> Half way through the survey process on the 1974 C&C 35 and hit an interesting point. 97 survey said minor blister problems.... 2000 diver report shows poor condition of bottom paint and 25% of the hull covered in blisters the size of a quarter. Thats a lot to happen in such a short time... its telling me owner neglect big time...
Will have to get a quote from the boatyard for repair and present it to the owners for reduction or I'll have to pass up this boat.

Matthew,
Could you elaborate on "not good". I am thinking of looking at a boat where the owner states that it has blisters. The boat is in salt water year round in S.C. I am in Toronto. So, for me to drive down there and take a look and maybe even lift it out to take a look or maybe even do a survey could cost a few >dollars. If there is major blistering I would like to get a better idea on what needs to be done. I would not expect to have a yard do it. I would do it myself as I am retired and can work on it myself. How long does the boat have to sit on the hard to dry out?
Peter - S/V Bon Vivant - C&C Redwing 30

Question: If the blistering is moderate you would think that the owner would haul it out and have the repairs completed himself. This would be normally be a $3-5000 job normally if soda blasting and 4 or 5 layers of epoxy are required. He may have reason to believe that the blistering is more extensive and EXPENSIVE than you think! I would probably not get involved with this vessel unless my own surveyor could examine the boat closely after haul-out at the owner's expense. Further, I certainly would not consider the long-distance-import route if you will permit me to express an opinion which is in your best interest,
Warren Davis - Jazz 41AC

Warren,
I looking for opinions as this could cost more money then I am prepared to spend and unless I can get a clear understanding of what has to be done, also whether or not it is permanent, I will not proceed. I have known about this boat for a little while and if there are blisters why not haul it out and dry it out and then sell it? Why keep it in the water? Questions that I am curious about. Will do a lot more research before I do anything.
Peter

Peter:
Greg Cutter's note summarizes the project basics. In my experience, blistering typically starts with little dimples, which may (I mean may) be controllable without too much expense. This would involve removing certain areas of gelcoat, fairing the area with an underwater compound, and putting on several coats of Interlux or some comparable product. By the time the blisters are the size of a quarter, you have probably (undoubtedly, in my experience) breached the fiberglass, and you are in for the big job that Greg described. The job cannot be rushed because, as Greg pointed out, everything has to be dried out before the bottom is re-done. Moreover, if the boat has balsa coring below the waterline, and if the balsa coring has been breached, the job gets even more laborious. Unless the price is dropped to cover the cost of the fix (and then some), and unless you are willing to wait for this otherwise perfect boat, I would pass.
Matt Wolford

Peter:
I just re-read your message. One more thing: unless you are very handy with major boat repairs, I would advise against doing this one yourself.
Matt Wolford

Ken:
The biggest problems with most major blister repairs are: 1) the boat is not dried out properly before the bottom is re-done; and 2) the new bottom is not put on thick enough. Although most yards will go with 2 coats of Interlux, 5 or 6 is more appropriate.
Matt Wolford

Hard to say. It is possible (likely) that there was further blistering between 97 and 00 if the boat was in the water. On the other hand the same surveyor may still classify the blisters as minor or just a bit worse. Hard to say. May be for the age of the hull it is 'normal' or even less than average what you have
The proof of the matter is in a couple of quotes and your ability to make the seller "see the light".
Are you sure about the 25% coverage?
Where is blister of unit diameter and 'space' is a unit square area without than pattern (where each 'square' is same) corresponds to 28% of blister coverage. Very high.
Leslie. - in nit picking mood, in the office instead at the marina.

