Four years after my '96 Catalina 42 MK II was placed in fresh water, I had it taken out of the water to paint the bottom. That's where the bad news began. The bottom had blistered. The manufacturer made a warranty repair and peeled the bottom and then insructed the ship yard to build up the bottom with VE and then paint with customary bottom paint. Now, four (or is it three?) years later, I've pulled the boat again for bottom painting. More bad news - the ship yard tells me the paint "just fell off" and the VE is damaged and needs to come off. So they are in the process of sanding off to bare figerglass and intend to put four coats of barrier coat on the fiberglass and then place on customary bottom paint. My question is, is this a good plan - that is, sand to fibergalss and place four coats of barrrier coat and then paint? Thanks in advance for your thoughts.
No end of trouble with my Catalina 42
- Thread starter rforsyth
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Catalina bottom roblem
Have you contacted Catalina to ask for their take on this? If not, may I suggest that you do?
Have you contacted Catalina to ask for their take on this? If not, may I suggest that you do?
Blisters and Barrier coats
I suggest you get a copy of our Gelcoat Blisters
iagnosis, Repair, and Prevention manual. There is a detailed discussion of the causes of blisters (there is more than 1 reason)and how to assess and determine a repair strategy. Of primary importance is that you be sure the hull is dried thoroughly before applying a barrier coat. I would also suggest that epoxy is the most effective moisture barrier you can choose. In fact, at the recently completed ACMA conference in Tampa, FL a presentation by Interplastic Corp. who manufactures gelcoats, polyester and vinylester resins, among other things outlined a quite thorough test program to quantify the moisture exclusion effectiveness of each of these materials. The bottom line was this - vinylester is not a good moisture barrier. It does not blister but acts as a semi-permeable film, so moisture can pass through it and then into the polyester laminate that your hull is built with, so all the problems a wet laminate can cause are still able to happen, only now the blister won't show and the symptom is hidden. Talk to your boat yard and insist on an epoxy barrier coat of at least 20 mils to provide an effective moisture barrier. Keep in mind that virtually nothing is 100% water proof, given sufficient exposure, but epoxy in this application is the only real choice. As an aside, one of the most often overlooked things you can do to minimize hull/moisture problems is to keep the inside of the boat well ventilated. This is very important. Water in the bilge, inside a hot, poorly vented hull, creates water vapor that is a much more energetic molecule than a liquid water molecule, meaning moisture can access the hull laminate from the inside.
I suggest you get a copy of our Gelcoat Blisters
iagnosis, Repair, and Prevention manual. There is a detailed discussion of the causes of blisters (there is more than 1 reason)and how to assess and determine a repair strategy. Of primary importance is that you be sure the hull is dried thoroughly before applying a barrier coat. I would also suggest that epoxy is the most effective moisture barrier you can choose. In fact, at the recently completed ACMA conference in Tampa, FL a presentation by Interplastic Corp. who manufactures gelcoats, polyester and vinylester resins, among other things outlined a quite thorough test program to quantify the moisture exclusion effectiveness of each of these materials. The bottom line was this - vinylester is not a good moisture barrier. It does not blister but acts as a semi-permeable film, so moisture can pass through it and then into the polyester laminate that your hull is built with, so all the problems a wet laminate can cause are still able to happen, only now the blister won't show and the symptom is hidden. Talk to your boat yard and insist on an epoxy barrier coat of at least 20 mils to provide an effective moisture barrier. Keep in mind that virtually nothing is 100% water proof, given sufficient exposure, but epoxy in this application is the only real choice. As an aside, one of the most often overlooked things you can do to minimize hull/moisture problems is to keep the inside of the boat well ventilated. This is very important. Water in the bilge, inside a hot, poorly vented hull, creates water vapor that is a much more energetic molecule than a liquid water molecule, meaning moisture can access the hull laminate from the inside.- Status