blisters on pre-1990 boats

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andi

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Jun 22, 2004
1
- - alameda
i am in the process of looking for a used catalina 30...i understand boats built prior to 1990 have blistering problems...is this something to be concerned about? should i stick to something built after 1990? what else should i look for? i have never bought a sailboat before!! and is catalina the way to go? what else is good value?? i had a sailboat many years ago and sailed a fair amount..any help is appreciated..thanks !
 
A

Allen

About Blisters...

Hey Andi, I am about to give you more info than you probably ever wanted to know about your questions & I'm going to apologize in advance. It's gorgeous outside right now & I wish I could be out on the water, but I can't. I figure the next best thing is to "talk shop" on this forum, so here we go: I bought my first boat about 4 years ago. It was a 1977 Catalina 30 & I still have her today. I never regret the purchase, but I did do my homework before buying so I knew exactly what I was getting into. As far as blisters go, it's important to understand what they are, how they're caused, what to look for, how to prevent & how to fix them. First, there are 2 types of blisters. Small, pin-head to pea-sized blisters without any moisture in them are just voids in the gelcoat and they're not that big a deal. They tend to form around the waterline & are easily ground down, filled in & painted over. The 2nd type of blister is more serious. These are osmotic blisters that are caused when voids in the laminate (not the gelcoat but between the actual layers of fiberglass themselves) eventually absorb moisture. Over time, this moisture accumulates and forms a very toxic acid that will expand over time & weaken the fiberglass. Osmotic blisters can be as small as a pea or as large as the palm of your hand. Unlike dry voids in the gelcoat, these blisters severly weaken the strucutral integrity of the hull & need to be fixed once they're identified. What causes them?? There's a lot of debate over this, but evidence suggests that inferior workmanship and/or quality of materials contributes to this. If there's a void in the laminate water will likely find a way in & a blister will eventually form. You want to take a close look at the hull below the waterline. Look closely for any bulges and/or uneveness in the hull. If it looks good to you, have a surveyor take a closer look. They should be able to let you know one way or the other. One of the benefits of purchasing an older boat is if it has never had blisters, it probably never will. My 1977 never did, which meant that, in all likelihood, the hull doesn't have any voids that I need to worry about. This isn't 100%, but it's probably not going to be an issue for me. Prevention is another area of debate. Companies like interlux make barrier cote products that are more resistant to absorbing water than regular fiberglass. Yes, fiberglass & gel coat absorb a certain amount of water & barrier coats are supposed to stop that. The problem is, if the hull isn't dry enough when you apply the barrier coat, you're going to seal in the moisture preventing the hull from drying out (as it might do during a winter layup) and blisters will either come back, or be more likely to form. The best way to prevent, Ive read, is to make sure your hull is as dry as possible & apply a good barrier cote as a preventative measure. To fix them, you need to grind out the weakened laminate, thoroughly rinse away the toxic fluid & let the hull dry for a considerable period of time, usually months (up north it can be done during the winter) often as long as a year. Once the hull is dry the fiberglass can be repaired with epoxy & glass mat. Overall, a good surveyor should be able to determine if a boat has blisters. They'll knock on the hull with a mallet, they'll use a moisture sensor to measure how damp the hull is. Go with his advice. He's a professional. If it's an older boat & it has one or two areas of concern, find a good yard, get a quote & negotiate the repair costs into your final price. If the boat is peppered with blisters, then walk away. There are a lot of C-30's out there & it's not worth the hassle to fix a bad hull (and they are out there). If the boat is older & has no blisters & no history of blisters, it's probably a good sign that the hull is in excellent condition. As for sticking to a boat that's built after 1990, I'm not aware of any evidence that newer hulls are more or less resistant to blisters than the older ones. Again, the benefit of an older hull is that it has some history that should help predict the future. A newer boat will have less history, but everything else on the boat will be newer and that may appeal to you. I'll get to the other questions on my next post. I hope this helps!! Allen Schweitzer s/v Falstaff C-30 Hull# 632
 
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agolden

Blisters

are not the problems they once were thought to be, and yes it can be costly if not montiored and repaired...but its not the end. If you like the boat and everything else is in good shape and the survey does not find anything else in bad condition...negotiate the cost of the the blister repairs into the purchase. Either the seller fixes them or have him deduct the cost of repairs from the selling price and you have them fixed at your expense. I found three quarter sized blisters on my C36 during bottom painting this sring. I had the bottom painted and I'll have the blisters fixed while the boat is on the hard over the winter.
 
