"Superficial" Blisters...

[BugsBunny]

Thank you all for the great advise on barrier paints, this has helped tremendously. The beginning of the week I had a chance to work on the boat and cleaned it down in a big way. Looks like new-ish. At least it is not brown any longer...

As I was cleaning the back end of the hull I discovered tiny pin-top blisters along the waterline. On either side of the transom (the last foot in each direction) and mostly along the starboard side extending forward by about 4-5 feet. They make up a strip of blisters that can be as little as 2" up to 4" wide/tall just above the boot stripe and existing barrier paint. 4-6 of them would fit inside the diameter of a penny just for visualization. They are tiny with slight blackish spots and brown discoloration right around the affected area. Photos: Picasa Web Albums - BugsBunny

I spoke with a local shop who suggested that they are merely superficial and to not worry about them. That they won't cause damage considering the thickness of the hull wall and further explained that they don't take on water since they are so small and in fact they are actually releasing "liquid" from the innards of the glasswork. All reasonable and more so since the gentleman is as a fiberglass shop owner, in a position to make money off repairs of my boat.

My question for those who are familiar with blisters of this type is simply: should I worry about them or simply get out and sail? I certainly don't want to create a bigger problem for myself by ignoring them. I have read mixed views and reasons and the problems they can cause, but lacking direct familiarity, I'm not sure how to proceed.

Additionally, if this is something to not worry too much about, is there a recommendation of what -if anything, I should do to keep them from getting worse or spreading? From what I understand a barrier coat i.e. Interlux2000E is more of a preventative to apply before the appearance of blisters. To actually do the job right I would have to remove the affected area's gelcoat, etc. and then reapply/rebuild? Photos:

Picasa Web Albums - BugsBunny

Thanks again for the great advise! I hope to hear some good thoughts, as this one is causing some real heartburn.

[sailingfool]

My suspicion would be these blisters result from plastic winter covering that was too tight under the transom, leading to moisture being trapped and little bubbles developing.

You don't pout barrier coating above the waterline. Ignore this condition for now, see what happens, be sure if you cover the topsides for the winter to permit some venting.

[BugsBunny]

I probably just answered my main question about "should I be concerned" with this article linked here for those who may be wondering about this subject in the future:

Buying a Boat or Yacht : Buying a Blister Boat

However, I would still enjoy knowing if there is something that someone has done to prevent more from surfacing. Further what would be the harm in wet-sanding them down with a high grain sandpaper so they are generally smooth with the rest of the hull?

Thanks!

[BugsBunny]

Originally Posted by sailingfool

My suspicion would be these blisters result from plastic winter covering that was too tight under the transom, leading to moisture being trapped and little bubbles developing.

You don't pout barrier coating above the waterline. Ignore this condition for now, see what happens, be sure if you cover the topsides for the winter to permit some venting.

Thanks Sailingfool,

Thats a good theory; hopefully this is the case. Unfortunately I doubt the gentleman whom I bought the boat from ever wrapped anything... The bubbles seem to be appearing where water would touch, but not having gotten in the pond yet I certainly can't be sure. I have my fingers crossed your thoughts are correct!

Thanks again!

[dgr]

Hey Bugs,
Small world. Your friend Steve asked me about those. They don't look like the blisters that most people think about with boats. Your pictures appear to be above the waterline and look like paint blisters due to bad prep or something holding water againast the hull vs. blisters that are below the waterline and extend into the fiberglass mat. Are you sure the boat hasn't been painted? Does a foul smelling liquid come out when you pop them?

I'd go sail it if it was mine.

[camaraderie]

Bugs...Pascoe goes against the common industry diagnosis and fixes on many subjects and is less than well regarded by many. His approach is specifically refuted by the actual research on blisters done some years ago at the University of Rhode Island for the Coast Guard. Suggest you review the following thread and associated links for a more comprehensive overview. Steve D'antonio's articles are based on a LOT of work in a well regarded yard for a couple of decades. I suggest you give his thoughts added weight.
FWIW...my opinion on your minor blistering would be to grind, fill and fair then epoxy coat at your next haulout. In the meantime....I would just go sailing for the summer! They look more like gel coat voids than blisters into the laminate.

http://www.sailnet.com/forums/gear-m...tml#post349900

[BugsBunny]

Hi All,

Had a chance to really dig into my blisters yesterday... I've decided I am not going to worry about them this year. Sand some, pop and fill some, put an anti-foul coat on and go sailing (not necessarily in that order). No bad smells, no goo, nothing. I stuck a knife to them and they just popped free to reveal some blue fiberglass. Everything looks dry as a bone. It does appear to be the gelcoat that is blistering however, (perhaps voids?), not just a bad paint-job as hoped. All for the most part seem to be above waterline. Without any appearance of the common signs of evil, I'll look seriously at them next winter. Now time to have some fun with jacks!

Thanks everyone for the suggestions, opinions and links to resources. All was beyond helpful!

BTW, dgr, it is a small world, good to hear from you, Steve never lets me down on the resourcefulness of him -and his friends! Thanks for your thoughts! Hope California is treating you well!