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Catalina 309 Osmosis Damage Hull

Jul 31, 2021
8
Catalina 309 Lake Ontario
Hello All
Has anyone else had trouble with fibreglass on Catalina 309 (mine is 2006 only 15 years old) - I have 6 small hollow holes on deck toe rail (1/8" to 1/4" in size) and bad pit marks on entire hull - hundreds of pit marks - see pictures - the boat has always been in freshwater, bottom paint every year and stored on land for 7 months of year (winter).....seems unusual for a boat that is only 15 years old...wonder if it is a manufacturing problem?
Any advice would be appreciated?
Thanks!!!
 

Attachments

Jul 19, 2013
308
Pearson 31-2 Boston
That sure looks like the classic bottom blister problem, which I find surprising in a 2006 boat as I thought manufacturers had solved that problem. I would get a surveyor to evaluate the bottom and go from that. If the entire hull looks like these photos, you could face a major repair involving peeling and replacing the outer skin of the bottom. You should check around with other owners, usually a problem like this would not be a one-off.
 
Jun 8, 2004
2,554
Catalina 320 Dana Point
Are the bottom blisters in the gel coat or just the paint ? If you open one is it wet and does it smell of resin ? I mention because I once had a boat get little blisters like that in the paint on the south (sunny) side at the waterline. Sanded and painted they did not re-occur.
 
Jul 31, 2021
8
Catalina 309 Lake Ontario
Thank all! Had the person who paints bottom check in spring and they are blisters that do “pop” if poked with a knife….he recommends sanding/blasting and an Interlux treatment - cost is about $8k though….guess it is too late for CatAlina warranty - but also, odd for a 15 year old boat….more opinions welcome! Cheers.
 
Jul 19, 2013
308
Pearson 31-2 Boston
Thank all! Had the person who paints bottom check in spring and they are blisters that do “pop” if poked with a knife….he recommends sanding/blasting and an Interlux treatment - cost is about $8k though….guess it is too late for CatAlina warranty - but also, odd for a 15 year old boat….more opinions welcome! Cheers.
Just a comment, if the blister is actually into the laminate, after draining and drying, you need to fill it with something like Watertite Watertite Boat Filler | Interlux which sets up like rock and requires a lot of subsequent sanding.
 
Jan 1, 2006
5,979
Slickcraft 26 Greenport, NY
I read the referenced article.
My Mark 25 had the pox, as I call those round small imperfections in the hull. I'm not calling them blisters because in my case I never saw or had any fluid leak out. Maybe they dried up after haul out. I'm told that could happen. All I did was pay the yard to strip the bottom paint, which I finished when they hit the maximum I would pay. Then I used a counter sink bit to bevel the pox. Never saw any fluid. Hundreds of them. I then filled them with a West system epoxy/filler and sanded and refilled and sanded again. Then barrier coat and bottom paint. The bottom was pretty cherry after that. I never saw more pox but I didn't own the boat too long after that.
Blisters have an irregular shape since they undermine the gel coat. I don't really believe that what you have is osmotic blisters. I think those circular irregularities are a different phenomenon. I don't know why they happen but I believe they can be successfully repaired with a tedious but not complicated process. I'd rather do a 26' boat than a 30' foot but it can be a DYI project. Not 8 boat bucks.
 
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Mar 20, 2007
500
Catalina 355 Kilmarnock, VA
I used to own an early-build 2006 C309, hull #14, that I purchased new in 2007. The first year it was hauled for the winter (by the selling dealer), the dealer noted several areas on the bottom that looked like patches of “pimples”, similar to your photos. The dealer consulted with the factory, and ultimately they spent the winter sanding the entire bottom down to remove all paint and gel coat, and applied 6 coats of epoxy barrier coat and new bottom paint. This was all done under warranty - dealer told me they suspected a bad batch of gelcoat when the boat was built. I never had any further problems, and sold it in 2014. The boat was kept in the brackish water of the lower Chesapeake Bay.
 
Jul 31, 2021
8
Catalina 309 Lake Ontario
I used to own an early-build 2006 C309, hull #14, that I purchased new in 2007. The first year it was hauled for the winter (by the selling dealer), the dealer noted several areas on the bottom that looked like patches of “pimples”, similar to your photos. The dealer consulted with the factory, and ultimately they spent the winter sanding the entire bottom down to remove all paint and gel coat, and applied 6 coats of epoxy barrier coat and new bottom paint. This was all done under warranty - dealer told me they suspected a bad batch of gelcoat when the boat was built. I never had any further problems, and sold it in 2014. The boat was kept in the brackish water of the lower Chesapeake Bay.
Thanks! I will talk to dealer!
 
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Likes: jssailem
Jul 31, 2021
8
Catalina 309 Lake Ontario
I read the referenced article.
My Mark 25 had the pox, as I call those round small imperfections in the hull. I'm not calling them blisters because in my case I never saw or had any fluid leak out. Maybe they dried up after haul out. I'm told that could happen. All I did was pay the yard to strip the bottom paint, which I finished when they hit the maximum I would pay. Then I used a counter sink bit to bevel the pox. Never saw any fluid. Hundreds of them. I then filled them with a West system epoxy/filler and sanded and refilled and sanded again. Then barrier coat and bottom paint. The bottom was pretty cherry after that. I never saw more pox but I didn't own the boat too long after that.
Blisters have an irregular shape since they undermine the gel coat. I don't really believe that what you have is osmotic blisters. I think those circular irregularities are a different phenomenon. I don't know why they happen but I believe they can be successfully repaired with a tedious but not complicated process. I'd rather do a 26' boat than a 30' foot but it can be a DYI project. Not 8 boat bucks.
Thanks! Yes…asking around everyone says same….sand the epoxy with Interlux…..appreciate the advice!
 
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Likes: jssailem
Sep 10, 2007
9
Catalina 309 Lake Tahoe
I had a problem with blisters the first year on my 2008 309. Let the the blisters dry and filled then used an epoxy barrier coat.
I have not had a problem since then.
 
Jul 31, 2021
8
Catalina 309 Lake Ontario
I had a problem with blisters the first year on my 2008 309. Let the the blisters dry and filled then used an epoxy barrier coat.
I have not had a problem since then.
Thanks! We are going to try that.....