Removing Anti-Foul with success !

[Richard_H]

Hi Everyone
Just attempted with some intrepidation the dreaded task of removing antifoul back to gelcoat. Tried several slow methods of scraping and peeling with poor results.
Eventually tried a domestic presure wash to soften topcoat and then used an angle grinder with a semi flexible wire brush with twisted strands. To my joy this made short work of many years fouling and took it off right down to gel or bare hull without damage. My friend and I managed to completely clean a 28foot Moody in les than a week-end. Never believed we could complete so early in the season!
I believe you can buy the wire brushes for your angle grinder from Machine Mart stores. ps. Suggest you wear a mask and goggles as it gets everywhere.

Need advice now on what best to put on my nice clean hull!

Regards

Richard h.

 

[Guest]

Question: Now that you have removed all that bottom paint (anti-fouling), and may have disturbed the gel coat, are you planning on first painting the bottom with an epoxy barrier coat?

Also, I would respectfully suggest that anyone "sanding or grinding" anti-fouling paint off of a boat wear not only eye protection but also a full body suit ...like coveralls, and also a respirator....not just a face mask.

Many bottom paints (anti-fouling) contain "cuprous oxide" and other "human unfriendly" chemicals that are rather hazardous for humans. The same procedure should be used when applying the bottom paint....the fumes can be deadly.

 

[longjohnsilver]

Yes agree with above, remember a recent post from some one who had suffered permanent health problems from not taking correct protection when removing anti foul.

Respirator a necessity.

 

[ccscott49]

I agree with above, you should never dry sand or grind antifoul, apart from yourself the stuff blows everywhere, wet blast the stuff or scape and hoover jobby! I still say wet blast. I avoid like the plague boat yards where people are sanding the stuff! ugh!

 

[rogerroger]

what are you supposed to do about the bits of the hull under the supports? (mine's sitting on about a dozen wooden posts)

Roger Holden
www.first-magnitude.co.uk

 

[ccscott49]

Remove and replace them one at a time, carefully!!!

 

[Guest]

I posted this question a while ago entitled 'Sky Hooks', in essence, dangle the boat form its chainplates or toerails. Had some interesting responses like; hire a Chinook and crew, turn the boat upside down etc. Funnily, a little while later, one of the mags published an article showing boats layed up and dangling to ease access.

 

[rogerroger]

Does it have to be removed?

Do you need to remove the anti-foul each year before re-applying or can this be done every other year for example.

I bought my boat last March and paid the boat yard to anti foul her as I couldn't be bothered (frankly)... I'm sure they just painted over the old stuff.

Can I not just do this?



Roger Holden
www.first-magnitude.co.uk

 

[ccscott49]

Re: Does it have to be removed?

If the old antifoul is well stuck on, theres no reason to take it all off just a light WET sand and apply new, unless of course its really thick and you want a very smooooooth bottom!

 

[rogerroger]

Re: Does it have to be removed?

why the emphasis on "WET" sand ? to keep down dust for safety reasons?

so spray with water then sand with fine glass paper ?

one always like a smooth bottom of course - but then don't really want to comitt to a whole weekend doing it!

Roger Holden
www.first-magnitude.co.uk

 

[Guest]

Re: Does it have to be removed?

Any reason why one cannot use a pressure washer that mixes grit with the water? That way dust is avoided and hopefully a lot of hard work.
regards Spits

 

[ccscott49]

Re: Does it have to be removed?

Yes, for health reasons and not just yours, you cant use normal sandpaper wet, the glue is water based and it falls to bits, use wet n' dry paper, this comes in all the usual grades. If you want a smoothish bottom, just scrape off the loose, sand the rest and get the new slapped on! (carefully)

 

[ccscott49]

Re: Does it have to be removed?

Perfect system, be careful with it, don't want to go through the gelcoat, I haven't seen one of the wet sandblaster attachments for a pressure washer for some time.

 

[Miker]

Can\'t you just slap the new antifouling over the old?

