How many coats of antifouling paint

[Biggles Wader]

I use Hempel's A/F that is left over from the commercial boat when they do A/F so cheaper.

I use 20 lits for my 15-meter boat that gives me 2 coats and some for the water line chines and keel edges.

It generally lasts me 2 years but could go longer as the as the Hempel's has a 3-year life span on the fouling is quite light when pulled out after 2 years.
I generally pressure wash and the get 2 guys from the year to paint the anyifouling which helps the local workers

I agree with this. I got hold of some Hempel Olympic left over from a local fishing boat, about seven litres left in a 20 litre drum and a bit of primer all for £65, which I slapped on liberally. It worked well for two years and then a fair bit of weed started to appear but would drop off easily with regular use. The paint is eroding but you need to get up a decent speed (5 knots+) for it to work. It did 4 years and was replaced with the Jotun Seaforce version because I couldn't obtain Hempel this time. The Jotun is not as good at growth prevention but still erodes well so the weed comes off with use. I'd use either again.

 

[Neeves]

I did an AF test comparing a dozen or so AF. I divided the hulls of our cat into vertical strips and applied each AF as 1,2,3,4, on one hull outside and then 12,11, 10 on the other hull, outside - and similarly on the inside of the hulls, 6, 5,4,3. I did the same for the mini keels and rudders. I found Hempel's Globic to be better than either of the 2 Olympic's formations. But its one of the products defined as to be only used by professional applicators and in commercial application (no idea why). Because there is a focus on commercial application the drums can be large (and impossible to lift, over the boot lip, into the back of a car). The larger drums need patience to mix - and a mechanical stirrer (I used a stirrer on a battery drill).

I found Jotan's Quantum Ultra to be the best and Globic a close second, Globic and Quantum might work slightly differently in a different environment., colder, warmer, more or less fresh water. International's offerings were adequate - but not as good. Because the 'free' sample I received of Globic was 'large' I then used it over the whole hill, when I had completed the trial and achieved a comfortable 2 years. The next time I used Quantum and also achieve a 2 year life.

My recommendation now would be based on cost, which was cheaper (Globic or Quantum) and similarly - availability. On availability a yard that handles commercial; vessels - fishing boats, would be my first port of call.

Jonathan

 

[Sailing steve]

But its one of the products defined as to be only used by professional applicators and in commercial application (no idea why).

I have an idea why.

The environmental argument that prevents the sale of "professional use only" products with a far higher level of effective biocides to the leisure market doesn't stand up because if a few litres of such a product on a yachts hull is harming the environment to the point where it has to be banned then how are hundreds of thousands of litres of professional use only antifouling products on tens of thousands of ocean going commercial vessels not doing many times more harm to the environment and why aren't they banned from using it too?

The answer of course is money. Commercial shipping makes a profit which is taxable and a heavily fouled hull compromises that profit by both slowing the vessel down meaning the crew have to be paid for more days at sea and causing more fuel to be burnt to overcome the friction from fouling.
More fouling on commercial shipping - less money to be made.

In the leisure market the situation is reversed. Combatting fouling increases profits which are taxable for boatyards by forcing more and more leisure boaters to cough up for one or two mid season lifts and scrubs because the antifoul products available to the leisure market are becoming increasingly ineffectual and chandlers are enhancing their bottom lines by flogging more and more tins of the wretched stuff at at prices that go up every season.
More fouling on leisure craft - more money to be made.

Simples.

 

[Bilgediver]

Not only is the dust a problem to the heath of you and others but antifoul removed must be collected in many marinas and disposed of in a responsible way.

I was surprised how much in weight could be collected. I used an old sheet below the boat.

 

[Rhylsailer99]

I use wet scotchrite pads as that way you get no dust. Then I just slap it on until the tin is empty.
That is usually about 2 coats, which I can manage between tides sat on bilge keels.
I was pleased with myself when I managed it summer time.