Hi Peter,
I attended a seminar which had Peter from Fastnet Yacht Surveys as the speaker and he discussed this issue. Bringing a boat from warm salt water to cold fresh water almost always causes blisters to appear so bringing up a boat that already has blisters may not be a good idea.
You might want to give him a call - he's in the phone book in Toronto
Regards - Jackie Thomas - Bella Luna

Talked to the boatyard today... something sounds fishy to me..
First he quoted under 5K for doing the bottom. When I made it clear I wanted it done right he was up to 7K which still doesn't sound right. The quotes seem to be $150 to $200 per foot when I am expecting $350 per foot for a job done right.
Second fishy-ness. He has something against hull peelers. He wanted to use a chemical on the gellcoat to help disolve it then grind away at the blisters, patch-fair-and cover... I personally am not for creating a toxic soup of god knows what underneath to brew--I am for removing the outer mat as well [hopefully its 1/8" or so on the C&C 35's] which means peeler machine.
Third fishy-ness. He claims only one boat - a Catalina done 15 years ago had problems with the repairs - and due to it being done without removing the gelcoat. I don't think Interlux is gods gift to hull repairs and I would have expected a higher failure rate especially due to FOUR.
Fourth fishy-ness. Its an outdoor yard only. He has no worries about doing all the work outside including putting on the interlux. I have no clue how they will clean/prep the hull before applying the interlux and when spending this amount of money would not want debris or airborne pollutents of good old LA smog and nearby industrial areas to get under there. There maybe an indoor facility in Marina Del Rey or perhaps San Diego but I havn't found one yet as all the local yards are small outdoor ones.
I mentioned 6 months dryout time, he was more into 2 months with dehumidifiers used.. outside too..
Then again people seem to not have a lot of bad things to say about the yard.
As the saga continues! :-)

Matt-
"The job cannot be rushed because,--"
Agreed, but it can be hastened somewhat by heating the hull and giving the water more incentive to get out that way.
Whether the cost of some heat lamps inside, etc. is worth the speed-up they might offer is something I'm glad not to need to figure out right now. In an Ontario winter, I wouldn't think so unless the boat was also stored indoors and kept warm.

Peter-
Putting on my cynic-hat:
Because some rube might buy it without looking at the blisters? Because it costs money to haul and the seller doesn't want to spend any? (Which might be why they HAVE the blisters) Because the next buyer might want to make up their own mind about the blistering, rather than seeing a boat already repaired and freshly painted?
In any case, it sounds like this boat is in the hands of someone who has not made "keeping it up" a top priority. That can mean a bargain, but usually means *more* problems from "ridden hard and put away wet" like leaks affecting the chainplates, floorboards, low engine maintenance, etc.
By the way, if you do make the trip to SC, why not plan on making it a longer trip (7-10 days) and lining up a half dozen more boats to look at in the same trip? Or if you are driving, perhaps Annapolis, NC, SC, etc, and make a serious shopping trip of it?

And here I thought that blisters meant uncured resin, which meant your hull was more like swiss cheese. I'd call that a structural failure from the "death of a thousand cuts", no?

What I have gathered is the urban legend of Oil problems in the 70's is half right.

Super summarized:
o Resin consitutes a major cost of boat production
1) A lot of the boat builders constantly searched for cheapend resins to build their boats from.
2) Resin manufacturers formulated cheapened resins to sell to the price misering builders.
3) All resin is not equal; they have different permiability depending on the formula.

o There is no excuse for the level of blisters today
1) In the 1960's gas stations discovered the blister problem with fiberglass tanks to replace steel tanks.
2) Original tanks had no problems, but resin was expensive.
3) The cheapened resin built tanks developed blister problems.

o From the boat perspective
1) The solution of cheapened resins on the inside and higher quality resins on the outside does cause more problems then it is worth and was extensively used. A.k.a. "tank coating" method.
2) Hatteras used cheapened resins and cheapened gel coat extensively over the 30 years of production because they painted the hulls rather than relying on a high quality gel coat. They also have extensive blister problems.
3) Hinkley used high quality resins. No real blister problems to report throughout the history.
4) Hatteras used the "tank coating" method and has had some blister problems throughout the history.

o Blister repairs do fail, some horribly
1) $10,000+ professional repairs done by qualified boatyards have failed. The major chemical and paint companies that formulated the cheapen resins also formulated the repair products.. Hmmm :-)

