At its heart, the question around antifouling is a matter of choosing between the lesser of two evils. There’s never a clear choice these days – never a simple decision between what is outright good and what is outright bad. There are just some options that are less bad than others, and it's a question of mitigating damage.
On balance, modern antifoulings, despite their high level of toxicity, are better than the alternative, namely a massive increase in global fossil fuel emissions and the widespread transfer of non-native species between delicate habitats.
Thankfully the international body with the power to clamp down on harmful antifoulings, the IMO (International Maritime Organization), has no plans to do so until there are viable alternatives. This is why it took the organisation nearly 20 years to ban outright a compound called trybutyltin – better known in the industry as TBT – widely known to damage shellfish populations. The IMO stalled because, while TBT was harmful, the localised damage was nothing compared with global efforts to tackle climate change and prevent the loss of biodiversity. The United Nations has listed these two issues as the most critical global environmental threats.
“So what is worse?” asks Albert Willemsen, the environmental manager of ICOMIA (International Council of Marine Industry Associations). “What I am saying is that the impact of the loss of biodiversity is greater than the impact of using copper biocides within antifouling coatings.”
However, this general understanding hasn’t stopped some governments and regulators from restricting what goes into the most common antifoulings. Despite heavy restrictions on copper-based antifoulings in places like Washington State and Sweden, more than 90 per cent of ships still use these products, according to Colin Anderson, an antifouling consultant with Ilara Consulting Ltd. That number is even greater within the yacht and superyacht markets.
And those in the industry don’t see regulations loosening any time soon. For this reason, manufacturers have begun to move toward more environmentally friendly products, with scores of chemists constantly testing out new theories.
“The ultimate mission is to produce a paint which still prevents any living organism from living on the bottom of your boat – but to do so without containing any solvent, without containing any metals and without containing any biocide compounds,” says Ken Hickling, the president of the International Superyacht Society and a global manager with AkzoNobel. In the very next breath, he says, “That’s probably impossible,” before going on to describe the closest thing his company has found yet: a fouling-release product called Intersleek. The product, along with its various competitors, doesn’t contain any metals or biocides and allows for barnacles to be wiped clear with a sponge.
The technology has been slow to catch on in yachting for various reasons, not least of which is the difficult application process. Jotun doesn’t recommend its use on yachts and Seajet has withdrawn its fouling-release coatings from its leisure line.
Still, many in the industry view these fouling-release coatings as the next step in fouling-prevention technology. Technically they are not antifouling because there are no biocides involved. And that is a major step toward making these bottom paints not only beneficial in terms of the larger issues they address, but also in terms of how they interact with local marine environments.
Leads and tins and other bad things
Ever since man has taken to the seas, he has been losing the battle against fouling.
Only in recent history has the tide begun to shift slightly in our favour, thanks to a great deal of innovation.
“Mariners have been experimenting with antifouling coatings since around 1500 B.C.,” says Ben Van Mooy, an associate scientist of marine chemistry and geochemistry with the Woods Hole Oceanographic Institute. Early Mediterranean civilisations coated their boats’ hulls with lead. “So if you think about it, putting metals on ships as antifouling goes all the way back to the beginning,” Van Mooy says.
Through the years, the metals changed as we understood them more. Compounds like lead and mercury were eventually replaced by tin-based antifoulings in the 1970s. By 1980, the self-polishing co-polymers combined with TBT proved to be a gamechanger.
The paint behaved differently. It continuously leached into the sea, like shedding a layer of skin, so a fresh layer always exposed. While great for ships’ hulls, it soon became apparent that leaching toxic compounds into marine environments was not rendering positive results below the water’s surface.
Heightened awareness, heightened regulation
It was around this same time that environmentalism became a cause for concern within industrialised countries. It quickly became apparent that marine habitats were being adversely affected by TBT, one example being that it caused a type of sex-reversal in dog whelks that killed off whole populations. It has also been linked to developmental problems in some marine mammals.
While TBT was banned on yachts as early as 1987, the IMO didn’t ban TBT outright until 2001 – and that ban didn’t officially enter into force until 2008, well over 20 years from the time bountiful evidence first emerged. The IMO defends the lapse, saying that bureaucracies are inherently slow.
Still, others claim the IMO was waiting for something equally effective to hit the market, which didn’t happen until copper acrylate antifoulings were introduced.
Notably, in the decades leading up to the TBT ban, globalisation was causing marine traffic to rise dramatically.
According to the World Trade Organisation, global trade has grown 27 times what it was in 1950. Of that, about 90 per cent of all goods are now transported by sea, according to some studies.
This presents the world with some serious problems. “Let’s just say we outlawed all antifoulings,” proposes Van Mooy. “Well, then our ships would be burning 20 per cent more fossil fuels, or even more.”
So while TBT may have been a problem, its use likely prevented the exacerbation of more pressing concerns.
“Efficacious antifouling saves bunker and greenhouse gas emissions as well as providing effective protection against transmigration of species on hulls,” says Jotun’s megayacht brand manager Marcus Reynolds. “Therefore, we may confidently state that: the better the antifouling, the greener the vessel.”
Jotun offers a copper-based antifouling to its megayacht customers: Imperial Antifouling. Its biocide is a combination of copper and cuprous oxide. Reynolds says it’s “the preferred option for a customer that wants to be green, together with up to three years performance warranty.”
