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Boating’s Copper Age: the future of bottom paint

From foul-release systems to organic biocides, copper-free coatings are gaining ground


Companies specializing in marine coatings are looking down the road to a time when all metal-based bottom paints, including copper, are a thing of the past. California may be leading the charge in that direction, but paint manufacturers everywhere are experimenting with high-performance mixtures that release copper more conservatively or, better yet, satisfy customers with alternative antifoulant chemicals.

While there's no denying copper is an effective biocide - it's been used on boats for centuries - research now is focused on how it is released and at what rate.

The search for the Holy Grail among paint manufacturers is the search for the next effective biocide - one that may ultimately replace copper, although that is probably still years away. Copper, in one of its forms or variations, will likely remain the dominant biocide in bottom paints for years to come. Why? It's relatively cheap, and customers know it works, according to paint manufacturers. Keep in mind that it took 20 years to ban tributyl tin, or TBT, after the first regional bans were enacted. There are presently no copper bans in the United States.

Don Zabransky, national marketing manager for Rockaway, N.J.-based Pettit Paint, says manufacturers are developing new biocides and new technology to make biocides more effective at lower concentrations. Composite copper, for example, is an alternative biocide that mixes copper with silica sand, reducing the copper footprint by up to 40 percent.


"The result is a copper biocide surface that provides superior protection for the boat, with a core that is made from materials found naturally in the ocean," Zabransky explains. "The lightweight silica core produces a lighter paint, which helps to reduce fuel consumption."

White copper is another new biocide that's lighter in weight than cuprous oxide. Zabransky says it's so powerful it requires 50 percent less biocide content than the heavy, reddish brown copper used in conventional antifoulants. And the white base allows for brighter colors, he adds.

Some of Pettit's new products, such as Ultima Fusion, use self-polishing copolymer (SPC) technology, which releases what the company claims is only the precise amount of biocide necessary for antifouling protection. Once launched, the SPC surface hydrolyzes, continuously exposing a new layer of paint film. This process keeps the surface clean and smooth, and helps to maximize speed and fuel efficiency, according to Zabransky.

While traditional biocides like copper are good for hard growth such as mussels and barnacles, they are less effective against soft fouling. That's where dual biocides come into play.

The future?

Another copper alternative, developed by Janssen Pharmeceutica, is Econea, which is touted as having an extremely low toxicity and is biodegradable.

Janssen says the chemical works well in small concentrations and its testing showed that antifoulants made with 5 percent Econea are as effective as those made with 50 percent copper. An additional advantage is that the non-metal formulation allows for a variety of paint colors and will not cause galvanic corrosion on aluminum hulls.

This fall, Pettit will introduce a new Econea-based copolymer paint, Vivid, that uses zinc omadine. Pettit's Zabransky says zinc omadine is extremely effective against marine slime, algae and other soft growth. In fact, it's so safe it is FDA-approved for use in dandruff shampoo, he says.

"Econea is, quite simply, the future of antifouling technology," says Zabransky. "That's our big immediate future, and our long-term future."

He's not the only one who thinks so.

Clearwater, Fla.- based Sea Hawk's Smart Solution paint incorporates Econea, which CEO Erik Norrie calls, the "technology of the future," noting, "It creates a slick film, it enhances the speed of the boat, and it protects against fouling."

Union, N.J.-based Interlux offers copper-free bottom paint, but vice president of marketing Bob Donat says the company's new Pacifica Plus bottom coat uses the dual biocides of Econea to target shell fouling and Biolux technology to control slime. Pacifica Plus, he says, has been formulated to meet California VOC (volatile organic compounds) regulations, the most stringent in the country.

Dave Helmer, director of sales and marketing for Janssen's Preservation and Materials Protection Division, is more modest as he talks about his company's first foray into the marine market.

"[Econea is] fairly unique at this stage of the game," says Helmer, director of sales and marketing for Janssen's Preservation and Materials Protection division. However, he stops short of calling it the technology of the future. "It's a step forward," he says simply.

Helmer says Econea opens the door for paint manufacturers to develop new formulations, such as brighter colors. And because Econea can be used in low concentrations, it leaves more room for other ingredients to improve the overall effectiveness of the paint.

