discovering blisters

[Ken Heyman]

I purchased my 1988 c34 in June 2003 and just hauled last week for the winter. Immediately after the boat was lifted I inspected for blisters as I noticed quite a few in the spring of last year prior to launch. I now notice many more mostly on the Starboard side beneath the waterline.
Before purchase, I retained a surveyor who asserted that the hull was free of moisture pursuant to his moisture meter testing. No blisters were noticed.I assumed he also tapped the hulls with a hammer but am not sure.  I called him last spring (aprox a year since his survey) and informed him of my concern. He felt that these bubbles were probably just air trapped beneath the bottom paint as opposed to a severe blister problem. Last week however, I punctured a few of the blisters and water oozed (not shot) out of a number of them.

Is it possible to have a moisture free hull in Spring 2002 and many blisters that "weep" in October 2004. My PO bought the boat in 2001 and also had a thumbs up survey report.

Hopefully a bottom paint issue? Supposedly the boat had a barrier coat applied in 2001. Could this be related if improperly done by the yard?

I have read a number of the posts on blisters but I didn't find a fact situation quite analogous to mine.

As always, thanks much in advance. I have found this forum to be terrific with knowledgeable helpful folks always responding.

[Jim Price]

I just had Lady Di pull this summer.  She had a barrier coat and bottom paint (cheap) done by PO in 2000.  My bottom man removed both paint and barrier coat.  We are in fresh water and his opinion was that barrier coat is expensive, unnecessary and will not stop water problems over long term.  Understand, these comment are specific to our water conditions and his 26 years experience doing bottoms on Lake Lanier.  I had total of 29 blisters smaller than fingernail on hull and had probably 40+ pencil eraser size on leading edge of fin,; no issue.  I replaceds with Trinidad and no barrier coat.  His comment was that my bottom was in great shape, barrier coat will not stop water absorbtion over time (expensive), and keeping bottom clean with 18 - 24 month short hauls for cleaning will give me about 3.5 - 4 years in our water.  But I will still have a few small insignificant blisters.  IT AIN'T POSSIBLE TO STOP THEM WITH NORMAL USE AND MULTI-YEAR PAINTING.   A few "weepers" are OK.

[APACHE]

Ken : There are a Zillion opinions out there on blisters.  Hard to believe that you now have blisters, if there was a properly dried out hull and a proper barrier coat put on in 2001!!
You can usually tell if the blister is a paint or gelcoat blister by the depth that you penetrate to bust it.  You have to go thru the barrier and gelcoat layers to be a problem type blister.  A gelcoat blister also has an "acid" taste and usually smells.  
Sorry, but you need to find a local expert and have him determine the extent of your problem.  
BTW, one of the theories is that there are more water molecules in a cc inch of fresh water and therefore the hull is better off to be in salt water?!?