Antifouling, how many coats, 1 or 2 ?

[BigJoe]

Antifouling, how many coats, 1 or 2 ?

Last year I got the boatyard in my marina to apply the annual antifouling.

After 6 months I had growth on the bottom of the boat.
I have been “ reliably informed “ ( well sort of reliably informed ) that I should have applied 2 coats.
Is this correct or am I being taken to the cleaners.

Any advice or tips would be beneficial.

 

[Cerddinen]

I stand to be corrected by those who are more informed but ... here's my comment. I would have thought that one coat of correctly applied anti-fouling was sufficient. I used to apply two but about 10 years ago began only applying one. My boat has never been badly fouled at the end of the season - certainly not enough to have felt a second coat was necessary. One coat also reduces the problem of old anti-fouling build-up.

You don't say which six months. I recall reading somewhere that launching earlier in the year makes fouling worse since immature marine life is searching for something to latch on to. One

 

[[2574]]

I only ever do one coat...........

and never had a problem with fouling. I only apply one coat to prevent a think build up of a/f. I suspect the type of antifoul and the quality of application makes a big difference. I always apply the a/f myself. When I purchased a new (to me) boat one spring it had been a/fouled by the sales agents guys and frankly you would have thought that they'd stood in the next county and chucked the a/foul over the hedge as a method of application - I had to make them do it again!

So, Seajet Emporer, carefully applied with a consistent covering works well for me.

 

[BigJoe]

Thanks for the reply’s.

I should have said that I applied the antifouling in March, and its in the med, although I am not sure that its of any significant consequence.

 

[Bav34]

Last year I tried an experiment and put a second coat on, but only from the bow to halfway along the keel.

The second coat made no difference.

 

[Jamesuk]

2 TWO,

 

[NPMR]

Conversation with International Paints about the appaling state of the bottom of our boat using 'Cruiser Uno' resulted in the comment that

a) the strength of the a/f was very important, so use a stronger/more expensive a/f

b) use the whole 'tin' (in our case) (but this would not equate to two coats everywhere - just in some areas , like the waterline/leading edges.

My understanding of what was said was that the antifouling, even though apparently still on the boat, i.e. it still 'looks' like it's there (thickness-wise) does not mean that all the 'working' stuff has not leached out and is no longer offering any antifouling properties. Or in other words, use the most expensive/quality a/f you can afford but it does not need to be mega thick to work. And of course, moving water will be better at keeping weed down than stationary water

 

[KREW2]

One coat of self eroding works for me, whats left over goes on the leading edges and my support buoy.

 

[Pete7]

Last year I tried an experiment and put a second coat on, but only from the bow to halfway along the keel.

The second coat made no difference.

Steve, nice keel

but WTF were you stood on to take that picture, you must have been about 15 feet above the water. Interesting the the second coat of Uno didn't make any difference. We always park facing due south so the starboard side has greater waterline weed, so was planning an extra coat, probably not worth the effort now though.

Pete

 

[V1701]

two seasons ago I took the time (and expense) to apply four coats to the leading edges and two coats everywhere else as instructed on the tin to "last two seasons" (well known reputable brand). Came back to the boat in the spring (it's kept in the water) to find it heavy fouled. Per the supplier "it has to move to work"!.

So back to one coat plus an extra coat on waterline and leading edges which works fine for me in the Med.

Marketing...

 

[jhr]

Interesting the the second coat of Uno didn't make any difference.

Most Antifoul manufacturers recommend two coats, and more on leading and trailing edges, waterline etc (well, they would, wouldn't they?).

However Uno is intended to be a one-coat application (hence the name), with additional layers for particularly vulnerable areas, as above. I've always found it reasonably efficacious (I use Cruiser Uno on my mobo) but then it gets "eroded" at 20+ knots, which probably helps keep things clean

I don't think there's really such a thing as an effective anti-foul, now you can't slap on a bit of TBT......