Other interesting observations learned over time.
o It is not possible to effectively solve blister problems of a hull that is water permeable.
o Water permability is not a function of resin alone but also how well the glass fibers are wetted out [a long history of horrible wet outs with lots of dry spots are out there]
o Blisters form above the waterline showing immersion is not necessary to cause blisters
o The continuous strands of fiber transmit water along its lenght through capillary action that is accelerated by vibration such as from the auxilliary motor.
o Incomplete/improper wet out has been found on about half the boats looked at by some surveyor companies. There is a direct correlation between low quality resins with poor wet out on blistering.
o Chopped strand mat used as a skinout to prevent weave patterns through the gel coat is a major source of blister problems as chopped strand just does not wet out well. There are millions of fiber bundles exposed that are capable of wicking and conducting water through the laminate.
o Exposed fibers on the inside of the hull are also responsible. Ther is a direct correlation between the location of blisters where bilge water lays. There is also a correlation of blisters to the edges of sheets of glass fabric.

Other intersting tid-bits
o Lay ups commonly occured in a dirty environment; commonly with the carpenter shop nearby and saw dust filling the air. The bonding surface becomes dry, contaminated or both resulting in eventual bonding failure.
o Peel your hull and look at all the millions of white spots. Those are all unsaturated fibers that will wick water. Without sealing all of that your blister repairs aren't going to be as effective.

and finally
Large blisters almost always occur under the skin out mat. Small pimply blisters are normally in the gel coat.

caveat emptor--don't even be sold on a "fix" even by well known companies until you really know what you are dealing with. Small areas of the gel coat need to be removed.

Things they asked themselves.
. Why are some manufacturers getting blisters and others not
. Why are some product lines within a manufacturer getting blisters and others not
. Why are the smaller boats not getting the level of blister problems that the large boats do

I have to agree with Klaus.
I've never read an article that definitively stated that hull blisters were a structural problem to worry about. They seem to have a lot more effect on resale value than seaworthiness. Maybe you will loose a knot of speed. Maybe some will tch, tch when you haul the boat. Maybe you will get a good deal and enjoy sailing.

Peter-
There are some other commonly "accepted" ideas for blisters. As boat prices went up in the 70's, mfrs went looking for cheap labor and rushed production. The cheap [read: inexperienced] labor did not do as good a job laying up the fiberglass, used too much resin, didn't press enough out, didn't keep things clean (uncontaminated) enough, etc. So a number of production-related issues also conspired [sic] to make the hulls built in that time of rising costs just not built as well.
THe use of chopped strand was also a cost-cutting technique introduced for those reasons,

You make a good point about the blisters. It does negatively effect the strength of the hull, but it would be unlikely to actually sink the boat.

There's a 38 Benneteau in one of the yards fronting the creek where I keep Belle. They've peeled the bottom, swathed the hull with plastic sheeting held down to the ground by timbers, and have a couple of heaters and dehumidifiers running inside. I'll have to ask Sam (the yard owner) how long the drying process is going to take when I see him out racing next weekend.
It is possible to peel and dry a hull outside.... if outside is in NC or SC, where the weatherman tells us we're having a "taste of winter" because the temp tonight will be in the low 40's.
I think it not likely in Canada, unless you wait for spring to arrive next June.
Rick Brass - la Belle Aurore - C&C 25 mk1

The boat that I am interested in and have talked to my Canadian broker about is a 1972 C&C 35 MK I. This is a solid fiberglass hull and I don't think the oil crisis had started yet or if it had maybe it had not yet impacted the boat building fraternity.. The boat is in the water and I am trying to get a feel for the boat before I drive to S.C. and find out that I just blew a couple of hundred dollars. The selling broker told my broker that the owner states that there are blisters. If I want more info then I need to drive down and see. Maybe I can make it a "fun in the sun" :) vacation. I have been Myrtle Beach in November and have gone swimming. The water was warmer than P.E.I. in July.
Peter - S/V Bon Vivant

