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Catalina 25 Specific Forum

Blisters?

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markd2
Deckhand

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4 Posts

Initially Posted - 05/02/2002 : 20:11:22

O.K. I’m the guy who is “new to sailing” and needed some advice. Last weekend I went to see 3 Catalina 25s and Catalina 27. Two of the 25s were dogs and the 27 didn’t seem to offer much more for the additional money. One of the 25s seemed great. A 1989 wing keel, tall rig, very clean, and mucho electronics. I’ve included the link.
http://www2.yachtworld.com/broker/br_listing_detail_handler.jsp?company=stbartsyachts&boat_id=919539&units=Feet&currency=&listing_id=&page=broker&mls_true=
The boat seems perfect. This week I negotiated a price of $11,750 and sign and fax the contract. The fact that this boat seemed to be the least expensive 1989 listed by Yachtworld started to worry me. It seemed to me that a 1989 in such apparent good shape should go closer to the top of the asking range. Especially since it’s a wing keel (according to the “Shopping for Catalina 25” the wing keels are more rare and thus more expensive). Also according to this article 1989 was the author’s choice year. So in a mild panic I decide to hold off sending the earnest check. I called the broker and told him that I needed to set a time for a survey. He seemed mildly annoyed that I wanted perform a survey on such an “inexpensive” boat. I then asked him about the condition of the hull. He then blurts out that all boats have blisters and that they would shrink when I moved the boat to saltwater. He then seemed to back track saying he doesn’t know if this boat has blisters. He volunteered to send a diver down to take a look. He hasn’t gotten back to me, but we have an appointment to do a survey a week from Saturday. The diver idea seemed fairly silly.

I’ve been reading a great deal about blisters, and need to know how much I should be worrying about. Do Catalina 25s have blister problems? I’ve including the link to some of the articles I’ve been looking at. According to these articles blisters are rare on small boats. Am being paranoid here or what? I can’t afford to make a huge mistake here. I don't want my dream of owning a boat to turn into a nightmare. Any advice is appreciated. Blister articles:
http://www.yachtsurvey.com/articleslist.htm
Look toward the bottom of the page for the blister articles.

Edited by - on

coldducks
Captain

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USA
342 Posts

Response Posted - 05/02/2002 : 22:36:17

DO your self a favor. get your own surveyer. remember the old adage " buyer beware". good luck on finding a great boat.

COLDDUCKS
FANTASY #409 C250WK

Edited by - on

Douglas
Master Marine Consultant

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1595 Posts

Response Posted - 05/02/2002 : 22:40:19

This broker either doesn't know what he is talking about or he is after a quick sale. I recomend you do an out of the water survey. In addition I would try to be there when the boat is hauled. My experiance with blisters is if they are small they will be very hard to see once the hull dries off. I have has my boat now for 6 years. The first time I hauled I had 2 blisters. I repaired them and launched. The next time I hauled I had 15 to 20 small blisters. I did a post in the general side on bottom rework with pictures. I recomend you don't let this broker rush you and that you get a survey.

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Greg Jackson
1st Mate

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84 Posts

Response Posted - 05/03/2002 : 07:49:49

I have experienced brokers who really don't care much about boat sales below $25,000 and see them as a waste of their time. I have also experienced brokers who are dishonest, and some who are just plain stupid. The broker you are dealing with appears to have one or more of these attributes. This does not mean the boat is a bad deal, but it does suggest that you need to be extremely careful.

The boat looks nice, but it is not the only wing keel, nor is the c25 the only boat model in the world. I think you will find that most C25 wing keels have roller furling, which can be around $2000 for lines, hardware, and the genoa.

Back to brokers, I actually had one guy who refused to show me a $16,000 boat. He would tell me where to find it, but he would not leave the show room. This was a really big place with an indoor show room filled with $150,000 to $250,000 power boats. The salesmen took turns as to who would get the power boat shoppers who came in the door. If he were out in the yard with me he would miss his turn. Since I had driven 8 hours to see this particular boat, you'd think the guy would have realized I was a serious buyer. I found a different boat and a different broker.

