Barnacles on 2nd year bottom paint

[Jay]

I have a question about anti-fouling paint and barnacles.Last year (2002), we did _lots_ of bottom work, removing patches of unsound bottom paint from our Hunter 23, put epoxy paint on the cast-iron keel and on the rudder, and finished it off with 2 coats (more at the water line) of Micron-CSC paint. This took me most of June/July in the heat. We finally launched in the middle Chesapeake Bay at the mouth of the Patapsco (this is mostly salt water) at the end of July, and kept the boat in a slip until Thanksgiving.When we pulled it out for the winter, the bottom looked great (after washing). This year, we put it in the water without doing much on May 9th, and didn't visit again until July 13th. When we sailed last Sunday, the rudder had a pretty good collection of new barnacles (and slime, which came right off) from just 2 months in the water.Did we do something wrong? I thought the paint would be good for 1.5 seasons at least. Do I have to haul the boat out and scrape it right now? And will the barnacles come off of the paint without much trouble, or will they be cemented on really tightly?Maybe someone from this area can give me some advice! Thanks much.

 

[Don Berger]

Ablative paint

I'm no expert but I've been told that the efficacy of ablative paint is nill if the boat just sits as your's. To be effective, it needs to slough off layers which it does when moving through the water. Don

 

[Chip Tobey]

I've heard some folks suggest

giving the bottom a thorough once-over with a hose or powerwashing it before relaunching. That takes the paint down to a fresher layer of cuprous oxide (or whatever the active ingredient is).I've had good luck with Interlux Bottomkote ACT. It's a single-season ablative. At the end of the season, I have the boat hauled and powerwashed. Before luanching in the spring, I put two more coats on (no sanding, minimal scraping). This scenario has worked well for me in the lower Chesapeake.BTW, I've also been advised to paint the rudder with a white antifouling paint, the theory being that a dark paint will absorb heat (light energy) which isn't good for foam core rudders. In any case, on my 23, I pull the rudder when the boat's not in use. It's a bit unwieldy, but my reasoning is that I'm prolonging it's life as when I bought the boat the rudder had already begun to split at the seams.

 

[S. Sauer]

CSC upkeep

I've used Shark White CSC on my rudder for several years, and although it is a soft ablative paint, I periodically wipe it down (in the water) with the softest 3M abrasive pad (NOT a Grill Scrubber). I would assume that you can beach the boat in shallow water and wipe down the existing paint, assuming you built up a decent coating with your original application. You shouldn't need to haul the boat. If barnacles are sticking, I'd carefully pop them loose with a small plastic scraper then try the wipe down treatment with the 3M pad.As far as power washing the bottom before launch, if you try it , do so on a fairly low pressure with a 'fan' spray pattern or you may just blow off the entire coating, and by that time you may not have much left on the bottom anyway.

 

[Jay]

ok

Thanks for the advice. I guess I'll decide whether to pull it out on the trailer and scrape. But next year it gets another coat or 2 of paint...

 

[crazy dave]

Jay

You have to be careful about ablative paints. On some, once the boat is out of the water say for example on a trailer, for over 60 days, the effectiveness of the bottom paint is lost. However, there are some for example the Micron CSC which taken out of the water will not be affected by drying out like some other ablative paints. When painting, always see what the local knowledge suggests as some paints work better than others. We can give you all the suggestions but on a trailerable boat, just remember the distinction of anti fouling properties when the hull is left to dry for more than 60 days.Crazy Dave Condon