Ablative bottom paint effectiveness questioned

[Rich Stidger]

I have used ablative paint for over 13 years. My practice has always been to apply 2 coats plus a 3rd on the high-wear areas every other year.I have kept the boat in the water for two years, hauling out in the spring for a quick bottom wash, and I have also hauled out for the winter and relaunched in the spring.I have used Micron CSC, Pettit Ultima, and West Marine's brand of CPP.What I have found in all cases is that the effectiveness of the paint in the second year is much less than in the first year.My conclusion is that I would be much better off applying a single coat of paint each year and not trying to get two-year performance out of these paints. The manufacturer's claim multi-year protection, but I disagree.IMO it appears that the ablative paint does in fact wear off, but perhaps too slowly at sailboat speeds. I suspect that the biocide also leaches out and leaves the paint less effective for the second year.Because after 6 years with my current boat I am starting to see some flaking and chipping, I am now considering stripping all of my bottom paint and starting over with just two thin coats the first year and one thin coat each year thereafter. I have *lots* of bottom paint on the boat, but it is just not effective.Anyone have any other ideas/experiences? Also, any pros/cons of using a chemical stripper vs just sanding would be appreciated.

 

[Warren]

Ablatives

I've had similar experiences with ablative bottom paint. When I switched from modified epoxy to ablative about 6 yrs ago, I followed the directions on the paint can: applied 2-3 coats as directed. When I was hauled in the fall, it was clear that not much paint had ablated at all. BTW, the paint worked great as I had no hard growth at all on a boat I keep in the mid-Chesapeake (brackish water). I agree that while some of the paint ablates, slow moving sail boats don't cause much to do so. So, after sanding a few coats off each year, I finally got smart: I only apply one coat now. I do put a bit extra around the waterline, and leading edges of the keel and rudder. Bingo. I've found that one coat annually works great -- I don't try to get any more out of the paint (Interlux ACT -- an annual paint)

 

[Alan]

Micron CSC

I've been using CSC for 5 years now. As an antifoulant it works very well. The problem as I see it, is that after a month in the water (spring launch) a slime will start to build on the surface of the paint. Little or no activity of the boat means that slime builds which reduces the amount of paint exposed to the water thereby defeating the ability of the paint to wash away. Once the slime appears, sailing alone is not enough to rid the bottom of slime. From this point on for the rest of the season I dive my boat every week. The wipe down with a natural sponge takes about 45 minutes and leaves fresh paint exposed to the water. The week’s worth of slime alone costs me over 1/2 knt of boat speed. If left unchecked by the second week I would loose nearly 3/4 knt of speed. The point being the key to success is to keep the bottom clean with regular wipe downs.

 

[Mike]

Opposite experience

I have used ablative paint since I bought my boat 5 years ago. I sanded down the hard shell paint and put on two coats of ablative. The first year, I used Micron. Except for touch-ups at the bow and rudder, I did not repaint the second year. The third year, I put on two new coats of the West Marine ablative. Again, except for touch ups, I did not paint the fourth year. The effectiveness has been excellent. No barnacles or growth that can't be removed with a powerwash. That first year, I painted the first coat red, and covered with blue. I only see the red coat at small parts of the bow and rudder at the end of the season.

 

[mrbill]

chg colors on coats?

Just hear intresting idea, paint 1st coat red, next 2 coats blue.... that way if you ever see the red, you know its time to repaint.

 

[Mark Mazour]

Warren, which do you use ACT or CSC

Which bottom coat to use? Extra, CSC, ACT...? Please see my post on 3/3/04. I've got 3/4 of a gallon of ACT from the previous owner. I'm going to strip the boat all the way down next month and put a new bottom coat on but I can't decide which to use Extra, CSC or ACT.

 

[Warren]

Ablatives, II

Mark, et al:I have used CSC in the past but found that its extra price was not worth it (I also found that I could not get any extra seasons out of it, too). I have been using ACT and think its a very good paint for the price. NEVER had any hard growth and I now only use one coat. When the boat is hauled in the fall, it does have some slime and soft stuff mostly around the water line, but that all goes down the drain when the boat is power washed. While I like ACT a lot and would recommend it to anyone, I see that Practical Sailor now rates the West CPP Multi-year ablative as "somehwhat" better than ACT, and it seems to cost a bit less. I may give it a try for a season and see how it compares.

 

[Mark Mazour]

Only one coat?

Warren,You only apply one coat? Straight on top of the gel coat or over primer? Do you apply two coats on leading edges ie bow stem, keel and rudder? Then each season you just sand lightly and roll on one more coat?

 

[Warren]

Ablatives, III

Mark:I have never owned a new boat or one that had to be painted directly over the gel coat, so I'm not able to give you much of an answer about applying bottom paint in those instances. I think there are some pretty definitive directions on surface prep on the paint can, however. I seem to recall that the key is making sure the surface is free of any residual waxes or blushes before painting. Check info on the can. I do apply only ONE coat of Interlux ACT on my boat, and directly over last year's paint. I now only do minimal prep of the surface: light sanding here and there where needed to make sure the surface is well adhered before painting. If I have any sanding residue on the boat, I "wash" it off with the recommended Interlux special paint thinners (I think its "213", but not sure -- its on the paint can too). Hope this helps.

 

[David]

Paint Peeling on Keel

I have Micron CSC over a barrier coat (2000) on an '82 C30. In one spot on the keel side, there is a 4" diameter circle of fairly thick CSC that is peeling off. Underneath there appears to be an older coat of same. If I simplly sand lightly and repaint the keel surface will not be that flat. What should I do? Is it customary to barrier coat the keel or just the fiberglas hull?Other than this issue, I've been pleased with CSC (Only had the boat one year).Thanks!

 

[Dale I]

Zinc's vs. Bottom paint

Well, I followed the instructions on the can and held my CSC back the recommended 2" from the zinc on my prop shaft....why, I don't know...and why they'd recommend that, I also don't know, but after 10 months the only hard bottom growth that was seen on the first bottom scrub-down was the wreath-like structure on either side of that zinc and the interiors of thru-hulls, which I had neglected to cover.There was some minor slime accumulation, but it lifted with a light brush down....CSC gets my vote.