Tiny Blisters

[Bill Earnhardt]

I just started to clean the brown off of my M 26, with star brite, it looks like it is blistering.
The stains come off easly, but Iam afraid it's destroying the gelcoat.
Has anyone heard of this problem before??

[Catigale]

Send us a picture Bill...EM to me if you dont know how to post it (no offense meant)

[Night Sailor]

Yes, I've seen blistering. After keeping my X in the water continuously for 18 months with the ballast filled for stability, I found the hull below the water line to be covered with blisters from the size of a straight pen head to the size of a pencil ereaser. When I broke the biggest ones, all were filled with water. The heaviest concentration was directly underneath the internal ballast tanks and tubes. Apparently our hulls are so thin that water migrates through the gelcoat easily and continues through the hull layups. The paint with which I painted the whole bilge area also came loose and flaked.
I now have bottom paint on and do not plan to keep the boat in the water continuously for more than six months at a time, with a dry out time in between launchings.

[Bill Earnhardt]

Thanks for the reply,
It definatly was from the Star-brite hull cleaner, but I think it was caused by the product not being shaken up enough,( word to the wise, empty out half of the bottle so it can be well shaken, and then add back into original container) there just wasn't enough room in the bottle to get it shaken well enough Iam getting a call from the mfg. & west marine tomorrow morning, I'll try to take & post pic's tomorrow.

[Frank C]

Don't be surprised to hear zero support from them. They're gonna tell you the blisters were caused by you ... leaving the hull in the water and permitting it to be fouled, and that Star-Brite is simply revealing the problem that already exists beneath the crud.

Search on "blister" to find numerous prior discussions on the topic.

[magnetic]

This sounds like a classic case of osmosis, which can occur at ANY time after the boat leaves the mould (note the English spelling of that word btw!).

Does the liquid in the blisters smell of anything?

Also, note that freshwater is much more aggressive than saltwater and that the osmotic process takes place at the molecular level - it's not that the hull is actually leaking, it's individual molecules which are migrating through the gelcoat. All the "drying" in the world isn't going to help.

Yachtsnet has some useful information on this - http://www.yachtsnet.co.uk/osmosis.htm

I also strongly recommend this paper on the subject - http://www.passionforpaint.co.uk/pdf/osmosis3v6.pdf

At the end of the day, it doesn't really matter much until you come to sell the boat; instances of the hull actually failing due to high moisture content are extremely rare

[Catigale]

Bill - I doubt the Starbrite is really causing the blistering more than it is just revealing the 'problem'

There are schools of thought that hull blistering is something that really can just be ignored and is cosmetic. I think on our boats I would share that view, particularly since you can trailer it.

The resale value is the only issue that might hurt the pocketbook, but if you did an expensive fix on blisters, and told the prospective buyer this, I bet they would treat it/price it like a blistered boat nonetheless!!

Strong case for not repairing or repairing on cheap only

[Bawgy]

If you plan on keeping the boat I would Pop the blisters and let dry for a couple of months inside warm and dry. When you are sure it has dried out enough wait another couple of weeks . Apply at least three layers of clear barrier coat and then a forth layer of color barrier coat (Epoxy) Sand smooth and re-apply one more color barrier coat . When sanding only sand away the color coat Use a long semi-flexible sanding block and you can get her smooth as a babies bum

[DaveB]

Use On/Off to remove yellow staining and rinse off. Gelcoat can absorb water thru it's tiny pores and will cause blistering at any time. Best to use Iterlux 2000 barrier coat with at least 3-4 coats to seal the gelcoat. This 2000 is a epoxy base and be sure you wash down the hull with acetone to remove layup wax and sand with 100 grit sandpaper.
You can than use any bottom paint or non at all.
I doubt water is penetrating inside the waterballest tank thru the Gelcoat coat, that would be extreamly rare and would have been thru a very rare layup poor job.(woven rovin,mat and cloth are not bonded togeather proper creating air pockets between layers).
Dave

I just started to clean the brown off of my M 26, with star brite, it looks like it is blistering.
The stains come off easly, but Iam afraid it's destroying the gelcoat.
Has anyone heard of this problem before??

[magnetic]

The "drying out" suggestion may in fact not help; once the gelcoat has started to break down the hull will absorb water at the molecular level directly from the atmosphere - the boat doesn't need to be in water for this to happen and - as before - fresh (rain) water is more aggressive than salt.

The bilge/water tank conundrum is another interesting one - here the issue is perhaps more to do with "wicking", as it's almost certain that the inner surfaces of the hull and ballast tank are less cured and have less surface integrity than the gelcoat.

If this is osmosis - rather than the gradual breakdown of the gelcoat surface through polishing, UV and abrasion -(which seems likely, given that your must be a relatively new boat) - then there is very little that can be done to arrest it, short of peeling back to the laminate, which is almost certainly not economically sensible.

I refurbed the hull of a 25 year old offshore powerboat a few years back and, after months sanding, filling and applying coat after coat after coat of Gelshield 200, the stress cracking and starbursts reappeared after the first outing.

My point is this - you have to ask yourself what it is you are worried about, and if it's money, give up now. If it's boating, just get on with it - the boat probably isn't about to sink any time soon, and all the work you could put in on the hull probably isn't going to make it sail any better or any safer

[puggsy]

I would agree with the others...its osmosis...I experienced it in the hull of a 24 ft. TANKARD which I owned for four years in the early 90's. The blisters were never rectified to my knowledge and the boat is still operational and has even gone up in price due to improvements to the topsides by various owners. Its still on a swing mooring in 2008 and looking good. floating even...And I am sure that none of those owners did a strip and re-gelcoat on it.

[dennisneal]

So, is there any way that this could have been prevented? Should I fear that this may occur to my boat at some future date?

Is there any recourse if it happens? Is there a defect? I doubt it is an act of God. Is this a warrantee issue?

I hate to see a situation where a purchaser is subjected to a significant loss that was not foreseen by the manufacturer.

Is this totally a random act?

[puggsy]

I'm no expert, but the Tankard was already twenty years old when I bought it . If it occurred in a new boat before the warranty expired, i would complain...It could also be in the quality of the resin...It does go stale you know.

[Brian26x]

Hello. I have a 1996 26X. It is in the water all season up here in Canada. I too had blisters, in the form of many small bumps. Looked like a rash, and it was spreading each season. At haul out I broke all the blisters, popped the heads off with a small chisel, and left it to dry all winter. In the spring I stripped off all of the VC17, repaired the blisters, 5 coats of Interprotect 2000 epoxy, and 2 coats of anti fouling paint. It was one hull of a job. The bottom looks good now. It sat in the water all last season, and I'm glad to say, NO MORE BLISTERS. Now the wife wants to move up to a 30' Catalina. Go figure.

[Catigale]

Unless the purchaser is intent on selling, there is no loss, methinks.

When you guys who bought used bought your boats, did you ever wonder what was under the bottom paint? What if you had known the boat had blistered - would that have impacted your offering price?