Bottom Paint?

BCC Forum
1

I apologize for the newbie question - we’re starting prep for spring bottom painting and just wondering how many gallons it should take per coat on a BCC for some ablative?

Thanks for the help!
Mike

2

I work on the following principles:

  1. Wetted area is about 24 sq metres (of course that depends on where your waterline is, i.e. whether you’re at lightship displacement or liveaboard displacement, so that’s all in the YMMV department)

  2. to last 18 - 24 months of sailing in tropical temperature seas, I want a total thickness of coating of 200 microns (micron = micrometre; I think 200 microns would be about 0.01 inch, but when I type that it looks wrong) of an ablative antifouling.

  3. a shag roller will lay a coat of about 125 microns wet (but that dries to about 63 microns). I prefer to use a yard with a good spray painter who can accurately lay a wet 200 micron coat, using an airless sprayer, that dries to 100 microns. That means I aim for either 3 coats if I roll on or 2 coats if I use the yard’s spray painter.

  4. so (using my usual poison of International Micron Extra) I work on 2.5 litres for one coat (if rolled) and a total of 7.5 litres (for three coats. That’s a little inconvenient, because locally Micron Extra is sold in 4 litre and 10 litre cans (but the yard deals in bulk). When we’re doing it ourselves, we’ll buy 2 x 4 litres and put extra coats on the waterline, leading edge of the rudder etc. Stir muchly. And if one hand is spraying, I like the spare hand to spend much of their time stirring. No point leaving the heavy stuff in the can.

3

I would like to say it is one gallon per coat although that is a bit of a stretch.It would require rolling it on pretty thin. I always use 4 gallons which is plenty for 3 good coats. I use Interlux Ultra which I have been very satisfied with in the tropical Hawaiian water.

BCC 97 Ho’okahiko
Kaneohe, Hawaii

4

Thanks for the help all.

As a note - we took the old paint down pretty far and put on 2 coats of JD Select Ablative (from Jamestown Distributors). Each coat took ~ 3/4 of a gallon.

I don’t think we put it on too thin, but we’ll see how well it lasts. We’re in Deale, MD (mid-Chesapeake) so not too demanding as far as fouling conditions go.

Cheers,
Mike

5

I also just finished doing bottom paint. I have had issues with previous paint being somewhat loose when sanding or pressure washing the bottom. It was determined I had way too many previous coats of paint affecting the newer paint. So all the old paint was removed with a grinder, not an easy job! A barrier coat was applied followed by bottom paint. This time I used 3 gallons which gave me about 2 1/2 coats allowing extra along the waterline.

Ron

Ho’okahiko 97

6

Mid Chesapeake is possibly the one of the worst spots on the Bay. Although I have harboured in Annapolis, I have never spent much time in Deal. However, you are at the “salinity line”. Where fresh water and salt water mix frequently, expect to be plagued by barnacles and tiny muscles.

All I can tell you is that it used to cost $50 per month for a diver to clean the hull, so that my boat could sail.