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OJ
Master Marine Consultant

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USA
4382 Posts

Response Posted - 05/03/2002 : 09:32:22

Bottom line on blisters - yes it's a common issue with Catalina 25's and no it does not require a great deal of skill to correct - if you can patch drywall, you can repair blisters. It is, however, a time consuming, tedious process if done correctly. Best resource for educating yourself about this topic and how to remedy it is in a $3.00 manual published by West Systems available at most boat supply stores.
Caveat about surveyors - you need to survey them first! You also need to find one that doesn't have a cozy relationship with the broker. I would certainly ask questions like what happens if the surveyor misses hidden defects that costs thousands to repair. Ask for a copy of his liability insurance. I've heard some real horror stories about boats that were surveyed, purchased based on the survey and then discovered blatant problems.
I don't think you're being paranoid - more a fear of the unknown. Professional skepticism is your best tool here. You need to talk with parties who have no bias, no hidden agenda. Those who know, often don't say . . .

Steve Madsen
#2428
OJ (Ode to Joy)

Edited by - on

markd2
Deckhand

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4 Posts

Response Posted - 05/03/2002 : 10:02:16

Yeah, This broker wouldn’t take time out of his busy schedule to show me this boat. The more I read about this blister subject the more I believe that the real issue is bad blister repair. There seems to be so many bad amateur/professional blister repair jobs. It seems that doing a bad blister repair is much worse than just leaving them alone. I’ve read stories of sailors who have 3 or 4 blisters “repaired” only to haul their boat in a year and find 30 larger blisters. Why does there seem to be such pressure to repair something that doesn’t lead to structural issues in the overwhelming number of cases?

Edited by - on

OJ
Master Marine Consultant

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USA
4382 Posts

Response Posted - 05/03/2002 : 10:26:13

The strategy should be to eliminate them before they can lead to structural problems. The best time to identify blisters is when the boat is pulled as they have water in them - causing them to bulge. There's a technique for identifying the smaller ones after the boat has been on the hard for a few months. The second and equally important part of the process is to apply a quality water barrier product to protect what has been repaired and prevent any new blisters from forming.
Are you intimitidated yet Mark <img src=icon_smile_wink.gif border=0 align=middle>?

Steve Madsen
#2428
OJ (Ode to Joy)

Edited by - OJ on 05/03/2002 10:31:09

Edited by - on

Bristle
Admiral

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USA
834 Posts

Response Posted - 05/03/2002 : 11:53:40

Hi Mark!

You may have a very good one there. Regarding the price, I think Greg is right about roller furling--most '89s on the market probably have it.

Regarding the survey, YOU should be the one who selects the surveyor and pays for it (a few hundred of the best-spent $$ you'll put into your boat). You should also be there, and should get a detailed report from the surveyer. You'll learn a lot! If you need help selecting one, go to a nearby marina and ask around. The surveyor should be accredited and insured, and his business should be in the phone book--not a "good friend who knows a lot about boats."

Blisters are more common in fresh water than in salt water, but by 1989 I think Catalina was using the better gelcoats that help prevent them. A key question for the owner is whether the boat has been barrier-coated (under the bottom paint) and when. If that has been done in the past 10 years, you probably have little to worry about there. But the surveyor can detect blisters quickly, and will also check your decks for moisture--another potential issue. S/he will also check for signs of water intrusion around the upper chainplates that bolt to the bulkheads below, the gudgeons for the rudder, and other key structural/safety items.

Good luck in your quest...

Dave Bristle, 1985 C-25 SR-FK #5032 "Passage" in CT

Edited by - bristle on 05/03/2002 11:57:46

Edited by - on

Gary B.
Admiral

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USA
969 Posts

Response Posted - 05/08/2002 : 15:38:12

Okay, I'll bite....what is the technique for identifying blisters after the boat has been on the hard for a few months? I bought this "project" C-25 this winter, knowing that it had some blisters within a foot of the waterline. After sitting on a trailer, under cover since December, I just went out to begin the repair and "voila" to my surprise I could only find one! I want to bottom paint it, but I am afraid it will be wasted effort if I don't repair the blisters that WERE there. Someone suggested splashing it again for a week or so to see if they re-appeared, but I hate to waste the time if I don't have to; it's obviously pretty dry now. I don't want to just paint it and sell it off the trailer when the blisters will probably reappear; I have too much conscience....What to do?? Thanks for all responses. Gary

Edited by - on

jm
Captain

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Canada
290 Posts

Response Posted - 05/08/2002 : 15:59:13

"Blisters are more common in fresh water than in salt water"

Interesting statement Dave. I would have thought it was the other way around, but only because I associate fresh water boats with typically being out of the water/on the hard during the winter giving the fibreglass the opportunity to dry out, before going back in. Less exposure to the time factors of osmosis.