Alternative alternatives

Interlux also recently introduced its biocide-free Intersleek 900 fluoropolymer-based foul-release system, calling it "the next generation of foul release technology ... significantly improving upon the performance of the best silicone-based systems."

The smooth and slippery finish, which reduces drag and subsequently improves fuel efficiency, features what the company calls "low surface energy." Fouling organisms generally have a difficult time forming an attachment to a "low surface energy" finish and when they do, it's only a weak attachment, Donat says. Fouling can be removed with sponges, window squeegees, soft-bristle brushes and fleece mitts, he says.

Intersleek 900 has several advantages, Donat says. It offers greater longevity than traditional antifouling paints, he says. And when washing bottoms, the absence of copper, zinc and organic biocides brings cost and environmental advantages in the treatment and disposal of wash water. The biocide-free aspect of Intersleek 900 also gives it superior color retention compared to antifouling paint, he says.

Sea Hawk's Mission Bay paint is a self-polishing antifoulant that uses zinc instead of copper. When exposed to UV light, the nano-based technology copolymer releases an active non-metal biocide that dissipates in seconds without bioaccumulation in the environment. Since it's copper-free, it can be applied to aluminum hulls without the use of a barrier coat.

Another new product from Sea Hawk is Silver Bullet, a low-drag, friction-reducing, high-performance coating that uses zinc dust instead of copper dust. Targeted for the Great Lakes, Silver Bullet is a finish designed specifically for racing in fresh water, according to Norrie.

Another new alternative foul-release product on the market is the Sher-Release Silicone Fouling Release Coating System from Sherwin-Williams Protective and Marine Coatings in Cleveland. The system's foul-release technology combines an epoxy anti-corrosive system and a protective silicone surface coat interlocked by a unique elastomeric formula.

"It doesn't prevent fouling, but once fouling is on the boat it comes off very easily and, for fast-moving boats, it's self-cleaning," says Michael Bentkjaer, marketing director for Sherwin-Williams' Protective and Marine Coatings, Marine and Offshore division.

Furthermore, because it is a foul-release system and not an antifoulant, it contains no heavy metals or biocides. It also features low levels of VOCs.

Meanwhile, Massachusetts-based ePaint has found a way to eliminate VOCs altogether with its Ecominder bottom paint.

"It's safer for the environment, it reduces the carbon footprint, and it's safer for people to use," says ePaint president and founder Alex Walsh.

The water-based Ecominder also offers boatyards more flexibility in application because it works in temperatures as low as 30 degrees and dries fast. It can be applied over older bottom paint, eliminating the need to strip old coats.

"We're really excited about it," says Walsh. "It's been really well-received in the market."

Walsh says all of ePaint's non-toxic bottom paints have also been well-received from a performance standpoint. All are copper-free and are formulated with a combination of what the company calls naturally occurring photoactive materials and organic biocides. Sunlight causes the photoactive pigments to catalyze oxygen and water to produce hydrogen peroxide, which creates an antifouling barrier around the hull. The paints are formulated with organic booster biocides such as zinc omadine or SeaNine 211. These compounds quickly break down into harmless materials once released into the aquatic environment, according to the company.

Old faithful

The main environmental issues with bottom paint are biocides - particularly copper, or cuprous oxide - and the volatile organic compounds from solvent-based formulations. Most VOCs, to varying degrees, contribute to the formation of ground-level ozone. Some are toxic and/or carcinogenic to humans and in high concentrations copper can be harmful to fish and other aquatic life.

Marine coating manufacturers are striving to produce the latest and greatest eco-friendly bottom paints, even though most believe full regulatory mandates are years away. "It's going to come ... but it's a slow process," says Pettit's Zabransky.

While Interlux offers copper-free bottom paint, Donat says his company still supports the use of copper as a biocide. "When copper is used properly in a paint coating it works well and it's an efficient, effective bottom paint," he says. "It offers better fuel efficiencies, and it reduces the risk of invasive species."

He argues that copper-free coatings do not last as long, aren't as effective or as strong, and require more frequent cleaning of the boat, which presents another set of environmental issues.

