"Best way" to antifoul?

tom_sail

tom_sail

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It's Getting towards that time of the year. I'm looking to buy a few tins of antifoul this week.
Now this will be the first time I have antifouled this boat and don't know what the previous owner used. (he's currently somewhere around the world in his new to him boat. So not a simple phone call)

The current anti foul is a light blue very hard wearing. No signs of it being in the slings at all and I can't rub it off with a finger.

Let's imagine it's international antifoul I don't want to paint hemple over it in case there's a reaction.

Shall I paint a coat or 2 of primer as a barrier then paint new antifoul onto that?

I would like to scrub of on our drying mooring can anyone recommend a suitable anti foul?

Thanks

Tom
 
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tom_sail said:
It's Getting towards that time of the year. I'm looking to buy a few tins of antifoul this week.
Now this will be the first time I have antifouled this boat and don't know what the previous owner used. (he's currently somewhere around the world in his new to him boat. So not a simple phone call)

The current anti foul is a light blue very hard waring. No signs of it being in the slings at all and I can't rub it off with a finger.

Let's imagine it's international antifoul I don't want to paint hemple over it in case there's a reaction.

Shall I paint a coat or 2 of primer as a barrier then paint new antifoul onto that?

I would like to scrub of on our drying mooring can anyone recommend a suitable anti foul?

Thanks

Tom
Click to expand...

Hi Tom

If you use for example International Paints Primocon primer this also acts as a barrier paint and you can put any make of antifoul over it.

Mike
 
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Personally I'd go with the barrier/primer; that's what I did on KS. I prefer Jotun products, so used their VinyGuard SilverGrey as a barrier coat over whatever the previous owner had used. It went on very easily and dried quickly - I think we might have put two coats of primer and two of antifoul on in one day, though it's possible I'm misremembering and actually did one of the primers the previous afternoon.

Of course, I have a small boat so each coat is cheaper and quicker than it would be on something bigger. If each layer is a major job one might be more inclined to investigate compatibility.

Pete
 
As above, the safest option would be to apply an primer coat and then paint on the anti-fouling of your choice. However unless the previous anti-fouling was teflon based (e.g. VC Offshore extra or VC17m) then I would be tempted just to abrade the old coating and then apply the new paint on top as most other paints appear to be compatible with each other.
 
If your boat is GRP it is worth spending the time and stripping it back to the gell coat. I did it four years ago and never regretted it. Smooth as a teenager's face now. I put on a tin of one-coat before lift-in and most of it (75%) goes in the season. Three or four years and I'll do it again.
 
Thanks for the answers. Obviously there's only one "best way" :D and that's to prime it first :)

I'll try buy a scrubbable antifoul then paint an inch square over the existing antifouling. And see what reaction takes place if any. Im thinking I may scrape back to the gelcoat. It's getting a tad rough in places I can then check over the hull and maybe borrow a friends moisture meter just to be sure :)
 
prv said:
Personally I'd go with the barrier/primer; that's what I did on KS. I prefer Jotun products, so used their VinyGuard SilverGrey as a barrier coat over whatever the previous owner had used. It went on very easily and dried quickly
Click to expand...

+1
 
A/F paints don't react to each other as badly as they used to. If you want the economic answer, paint a bit of your chosen jollop on somewhere well below the water line, and see if it reacts. If it does, then use a primer (Hemple's is as good as anything else). If it doesn't, omit the primer and go straight to your jollop.
 
Do the experts on here consider it odd that the AF doesn’t rub off? I’m guessing that the boat is a yacht, in which case would it not be likely that an eroding AF would have been used? The other alternative could be coppercoat which is hard and non-eroding as described in the OP.
What condition was the hull in when it was lifted, was there much fouling and did it wash off easily?
 
Baddox said:
Do the experts on here consider it odd that the AF doesn’t rub off? I’m guessing that the boat is a yacht, in which case would it not be likely that an eroding AF would have been used?
Click to expand...

Mine is non-eroding, because otherwise the mud would erode it twice a day until there was none left. The OP is on a drying berth so will presumably be applying new non-eroding. We don't know where the previous owner kept it, but since it's a boat that can take the ground, perhaps he did the same, hence the hard antifoul.

Pete
 
Antifouling

It is most likely a hard a/f paint designed to be cleaned by rubbing. I would buy a similar hard racing type a/f and slap it on over the existing paint. Give the old stuff a rub with wet and dry sand paper.
For me in different circumstances I don't take the a/f too seriously. I use what is apparently a soft a/f paint but it only lasts about 6 weeks before it needs a wipe over and now after 2 months patches are showing where I have rubbed it off. It will mostly be gone in 2 more months. You will need to do it all again next year so why worry so much. (now 29 th year of a/f on same boat)
(different circumstances mean 35 degree temps warm water and I often end up wiping it over 3 or 4 times per week. Obsessive perhaps) olewill
 
Baddox said:
Do the experts on here consider it odd that the AF doesn’t rub off? I’m guessing that the boat is a yacht, in which case would it not be likely that an eroding AF would have been used? The other alternative could be coppercoat which is hard and non-eroding as described in the OP.
What condition was the hull in when it was lifted, was there much fouling and did it wash off easily?
Click to expand...

Yes the boat is a bilged keeled yacht which drys out twice a day on muddy sand. When the boat came out of the water there wasn't any fouling and I didn't scrub anything last season just around the boottop. The a/f stills looks brand new on the GRP hull and a bit patchy on the keels.
 
I too am having a similar problem - the idea of a test patch appears a good one - I presume the reaction will occur whether its in the water or not ? I only got my Mobo last year but when I pulled it out it was a nice black slimy colour underneath - jet wash soon took care of that but I suppose this suggests the antifoul needs to be redone ?:confused:
 
dodgey rascal said:
I too am having a similar problem - the idea of a test patch appears a good one - I presume the reaction will occur whether its in the water or not ? I only got my Mobo last year but when I pulled it out it was a nice black slimy colour underneath - jet wash soon took care of that but I suppose this suggests the antifoul needs to be redone ?:confused:
Click to expand...

The "reaction" is more a lack of adhesion that anything chemical with a satisfying bang at the end
 
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