Antifouling Paint : A Double Edged Sword !

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  • Innovation in the field of ship hull coatings is helping to improve fuel efficiency.
  • If not treated with special coatings, small marine organisms can accumulate on a ship’s hull and increase the vessel’s resistance in water, leading to higher fuel consumption.
  • Furthermore, the sections of ships below the waterline become vehicles for the transfer and spread of aquatic invasive species such as zebra mussels, barnacles, and tunicates.

Before diving into the specifics of hull coatings, their benefits, environmental impacts, technological advances and how they are regulated, let’s look at why they are needed in the first place.

About Biofouling

Have you ever noticed the buildup of algae or shellfish on the submerged parts of waterside structures such as the pillars of a pier? If so, you have witnessed biofouling. Through this process, also referred to as marine growth, marine organisms and species settle and accumulate on the many surfaces, nooks, and crannies of underwater structures. When biofouling occurs on the hulls, propellers, intakes, and other parts of ships that contact the water, marine species can ‘hitch a ride’ from their home ecosystem to a new one. They are then considered invasive species because they are disturbing the new ecosystem’s balance which can threaten the survival of native species in the area.

When marine species attach to ships, they roughen the hulls, which creates friction and drag through the water. This resistance causes ships to use more fuel and emit more air pollutants and greenhouse gasses during their voyages. And not only is a higher fuel consumption bad for the environment, it raises the operational cost for ship operators and, ultimately, for consumers worldwide who depend on marine shipping for access to goods and commodities. In-water friction caused by hulls and propellers fouled with marine organisms can also influence the levels of underwater noise ships emit in the marine environment. 

Are Antifouling Paints Harmful To Marine Life?

Anti-fouling coatings are a type of paint applied to the hull of a ship to prevent marine species and organisms – barnacles, zebra mussels, algae, and more – from attaching to the surfaces of vessels that contact water. By doing so, anti-fouling paints play an important role in preventing the transfer and spread of invasive species by ships and ensuring that commercial vessels can navigate without unnecessary resistance, improving their flow in the water, and the overall performance and sustainability of their voyages.

Hull coatings are not new. For centuries, sailors and mariners have been trying to prevent aquatic life from growing on ships through hull linings, notably thin sheets of copper nailed to the hulls. Because of its toxicity to marine organisms, copper was the preferred solution against biofouling since the early days of marine transportation. But because it accelerates corrosion, copper was no longer a viable solution when iron replaced wood as the predominant material used for ship building.

Although effective at preventing bioaccumulation, these paints – made from compounds such as copper, arsenic, and other biocides – eventually flake off or leach out into the water releasing harmful chemicals into the marine environment. Those toxic compounds are being ingested by marine organisms, contaminating the food chain, and disrupting the growth of marine life. Low friction anti-fouling paints that make it harder for marine life to attach – rather than killing it – are an alternative.

New Antifouling Technologies

Three Canadian companies are working on antifouling technologies that are both safe for the marine environment and improve the efficiency of ship voyages.

  • A20 Advanced Materials Inc : To prevent pollution of anti-fouling paints into the marine environment, Vancouver-based A20 Advanced Materials Inc. has developed a novel underwater adhesive that can prevent corrosion and enable durable bonding of low-friction foul-release coatings. Using proprietary self-healing technology, their non-toxic coating can extend the working lifetime of marine assets while improving vessel efficiency through reduced drag. 
  • Graphite Innovation & Technologies (GIT): This Halifax-based organization has taken a different path by developing a durable low-friction coating impregnated with microscopic graphene particles that make it extremely slippery and durable. In addition to making it hard for marine organisms to attach to the slippery surface, this coating contains no biocides to leach out nor microplastics to flake off. It also has surprising sound deadening properties. 
  • Mirapakon: Quebec-based company Mirapakon is working on bringing to market a silicon-based coating – that is free of toxic compounds – developed by the U.S. Navy, with the primary goal of improving the efficiency of maritime activities such as shipping. This includes fuel economy provided by hulls that are free of organisms that could create in-water resistance. 

Anti-fouling coatings appear to be a win-win solution by preventing the spread of invasive species and reducing air emissions from ships. But, in many instances, actions and solutions meant to solve a specific problem often come with unintended consequences and environmental trade-offs.

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Source: Clearseas

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