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Catalina/Capri 25/250 Sailor's Forums

Catalina 250 Specific Forum

Bottom Paint Suggestions

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slaedlein
1st Mate

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USA
51 Posts

Initially Posted - 01/27/2014 : 20:11:57

The bottom of my 1997 WB has a heavy coating that was applied by the dealership (according to Catalina). No idea what it is, but it is black and definitely not smooth. On top of that is an ablative bottom paint. The paint is a couple years old and needs to be repainted. However, the coating beneath is starting to flake off in spots. After a number of years sailing on the Gulf Coast, I now sail on Lake Michigan and other than a little slime, don't have to deal with much growth. I expect to head back to the Gulf in a few years. I have not heard of any blistering problems on the forum and am wondering if after scraping off the thick coating if I need to put on a barrier coat or if I can just go with a bottom paint.

Scott
HuBeStu
1997 WB
Hull# 250

Edited by - on

TakeFive
Master Marine Consultant

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2272 Posts

Response Posted - 01/27/2014 : 20:59:59

My boat has no barrier coat. I have heard that the newer vinyl ester boats like the C250 do not need it.

Don't go on my advice alone - get opinions from others with Catalinas of similar vintage (C250, C270, C309, C310, etc.).

This is one topic where the advice of C25 owners may be irrelevant. Those boats are from the pre-vinyl ester era. They generally need barrier coat.

If you strip down to bare vinyl ester, you may need a sandless primer to promote adhesion. Sanding the vinyl ester can damage its beneficial properties. Many of the sandless primers are isocyanate based, and need to be applied wet-on-wet, so technique is important.

Edited by - on

GaryB
Master Marine Consultant

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4316 Posts

Response Posted - 01/28/2014 : 06:35:45

Call the dealer to see what it is they applied and get back with us. You probably should also contact Catalina to see how they suggest you proceed.

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Steve Milby
Past Commodore

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5909 Posts

Response Posted - 01/28/2014 : 07:35:27

The ideal solution would be if the dealer can tell you what was put on the bottom, but I'd guess that the likelihood is that he won't be able to do that. If you know what it is, then that will lead you to the best method for removing it.

But, if the dealer can't identify it, what then? We can only guess. My guess is that it is an accumulation of some type of black, hard finish antifouling paint. (From your description, it could be coal tar epoxy, but there would be no reason why a dealer would apply it to a C250 with a vinylester bottom.) If it's a hard finish paint, then the question is, how do you strip it off a boat with a vinylester-protected bottom without damaging the vinylester coating? I'm not sure, but I think it can be done with a chemical stripper. Nevertheless, I would suggest you put that question to Catalina, to be sure. Ask them to recommend a specific stripper, because there are lots of different types and brands of strippers, some of which would definitely not be appropriate.

But, let's assume the worst case scenario. If you find that the substance can't be removed without damaging the vinylester coating, it still isn't a disaster. It just means that, after you remove the old paint, you should replace the protection that was previously provided by the vinylester coating before you re-apply antifouling paint. Barrier coatings are available to do that, and it will probably add about one day to the time that will be required to do a bottom job.

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CJRoxs
Navigator

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USA
114 Posts

Response Posted - 01/28/2014 : 07:52:39

How can you tell if the bottom is vinyl ester? What year did they start putting that on? I want to have the bottom Lily redone this year but do not know what is on it. The PO doesn't remember when the bottom was last done. When I dove under it last summer the bottom looked fine. Although, I do have to do the shims.

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Steve Milby
Past Commodore

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5909 Posts

Response Posted - 01/28/2014 : 08:10:01

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by CJRoxs
 How can you tell if the bottom is vinyl ester? What year did they start putting that on? I want to have the bottom Lily redone this year but do not know what is on it. The PO doesn't remember when the bottom was last done. When I dove under it last summer the bottom looked fine. Although, I do have to do the shims.
<hr height="1" noshade id="quote"></blockquote id="quote">
All C250s have vinylester.

This makes a good point. Most buyers of used C250s don't know what kind of paint is on their boats, and don't know how to remove it. One of you C250 owners should explore the issues with Catalina, and furnish a tech tip that can be posted here, so that all future buyers won't have to go through the same process and ask all the same questions again and again.