 

[HoratioHB]

Depends on whether you use a hard or ablative antifouling. If its ablative then the boat needs to be sailed to ablate it!! even so I used Seahawk island 44 (ablative) in the caribbean (illegal elsewhere cos its got tin in it) and got barnacles. They warranty against this and when I claimed they paid for new paint. However they made the point that every month the boat should be lightly cleaned to keep slime off which can from a barrier. My reaction was to tell them to get real!!
Sorry the point of this diatribe is that if you leave your boat in one place for any time, especially in warm water its likely to get a slime build up which will compromise the paint. Next time I am going to use a hard paint as I can dive and scrub the hull without the soft stuff coming off.

 

[pugwash]

A single word has made more dosh for shampoo manufacturers than anything else and it appears on every bottle -- REPEAT. Maybe it's the same on tins of antifouling.

Do you shampoo your hair twice? Not me.

 

[pmyatt]

Antifouling, how many coats, 1 or 2 ?

Last year I got the boatyard in my marina to apply the annual antifouling.

After 6 months I had growth on the bottom of the boat.
I have been “ reliably informed “ ( well sort of reliably informed ) that I should have applied 2 coats.
Is this correct or am I being taken to the cleaners.

Any advice or tips would be beneficial.

It's not the number of coats that are important but the number of microns cover. Two coats are generally recommended because, the manufacturer advises, that is the only way to ensure adequate coverage by roller application. To get the thickest application, apply by brush; to get the next thickest application apply by spray. Notwithstanding any of the aforementioned, the boat has to move periodically to remove scum (and I am not talking about HMRC here - although, on second thoughts, if they were held underwater for long enough it would work) and re-activate the biocides at the water/paint boundary.

 

[BigJoe]

Thanks for all the advice, and after some carful deliberation I will go with 2 coats this year, as the 1 coat I had the yard apply, didn’t do anything.

Great sailing to you all.

Live long and prosper.

 

[SimonJ]

Seahawk antifouling

Depends on whether you use a hard or ablative antifouling. If its ablative then the boat needs to be sailed to ablate it!! even so I used Seahawk island 44 (ablative) in the caribbean (illegal elsewhere cos its got tin in it) and got barnacles. They warranty against this and when I claimed they paid for new paint. However they made the point that every month the boat should be lightly cleaned to keep slime off which can from a barrier. My reaction was to tell them to get real!!
Sorry the point of this diatribe is that if you leave your boat in one place for any time, especially in warm water its likely to get a slime build up which will compromise the paint. Next time I am going to use a hard paint as I can dive and scrub the hull without the soft stuff coming off.

Interesting! Island 44 did not work for me either in the Caribbean - after 2 months I had plenty of barnacles. They then were rather insulting and told me I was the only person to report any problems. When I told them I already knew of other cases which they had already acknowledged they changed their tune! Although they promised to provide replacement antifouling (I had applied it myself and was not therefore eligible for their guarantee) they failed to do having then insisted I should have applied 3 times the amount I had habitually applied. This would have been 3 US gallons! Crazy!
Do NOT use this product!

 

[HoratioHB]

I was ridiculously lucky with this. I emailed them some underwater photos and they asked if I could be in Rodney Bay at a certain date, which I could. The MD and TD of the company were in the island and I got them on the boat. At first they refused to acknowledge there was a problem as they couldn't see any on the waterline. I got 'a bit cross' and the MD then borrowed my mask and snorkel and dived the hull - in the marina!! When he came up he agreed there were barnacles on the keel, hull and rudder. They then asked me what I wanted - I simply said I wanted them to honour thier warranty!! They did but had I not had the visit I don't think I would have got anywhere as they also initially claimed noone had had this problem. However I have met quite a few people who swear by the product - I did therefoer suggest that they look as to whether there was a quality problem in the factory.

 

[Ex-SolentBoy]

I have a different approach. First a coat of red and then 2 coats of blue. When you start to see red put on a single coat of blue.