Four years ago when I first took my boat out of the water I tried sanding the bottom with wet and dry after a good wash down with a pressure washer but it was a hell of a job - continually having to dunk the sandpaper in a bucket of water. I gave up for the sake of my health and settled for only sanding around the loose bits and then painting these areas over with primer. Two years ago I changed to cheap antifouling which flaked off badly so last year I went back to International which again has stayed on.
I had thought of taking the antifouling off with slurry blasting this winter but I reckon that I can get away with another year. The underside of the boat is getting a bit like the surface of the moon in a few places so eventually, I suppose that I will need to take the old antifouling off. Perhaps next year!

 

[rogerroger]

Re: Can\'t you just slap the new antifouling over t

this was kinda the question I was trying to ask but didn't want to appear (too) stupid...

I've spent too much time on my house stripping windows and doors back to the wood to re-paint to want to do it with my boat!

Roger Holden
www.first-magnitude.co.uk

 

[pvb]

What to put on your nice clean hull

If your style of sailing allows it, use an eroding antifouling such as International Micron. As it naturally dissolves in use, it minimises the build-up of antifouling over the years. It's also possible to clean the residue off the hull fairly painlessly by wet-sanding with a nylon pan scourer and a running hosepipe. (Use gloves, goggles, mask).

I have a theory that most people put too little antifouling on. I know it's expensive stuff, but the associated lift-out and relaunch is also expensive. Instead of the annual antifouling ritual, I give my boat at least 3 good coats of Micron, using a brush not a roller, every 2 years. This has worked well for the last few years, although the boat is based in a locked marina so probably benefits from the generally poisonous water.

 

[ccscott49]

Re: What to put on your nice clean hull

I agree about not enough antifouling! I buy 25 litres evry two years and put the lot on, two coats and then more on waterline, bows etc until its all gone, I dont have fouling problems anywhere, jotun antifoul normally, its what the fishermen use, where I buy it! Not from the chandlers, fisher supplies, but you have to buy a 25 litre drum!

 

[robp]

It really isn't a good idea to consider moving any of the props. I know you said "carefully" but a boat went over the season before last at our marina. Many marinas (probably most) absolutely forbid any movement of props.

Leave the remains of the pot and ask that the bits are filled in when in the slings on re-launch. They'll do it for you.

 

[ccscott49]

Put another prop close to the one you want to remove! However most yards will move the props for you if you ask. At galmpton creek, Dartmouth, (MDL) one move of props is included in the lift out cost, they are aware we need to move them. Antifoul put on just before launch, ie, 1/2 hour has a tendency to wash off, when launched, not a very satifactory way of doing things, but go ahead if you want to, I don't.

 

[Guest]

If you use a hard epoxy type of anti-fouling such as Pettit Trinidad, you can lay on three coats with a roller and another coat at the water line and you may get as much as three years out of a bottom job. I do that and get three years here in Florida. I have a diver clean the waterline and keep my prop and shaft clean of growth as they are not painted.

If you don't want a buildup of paint, use an "ablative or sloughing paint". It slowly wears away as the boat is used and they tend to have less biocides in them as the motion of the boat in the water produces the cleaning action. Some of the paints like Interlux's Micron CSC are "multiseasonal".

One thing you may wish to consider for your propshafts and props...if it is available in the UK or elsewhere is a product known as Interlux Veridian. There is no biocide in it at all. It is a liquid teflon coating that was designed for powerboat outdrives and such. The product makes whatever it is applied to.....too slick for anything to adhere to, including barnacles and other marine growth. The product was tested by Practical Sailor here in the US and it was rated as excellent. Anything that manages to adhere to it will be brushed off by the movement of the boat, or with a soft brush. I will be using this product on my next haulout.

Generally when it is necessary to move "jackstands" or props around a boat, the yards here in the US want to do it themselves. This is to prevent an accident and toppling of one boat against another, injuries and death....not to mention civil liabilities. Where I have my boat hauled they do it as part of the service included with the lift cost and daily yard fee.