antifoul question

[Stevie_T]

This is the first time I have had to do it myself.
I have no idea what the existing a/f is, I have sanded down lightly and wish to apply a single coat of soft a/f as I am only in the water for 6 weeks this year.
What is the likelihod of a mismatch with the old a/f and how bad a problem is it likely to be? Should I bother to paint on a primer?

Thanks
Steve

 

[savageseadog]

You probably shouldn't have sanded it, it's poisonous, hope you didn't breathe much of it. If you're only going in for 6 weeks it might not be worth bothering.

 

[PeterGibbs]

Like different makes of mineral oils in car engines, antifouls almost always tolerate and so adhere to each other. Go for it, a roller is easiest, once all over and double for the first foot below the waterline - that's where the late season weed will try to adhere (cos more sunlight there)

Next time, only scrape loose flakes off with scraper used at a distance - ie on a pole or handle - or suppress dust with damping down. If you've got antifoul in your hair/hands/face it's not good news! Old paint as well as new!

PWG

 

[Stevie_T]

Thanks Savage and Peter
Shouldn't have breathed much in, used a respirator, though I guess I caught some when I took it off. Oh well next time I know.
Okay I will just stick one coat on and as you suggest a second near the water line.

Thanks again

 

[Pye_End]

Would hate to throw in another point of view, but taking off a layer of half-flaking antifoul if it doesn't stick is a pain. Most of them seem pretty compatible, but not all. I think I would try to find out what is on there already, and if you are can't then personally I would re-prime.

 

[mandlmaunder]

recently did ours- decided to do proper job by taking all the old A/F off took a few days , but will be worth the effort in the long run as all A/F is now a known quantity and quality, so next time we can just wash down and go for it .
Used chemical stripper to remove vast majority of old A/F,
worked well. Check where you are doing any A/F work as everywhere has different rules on what you can and cant do re removal and disposal. we are in caribbean and each country and even individual marina yards have a list of do's and dont's.
the yUK is stricter than many.

 

[PeterGibbs]

Hannabella,
One PS - a small tin of antifoul primer splashed on where the old paint has flaked off will give good adherence for the antifoul. Well worth the effort - Blakes is cheaper usually than International.

Oh, and quality of antifoul is not proportionate to price - something that the bretheren don't want to hear....

For the future: removing all the antifoul to achieve a "smooth" finish is perhaps justified for racing boats, but it's otherwise a hobby for those perfectionists who don't actually get much time in on the water, so don't learn that it doesn't make a blind bit of difference to passage times! (because they carry so much rubbish in their boats that skin drag is as nothing to being 3 inches down on the waterline!)

Shhhh.... don't spreaad it around - folks can get a bit upset at these comments!

PWG

 

[richardabeattie]

I crack and rise to the antifouling challenge again! If you have a bilge keeler that can dry out, and if you don't race then why antifoul? It's expensive, it's hard work, and it's generally ineffective. I haven't antifouled at all for the last 15 years. I pressure wash when I haul out for the winter and then once each summer I dry out on a sand bank and spend a whole half hour scrubbing off with the back of a broom.

 

[oldharry]

I have found it very odd that some boats you can get away with quite severe fouling without affectinbg the speed much, whereas others can lose up to 40% speed with just a little fouling. I had a small motrsailor and it really wasnt worth bothering. 6kts clean, 5.8kts badly fouled. The next boat - 6kts clean, 4knots fouled.

It makes a lot of difference where the boat lives. A fresh or semi freshwater marina will produce far less fouling than a half tide mud bank (like mine!). The boat sits in a sea of mud at LW, and fouling thrives on it! If I didnt anti foul I would be in for a major scrub-off every 3 or 4 weeks during the summer.

Only Tiger Extra is strong enough to keep it at bay! Most other AF's are a waste of money in my corner of Chi, while International Bootopping seems to actually encourage growth!

 

[Richard10002]

As I've said, I have a growth of short grass/weed all over the hull, which is fairly easily rubbed off with a sponge.

However, in a couple of places where the antifoul has flaked off back to the white of the GRP, (presumably), no growth.... no grass, no barnacles, no nothing - what's going on there?

I can kind of understand the grass - the boat has mainly sat in Lagos Marina from September till June, with only the odd afternoon out until Yachtmaster prep and the current trip, so the antifoul hasnt really had a chance to erode and drop the grass off before it got a hold - I think that's how Cruiser Uno works?