Bottom Coating or Not

[MarkD]

I am about to purchase a brand new SR 185 Sport with the 4.3 engine (as a second "for fun" boat) and am looking for some advice on a bottom coat for the boat. I ideally want to store it in the water to keep things easy & live the "get up and go" lifestyle. I am in completely fresh water on the mid-Hudson River in NY state. No barnacles or zebra muscles that I have ever seen. Here are my questions:

1) Is it worth it to barrier coat the bottom with epoxy paint prior to any bottom paint? I have heard that SR's vinylester resin is superior to that of the older polyester resin (aka my existing boat) and is not prone to blistering. Can someone confirm that this is true?

2) If barrier coat is not necessary, is it even worth doing this bottom coat and just power wash when it is pulled out or would an ablative paint with primer undercoat be the best choice???

Any advice would be appreciated...
Thanks,
Mark

 

[sbw1]

I've owned a Formula, a SR and a Boston Whaler that were wet slipped without paint for years and non ever developed a blister. There is an article in one of the recent boating mags that discussed blisters. Vinylester resins have pretty much eliminated the issue. I'll check later today on the article so you can read it yourself. As far a painting the bottom, I would use a high quality ablative paint that is suitable for your water conditions and applied to a properly prepared surface. This will greatly simplify your fall clean up. Awlgrip is one company that make high quality paints for this purpose.

 

[sbw1]

Read Bill Pike's article in the April 2008 Power and Moteryatcht. It starts on page 95. He more or less debunks the theory that blisters are inevitable. There is still a strong case to be made for painting the bottom simply to make clean up easier when the boat is hauled.

 

[Pirate]

Read Bill Pike's article in the April 2008 Power and Moteryatcht. It starts on page 95. He more or less debunks the theory that blisters are inevitable. There is still a strong case to be made for painting the bottom simply to make clean up easier when the boat is hauled.

I read the same article. It didn't make it any more true. I think what he meant was that the current materials are much more RESISTANT to blisters, but they are not immune. It wasn't uncommon in the 80's to pull a 35' boat and have 300-500 blisters. That generally does not happen anymore. Now you pull a 50' boat and it has 2 or 3. I still want bottom paint to eliminate the 2 or 3 and keep the growth off of the hull. The growth etches the surface of raw gel coat anyway, so each successive pull and pressure wash session gets worse.

 

[barryg]

Sometimes painting the bottom of a small boat devalues it in the resale market. For my last boat (a 25' Doral) the market would have given me 10-15% less if I would have painted the bottom, and though I had a trailer, I wanted to keep it in the water. I went and purchased a boat bunker, from boatbunkers.com and kept it in the water for a year before selling it and it worked great. I sold both the bunker and the boat, and when I bought the 320, I bought a new larger boatbunker for this boat so that even though it is bottom painted, it wouldn't need to be repainted for many many years. It's a pretty cool and simple concept and though I was doubtful it would work, it did and does. Any questions you can pm me.

Barry

 

[sbw1]

Bottom paints are not barrier coats, but simply FG anti-fouling coatings. The "Rockett Report" suggested that manufacturers focus on a handful of production changes to mitigate blister formation. Temperature control, gel coat thickness of 35 mils, elimination of air during the curing process, cleanliness and complete spraying of gel coats without curing to achieve 35 mils are several of the key recommendations. The quality of resins, especially the fillers can introduce variation that cause problems. Said another way, a carefully laid up boat should not develop blisters, especially with the new resins we have today. Another factor is the use of chopper guns to build boats. Strands introduce the opportunity for air infusion during the curing process which is not good. Keeping a boat in warm water (90 degrees) for extended periods of time is also generally not good for older boats built with the old resins. These boats should have barrier coats to prevent blisters and bottom paint to prevent fouling. People who boat in the north in cooler water temps for 6 months do not see blisters often, even on boats built 30 years ago. I've not seen any blister repair work at my storage marina in years of looking at old boats. And, I did not experience any blisters on my boats without bottom paint nor the boats that had bottom paint but not barrier coatings. Where you boat makes a huge difference.