Antifouling

[AlexL]

I'm coming to the end of my first season of boat ownership so I'm about to embark on the process of lifting my boat out and giving it a coat of paint. However I have absolutely no idea how to do this! Does the existing antifouling need to be scraped off? if not are all paints compatible as I have no idea what is currently on the boat. How do I calculate how much paint i need?



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[craigbalsillie]

Re: Antifouling - Newbie Alert

A quick aside question on same subject from non boat owning newbie ..
when you are doing your antifouling and you have your craft out of the water ..
If it's on a cradle or legs , how do you get to the bits that are resting on the legs/cradle...

sorry if its a stupid question, if it is then feel free to hit back with stuipid answers..?



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[tony_brighton]

Re: Antifouling - Newbie Alert

Choice of 2 ways:

1) you ask the boat yard to move the props so you can paint them (bit more difficult in a cradle)

2) you keep back some paint and a brush and slap it on the patches when its craned up for lift-in. If really smart, you can get the boat yard to do this for you.

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[Hurleyburly]

You're kidding aren't you, I mean this is a wind-up isn't it ?

You've got a 50 grand boat which you've had for a year and still know nothing about A/F ???

You must have wandered around a boat yard at lay-up time ?

Next you'll tell me you don't know what a seacock is.

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[Bottle_of_Rum]

Nice helpful answer, that's what we like.

Surely everyone has to start some where.

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[Rich_F]

Re: Antifouling - Newbie Alert

Last time, we used a cradle that was big enough to put the pads entirely above, or below the waterline. We just got the yard to move them when going between antifouling and topsides.

Still had problems with the bottom of the keel though!

Rich

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[tillergirl]

The easiest way to deal with your question about compatibility is to get down to the chandlers and ask them if they have a copy of either the Blakes or International paint booklets - they are free - and contain details of preparation, coverage, adherence, volume required. The Blakes booklet invites you to join the Blakes Paint Club! Basically, if you are going to stick to the same AF and you have (presumably after high pressure hose off) a sound, even, flat paint surface, then you can just paint over. You don't need to remove the old if its sound stuff.

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[Rich_F]

Last year was our first time on the hard. We completely cleaned the hull down to polished gelcoat, then epoxied and coppercoated it. In theory, no more antifouling for 10 years!

However, having done this, my recommendation would be that if the existing surface is sound, just antifoul over it. I'm sure that the (weeks of) work we did exceeded 10 years of antifouling effort! The antifoul manufactures will provide compatibility information. Is there really no way to find out what is already on the boat?

Rich

PS My long-suffering wife, who did more than her fair share of last years labours, would heartily second my recommendation!

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[AlexL]

Blimey

Theres me thinking the point of this forum is to find out answers to stuff I don't know - Never mind silly me eh.
Yes I have walked around yards in the winter , for many years whilst i was dreaming of buying a boat -and guess what - some people had painted hulls (were they just newly painted or still awaiting this years paint - i don't know) and some people were scraping stuff off. Nobody had sums painted on the underside of their boat to calculate how many litres of paint they required, no were there chemical formulae to indicate the compatibility.

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[AlexL]

slapping it on over the top sounds good to me!

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[Gordonmc]

Some might disagree, but I will fire away anyhoo...

Your yard guys should give the hull a good powerwash after lifting. This will let you see the state of the antifoul right off. If there are areas of cracking and lifting, best to take it all off. The choice is yours... pay someone to professionally blast it off or prepare for skint knuckles and start scraping. A two handled Sandvik type scraper is best.
When all is done the hull will need priming before application of antifoul of choice.
If, however, the antifoul on the boat is found to be sound with no areas of lifting I would apply a couple of fresh coats. Abraid if the existing AF is of the "hard" variety.
If you can't check with the previous owner what was last applied, ask around the yard for someone with a bit of experience. If that's not possible, wet a piece of rag and rub the hull with it. If a fair amount of colour comes off on the rag, its probably self-eroding, so use a soft antifoul for your new coats.
I guess for a 50 footer you will need about 7.5 litres per coat, rolled. Use hard antifoul for the boot top, the line that runs around the waterline, such as MXP. One 50Ml tin should do.
Whether to use hard or soft AF depends on use... soft for cruising, hard for racing to keep friction at a minimum... or if the boat is taking the ground with the tide and soft stuff will wear off too quickly.


