Never Antifouling Our Boat Again

By Hayley Tia

Copppercoat antifouling seems to carry a very polarizing opinion amongst yachties. Since, we have been considering this new antifoulant system for our vessel we have been met with a range of questions or strong statements, both strongly for and against the product.

Coppercoat antifoul

“Is it even legal?” -skeptical cruiser in the anchorage

“We have had Coppercoat for well over a decade and have never looked back!” -fellow yachtie with first-hand experience

“Isn’t it expensive?” - the budget conscious cruiser

“It’s won multiple awards for its reduced ecological impacts as an antifoulant!” -International Boat Show 2011

“I’ve heard it’s difficult to apply?” -New cruiser on the scene

“It’s a product that been on the market for over 30 years servicing runabout tenders, circumnavigating superyachts everything in between, even commercial off-shore wind farms!” -Coppercoat Distributor Australia

And plain and simple “Oh that sh*t doesn’t work!” -Boatyard manager

After chatting with The Wholesome Sailors Marine Toxicologist, Sam Gaylard about a range of ‘alternative’ antifoul options (check out his article on the topic HERE) as well as completing our own research, we decided to try this controversial product for ourselves on our vessel Chasing Eden.

So, to set the record straight from the beginning here are the answers to a few of the common misconceptions of this debate;

Why Copper?

There are many marine antifoul products around that use copper as part of their ingredients list- in fact, copper is the most common and also longest-standing ingredient in protecting ocean-going vessels for centuries, with early seafarers hammering copper sheets to the hulls of their vessels as early as 1500-300BC. So, utilizing the properties of copper is no new idea and is a compound that has been proven time and time again as a highly effective antifouling agent. It is available as both ablative and hard paints with varying concentrations and booster biocides.

What actually is Coppercoat?

There are various brands of Copper-based antifoul paints, and it is even possible to make your own (with varying degrees of success), but following our own research we decided to opt for AMC’s Coppercoat product. Not only is it the original but it has been on the market for some 30 years.

This particular product uses a water-miscible epoxy resin which is then mixed with pure grade fine copper powder. It is essentially a hard bottom coating rather than paint. Suspended within this protective epoxy barrier is the fine copper powder, which when exposed to the saltwater, creates an oxidized coating that is inhospitable for mollusks and organic weed species to make it their home.

Coppercoat in the boatyard

But isn’t Coppercoat illegal?

The common misconception of Coppercoat being illegal is based on some proposed restrictions in US states of California and Washington as well as some European countries like Sweden and The Netherlands. Concerns had been raised over the large percentage of copper compounds found in harbors and marinas in these regions. In California in particular, studies were conducted and it was concluded that a large percentage of this copper pollution was due to boat owners having their hulls cleaned by divers, many of whom had used ablative antifoul paints that contained a high level of copper as well as strong biocides. This underwater hull cleaning was seen as being responsible for much higher concentrations of copper and chemicals in the water.

Many of these locations had considered creating a blanket ban on antifoulants that contain more than 0.5% copper, ablative or not. It seems these bans have since been delayed or are still under consideration. Further studies are required to prove the perceived risk of copper on the marine environment. There may be reason for concern surrounding the effects of copper substitutes like the new man-made ‘active’ ingredients that are emerging on the market, with little long-term data on some compounds and their persistence in the environment as well as poorly-investigated adverse effects on non-target organisms.

It is hard to deny that many studies still find copper to be superior when compared with alternative biocides. A recent 5-year trial conducted by Plymouth Marine Laboratory Applications Ltd (PML) on behalf of EDF Energy, a wide variety of anti-foul coatings were tested for longevity and efficacy. To quote the report published in March 2018: “After 60 months of testing, Coppercoat was the best performing coating.” But of equal relevance was the environmental information that came out of this test. On average, the test panels of traditional products lost between 90% and 100% of their antifoul and 10 to 20% of the underlying epoxy primer. In contrast, the Coppercoat treated panels lost only 4% of their topcoat (Coppercoat Australia, 2022).