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CJRoxs
Navigator

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114 Posts

Response Posted - 01/28/2014 : 08:17:17

So with the bottom having vinyl ester, how long does this last until the bottom needs refinishing? Is this permanent or ???

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TakeFive
Master Marine Consultant

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2272 Posts

Response Posted - 01/28/2014 : 08:37:03

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Steve Milby
Past Commodore

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5909 Posts

Response Posted - 01/28/2014 : 08:58:57

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by CJRoxs
 So with the bottom having vinyl ester, how long does this last until the bottom needs refinishing? Is this permanent or ???
<hr height="1" noshade id="quote"></blockquote id="quote">I don't know if anyone knows how long it will last. What we do know is that it is apparently still protecting the first C250s built, because no osmotic blister problems are being reported with C250s.

Vinylester is a water barrier. It prevents moisture from penetrating the fiberglass by osmosis. It doesn't have anything to do with how soon the boat needs the bottom refinished.

The factor that determines when the bottom should be refinished is it's smoothness. It's really very much like looking at the painted surfaces of your house. When the paint becomes thick, and begins to peel, it's time to think about stripping off the old paint. On your house, peeling paint looks bad, but on the bottom of your boat, it makes the boat perform badly.

We can quibble over whether "coating" is the perfect word to describe it, but the bottom line is that, if you sand it away, Catalina's warranty against osmotic blisters is invalidated.

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CJRoxs
Navigator

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114 Posts

Response Posted - 01/28/2014 : 10:49:42

But putting a abative paint over it to prevent biological growth is ok, correct? Just clarifying.

Edited by - CJRoxs on 01/28/2014 10:51:36

Steve Milby
Past Commodore

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5909 Posts

Response Posted - 01/28/2014 : 11:22:34

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by CJRoxs
 But putting a abative paint over it to prevent biological growth is ok, correct? Just clarifying.

<hr height="1" noshade id="quote"></blockquote id="quote">Exactly! Vinylester (and other types of barrier coatings) prevents moisture intrusion, and antifouling paints (including both hard finish and ablative paints) deter biological growtrh. The moisture barrier is applied first, and the antifouling is applied afterwards.

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CJRoxs
Navigator

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114 Posts

Response Posted - 01/28/2014 : 11:52:44

That's what I was thinking but wanted to make sure. Thanks for the info.

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CJRoxs
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114 Posts

Response Posted - 01/28/2014 : 13:27:34

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Steve MilbyWe can quibble over whether "coating" is the perfect word to describe it, but the bottom line is that, if you sand it away, Catalina's warranty against osmotic blisters is invalidated.
<hr height="1" noshade id="quote"></blockquote id="quote">

One more clarification, you are talking about more then just scuff sanding, correct?

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Steve Milby
Past Commodore

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Response Posted - 01/28/2014 : 13:46:53

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by CJRoxs
 <blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Steve MilbyWe can quibble over whether "coating" is the perfect word to describe it, but the bottom line is that, if you sand it away, Catalina's warranty against osmotic blisters is invalidated.
<hr height="1" noshade id="quote"></blockquote id="quote">

One more clarification, you are talking about more then just scuff sanding, correct?
<hr height="1" noshade id="quote"></blockquote id="quote">I have never seen any discussion of how much sanding you can do without damaging the vinylester. Catalina has always recommended the use of sandless primer, and has strongly discouraged any sanding at all. If I had a boat protected by vinylester, I wouldn't sand it at all, unless the bottom was so damaged that I had to apply a new barrier coat.

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CJRoxs
Navigator

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USA
114 Posts

Response Posted - 01/28/2014 : 20:38:30

Got it. Thanks.

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ruachwrights
Captain

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USA
258 Posts

Response Posted - 02/03/2014 : 11:50:38

If the black stuff is flaking off just used a scraper to get rid of the flakes. Another reason to be careful of sanding is that it is toxic to inhale and most boat yards will have a fit if they catch you out there "smoothing" your hull without proper equipment such as tents and special masks.

Scrape off the loose stuff and slap on a new coat of ablative paint. It won't cost you much and it will smooth things out pretty well.

Vern Wright
Hajime

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