Catalina's Oil Based Paint & Mold

Jun 6, 2016
204
Catalina 275 Wilmette, IL
I've mentioned this in the Problems' thread, but this is a big enough problem, it deserves its own thread. Summarizing the Problems' thread, I was growing mold on the underside of the cockpit lockers starting in the first season and could not wash it off. This was because the mold was embedded in Catalina's oil based paint (see Problems' post nos. 2, 21 & 28). Obviously, I do not want mold spores in the boat because it will just continue to travel to a new location and perpetuate the problem.

I've been dreading the removal of the oil based paint, especially in the tight spaced stern, but things were starting to get out of hand, but certainly not as bad as the water tank compartment (see Problems' post no. 2). Here is a picture of the starboard side (the port side was worse, but I forgot to bring my camera to document before stripping):

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And this is after removing the most stern portion:

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As you can see, the mold is spreading to the ceilings (cockpit underside) and this was becoming a big concern. I thought after I removed the mold embedded paint from the hull, I could just steam-clean the ceilings. But unfortunately, I discovered yesterday that the cockpit/deck underside has been painted with oil based paint. What a pain in the ass. You can see the oil base paint has yellowed, which is accelerated in non-lit areas, as compared to the speckled gelcoat used for texture:

P1030740.JPG


And this is after I spot tested with the stripper:

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The two pictures are not perfectly aligned, but you can see that the stripper removed the yellowed oil based paint as well as the embedded mold. Really, really not looking forward to stripping the cockpit/deck underside, especially by the rudder, but if I want to stop having a mold farm, I don't have much of a choice. Here's to hoping the cabin ceiling has not been painted with oil base paint. As I have no mold there, maybe Catalina didn't completely screw me. I forgot to bring elbow pads for stripping the port stern and now both elbows are sensitive to pressure. Thanks Catalina.

And as for my paint experiment in the water tank compartment, two seasons later, still looking good and very white, including the clear coated water tank:

P1030733.JPG


And even the stripped and unpainted hatch covers are holding up well. They had very minor mold specks after two seasons, which easily cleaned up with vinegar. I'm hoping even that will stop after I get all of the adjacent mold removed from the deck underside.

Is anyone else seeing this problem? You can see the water tank compartment from under the sink in the head and do not need to remove the cover under the saloon seat.
 
Jul 24, 2018
34
Catalina 275 36 Sydney Harbour
Sapphire came with very little visible interior mould, but I started leaving moisture collectors in her cabin/head/cockpit locker after reading your post. The last thing I want is mould propogating in a space where my wife, kid and I sometimes sleep and particularly difficult areas to get to. Fortunately the collectors are always dry and no mould showing. I can only assume they might have sorted that oil based paint issue by 2016/hull #26 and/or local the climate here lacks the humidity for it to become much of a problem. Touch (maple) wood.
 
Jun 6, 2016
204
Catalina 275 Wilmette, IL
Boxing Roo, I think our climates are different. I go through 3 hanging damprids in about a month. I suspect that we have more humidity in Chicago where the temperature often goes below the dewpoint. The lake being about 45 degrees in early May does not help. Most mornings, the deck of the boat will have dew on it. The fact that your collectors are always dry really indicates there is a difference. If you ever use the hanging damprids (not sure if you have these in Australia) make sure to double bag the plastic portion because they are prone to leaking. I also secure the plastic hanger with tape because they can separate, again making a mess.

Under the saloon seat, it does not help there is zero air circulation. But I don't really have the problem on the starboard side, so Catalina must use more gelcoat by the battery.

Because this is not a new issue for Catalina, as I had the same problem on a 1989 model, and my post probably came out after yours was made, I'm doubtful that Catalina changed it's paint. It could be that maybe you are in a dryer climate. But it would be interesting if they made changes based on my post by now. I have to assume that someone will have pointed out our C275 forum to them. Your's is two years newer, but maybe go to the back of the rear bunk (darkest area) and look up at the ceiling and see if you can see any yellowing compared to the gelcoat speckles. Also, even after 5 years, the paint in some areas feels just a bit tacky, which is not normal. Maybe there was an application issue as well, compounding the problem.
 
Jun 6, 2016
204
Catalina 275 Wilmette, IL
jviss, the "C275 Problems" is under the "Catalina 275" forum (up one level from here). As I made it possessive to the noun "thread", this is the reason for the trailing apostrophe.

I haven't had the paint analyzed, but nothing yellows, especially in the dark, like oil based paint. Having used it on trim for decades, it is not difficult to spot because of this feature. It is an informed, educated guess and certainly explains the reason for the mold, which is not forming on nearby gelcoat.
 
Jun 6, 2016
204
Catalina 275 Wilmette, IL
Finished stripping the entire boat of all of the paint I could get access to. I'll do under the fuel tank in a year or two when I empty it. This was not a fun project but I'm extremely happy to have completed this godawful task. It's possible I may have some residual paint, but I know I have greatly reduced Catalina's mold source. Possibly, I'll do a second round at my convenience and repainting with the proper paint is also in the plans, especially on the stern bunk hull.

Anyway here are some more pictures. Make sure to cover your wife's eyes if she is screamish.

Ceiling above throttle (partial):

P1030748.JPG


Ceiling above instrument (partial):

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Rear berth hull (partial):

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Rear berth hull (after, this will need to be painted):

P1030772.JPG


Under rear berth (before):

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Under rear berth (cleaned with white vinegar):

P1030767.JPG


Under rear berth (after):

P1030768.JPG


Under forward rear berth (before):

P1030769.JPG


Under forward rear berth (after):

P1030771.JPG


Cabin seam (before):

P1030761.JPG


This is the only good news. Notice the left (aft) has yellowed and the right (forward) has not (except for the vertical paint stroke). This was also the dividing line where specs of mold existed and didn't. This suggests the main cabin ceiling is all gelcoat and not painted. I can be thankful that Catalina didn't totally screw me.
 
Jun 6, 2016
204
Catalina 275 Wilmette, IL
And I've saved the scariest for last.

Ceiling below stern deck (before):

P1030751.JPG


Ceiling below stern deck (after):

P1030762.JPG


Happy Halloween. Hopefully, I didn't give you nightmares about mold.
 
Jun 6, 2016
204
Catalina 275 Wilmette, IL
I'm selling my boat this spring, so I thought I would take one last look at my seven seasons, acrylic latex paint with 1.5 oz MX-3 mildewcide experiment. I applied the paint below the port cabin bench where the water tank is, which gets no air circulation and plenty of condensation from the cold Lake Michigan water. Happy to say it is still looking good. For reminders, this is Catalina's oil based paint after three seasons:

P1030257.JPG


After I stripped Catalina's paint and painted it with the acrylic latex:

P1030287.JPG


Acrylic latex after seven seasons (water tank not removed and the spec appears to be a dead gnat that probably fallen in when removing the bench cover):

P1040632.JPG


From above (water tank obstructing view):

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Catalina has been using oil based paint for decades which I know first hand as it was on my 1989 Capri 22 and my 2014 C275. Hopefully, this thread has corrected this for future Catalina owners.