Two major mitigating factors that caused regulators to reconsider an outright ban on copper were that a fouled vessel dramatically increases hull drag, which in turn leads to heavier fuel consumption and, therefore, higher carbon emissions. Not to mention, less effective antifouling would also allow the transport of invasive marine species beyond their normal habitat. These factors alone are reasons enough to weigh up both sides of the argument.

If Copper is such an effective antifoulant how can it be ‘better’ for the environment too?

This highly effective coating is considered kinder to the environment than conventional self-eroding antifouls because;

  • CopperCoat is classified as a ‘non-leaching’ antifoul system. Unlike traditional antifoulants which are a toxic concoction of chemical biocides that leach into a thin layer of water around the hull and flake off with any growth that does form on the surface.

  • Reduces fuel costs. Being a ‘hard’ bottom coating means that it should be applied to a smooth faired surface, and in accordance with the manufacturer's recommendations, it should be lightly sanded to provide an extremely smooth, almost polished finish which obviously significantly reduces surface resistance and drag in the water.

  • Reduces the need for annual haul-out maintenance and the continued use of regular antifoulant paints. With a suggested lifespan of Coppercoat lasting anywhere from 10, 15 or 20 years between recoating this substantially reduces your impact of waste, reduces the chances of possible chemical runoffs, and as well as greatly reduces the use of all the resources generated with regular applications of antifoul paint.

  • Being water-based and V.O.C free (void of smelly solvents) makes the application process a whole lot more enjoyable. Sure, we still wore adequate PPE during the application process but found this product to have no offensive smells and was easily washed up with soapy water.

  • No more scraping and swimming around in plumes of toxic ablative paint. After how ill we both became following any previous maintenance we undertook scraping and cleaning the hulls of regular ablative antifoul paint, there was no way we wanted to continue this process year in, year out. As well as exposing ourselves to these chemicals on a daily basis as we swam from the back deck of our vessel, drunk water from water maker passing directly over our hulls or even just in using the saltwater washdown, again passing over the highly toxic chemical and biocides that slowly leach into the water surrounding our hulls.

  • For more details, you can check out AMC Coppercoat Environmental Report

Can Coppercoat be applied to all types of boats?

Yes. Iron, steel, aluminum, Ferro-cermet, form, or wood- all can be successfully treated with Coppercoat.

Is it expensive? *Please note all prices are in Australian dollars as of 2022.

Yes, it’s true, a pot of Coppercoat paint is more expensive than a pot of regular ablative antifoul. BUT there is a little more to this;

  • In the past, we have spent approximately $370 per 4 liter tin of ablative antifoul paint every year. Add to this the cost of slipping the boat, labor, all the consumables required to apply the product, the inevitable price rises from year to year, and the inconvenience of annual antifouling.

  • In comparison, we spent $1832 on Coppercoat. Sure, we had to add slipping costs, labor, and consumables but this is a one-off cost. The lifespan of this product is said to be anywhere from 10-20 years!

With the current cost of Coppercoat at $229 per liter kit, we assume that to break even from the financial investment in the Coppercoat system to be within 2-3 years.

Our Application Process

We had watched every Youtube tutorial of CopperCoat application, read almost every forum and blog post, and been watching and waiting for the perfect weather conditions for our antifoul application day to arrive. With David, our CopperCoat distributor and application guru, on speed dial we were ready.

Sure, CopperCoat can’t be ‘slapped on’ between tides time on a quick dry out on the beach, but it certainly isn’t rocket science as some may think. There are, however, just a few golden rules to ensure you get the best application for the longevity of the product. Given this was an investment, we really wanted to get it right the first time.

  • As a rule of thumb, Coppercoat can’t be applied below 8c, and given it is water-based it best cures in mild temperatures, with minimal humidity and good airflow.

  • As with any boat painting exercise, the finish is only as good as the preparation. All surfaces must be cleaned of all contaminants; including dirt, dust, grease, rust, or loose paint (including any existing antifoulant).

  • Ensure the mixing of the product is done properly and then applied directly after mixing.

  • Multiple light coats are key, either with a roller or by spraying. The idea is that with thin coats the copper cannot settle within the film of the resin. Under normal circumstances, a minimum of four coats are required, applied wet on tacky to achieve a single thin homogenous coating.