And I associate salt water boats as being in warmer climates (except perhaps the north eastern/western seaboards) where the boat is left in the water for years at a time - increasing the likelihood of blisters through an uninterupted osmosis process.

Edited by - on

MarkTM
Navigator

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USA
178 Posts

Response Posted - 05/08/2002 : 16:14:49

Although you may need a good background in chemistry to understand the following explanation of GCB (gelcoat blistering), it is interesting nonetheless. If comes from a company called "Fraser Fiberglass" in North Vancouver, British Columbia:

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>The Causes of Blistering

There are two distinct types of gelcoat blisters. The first stems from air voids in the laminate. Voids can sometimes be detected visually, especially in unpigmented laminates. Voids can cause fractures in the surrounding laminate when the air they contain contracts and expands. Moreover, moisture can enter an intact void, either by penetrating the somewhat porous resin itself, or by capillary action along strands of fibreglass. Once through the gelcoat, water can swell a void and initiate delamination. Pressures of several atmospheres are believed possible in water swollen voids.

Apart from causing internal pressure, water in the laminate can hydrolyze free vinyl acetate monomer (used in fibreglass production) and give rise to a solution containing acetic acid (like vinegar). In many cases, the pungent odour of this acid is unmistakable when blisters are ruptured.

Air voids can be induced during lamination when methyl ethyl ketone peroxide (MEKP) is mixed into the base resin, but by far the commonest source of voids is poor laminating technique. Fibreglassing is often carried out by workers who lack the skills needed to remove all the air bubbles from the layout. Some builders have a good reputation for workmanship, while others do not. If you're contemplating a new yacht and wish to reduce the risk of GCB, investigate how the yacht is made. If more people become knowledgeable and aware of the differences between good and bad fibreglassing practices, builders will be forced to improve to sustain sales.

Although air voids in the laminate can lead to GCB problems, a second type of blister causes even more trouble and has received more attention in the technical literature. These blisters are caused by a process known as osmosis. Osmosis is a scientific term for the movement of a solvent (such as water) across a semi-permeable barrier (such as a typical gelcoat) from a less concentrated solution toward a more concentrated one.

For osmosis to take place in a fibreglass boat hull, it is necessary, not only that the gelcoat and layup be somewhat water permeable, but that a more concentrated solution be present within the laminate than outside. Microanalyses of the contents of osmotics-type blisters typically contain acetic acid, trace quantities of unreacted styrene monomer, phthalic acid, phthalic anhydride as well as soluble copper, calcium, and magnesuim salts. Similar substances can be found in air voids that have filled with water. Of course, a lower solution concentration outside the hull would tend to accelerate osmotic blistering, and indeed, GCB sometimes appears to advance more rapidly in fresh water than in the ocean. On the other hand, not all authors agree as to the importance of osmosis in GCB, and some assert that the term is frequently misused.

Gelcoat Formulation and Application

To form concentrated chemical solutions within the laminate and initiate osmosis, water must either penetrate the gelcoat initially or be incorporated in the laminate during manufacture. Gelcoat is polyester resin, a condensation product formed by the reaction of polhydric alcohols and poly basic acids. In order to obtain a consistency suitable for spraying onto a hull mold, the resin must be thinned with either a simple solvent or a reactive solvent. Use of a simple solvent such as acetone as a diluent is an unacceptable practice that can lead to premature degradation of the gelcoat. The more common practice is to use styrene monomer as a diluent because limited amounts of styrene will form an "additional polymer" with polyester (MEKP and the cobalt initiator activate unsaturated linkages in the polyester where styrene molecules can bond on what is known as a free radical polymerization).

If too much styrene is used, unreacted styrene monomer will lower the quality of the cured resin. Styrene loading should not exceed 25% to 30%, but some builders use more in order to thin the resin sufficiently to spray with conventional equipment instead of airless spray guns. Gelcoat and shop temperature should be at least 64* - 68* F before application. At lower temperatures the gelcoat resin will require more diluent to make it sprayable and will exhibit poorer flow-out properties. In addition, there is a higher risk of entrapped air bubbles remaining in the gelcoat to form voids when it cures.

