Newbie Antifouling Questions

CaptainBob

CaptainBob

Well-Known Member
Joined
7 Nov 2007
Messages
1,477
Location
North Yorkshire
www.yacht-forum.co.uk
Hi,

Antifouling... my yacht has some on it that's been on it for circa 12 months while it's been out of the water. I'm told I need to add some before going back in the water.

Questions:

1. I was told by the previous owner that I should sand down the current surface prior to applying a single new coat. Is this good advice? If so, what paper type/grade should I use? And will I need just the one coat of anti-foul?

2. Is Blakes worth the extra? There's other cheaper brands out there.

3. What's the best way to apply it? Small roller? Any tips on how to avoid getting in a right mess?

4. Do I need to apply the anti-foul within some time-limit before getting in the water?

Anything else I ought to know? (I know nothing)
 
1. Scrape off any loose. Sand lightly to provide a key. (Wear filter mask, nasty stuff)

2 Depends. Opinion is mixed, but most seem rubbish. Depends where you are moored. Cheapest works for me.

3 I've used a brush and a short pile mini-roller. Try both, they're cheap enough to discard if it ain't working. Roller gave better coverage.

4 It should say on the tin or in the specs what are the immersion times.

That's my opinion.
Someone will be along shortly to contradict me.
 
Don't want to contra dick young LS, but the only additional thing about antitfouling is that you should not just hose away the scrapings etc into the nearest drain. It is, after all, a poisson poison (and many other things too).

Professional painters have to dispose of the stuff as regulated waste (or they should do /forums/images/graemlins/grin.gif)
 
Remove the log paddle wheel if necessary.
Sand hull wet with coarse wet & dry to keep the dust down.
Rinse with fresh water and allow to dry.
Stir the tin very thoroughly - use electric drill/stirrer at slow speed.
Most A-fouls recommend roller application.
Wear gloves and overalls.
If there is any left apply to waterline and leading edge of keel and rudder.
If you use a different colour it helps to see coverage.
Masking tape on the waterline - remove it soon or it sticks for ever!
 
First question

Is the antifouling hard racing type or soft eroding type. Usually the eroding will come off when scubbed with a pan scourer and lots of water.

If eroding clean and another coat or 2 of same using an old 2" brush for the awkward bits and an emulsion radiator roller for the rest.
If hard type scrape off to smooth and replace with same. Tends to be hard type if boat dries out on mooring
Air time is as specified on tin, Hard types have a longer air times.
Sanding is not good as high toxicity, use a good mask and goggles as well as gloves etc.
As to whether they work......... in a mud mooring nothing does.
 
In the autumn:
1. Give it a good going over with a stiff brush and lots of water or a D.I.Y pressure washer. Don't let anyone lose with an industrial one (Nasty things that rip perfectly good antifoul off)
2. Sand / grind any rust out of the keels. Then rust kill and first coat of underwater primer in same day
3. Lightly sand, especially around the water line. Use wet and dry and / or those sponge sanding pads. Then make absolutely sure you have got all the sanding residue off the hull (It looks similar to good antifoul when dry!!) I do this with the pressure washer. If you dont get it off it will be a nightmare next year, trust me I know through experience!

During the winter:
Another coat of primer on the keels everytime you visit till 6 coats (Dont be tempted to shortcut on this)

In the spring:
1. Masking tape then antifoul the water line + anywhere else where the antifoul was stripped off. (Fouling is greatest where the sun shines)
2. Personally, I use a roller. Beware of fluff for first 5 mins. Try to avoid antifoul dripping down your arm when applying to the underside!I buy a cheap roller and tray and scrap it at the end of the job.
3. If you can, touch up under the keels as it is lifted into the water. I missed this step last year and paid the price

My antifoul says max of 3 months before launching. Even if it didn't I would wait till the spring!
 
Hello

I use blakes ocean performer in Chi Harbour which is pricey but one coat does 6 to 7 months with minimal growth and works out only a bit more than 2 coats of cheap. It's currently available from a number of south coast chandlers at 1/3 off. I do use 2 coats around the waterline and use a 4 inch foam roller on a long handle.

having seen the gardens that have grown up on friends boats using cheaper ones my advice is "its better to use one coat of good stuff than 2 of cheap".

(Incidentally the blakes comes in 2 cans but is still an erodable antifouling - some people assume its a hard one.)

I would agree that if you're on a drying mooring the only real solution is a hard anti foul or copper coating (ouch)
 
Repeating most of what has already been said:

Clean it down thoroughly with water and a stiff brush (I find with old dried on mud and fouling a little washing up liquid added helps if you are using a bucket)
(Excellent for cleaning off is a bit of an industrial floor scrubber pad... like big Scotchbrite)
As said scrape off any loose and dispose of scrapings responsibly ( ? )

Sand WET if you feel it needs it ( but not worth the bother IMHO) with a fairly coarse paper.

Apply the new stuff of your choice (best to use what ever the locals prefer probably ) with a small roller, and brush for any awkward bits, after masking off at the waterline. Good round coat(s), don't try and spread it out too far. If you are overcoating an "unused" coating one coat will be enough. Check the compatibility of the stuff you are applying with what is already on their (use the same again if you can) and follow the manufacturers recommendations for any special treatment.

Read the AF manufacturers recommendations (online for International and Blakes)

Also look at the manufacturers websites for advice before choosing your AF
 
If the existing coating is in poor condition, with lumps, crazing, flaking-off bits, it is worth scraping down before applying new paint, just as you would with any painted surface. Although I don't subscribe to the theory of the incredibly toxic nature of antifouling, it is undoubtedly nasty stuff to get into the lungs, so any measures taken that do not create dust and draw it away before reaching your mouth are to be recommended.

I have used the scraper tool that attaches to a vacuum cleaner with some success. It is basically a tube, with a scraper at one end and of suitable diameter at the other to connect to the vacuum cleaner hose. They are sold by many chandlers, mostly seem to be yellow, and have a hardened blade at the business end. The corners of this blade are very sharp and can dig into the hull very easily, so I grind them off with an angle grinder. I find that it is quite difficult to keep the tool attached to the vacuum cleaner when in the full flush of scraping, so I put a short length of old bicycle inner tube over the joint and either connect ewith hose clips or some soft wire.
 
Cheers for the advice.

Priming has been mentioned above... I assume this is something I need to do whenever sraping back the anti-foul to the gel-coat? As my existing layer of anti-foul seems basically sound, I just need to sand it, right?
 
It's not a technical paint finish and it's not for the next 20 years.

It's just a growth inhibitor to slow down fouling. (sometimes)

Just daub it on. Next year you'll see if it worked when you haul out.
 
[ QUOTE ]
Cheers for the advice.

Priming has been mentioned above... I assume this is something I need to do whenever sraping back the anti-foul to the gel-coat? As my existing layer of anti-foul seems basically sound, I just need to sand it, right?

[/ QUOTE ]

No. You need to understand what the existing antifoul is before you know waht to do with the new. All A/F's give a "compatability" grid on their web sites, so you klnow whether you can over coat A with B, whether you have to sand down A before overcoating with B, whether you have to prime before, or even whether you have to fully remove.
 
I couldn't agree more, the stuff is pretty mild nowadays and considering its effectiveness per cost, is probably the worst value of anything you can do to your boat. That doesn't change the fact that accumulated coats tend to flake off, form lumps and pits and even blisters. Scraping down is needed from time to time, even on the minimum-effort boat.
 
You must log in or register to reply here.

Share this page

Top