4 coats of cheaper antifould v 2 coats of expensive stuff?

seanfoster

seanfoster

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Ok, I realise this question may divide opinion, but I suppose that's why I'm asking it!

I've sanded down to gelcoat and will be antifouling from scratch (I'll be putting a primer on first).

I have a 25ft fin keel yacht and would probably just squeeze 2 coats out of a 2.5L tin of antifoul.

So I could buy one tin of something like International Micron Extra for around £95 or two tins of say Flag Cruising at £33 per 2.5L tin and put 3-4 very generous coats on.

I realise there are antifouls priced midway, something like EU45 or Mare Nostrum is around £60 per 2.5L tin, but my question is about the number of coats of a cheaper product over fewer coats of a more expensive type.

Any thoughts on this?

By the way, my boat will be on a fore and aft mooring on the Hamble not far from Hamble Point.
 
You have spent all that time sanding off the built up layers of AF and now you are thinking of applying 4 new coats where as you can do it in 2 .Must like sanding .
 
It is because when you next (assuming it will be you) come to scrape and sand it back to gell coat you will have twice as many layers. It doesn't really wear off in use, more like stays on the hull but becomes ineffective. Personally I'd go for the better stuff.
 
Ok mabe not hope this is better,I like to youse a hard AF,2 Coats ,this for me lasts a good season,I may dive on hull and wipe off the slime mid summer, then to try and prevent to much of a build up, it's good to wet and dry some off before applying more ,I like the micron extra , am sure that if you will be lifting boat out for winter the cheaper ones will be just fine and would doubt the need to apply 4 coats prob over kill unless it erodes a lot ,hope that's a bit more helpful
 
Carl s said:
Ok mabe not hope this is better,I like to youse a hard AF,2 Coats ,this for me lasts a good season,I may dive on hull and wipe off the slime mid summer, then to try and prevent to much of a build up, it's good to wet and dry some off before applying more ,I like the micron extra , am sure that if you will be lifting boat out for winter the cheaper ones will be just fine and would doubt the need to apply 4 coats prob over kill unless it erodes a lot ,hope that's a bit more helpful
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Thanks Carl, no harm intended in the first reply!
 
Until last I would have sworn by micron extra. But last year we had a lot more growth than normal. Not sure it was the increased average sea temperature or something else.

To be honest you should be able to do two coats for about one tin, so the cost differentiation is fairly small.

The effectiveness of the various anti fouls seems to depend on where you are, eg estuary with fresh/salt water or other etc. wherever you keep your boat, worth asking around as to what works for others.
 
seanfoster said:
Ok, I realise this question may divide opinion, but I suppose that's why I'm asking it!

I've sanded down to gelcoat and will be antifouling from scratch (I'll be putting a primer on first).

I have a 25ft fin keel yacht and would probably just squeeze 2 coats out of a 2.5L tin of antifoul.

So I could buy one tin of something like International Micron Extra for around £95 or two tins of say Flag Cruising at £33 per 2.5L tin and put 3-4 very generous coats on.

I realise there are antifouls priced midway, something like EU45 or Mare Nostrum is around £60 per 2.5L tin, but my question is about the number of coats of a cheaper product over fewer coats of a more expensive type.

Any thoughts on this?

By the way, my boat will be on a fore and aft mooring on the Hamble not far from Hamble Point.
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Firstly it would be a mistake to "squeeze" two coats out of 1 tin. You should apply the paint at the recommended rate to give the specified film thickness. For a Dufour 1800 that will be about 1.4 litres per coat.

I guess the Hamble is a high fouling area which will require a high strength A/F There will be nothing to gain by using extra coats of an inferior A/F. If it is not of high strength it is not of high enough strength.

No brainer. If you need a high strength A/F then use it and apply it at at the recommended rate.

3-4 coats of Micron Extra should give you 2 seasons protection,

Read the product data sheet for whatever you choose to use and follow it as closely as possible
 
Interesting thought and I have to agree with some of the earlier comments, don't put on more coats than are needed. I have always taken off as much antifouling as is reasonably possible so that I do not get a build up which leads to more work in years to come. I too am on the Hamble and I followed PBO's advice and went with International Micron Extra 2 and I would definitely recommend it to anyone on the Hamble. We went in late April and lifted out in January with only slime present, no weed or barnacles. That is the best result I have ever had in all the years I have moored on the Hamble. And of course its your choice and I can send you photos if you want.

There is another thought, if you know what you want I can check my prices and perhaps with a bigger order I can negotiate a greater discount. PM me if you are interested.
 
FWIW I have used two coats of Micron two "seasons" running. That takes nearly 15 litres so its not cheap. However Micron lasts two full seasons - might even go a bit longer judging by the state when it comes out but the anodes need doing by then anyway. Each summer it gets one gentle rub over underwater. The Micron is a different colour to the previous antifoul and it has mostly eroded away over the two years by the time it has been blasted and scrubbed after haul out so I reckon that works well.
 