A

Allen

Other things to look for

Hey Andi, Me again. Still at it. Here are some other things to look for as you choose a used C-30: 1. Starboard chainplate supports. The starboard chainplates are weaker than the port & may tend to pull away from the hull. Check the tabbing on the starboard bulkhead & make sure it's not pulled away from the hull liner. Make sure the knee boards aren't cracked & that there's little or no spider-cracks in the gelcoat where the lower stays bolt to the deck. 2. Mast compression block. Look at the area where the mast attaches to the deck. Make sure it's not depressed. If so, the mast compression block in the bilge may be rotted & need replacing. Not a huge deal, but something you'll have to get to. 3. Spreaders. If you're looking at an older boat with wood spreaders you'll want someone to check those out. Make sure the tops are in good shape even if the bottoms look good. 4. Soft spots in the deck. The C-30 deck is cored with wood. Make sure the deck has few, if any soft spots. A deck core that's absorbed a lot of water can make the boat worthless. Check around any deck hardware for softness or crazing. Other than that, you'll also want to check all of the other things (engine, electrical, rig, sails, etc.). Overall, there are 2 things about the C-30 that you'll be hard pressed to find in another 30 footer: First of all, it's an incredibly comfortable & roomy boat for it's size. In my opinion, Frank Butler really hit a home run when he designed this boat. As a 30 footer, it's possible for a person who knows how to sail to buy this as their first boat. It's not too tough to single hand (with a decent autopilot) and it sails pretty well, especially if you have a tall rig (though I don't). It loves big wind and is comfortable in winds up to 20 knots with a reefed main & a 100% jib. It's also extremely comfortable for it's size. It's perfect for a long weekend or the occaisional extended cruise for a couple. I've heard that people bring the kids, too & find the boat big enough. The second benefit is that Catalina made over 10,000 of these & continue to build it today. There's a HUGE amount of resources out there, including this forum. You can call the factory and get parts, your boat's original factory order sheet & more. Sails, rudders, rigging upgrade kits that are specific to the C-30 are all readily available from a number of different sources. There are national and regional C-30 clubs, races, cruising trips & more. I don't know of any other boat of this size that has so much support & resources behind it. It's fantastic. Good luck with the search. If you're looking for price comparisons, go to www.yachtworld.com and do a search for Catalina 30's. There are literally hundreds of them & you can see pictures to help you find the boat that's right for you. Fair Winds, Allen Schweitzer s/v Falstaff C-30 Hull# 632
 
Jun 8, 2004
2,958
Catalina 320 Dana Point
My '94 270 had some blisters when I purchased,

My surveyor and I found 4 during survey, negotiated by phone with seller, they paid repairs, boat yard found one more during repairs. These were apparently first blisters on the boat and not unusual (better than average in fact for 10 year old) per surveyor & boat yard. Boatyard hauled for survey at lunch with understanding I would either reject outright or accept and have them place on hard for repair (blisters & bottom paint, stuffing box etc.). End of lunch deal was finalized, boat on stands, seller paid for negotiated repairs from escrow account of his broker, I paid my share of yard bill for stuff I wanted done. I had also heard the theory of improved blister resistance of post '90 hulls and have not found it to be so. Most of those I have spoken to also seem to be of a mind that blisters are a way of life for fiberglass boats that stay in water. Best advice is as above, repair promptly, keep boat dry inside as well, (why I had stuffing box done right away) well painted, and clean never hurts either.
 
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