisters exactly like those emerged along the bootstripe, up about 2-3” from where the water laps. Boat was hauled for another reason and decided to move the waterline up, removing the wider bottom stripe. Thought it would be simple, just sant the Awlcraft off, barrier coat and then bottom paint. Not so lucky. Sanding down to the bottom of the blisters resulted in needing to apply three coats of epoxy to build the level back up.

Awlcraft at least is not fully waterPROOF, sitting/standing water will penetrate and migrate into the substrate. Once it’s trapped between the paint and glass nasty things happen.

In my case fixing it was relatively straightforward as I just sanded down the whole “band” around the boat rather than attacking them individually. On a broader area, or on the deck fixing all that would be a nightmare.

If those blisters are all over the boat I would walk away unless I was willing to live with them or fix them over time and ultimately repaint. That looks like a nice spray job. Probably $20k or more to have it redone to that level of finish if you don’t do it yourself and that’s just for the paint work and not the repair work beforehand.

[gmakhs]

In the one open bumble you can see fiberglass beneath it , that looks like osmosis to me.

My boat is suffering by bubbles on the paint I will tell you my example.
When my boat used to be used for racing it was painted all red even under the water line , 18 years after the paint is fading away above the waterline , and under the water line I noticed some small bumbles , thinking that it might be osmosis and because I wanted to remove the old falling antifouling I scrapped thoses spots , the result was clear smooth gellcoat with no bubbles appearing under the falling paint and antifouling .

If you can see fiberglass and not gellcoat under the bubble the issue might be more serious than you imagine .

PS: The paint had cracked around the bublled spots so I think this is how moisture got inside .

Anyway if it's just the paint just get an estimate to fix it and ask for the price to be lowered but it seems more serious to me

[SaltedEgg]

I appreciate the replies!

If it is just water bubbles then the paint must be completely stripped = lower price

If brown liquid that smells like vinegar = resin hydrolysis = walk away

If the bubbles are opened up and fiberglass is below = walk away ; does this apply to areas above and below the water line?

If bubbles are opened up and gelcoat is below = lower the price

I am going to see the boat again this weekend and the boat will be beached. Is there anything else I should be looking for?

[gmakhs]

Chain plates , rigging , all the gear , hull stress marks , bilges stress marks , delamination on the stingers , engine , propeller shaft , rudder and rudder bearings , the quandrand , keel bolts .

There are a lot to check ... If the boat is expensive walk away if it's cheap hire a.surveyor if.you are new if you can do your own survey and have faith in it proceed .
Wish you luck I personally would have walk away .
Cosmetic work is the harder work on a boat for.me .

[boatpoker]

Originally Posted by SaltedEgg

I appreciate the replies!

If it is just water bubbles then the paint must be completely stripped = lower price

If brown liquid that smells like vinegar = resin hydrolysis = walk away

If the bubbles are opened up and fiberglass is below = walk away ; does this apply to areas above and below the water line?

If bubbles are opened up and gelcoat is below = lower the price

I am going to see the boat again this weekend and the boat will be beached. Is there anything else I should be looking for?

Sounds like you have the right approach. You might fins some value in reading ...
Moisture Meter Mythology.
Osmosis Testing.
Marine Survey 101.

[SaltedEgg]

The PCMS 101 is a nice resource. I've also been able to draw a lot of information from the survey reports.

If only the guy running that website was in Malaysia.

[Suijin]

Originally Posted by SaltedEgg

I appreciate the replies!

If it is just water bubbles then the paint must be completely stripped = lower price

If brown liquid that smells like vinegar = resin hydrolysis = walk away

If the bubbles are opened up and fiberglass is below = walk away ; does this apply to areas above and below the water line?

If bubbles are opened up and gelcoat is below = lower the price

I am going to see the boat again this weekend and the boat will be beached. Is there anything else I should be looking for?

I would not really differentiate between just bubbles in the paint and deeper blisters in your decision making process. It’s the difference between the repair taking 150 hours vs 180 hours kinda thing. It depends on how many blisters there are.

I’m pretty sure you’ll find brownish liquid in all of them.

Either way it’s a huge job to fix properly. That said if you’re not concerned about cosmetics, no boat ever sank from blisters, certainly not from those above the waterline. It comes down to priorities.