When is new anti-fouling really needed?

[sailingunity]

Our boat was painted with Ameron in 2014, a black with red over top. In all but the higher wearing places (right at the bow, around the prop) its still thick enough that the black is not showing through. There are a number of small "pot marks" I'll call them, where it looks like a stuck on barnacle took a chunk of paint with it, you can see the grey primer (this could be due to the pressure washing at haul out)

We bought our boat and launched it in 2016 after 1.5 years on the hard. The paint only had about 6 months time in the water at that point, but we found we had to clean it about every 2 months to keep good speed up (this was in the AICW). Ameron advertises no max time to launch, and 60 month performance. We had it in the water about 1.5 years then hauled Jan 2018. So, in total we only have about 2 years in the water.

So is this normal performance? There is plenty of paint on the bottom, but it seems like it's not really "anti-fouling" anymore if I have to scrub it every 2 months. Time to re-paint? Or touch up and wait until black starts showing through?

[Tillsbury]

I don’t know about that brand, but I’ve always been told boats need to be back in the water ASAP after new antifouling. I’m having it done at the moment alongside a couple of other things, and the boatyard are insistent that the antifouling is absolutely the last job such that it’s in the water the following day.

[Boatguy30]

Must have had a ton of coats to be able to scrub every 2 months and have paint left. I have same paint and is much softer than that

[sailingunity]

Originally Posted by Boatguy30

Must have had a ton of coats to be able to scrub every 2 months and have paint left. I have same paint and is much softer than that

Well, every two months while we were travelling. It sat in the water for about 5 months before the first cleaning, then I cleaned about every 2 months until we parked it again for about 6 months. I used to scrub it with a green pad and noticed that it ablated pretty easily as well. I switched to using a plastic scraper and that cut back on the amount of paint coming off. So I would use the scraper to get the barnacles off, then lightly scrub with the pad for the last bits of algae.

I've heard that about paint as well that it needs to be splashed as soon as possible, but according to Ameron that doesn't apply to this paint, supposedly they use it on big ships.

[Cpt Mark]

How often depends on a lot of factors.

Quality of the paint, the paint job itself, number of coats, thickness of coats

Environmental. Warmer water, more sun equals more cleaning.

Use of boat. Just sitting will require more cleaning than actively sailing. Racing will demand a cleaner bottom than just sailing around.

Personal preference . How clean do you want it?

If you use an ablative paint there "may" be some truth to putting it in the water right away. With hard paints this is not the case. The paint formulas have changed over the years so what used to be truth (get it in the water fast) no longer applies. Check with the manufacturer of your paint.

I put on 3 coats, alternating colors as I go so when I see a new color I know where I am and can judge how long before I need to repaint. 2 years, 2 coats is a boatyard thing. It's a nice profitable side of the business and you might benefit from a haul out every 2 years. Certainly if you have a wood boat you should do this. Mine is fiberglass so I don't worry about hauling out every 2 years.

[jmschmidt]

The answer to you question is NEVER if you want to clean the bottom, say, once a month, depending on the waters where the boat is located. Anti-fouling bottom paint does exactly nothing to prevent water incursion into the hull material, nor does it enhance the speed, looks or any other practical function except prevent growies for a short period of time. As the inviro-nuts keep insisting on laws to keep manufactures from formulating their bottom paints with anything that actually works, their paints effectiveness will continue to diminish. I think you could have a bottom cleaner do a one-a-month job for way less that a once-every-two-years haulout. But then the inviro-nuts will make it illegal to even scrub off the growies and harm the little bastards, even though growies come from the very sea they think they are protecting. Its the world we live in.

[thomm225]

Originally Posted by Tillsbury

I don’t know about that brand, but I’ve always been told boats need to be back in the water ASAP after new antifouling. I’m having it done at the moment alongside a couple of other things, and the boatyard are insistent that the antifouling is absolutely the last job such that it’s in the water the following day.

Many antifouling paints allow 60 days before you need to launch.