Jared,
If I do the trip then it will be a 7 day trip at least. I may be starting a contract and the most time I can get off is 7 days. And yes, there would be other boats that I would want to look at. I have had the the same cynical thoughts as you but then I looked at a C&C 35 MK I two years ago in Ontario and the bottom had been done and the motor, Atomic IV, overhauled. My gut feeling was that it was done to sell the boat and it looked good but how many coats of Interprotect 2000 were put on? What did they do when they said the engine was overhauled? So I was pretty reluctant and I did not buy the boat but there were other reasons on top of those that were the deciding factor. My preference, just as with cars, is to see the original. Cars that are painted will always rust within a couple of years and usually have something to hide. When I bought my present boat I ground off the accumulated anti-fouling paint and then put on 4 coats on Interprotect 2000 and then VC 17. The bottom still looks fabulous and I am pleased with my job. From all of the information I am getting it sounds like: Haul the boat out
Get an idea of the problem.
Get a survey ( I may need a "good" surveyor in S.C.)
If manageable then proceed with repairs if not - end of story
I presume a moisture meter would help with determining how much moisture there may be.
Let it dry out in S.C. (costs ????) or ship it up here and let it dry out at the cottage
Grind out the blisters
Fair it with underwater epoxy
Put on at least 6 coats of Interprotect 2000
An interesting aside is that the topsides were done and the cushions are new. But then again it could be strictly to sell the boat. The owner may have made the decision that the new owner would want to commission and or do the repairs himself. I know of only one C&C 35 MK I for sale here in the Ontario area that has not been modified or upgraded to the owner's taste or is in the $55K to $65K range. This boat costs $45K and I have a good survey on it. The bottom is done, the Atomic IV sounds great but it needs a new set of sails. The S.C. boat is quite a bit cheaper but then how much cheaper after all is said and done. Some of the costs are known: Either trucking it up here or sailing it up here will be $3K. GST will be another 2K. A cradle will also be needed. If the repair consists off: peeling off or powder blasting the hull and then putting on 6 coats of Interprotect 2000, I have done that. I would do this with any boat I would buy, if it has not been done already, as it gives me peace of mind. If the blisters are "minor" I can deal with that. Drying out the hull for 6 month to a year, until the moisture meter gives acceptable readings is expensive, i.e. cost of money and no sailing or chartering. The difference in price is between $10K and $20K as I can't tell how much the S.C. will cost when all is said and done. If the bottom is good and can be done by just painting the difference is close to $20K Canadian. A fair chunk of change.
Thanks for all of the feedback and I will keep the list posted on any decisions I make.
Peter - S/V Bon Vivant

In northern climes, the best time to open up minor blisters is at fall haul out. I have some minor blistering in my 34, and I opened up all the blisters within a week of haulout. This allows you to see them better (they're biggest when the boat first comes out), and opening them up allows them to dry over the winter, when the relative humidity is very low. Where I sail, this provides about 6 months of drying time. I do not anticipate the need to use heaters/dehumidifiers in the spring. Finding a string of two warm, dry, bug-free days to apply the Interprotect is a different story.
It would be nice to be indoors for that.
Matt Wolford

In my part of the world (Texas), there seems to be a lot of boat blistering. My own theory is that boats that sit in relatively warm water year round are much more likely to develop the problem than our Northern neighbors who haul every winter and allow the boats to dry out. If nothing else, a comparable boat up North will probably have less than half the time in the water as a similar boat down South.
At my marina, where Valiant Yachts is located, there is a fair amount of blister repair work done. The process involves peeling the gelcoat down to good glass and waiting for the hull moisure to reach 5%. Allowed to sit outside without heat lamps and such, the process can take 6 months to a year plus. Vinylester is applied to the dry hull to some thickness (can't recall) and the boat is then primed with several coats of Interlux 2000 epoxy primer and painted. Cost is just over $150/ft when last I inquired.
I wouldn't necessarily eliminate a boat from consideration because of blistering, but a proper repair of an *extensively* blistered boat is time consuming and expensive. I have seen some statistics that solid glass hulls are less prone to blistering. The Valiants are solid glass and the resins are hand mixed a gallon at a time and the new Valiants seem to be blister free. There seem to be lots of theories about blisters, but I don't believe there is any widely accepted view at this point as to cause and cure.