Antifoul is only active for a certain length of time, you need to read the tech spec. However after a period of time it is dead and all it is doing is building a thickness of paint that in time will flake, blister and fall off. A lot depends on how you were brought up in sailing, if you raced, you put in time preparing the hull to get the best finish. Lots of people don't race and are happier doing less and just patching up each year. I don't do that even though I don't race any longer.

It horrifies me to see a boat being lifted out, pressure washed off and then the owner is applying more antifouling without either rubbing any off or even preparing the surface. That for me is not good practice.

When you come to sell your boat if you can show that the hull is fair and the substrata is in good condition, you can expect a return in price. Some will argue against that however a surveyor will report that 'there is a build up of layers of antifoul paint which is flaking and ...that the hull should be scraped back and made good.' deduction in price is now on the cards or it should be.

Any how when I am sailing I feel far better knowing that the underside is good and slipping through the water as she was designed to do.
 
I would tend to suggest that OP put less coats of cheap a/f and see how it goes. Of course this must be tempered with considerations like willingness to dive and scrub, dry out on piles or lift out if the a/f fails in its job over the next season.
My boat lives in serious fouling type water. (warm and sunny). I am very much afraid of the dreaded paint build up. So every winter I make an effort to remove as much a/f as I can. It comes home on a trailer but actually access to all the bottom is very difficult.
I have settled into a habit of 2 thin coats of cheap a/f. This lasts about 6 or 8 weeks before scrubbing weekly becomes necessary. The scrubbing turns to using wet and dry sand paper near the end of the season so that a/f build up has not been a real problem in 30 years of a/f ing.
This regime of course is only possible but also necessary in warm water. So not applicable to UK sailors. good luck olewill
 
My boat in a heavy fouling area will get one top up coat of Gaelforces own brand and it will come out in the autumn clean.
£35 for 2.5 litres and if you buy two tins you get a sizeable anode for free.
 
Sorry - can't resist repeating posts I made years ago. I have a 27ft twin keeled Sabre. I have not antifouled her since I bought her in 1999. I launch her in March with a clean bottom. I dry out on a sandbank in June and sometimes spend as much as half an hour scrubbing off with the back of a broom. I then pressure wash her at the autumn haul out. This appears to me to be simpler, cheaper and less polluting than other strategies.
 
Thank you everyone for your replies, it certainly has answered a lot of questions!

To reply to a few posts here:

VicS, Thanks for the Advice on Micron Extra,

Derm, Again, thanks for the advice, I'll look into it and get back to you,

ip485, Another vote for Micron Extra, seems to be a theme running here!

MM5AHO: My boat has been out of the water for quite a few years and the A/F was about 10+ layers thick, very rough and peeling, so I've stripped the whole lot off (Caustic soda mixed with wallpaper paste, very effective if hazardous should it land on bare skin)

William H, thanks, I may well try a 'mid range' AF as I can scrub off easily at the yacht clubs scrubbing posts

Once again, thanks everyone for your input, it's given me a lot to think about.
 
If you really want to nail this then

Divide the hull into 4 quarters and paint each section in a different way. 4 coats of cheap AF, 2 coats of Micron Extra, do you have Micron 66? etc. In 12 months time you will have an answer you can share here. The result will give you the answer for your future servicing.

I did this here in Oz, not relevant as we have the same paint names but slightly different formulations and our water is warm - but Micron 66 was one of the best from 12 AF (and Micron Extra was very average).

But one comment that needs underlining - be generous with your coating thicknesses. Most people try to eke it out and spread the AF thinly (and then complain when it does not work very well). Even ask international how much pain they think you will need, at the right coverage rate and then apply that amount of paint until you run out - you will then have the correct coating thickness. Another aspect - the manufacturers recommend specific periods between coats - try to follow that regime. This might mean a coat per day - but I assume there is a technical reason for the recommendation which merits following.

But you pose an interesting question - and I would favour 2 coats of a better AF (than more coats of a poor AF). One aspect you do not mention of your regime - AF paint weighs a lot and leaving 20 years of AF on the hull means you have left a lot of heavy and unreactive copper to slow the boat down. So its not just an irregular surface but the extra weight you need to carry.

I for one will be interested in how you progress.

Jonathan
 
I only put one (generous) coat of local antifouling on, and that's in the Med.

By the time the boat comes out of the water 6 months and 1500 nm later most of that has gone but there's no weed on the boat (perhaps some barnacles).
Can't understand why people want to put on so much antifoul, only to have to take it off, painfully and expensively, every 10 years.
And for those that say "That's what the manufacturers recommend", I'd reply with the immortal words of the late Mandy - "Well they would, wouldn't they..."
 
charles_reed said:
I only put one (generous) coat of local antifouling on, and that's in the Med.

By the time the boat comes out of the water 6 months and 1500 nm later most of that has gone but there's no weed on the boat (perhaps some barnacles).
Can't understand why people want to put on so much antifoul, only to have to take it off, painfully and expensively, every 10 years.
Click to expand...

I usually alternate between blue and black A/F [one coat except for leading edges which get two] and so can see how much comes off during a season. I would guess that about half of it disappears.
 
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