Anti-fouling alternatives feature new approaches

Copper-based paints come under increased ecological scrutiny

For decades recreational boats have used a variety of anti-fouling products to prevent marine growths from adhering to vessel hulls. 

In the 1960s, in an age of increasing concern over air and water pollution, it was found that some bottom paints were impacting a wider variety of aquatic organisms than imagined – particularly when found in high concentrations, such as in the vicinity of harbours and marinas. 

Classed as biocides, bottom paints containing the tin-based compound tributyltin were banned in many countries beginning in the late 1960s after the chemical began showing up in seafood, including salmon and shellfish.

Anti-fouling paints come in two basic forms – ablative paint, which is designed to wear off and constantly expose fresh layers of biocide, leaching copper into the environment in the process, and non-ablative paint, which doesn’t physically erode but also leaches copper into the water in order to work. How much? Estimates suggest a 30-foot sailboat will leach about two pounds of copper into the water each year. 

The trouble starts when boats are found in concentrated environments like marinas, where copper levels can quickly build up and exceed U.S Environmental Protection Agency toxicity standards of 3.1 parts per billion. 

MacGlide is a biocide-free, self-adhesive film which is attached to the hull below the waterline, then coated with a special sealing varnish.

In the United States, bottom paints that contain more than 0.5 percent copper will be banned in Washington State effective Jan. 1, 2020, leaving boaters to wonder what alternatives exist.

While much of the recreational boating industry’s attention has focused on developing alternate forms of liquid bottom coatings, a handful of companies have taken an entirely different approach to the problem by focusing on creating physical or electronic barriers. 

MacTac – once popular as a self-adhesive shelf liner that was used in nearly every 1970s American kitchen cupboard – has developed a new antifouling barrier product in Europe that could find a niche in North America. Called MacGlide, the biocide-free product consists of a self-adhesive film which is attached to the hull below the waterline, then coated with a special sealing varnish that the company has developed in cooperation with paint manufacturer PPG. “MacGlide antifouling protects the hull from the colonization of marine micro-organisms without spreading toxic substances into the ocean,” said PPG business development manager Daniele Perotti, during a Pitch The Press event held in conjunction with the 30th annual METS trade show in Amsterdam. “It is 100 percent biocide-free, and will last approximately five years.”

Coventry-based NRG Marine used METS to debut its new Soni8 ultrasonic anti-fouling product, based upon the company’s established Sonihull system which has been used in commercial applications for years. 

With more than 15,000 systems installed worldwide and a customer list that includes the U.S. Coast Guard, NRG Marine is expanding its footprint from commercial vessels into larger yachts. The company claims its Soni8 system, which protects hulls, rudders, drive shafts, stern drives and even jet drives, deters all forms of marine growths and can ultimately reduce fuel costs by up to 30 percent. 

“It’s a fit-and-forget system. With one panel and a few transducers you can protect the entire yacht,” said NRG Director Darren Rowlands. “Our technology is reducing the marine industry’s dependence on toxic chemicals while simultaneously reducing environmental impact and lifetime maintenance costs.”

Gloucester-based CMS Marine used METS to showcase its SonicShield anti-fouling system.  “The ultra-high frequencies are not harmful to humans, fish, plant life or any other marine-based life forms,” said Sam Crawford, CMS sales director.

The clear advantage to ultrasonic systems is that they don’t need to be re-applied again and again. The disadvantage is price – the entire cost is paid up front at the time of installation, unlike bottom paints which spread the cost of anti-fouling over the life of the boat. But that higher cost will likely come down if the technology can achieve critical mass in the marketplace.

As new alternatives gain traction and the ecological impacts of copper-based bottom paints come under increased scrutiny, changes are coming to the anti-fouling segment. What form they will take remains to be seen, but the innovation shown so far holds promise for the future.   


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