Stretching Antifouling

Gunni · May 17, 2017

No. What kind of antifouling paint are you using? Ablative or hard AF? Many ablative do not need to be reapplied, just touched up.

Don S/V ILLusion · May 17, 2017

You might be the first to try that.

My guess is that the carrier solvents are different making it impossible to create a homogeneous mix which likely will result in uneven distribution of the antifouling.

You would be better served by simply diluting the antifouling with the same or compatible carrier solvent and put two coats of the diluted mix. Or just buy some cheap antifouling paint.

rgranger · May 17, 2017

I see you have a 25. Are you trailer sailing or leaving it in a slip? I feel that trailer sailing does not require anti-fouling paint at all. If leaving in a slip... what @Gunni said.

Rich Stidger · May 17, 2017

I vote for a touch-up. Mixing potions could cause problems far worse than the expense of more bottom paint IMHO. Speaking of frugal, I have for many years IGNORED the bottom paint instructions to apply two coats with a 3/8" roller. Instead, I apply one coat, just as thin as I can and still cover, with a 3/16" roller. I paint every year after sanding and a solvent wash, and I do not get build-up that will eventually chip and flake. This year I used 3/4 gallon on my 40 foot sailboat, but depending upon the individual paint, I have used as much as 1-1/8 gallons. Prior to this procedure, I applied two heavy coats per the manufacturer and had terrible build-up and massive chipping.
This is just a suggestion for future planning.

plenny7 · May 17, 2017

The application instructions for the ablative paint I used, Pettit Vivid, indicates that you can add up to 10% thinner. I did this for my second coat and I think I got more than 10% additional coverage with that 10% thinner.

shemandr · May 17, 2017

I've never kept a boat in FL but around here I have gone two seasons without re-applying ablative paint and two seasons with hard paint (Not the same boat). I do clean the bottom regularly during the season. As said above you could just touch up where the paint has worn thin, typically the leading edge of foils and hull.

Siamese · May 17, 2017

Sounds like rolling the financial dice. If money's tight, why put it ask risk? If your paint mix doesn't work well, the fix will not be fun or cheap.

Warren Milberg · May 17, 2017

I do exactly what Rich Stidger describes above: One thin coat of ablative (I use Hydrocoat) using a smooth 3/16th roller each year. No fuss, no muss, no sanding, no buildup. And no hardgrowth on the bottom. Water based Hydrocoat can be thinned a bit with plain water. A half gallon should be plenty for a 25-ft boat. Figure the amount you need this way (most gallon cans of bottom paint typically cover 400 sq ft): Length at waterline x max beam x .85.

Davidasailor26 · May 17, 2017

I don't think any good could come of mixing the antifouling with topside paint. The risk is more than just losing the antifouling properties - if (when) it doesn't work you'll have to sand off all the topside paint on the bottom. Half a can should be plenty of thinned with the proper solvent. Use a 3/16" roller as other as others have suggested to get a thin coat. Start with the leading edges and waterline. If you run out getting to the bottom of the keel or some other out of the way place then the existing ablative will probably still work.

capta · May 17, 2017

Antifouling paint has a shelf life. I'd get the product data sheet before I applied it to make sure you aren't just wasting your time putting on paint that won't antifoul.

agprice22 · May 17, 2017

Do not mix them. They are two different paints. The topside paint may well FEED the very organisms the antifouling paint is trying to prevent. Additionally, topside paint is definitely not formulated for use below the waterline.
I also agree that 1/2 gallon is enough for a 25 footer. If you find that it evaporates and dries fast in the roller pan, try putting the paint in a squirt bottle and squirting it on the foam roller.
You should powerwash carefully and look for thin spots where you can see the Interprotect through the paint. Those are spots on which to focus. I get multiple seasons out of VC17m with a powerwash and some touch up. I realize you aren't using VC17m, but the idea is the same.

Terry Cox · May 17, 2017

Just got my annual diver report where he says that the two coats of ablative that I applied six years ago is thinning. He did his usual checks, scraped mussels off the keel and a few barnacles from the bright work. Shaft, strut, prop, though hulls, rudder and speed transducer all in good condition. Belle-Vie ready for another season of sailing around PNW waters with new shaft zincs.

All U Get · May 18, 2017

Sitting here in Beaufort, NC I just had the bottom cleaned. While doing so I asked the divers about growth in this area. "Oysters and Barnacles depending on how close you are to the bottom." was their reply. "The next marina over has more algae and other growths." In Plymouth your needs will be different than what I get in Maine. Talk with a paint rep at a boat show and ask about performance specific to your area. Better yet would be a local diver that's cleaning boats in the water. I've used left-over paint on our former boat to touch up leading edges and had good results. Now I'm using white over a green signature coat. When the green is showing, it's time to paint.

All U Get

jibes138 · May 18, 2017

All U Get, curious what brand of paint you are using that comes in white? I paint my rudder white so it doesn't get as hot when baking in the sun when the boat is on the hard, and makes it easy to see if it is clean or not. I have only found Vivid in white around here. I just get a quart since it is just the rudder but a quart is over a hundred bucks with tax.

Ron20324 · May 18, 2017

For you Annapolis skippers, The Hillsmere True Value Hardware on Forest Drive has a good close-out sale on Micro bottom paints. They really cut back on their boating stuff, so maybe they will not carry paint after this sale?

Chief RA · May 18, 2017

My hull has ablative paint and it is a trailerable used much as Plymouth uses his. I definitely need bottom paint. I spray with fresh water when boat comes out in the fall, remove any loose growing grass and do NOT scrub the hull and remove the slime and a part of the ablative paint as well. My hull bottom has not been repainted since 2012 and is in great shape. My contention is the dried slime becomes a retainer for my ablative paint and in some way helps it oppose long growth as well as barnicles and other varment attachments. It appears that I am not losing much or any of my ablative paint. The only part of my boat that gets much long growth is the rudder. Chief

Rich Stidger · May 18, 2017

jibes138 said:
All U Get, curious what brand of paint you are using that comes in white? I paint my rudder white so it doesn't get as hot when baking in the sun when the boat is on the hard, and makes it easy to see if it is clean or not. I have only found Vivid in white around here. I just get a quart since it is just the rudder but a quart is over a hundred bucks with tax.

I used to do this but now I paint with my blue bottom paint. When on the hard, I cover the rudder with a piece of white shrink wrap that would have been recycled anyway.