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Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

bottem Blisters

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budman
Deckhand

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3 Posts

Initially Posted - 03/06/2011 : 12:38:42

Just pulled my catalina 25 out for the frist time to paint the bottem and check the keel cable. Looks like the boat has lots of blisters. Not sure if I must fix all of them or just repaint. The boat is a 1984 and has been in the same lake for years. I know it has not been out in at least 7 to 9 years.

Budman

Edited by - on

Steve Milby
Past Commodore

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USA
5906 Posts

Response Posted - 03/06/2011 : 12:47:48

What you see might be osmotic blisters, or it might just be old, peeling antifouling paint. If you can post a photo of them, we might be able to give you better advice. If you haven't already done so, however, you should have the bottom pressure washed, so you can see what's underneath the dirt and algae.

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budman
Deckhand

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3 Posts

Response Posted - 03/06/2011 : 13:48:37

Here are some pictures I took yesterday of the boat. They are not the best pictures to show the blisters, but they are the best I have at the moment. I will take better pictures next weekend to better show the hull blisters.

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Steve Milby
Past Commodore

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5906 Posts

Response Posted - 03/06/2011 : 15:11:22

I suggest you burst the blister in the last photo, and peel the paint off it. If there is solid, smooth gelcoat underneath it, then it's just peeling paint. If the gelcoat underneath the paint is lifted like a blister, it's probably an osmotic blister. Big osmotic blisters should be ground out, dried and filled. Little ones can probably be deferred, but you might as well fix them too, while you're at it.

Edited by - on

OJ
Master Marine Consultant

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USA
4382 Posts

Response Posted - 03/06/2011 : 18:04:29

Well, as they would say in West Virginia . . . "m r blisters"

Read this - thoroughly:

http://www.westsystem.com/ss/assets/howto-pub2/Gelcoat%20Blisters%20Diagnosis%20Repair%20and%20Prevention.pdf

Once you've remedied the blisters - use this to prevent future blisters:

http://www.yachtpaint.com/usa/diy/products/primers/interprotect-2000e.aspx

Next: Prepare yourself for the naysayers about repairing blisters

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OLarryR
Master Marine Consultant

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USA
3477 Posts

Response Posted - 03/07/2011 : 04:50:09

I wouldn't exactly say that I am negative on repairing blisters but this is an area where there are a lot of articles on whether to do something or not regarding blisters. Sorry I do not have any links to share right now but I know there are some articles written by surveyers and you have to do a search in Yahoo or perhaps buried in our archives you can find some articles and links. Here is my own experience with blisters on a 1989 Catalina.

My boat remains in the water all year-round and the PO did same thing. It only comes out for an annual pressure wash and every 4-5 years for bottom painting. When I bought the boat in Fall of 2005, I had it pressure washed at a nearby marina and it was then we saw approximately 20 mostly dime sized blisters on the port side of the hull and maybe 10 on the starboard side. The marina that did the pressure washing indicated that these blisters, some could be just paint blisters and the others, well they are not that big and may have been there for years. The recommendation was to see what they look like when I remove the boat the next year for bottom painting and then see what's what. Meanhwile, I read a bunch of articles on blisters and a number of articles indicated that in many cases, not all, the small blisters are more of a cosmetic thing than anything else but need to be watched and action taken if they grow or more appear.

When my boat was pulled out a year later for bottom painting, first thing was that there were no addl blisters and no growth. I had the marina guys prepare the bottom and repaint the boat and so they took a better look at the blisters once they got into preparations. At least half or more of the blisters were paint blisters...so that was great. No issue there. Approximately 3-4 blisters, they opened up and repaired with just a bit of epoxy or something...not sure. So, I have perhaps 10 or so blisters that remain and I have inspected the bottom every year the boat has come out for it's annual pressure washing and I have seen no addl blisters and no growth from the original ones. Next Fall, it will be 5 years since I last had ablative/co-polymer multi-year bottom paint applied and so it may be the time to have it done again. I had more slime this past fall and so I am going to get a pressure wash earlier this year probably in June or thereabouts and see what the slime growth looks like and then decide if I go for bottom painting this fall. If I do, I may have a few more blisters squared away.

So, I would not panic over blisters but if you have a lot of them and I do not know what you mean by a lot, then you may need to have the whole bottom squared away or if you are lucky, many may turn out to be paint blisters and the others you can decide if you are going to square away some or all depending on what you are left with. If you really have a lot, then you may have to repair and then have the bottom resealed/waterproofed after all bottom paint is removed. Just that this is a good time to search the web and read what you can about blisters and what to do about them.

Edited by - OLarryR on 03/07/2011 04:54:47

Davy J
Master Marine Consultant

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USA
1511 Posts

Response Posted - 03/07/2011 : 05:51:47

Here is an article on the subject:
http://www2.yachtworld.com/mustangyts/mustangyts_5.html

The last time I replaced my keel cable, I put my C25 on my powerboat lift. At first it seemed like there were hundreds of blisters, but after a few days on the lift, they disappeared. I'm guessing they were just paint blisters. Hopefully that is your case as well.

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OJ
Master Marine Consultant

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USA
4382 Posts

Response Posted - 03/07/2011 : 06:17:40

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by budman

<hr height="1" noshade id="quote"></blockquote id="quote">That keel hinge hanger bolt (term?) looks like it may be loose? The heads of my bolts were flush.

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OJ
Master Marine Consultant

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USA
4382 Posts

Response Posted - 03/07/2011 : 06:24:00

OLarryR - your boat is newer - Catalina used a different resin which may explain your low occurence of blisters.

DavyJ - seeing bumps immediately after pulling a boat out of the water - which then recede is a classic sign of blisters.

Edited by - on

Captain Max
1st Mate

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USA
87 Posts

Response Posted - 03/07/2011 : 09:42:33

Are blisters a common problem on catalina 25's

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WesAllen
Navigator

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USA
222 Posts

Response Posted - 03/07/2011 : 16:43:33

I have an 82 SK and my pivot pin bolts are flush also. I have a few very small blister (1/4") and I will just watch them for the time being.

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OJ
Master Marine Consultant

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4382 Posts

Response Posted - 03/07/2011 : 18:15:51

When I was opening blisters on our 1981 C25 I stopped counting after 300. The newer 1989 C25 showed no signs when we pulled last fall.

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Steve Milby
Past Commodore

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5906 Posts

Response Posted - 03/07/2011 : 18:18:06

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Captain Max
 Are blisters a common problem on catalina 25's
<hr height="1" noshade id="quote"></blockquote id="quote">+
To some extent, blisters have always been a problem for fiberglass boats. A long-time fiberglass technician told me that water is one of the most invasive substances known, and that, given enough time, it can penetrate almost any substance. During the period from about 1982-1989, for reasons I can't explain, blisters became an industry-wide problem. In about 1989, boat manufacturers began using a different type of fiberglass, and many also coated them with a barrier coat from the factory. Since that time, blisters have been much less of a problem. To answer your question, blisters were an industry-wide problem, not just a Catalina problem. Nevertheless, boats built during that period can be protected with a barrier coat paint.

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budman
Deckhand

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3 Posts

Response Posted - 03/07/2011 : 21:26:22

Thanks for the advice I will take a close look at the bolts this weekend when I go up to work on the boat. Should I just try and tighten then ? I think I may try and fix the larger blisters and take some close up pictures then new bottom paint and next year pull it out and see what it looks like.

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