With Micron CSC Ablative, there is no time limit but you should scrub the bottom with a stiff brush before you launch if it's been more than 60 days. This according to them to reactivate the paint.

I painted the bottom in early December. I'll be launching late Feb early March.

[Cheechako]

The problem I have noted about antifouling paints is they kill the growth AFTER it's already attached. So if you are looking for a clean bottom from AF paint it's likely not going to happen. It does seem to retard growth sometimes though.
But I found in the Caribe that name brand, 6 month old max, Trinidad AF done in Florida allowed many hundreds of barnacles to grow up to maybe 3/8" diameter max before they were killed. I remember scraping my Cat in Luperon and taking off maybe a large bucket of them after a 5 week stay there. They probably love the fecal content in the harbor or something.

[sailingunity]

Ok that is good advice, I had kind of thought that maybe as long as there was still paint on the bottom, it was still OK. I'll have to check with the yard on what to do about the thin spots.

[Jd1]

FWIW, in my experience you get to a point where effectiveness of the coating decreases. I am assuming it is from the active components leaching out. This is with Micron CSC. I repainted every 2 years with two coats with a third on high wear areas.

[fstbttms]

Anti fouling paints leach their biocide at a proscribed rate which is determined at the factory. It comes out 24/7/365, whether the boat moves or not and whether the bottom is cleaned or not. This means most anti fouling paints have a maximum useful lifespan of somewhere between 3 and 4 years. I do not believe claims of significantly longer periods of time. You can certainly shorten a paint's lifespan, but you cannot lengthen it. Once the biocide is gone, the paint is done.

[inspectr]

My boat lifted and antifouled in December 2018 after 22 months in the water.
Seaweed, 15mm barnacles, slime, black spots, looked horrible.
Cost $3,800.00.
Already, 10 weeks later, small barnacles are growing on some areas, and last week while swimming around the boat I found three dead barnacles under the fresh paint! The boat is slimy and discoloured.
I am starting to wonder whether no antifoul and regular dive maintenance would be better.
Dive cleaning every 3 months costs about $220.00 each time, say 8 dives in 2 years = $1760.00.
Dive cleaning with ablative coatings just removes the antifoul
Even hand cleaning the waterline and 400mm below with goggles and snorkel occasionally removes clouds of the paint
I am increasingly confident that antifouling simply does not work due to the greenies and probably the paint suppliers removing the active ingredients
On the other hand, straight back in the water, the boat does 7.5 knots at 2500rpm, it reduces to around 6.25 knots at the same rpm when the bottom is even a little dirty.

We all can vote, put the greenies and their fellow travellers LAST.

[fstbttms]

Anti fouling paint does not eliminate fouling growth, it merely retards it. And you wouldn’t suggest going without it if you’d ever tried cleaning an unpainted hull. Both are needed- anti fouling paint and regular in-water hull cleaning.

[inspectr]

Originally Posted by fstbttms

Anti fouling paint does not eliminate fouling growth, it merely retards it. And you wouldn’t suggest going without it if you’d ever tried cleaning an unpainted hull. Both are needed- anti fouling paint and regular in-water hull cleaning.

But the divers in Sydney Harbour are using air driven scouring brushes that remove the crap paint. Effectively my hull is unpainted less than 3 months after an expensive lift out and painting with what I feel is a rubbish and totally ineffective product.

Feels like a waste of time to lift out and paint with something that is less than better than cheap house paint.

Maybe hard antifoul and regular cleaning might be better, but I am not convinced.

One hull cleaning with our set of divers removed almost all of the so called protective paint and I am left with an unprotected bottom - why bother?

I am seriously considering legal action on the basis that the products and services fail to meet the requirements of our Trade Practices Act in regard to fitness for purpose.

What is claimed to be an antifouled hull - 10cm barnacles and slime less than 3 months after dropping the boat back in the water. What other industry gets away with such incompetence, and failure of goods and services to meet minimum standards of service and competency?

[Maka]

Going back and forth between salt and fresh water kills most marine growth.