The copper question
For the foreseeable future, the world is mostly content with copper-based products. After all, copper appears to be significantly less dangerous than tin – at least so far as scientists have been able to document. There have been some localised restrictions on copper-based products in Washington State and the Netherlands, but most people shrug off the tightening regulations seen as having no foundation.
Anderson describes the evidence used to justify a ban in Washington State, where there was concern over whether copper affected salmon farming, as “absolutely ridiculous.” The restriction limits the amount of copper used in paints to 0.5 per cent. But that tends to be how these things work: a substance is wonderful until proven otherwise.
“When you think about TBT, everything was fine when it was first introduced. And nothing changed about how it worked; what changed was what we understood about how it worked,” Van Mooy says. “You’re talking about long-term effects here…The evidence that we’re seeking is also extremely hard to gather.”
California has also placed tighter regulations on copper antifoulings in localised areas, restricting the rate at which an antifouling leeches into the sea. Anderson considers these to be much more sensible. “It’s not what’s in the paint; it’s what comes out of the paint that really matters,” he says. “This is the way I think it’s going to happen in the future. Governments are going to regulate based on what comes out of the paint rather than what’s actually in it. It could be full of something really horrible, but if it doesn’t come out then it’s not going to have an environmental effect.”
Many companies have been working to reduce the amount of copper in their antifoulings. Seajet, for example, developed 031 Samurai Antifoul in 2012 – “a budget-conscious, self-polishing antifoul protection for yachts and boats with significantly reduced amounts of copper content,” says Adam Fiander, a spokesman for Seajet. The product contains 30 per cent copper by weight and was given five-out-of-five stars by Motor Boats Monthly.
Other companies are producing copper-free antifoulings – even biocide-free antifoulings. “We’ve already gone to a lot of biocide-free products which may just rely on the fact that they are self-polishing or sometimes they have a zinc component which – while itself isn’t classified as an antifouling – does act by its nature as a fouling-deterrent,” says Drew Allen, a 22-year AkzoNobel employee who now works as an independent coating consultant.
“For us, it’s a full-time job to keep up with the regulations that are – not just the ones that are in force now, but the ones that will be coming into force in the next five to 10 years that we haven’t planned for,” says Hickling.
This is why Anderson calls himself a “student of antifouling,” because “it’s a constantly changing subject.”
The great unknown
This ever-changing regulatory environment is good news to one group of people in particular: chemists. Antifouling manufacturers employ hundreds of chemists to constantly improve products – to make products as effective with less copper, less biocide, less everything. “They’ve got all these guys that sit over there and that’s what they think about – that’s their life,” says Jim Seidel, a marketing manager with Interlux and Awlgrip Yacht Finishes, which is part of AkzoNobel.
In response to restrictions on copper, the company recently released Micron CF, a copper-free antifouling that uses econea as its biocide. “It’s a fairly nasty chemical in its deep form when you get it,” he says. “But when it comes out of the paint form and into the water column, it breaks down into its various constituents very quickly.”
This seems to be the way things are going. Despite copper’s dominance, companies are already testing out replacements due to what they view as an eventuality: that copper will ultimately be banned or restricted to such an extent that it may as well be banned. But this will be gradual, and only done if there is something to replace it.
“There will only be a complete ban on biocides if there’s a product that can replace it and work as well,” Anderson says. “And at the moment there aren’t any biocide-free products that work at exactly the same level.”
One of these – one that holds great promise in the eyes of Mooy and others – is the various forms of fouling-release coatings, like Intersleek. The product is one of several fouling-release coatings on the market, a fluoro polymer that is difficult for anything to stick to. “The boat becomes self-cleaning at about somewhere around 5-to-10 knots,” Seidel says.
“Intersleek shows us the promise of what that technology could have,” Van Mooy says. However, there are drawbacks: the price of application is more than three times more expensive and it is not as effective on ships at anchor.
Ships and yachts. Organisms can grow and build on stationary hulls, whatever the size. Reynolds says Jotun only recommends fouling-release coatings if a vessel is active half of every day, adding that the average charter yacht is normally only active 20 per cent of the time.
Additionally, it requires very precise application. For the time being, Seajet pulled its fouling-release coating from its leisure line because of this, says Fiander.
“If you had a charter yacht and you were prepared to clean it every so often, then it would be entirely in your advantage,” says Allen. “But it is a niche market.” He worked with AkzoNobel to launch Intersleek in the Netherlands two years ago and says the sales “have been extremely slow.”
“We have coated some superyachts with it,” he says. “But they tended to be people who were shipowners, so they knew the product.”
Part of the problem may be the product’s extremely long lifespan, says Allen. While it is delicate and expensive and very difficult to apply properly, it can last more than a decade. “You’re kind of cutting your own throat,” he says. Shipyards want repeat customers – and regularly, because that’s a lot of business.
“At the moment, they get these people coming back every 24 months – new coats of antifouling and loads of other work, because it’s seen as a service period,” he says. “If you don’t need that – don’t need to haul out – then that’s a lot of money lost.”
However, these drawbacks are still enough to send owners back to yards for antifouling. “We get a lot of interest,” Hickling says, referring to the yacht market. “We talk people through the pros and cons, and that interest winnows down to a small number of people who really want to have it.”
Hickling still considers it a niche product, though it has gained traction outside the yacht market. And Intersleek has had a new development. In April, it came out with a version that contains a new, non-toxic additive which creates a surface effect that is less hospitable to colonizing organisms, Hickling says.
So the market appears to be shifting in favour of these innovative technologies. “As regulations tighten down,” Hickling says, “Intersleek and its various competitors will become increasingly in demand.”