  • And given this style of epoxy is water-miscible until cured, ensure you protect the hull from rain (or dew) for at least 48 hours (or until hard to touch).

Step 1-

We had bitten the bullet and had our hulls professionally blasted with a dustless blaster, a 2-hour process that required no contact with our original antifoul and only minimal additional sanding to prepare the hull for a new barrier coat.

Step 2-

Whilst barrier coat was not strictly necessary and AMC’s Coppercoat can be applied directly to abraded Gelcoat, given that its two-pack epoxy qualities provide a certain level of protection from blisters and osmosis we had opted to apply two coats of Wattyl UC230. Following a chat with our new Coppercoat guru Dave we agreed that given the Coppercoat product was going to be on our hulls for a very long time we would go the extra mile with the added protection from a specially designed barrier coat.

Step 3-

Before application of the Coppercoat, we gave our hulls a light buffer using 120-grade sandpaper on an orbital sander, just a little more glorious sanding J This process provides a good key for the new epoxy coating to adhere to. And following a wash with fresh water and sufficiently dried we were ready to go!

One hull in coppercoat

Step 4-

As with any boat works you are often fighting the elements and our situation was no different. We had warm conditions above 30c and knew that at this temperature the pot life was around 20 minutes and between coats, we would have less than 30 minutes. We decided to tackle one hull at a time and to give ourselves the best chance at success Dave suggested thinning the product with Isopropanol. This can only be added at the start of the mixing process, adding thinners later when the coating thickens will only adversely affect the curing process. For roller application Coppercoat can be thinned up to 5%, or for spray application by 15-20%.

Step 5-

We set off in the cool of the morning, applying very thin coats using a short-pile simulated mohair roller, allowing each coat just long enough to tack off before applying the next coat. Given there were two of us we found switching sides each coat provided an even finish, given our tendency to apply on different angles. With 8 x 1 Litre packs we achieved 5 even coats and a tiny bit extra just to go over the waterline once more.

The minimum finish application rate is 1 liter per 4m2 (1 liter per 16m2 per coat), but when applied particularly thin, five coats would see 1 liter per 20m2 per coat. Of course, more coats above the minimum just extend the service life of the Coppercoat system.

Step 6-

We found the clean-up process to be very easy, simply washing roller sleeves with water (avoiding any water to go into the drains), and once cured we peeled the Coppercoat from the roller trays and mixing buckets.

Allow it to fully cure. At 20c this is said to be 72 hours after application, but really the coating is sufficiently hard enough when you can’t mark it with your fingernail. For us, this was approximately 36 hours later. At this stage we lightly burnished the surface with a fine burnishing pad, allowing the top layer of resin to be buffed exposing the copper.

Unlike regular antifoul paints, there is no rush to get the boat in the water, in fact, you can leave a Copper-coated boat out of the water without any fear of it drying out, cracking or flaking off.

L.W.C.C (Life with Coppercoat)

To be fair we have only been back in the water for a little over two months since publishing this so the growth on our hulls is non-existent as to be expected by any antifoul paint. We will keep you posted on this one in the comments below.

One thing we have noticed, however, is the incredible difference in performance with our copper-coated bottom. We are still in the testing phase but could attribute at least 1.5knots of speed to our extraordinarily smooth and shiny butt, maybe even 2 knots! It’s not surprising Sir Robin Knox Johnson chose Coppercoat for his famous ketch Suhali, leading then to the Clipper Round the World Training Fleet having CopperCoat applied, then going on to set new race records in the 2017/18 Round The World event.

Stay tuned for our next Copper-coated instalment by subscribing HERE.

Hayley Tia

A liveaboard sailor and professional copywriter, creating content from the cabin of her floating home. Prior to life on the water, Hayley owned and operated a seaside cafe for over 7 years whilst starting a degree in marine biology. She now enjoys the space and time the liveaboard life has given her and enjoys preparing nutritious meals in the galley as well as utilising her qualifications as a yoga instructor to lead morning yoga sessions on the beach at each new anchorage.

See her on Instagram


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