I need an education in ablative bottom paints

[Paul Moir]

For years now we've been using a hard, traditional antifouling paint on the bottom of my brother's Shark. Although it has worked very well, I'm getting tired of the sanding and repainting. We've been sanding down hard every two years and recoating every year.
Am I a fool not to be going to ablative? Do I understand correctly that the maintenance for these coatings is to give the boat a scratch sanding and re-apply yearly? If so, what are the disadvantages? Is there much work in switching? As far as I know, there's no barrier coat but we've never had trouble with blisters or anything.

The boat is tied up for 7 months of the year in a heavy fouling location. The rest of the year it's laid up. The fouling should be getting a lot better soon as the harbour's sewage diversion project progresses. We don't bother burnishing the hull or anything although we do race it for fun.

I thought that the Sailing forum makes more sense than the boating forum in this case.

Thank you.

 

[tommays]

Re: I need an education in ablative bottom paints

I allways used standard bottom paint

There were plenty of people in my fleet that had the money to have Micron-22 sprayed and 400 grit wet sanded

They both required regular brushing during the season to keep the bottom race clean

The only people that had a real speed advantage had the bucks to go for a full bottom, keel and rudder failing job

C&P
Special multi-year bottom paints claim to end the annual ritual of painting the bottom of your boat. Do they? The answer is yes, although multi-year paints are not for everyone or every application.

Lakeland Boating applied International Paint's Micron-22 to the bottom of a test boat in the spring of 1982. The boat, Sea Gull, is owned by LB Senior Editor Dave Brown. He says the original paint is still on the boat after four seasons, although in some spots it is growing noticeably thinner. Repainting will not be necessary for the 1986 season, but will probably be necessary for 1987.

"Micron-22 does not seem to prevent slime buildup when the boat is sitting in the dock as well as some conventional paints," Brown says. "But, sailing for an hour or so seems to scrub the slime off and leave the paint clean of growth.

"Micron-22 is subject to the same physical damage as other paints. We always scrape some off with the slings when hauling or launching Sea Gull. I repair the damage each spring by spot painting the damage.

"Getting the bottom ready for launching takes about a half hour," Brown says.

Micron-22 is designed for professional installation only, but International also offers Micron-33 for amateur application. Pettit Paint's Horizon brand of multi-year paint adds copper biocide in addition to tin. Pettit claims this formula helps fight marine growth on boats that sit still in the dock for long periods of time.

Tommays

 

[Paul Moir]

Re: I need an education in ablative bottom paints

Ok, it's taken all weekend but I think I've got my brain wrapped around the idea that hard anti-fouling isn't so bad.

I take it an orbital sander is the best way to attack the bottom? Chemical strippers not worth it for only a couple layers of bottom paint?

 

[tommays]

Re: I need an education in ablative bottom paints

I think the issue is controling the sanding so the gelcoat is not dammaged which could make it easery for the blister deal to start

With the right stripper you dont need to worry about the Hazmat issues with bottom paint dust flying around


Tommays

 

[flashback]

Re: I need an education in ablative bottom paints

I've used pettit for years and have had good results. The last time, (1year ago) I used pettit trinidad SR. I'm in freshwater so slime and alge is the problem.. so far so good....will see how long it lasts....

 

[Paul Moir]

Re: I need an education in ablative bottom paints

I've been using Interlux BottomKote (not XXX or ACT) and it's worked as well as I can expect. Slime but no actual nasties. But I'm thinking of switching to Petite since it's got such a great reputation and is a lot less money. Frankly, a coat is just over a quart so it's not really a big deal.

How much stripper do you need? I know it really depends on the boat, how many layers you've got to strip, etc, but anything to go off of would be better than nothing. Everyone around here seems to sand off. So far I've been avoiding the gel coat by only sanding into the last antifouling coat, which is a different colour.

 

[tommays]

Re: I need an education in ablative bottom paints

If your doing good with the sanding go with it

Down here the dust is a bigger issue as there are so many boats in a small area and many boat yards have become HAZ-MAT sights from the years of older more toxic paints

Tommays

 

[Paul Moir]

Re: I need an education in ablative bottom paints

Ok, will do. As I understand the cuperous oxide based paints are not really very bad. But I think I'll rig up the shop-vac to the sander. At least I won't look so much like a coal miner when done!

We managed to get decent wind for the last race of the year. Haven't seen much of anything since July.
http://www.dyc.ns.ca/user/File/2006_Chinatown_Race.htm
We're starting to get a little better at this... Or perhaps just a little luckier.

Thanks again flashback & tommays!