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[AlexL]

its a 30 footer, but your figure gives me a rough idea to check costs. I'm pretty sure its not racing antifouling. I'll go with the eroding stuff, as we don't race (well not unless there is another boat trying to overtake!) and we don't take to the ground (err, well, mmm, not intentionally anyway, although there may be a small sample of the east coast mud on the bottom of the keel when I lift her out!)

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[AndrewB]

Good advice from Gordonmc on determining the old antifouling. If your boat was not used for racing it very likely to be an eroding antifouling like Blake's Tiger or International Cruiser. Pretty well all of these are compatible with one another across makes.

Your decision whether or not to take off the old. Most people don't unless the build up is getting thick or the surface is very uneven or peeling. If you don't need to, just clean off the weed and barnacles, and slap on a coat of new, on a reasonably fine day. Its a fairly easy paint to apply, and dries quick, but remember to stir well. A roller is quicker and better than a brush. Use masking tape at waterline for a neat line. There is a special thinner for antifouling (International no 3), which may be useful towards the end of a tin or for cleaning tools and accidental smears, but generally very little is needed.

If you do decide to remove the old, remember that antifouling is poisonous. Use full protective gear if sanding and make sure no other boats will catch the dust.

There is a useful website with info on many different manufacturors products, coverage, compatibility etc, at http://www.boatpaint.co.uk/acatalog/

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[dulcibella]

There are other options. If you are in the Solent area, Boatscrubber have installed their machines (like an underwater car-wash) at Haslar and Port Solent and I believe more are coming. Most people antifoul normally but have a few scrubs during the season to improve performance by removing light fouling. However, an interesting option is to clean the hull back, then use a paint system that gives a smooth silicone surface that only fouls slowly and will put up with scrubbing for several years, so doing away with the highly polluting copper-based antifouling paint entirely.

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[dulcibella]

There are other options. If you are in the Solent area, Boatscrubber have installed their machines (like an underwater car-wash) at Haslar and Port Solent and I believe more are coming. Most people antifoul normally but have a few scrubs during the season to improve performance by removing light fouling. However, an interesting option is to clean the hull back, then use a paint system that gives a smooth silicone surface that only fouls slowly and will put up with scrubbing for several years, so doing away with the highly polluting copper-based antifouling paint entirely.

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[dulcibella]

There are other options. If you are in the Solent area, Boatscrubber have installed their machines (like an underwater car-wash) at Haslar and Port Solent and I believe more are coming. Most people antifoul normally but have a few scrubs during the season to improve performance by removing light fouling. However, an interesting option is to clean the hull back, then use a paint system that gives a smooth silicone surface that only fouls slowly and will put up with scrubbing for several years, so doing away with the highly polluting copper-based antifouling paint entirely.

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[ashanta]

Alex,

Theres more to this than applying paint and being lifted in. You do not know the condition of your AF and how long will the boat be on the hard? What AF is effective for your mooring? etc etc.
When the boat is lifted, wash the hull including top sides, Polish the gel coat. If it's staying out for the winter season leave it as the cold frost can have a major effect on AF. If your old AF is secure at the end of the layup period repaint with the preferred AF. If yor cradle legs are covering parts of the hull all you have to do is place a wooden or padded metal prop alongside the cradle leg and drop the cradle leg. When the AF is hard repalce the cradle leg and go onto the next leg. ie one at a time. As a previous post mentioned, you always keep the remains of your AF and the brush available when the boat is lifted in to do the Heinekin bit. I hope this helps?

Regards.

Peter.

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[kesey]

International Paints have a good manual, free, on anti-fouling and its application. It details what kinds can be left in situ and what kinds have to be sanded off etc. If you have a good chat with yourt boat-yard and your local chandler, you will learn a pile.

The first thing you want to know is: what type of anti-foulant is on your boat. You may be able to find out from the broker who sold her to you. I.P. have a compatibility chart in their brochure for all sorts of brands. Many anti-foulants do not like to be left high and dry...so the time to apply them is just before you re-launch the boat, not when you take her out. When you haul her, give her a good clean and do all the maintainance bits and pieces. Next Spring, you can get yourself covered in anti-foulant, unless you have a good pair of over-alls

Adrian

 

[sailorman]

ask sail east on thier after sales serivce, or sign-up with Les Rant ( Beyond Reality s.y.h.) & learn how to sail with a propper sail school!.

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[sailorman]

Wots a seacock?.

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