A cold mold, one that has been stored outside until shortly before use, can become coated with condensation. If resin is sprayed onto a wet mold, the resulting gelcoat will be exceptionally porous, and moist right from the start. For similar reasons a completed hull laminated should be stored in a warm, contaminant-free area for perhaps 20 days at 68* F until it is fully cured. Otherwise it will absorb excessive moisture from the air.

Brush application of gelcoat should be avoided because a uniform coating thickness cannot be obtained. Thin spots near the end of a stroke will resist water poorly, while overly thick areas will be brittle and prone to crack.

When possible, gelcoats below the waterline should be unpigmented or white because dark colours have proven more porous and susceptible to GCB. Applying a lightweight fibreglass cloth to create a resin-rich barrier layer just beneath the gelcoat, but outside the laminate proper, has proven resistant to blistering and at minimal extra cost.

At least three kinds of glecoat resin have been used in building GRP hulls: orthophthalic, isophthalic, and isophthalic NPG (neo pentyl glycol). Recent research has shown that, of the three isophthalic NPG offers the best water resistance. Boatowners should clamour for the use of less permeable resins of this sort. Unfortunately, "boatpox" prone orthophthalic resins have seen widespread use and even today, gelcoats containing 50% orthophthalic resins are common. The reason, of course, is cost. Yet the old adage "buy cheap pay dear" certainly applies here. Our back-of-the-envelope calculations indicated that a fibreglass yacht fabricated with pure isophthalic resins would cost between 2% and 5% more than a yacht made with conventional resins. Naturally, even quality resins will not prevent problems if the builder fails to use them correctly.

Repairing Blistering Problems

For mild and isolated GCB, the damage should be ground out, thoroughly cleaned, degreased and dried. The desired surface profile should then be restored with a 100% (solventless) epoxy fairing-compound. Use of polyester fillers is a waste of time because these Bondo-type products are usually more susceptible to blistering than even a low quality gelcoat. Care should be taken to conduct repair work at low relative humidities; otherwise water may condense in the cavities to be filled.

Where serious GCB has occurred, it is generally best for extensive areas if not the entire hull, to be sandblasted or ground out. Since improper sandblasting can cause serious damage to the laminate, the latter, although more troublesome and expensive, is preferred. A mini-grinder offers the best control.

Having stripped off the gelcoat, the laminate should be dried thoroughly by keeping the hull in a well-ventilated area for a period of weeks or months. Obviously this is both awkward and expensive, but if the hull remains wet the chances of a successful repair are slim.

For surface restoration, both epoxy coatings and polyurethane coatings have been used. Today the emerging consensus is to favour epoxies below the waterline. Epoxy compositions also tend to have the high "build up" properties necessary to replace the missing gelcoat and restore the original hull contours. They can also be outstanding in their ability to mechanically key to underlying laminated, as well as being highly resistant to chemical degradation.

In view of these advantages, why aren't epoxy resins used in place of polyesters in the manufacture of GRP boats? Again, the drawback is cost. However, it is really a good idea to apply a layer of epoxy to underwater portions of the gelcoat of a new yacht before antifouling is applied; an owner can conceivably do this himself. However, even if a professional is engaged for the job, epoxy coating on a new boat is inexpensive when compared to the costs of GCB repair work. Above the waterline, epoxies tend to fade in sunlight. A two component polyurethane topcoat provides a superior finish.

While other articles have discussed GCB repair techniques in detail. The discussion here has deliberately been kept at a basic level. This is because a careful diagnosis of each individual case is necessary before the best repair procedure can be selected, and because of the difficulty of drying out a blistered hull, there is never a guarantee that the problem will be solved. It takes a good deal of experience to accomplish thorough and trouble-free repairs. Should you find that your boat is stricken with "boatpox" you would be well advised to consult those experienced in dealing with GCB before embarking upon a particular course of treatment.
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

Mark Melchior
C250wb "Lorelei" #384
[url="http://www.texassailor.com/"]<img src="http://www.texassailor.com/texas.gif " border=0>[/url]
(click flag to visit Central Texas Sailor)

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jm
Captain

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Canada
290 Posts

Response Posted - 05/08/2002 : 16:55:51

Ok, boats in fresh water in southern/warmer climates that are kept in the water for years on end, might experience a higher probability of osmosis than those in fresh water that are hauled and stored for half the year, or those in salt water.

Ahh, who cares - Got blisters ? Do the zit fix..

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