Sea Hawk's Norrie says most boaters won't catch on to copper-free bottom paint until they're forced by law. "I think that's years away," he says.

So if stricter regulations are years away, why are paint manufacturers working so hard now to develop and market paints that are free of copper?

"We developed these products just in case," says Norrie. And, he adds, "It usually takes a considerable amount of time for people to gain confidence in a product."

Depending on release rates, longevity and the type and amount of copper used, the price for a gallon of bottom paint containing copper and other biocides can range from $100 to more than $200 a gallon.

Traditional copper-based antifouling paints, such as Cukote from Sea Hawk (about $165) and Trinidad SR from Pettit (about $120), remain popular among consumers.

The most obvious reason is the price point. The Interlux line in price and performance runs from Bottomkote Classic at $150 a gallon to Micron Extra, which lists for $239 a gallon. Street prices start at about $125 a gallon.

Walsh acknowledges that the price - at about $200 for a gallon of ePaint - has detracted some budget-conscious boaters. To that end, the company is working on a line of eco-friendly bottom paint at lower price points, and Walsh says he hopes to launch the new line in October, in time for the International BoatBuilders' Exhibition and Conference.

The battleground

In California, a phaseout of copper has been proposed because of high levels of the metal found in places like San Diego's Shelter Island Yacht Basin, where there are many boats and little water flow.

"Some areas of California exceed allowable limits of copper in the Clean Water Act," says Neal Blossom, director of research and global environmental affairs for American Chemet, an East Helena, Mont.-based copper supplier for paint manufacturers. "Alternative coatings to copper will play a more significant role in this market than they currently do. Time will tell on their performance and their effect on the water."

Interlux's Donat says his company decided to launch Pacifica Plus into California first because of some unique characteristics of the California market. "Boat owners in California will leave their boats in the water for very long periods of time and are used to having the bottoms cleaned by a diver on a regular basis."

He says Interlux learned from an earlier version of the Intersleek paint - Veridian - that maintenance is key to the paint's performance in the recreational market. Veridian was introduced in the early 1990s on the commercial side, for ships that are constantly on the move and don't remain dormant at the dock.

"The fouling challenge isn't as great," says Donat. "When we tried introducing it to the recreational market we had some boat owners who didn't really understand the cleaning requirements if the boat is not being used a lot. Without maintenance, the coating doesn't hold up as well."

He says Intersleek 900 has a lot more benefits than older versions, such as a smoother, hard finish. It still requires regular maintenance, however, which is why it is better suited for California, says Donat.

"We are looking to expand it to the rest of the country," he says. "However, we are taking a very cautious approach. We have to work with the boaters to educate them on what is expected of them."

For now, American Chemet's Blossom says he does not anticipate a statewide ban on copper in California or any other state. "That would be excessive," he says. Even at Shelter Island there is no ban, but rather a requirement that 75 percent of boats be copper-free.

Blossom notes that the Environmental Protection Agency is looking at the use of copper as an antimicrobial in a variety of products, including paint, shingles and treated lumber. "There is no indication that copper is going to have any significant restrictions put on it for these applications," he says. "The U.S. EPA, I believe, will go ahead and reregister copper for these applications."

Zabransky says more boatyards are paying attention to copper issues because of what's happening in Shelter Island, but he doesn't think the boating public is in a rush to abandon copper-based paint. "Many boaters will continue to use copper because they know it works," he says.

Bottom line

Overall, opinions among the manufacturers are mixed on consumer buying habits in this down economy. Some paint manufacturers say their sales are off and that distributors, boatyards and retailers are being very conservative in what they are stocking. They say consumers are gravitating more toward the lower and middle price range for paints, and some are painting their own boats to save money.

However, other manufacturers say their sales are actually slightly better than a year ago, and that higher-priced paints are selling well because consumers are more interested in getting value for their money.

Still, none of the paint manufacturers seems overly concerned about the future. They believe the economy will turn around - hopefully sooner rather than later - and there will always be a market for their products.

"People still need bottom paint," says Sea Hawk's Norrie.

This article originally appeared in the June 2009 issue.



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