The growing problem of invasive mussel species in the Great Lakes has prompted researchers to create innovative solutions aimed at preventing their spread to inland lakes and reservoirs. These mussels attach to various surfaces, both in the upper (epilimnion) and deeper (hypolimnion) layers of lakes. During the winter months, mussels will die off, leaving the large structures constructed of their shells on the lakebed. Their colonies recede into the deeper waters where water temperature is warmer than the icy conditions on the surface. In the spring and summer, the mussels return shoreward, recoating the left-behind shell structures and adding layers of shell material to the submerged landscape. Juvenile mussels are released from fish hosts and can migrate or float to nearly any structure or vehicle, with bilge water from ships often transporting them to new locations. Once attached, mussels begin their reproductive cycle, and this adherence is key to their spread. If prevented from attaching, they are forced to relocate, increasing competition for space and resources.

To combat fouling, researchers have developed a clear, tri-cure hybrid silsesquioxane coating that is inexpensive, easy to apply, and safe for aquatic environments. When applied to glass or fiberglass, materials they readily attach to, this coating prevents the bonding of mussel proteins to surfaces, making them resistant to fouling. By coating boat hulls, boat owners can reduce mussel attachment, slowing the spread of invasives, saving on costly maintenance, reducing drag, and contributing to the protection of other aquatic ecosystems.

Introduction

Marine biofouling, which is the undesirable accumulation of microorganisms, plants, and animals on submerged surfaces, poses significant operational and environmental challenges to maritime industries and aquatic infrastructure.^1-3ĚýThe consequences of biofouling are far-reaching. It causes increased hydrodynamic drag on vessel hulls which reduces fuel efficiency and speed, while simultaneously contributing to higher greenhouse gas emissions.^4-7ĚýIn addition, biofouling accelerates the corrosion of submerged metal and concrete surfaces, clogs pipelines in coastal and nuclear facilities, and disrupts water flow and nutrient exchange in aquaculture systems.^8,9

One of the most practical and effective strategies for mitigating biofouling is the use of protective surface coatings or coating additives. These are broadly classified into biocidal and nonbiocidal types. Biocidal coatings rely on the controlled release of toxic agents from a polymer matrix to prevent organism settlement and are considered antifouling coatings.¹⁰ĚýThe efficacy of such coatings is governed by the biocide’s release rate and its environmental compatibility that should ideally combine strong antifouling activity with low toxicity and moderate fresh and sea water solubility. Unfortunately, only a limited number of biocides meet these stringent requirements for safe and sustained marine use.¹¹

Nonbiocidal coatings primarily include fouling-resistant and fouling-release coatings (FRCs). Fouling-resistant coatings are typically based on hydrophilic polymers such as poly(ethylene glycol) (PEG) and zwitterionic materials, which prevent initial organism adhesion.¹²ĚýHowever, their tendency to swell in saline environments leads to poor mechanical performance. In contrast, FRCs utilize hydrophobic, low-surface-energy materials that allow weakly adhered organisms to be easily removed under mild shear forces. Polysiloxanes are commonly used as FRCs and offer excellent thermal and photochemical stability, though their long-term performance is limited by hydrolytic degradation. To overcome these limitations, hybrid organo-silicon coating systems have been developed. These systems integrate organic and inorganic elements to combine durability, antifouling characteristics, and environmental resilience.^13,14ĚýFor instance, R-alkoxysilanes, particularly methoxy and ethoxy variants, have long been employed to consolidate porous substrates like stone by forming crosslinked siloxane networks with the ratio [RSiO_3/2], or silsesquioxanes that also contain organic bridges. When incorporated into coatings, these networks offer benefits such as low thermal conductivity, oxidative resistance, and mechanical integrity.

Among silicon-oxygen-based coating systems derived from alkoxysilanes, tetraethoxysilane (TEOS) is a widely used precursor.^15,16ĚýHowever, its slow curing rate often necessitates acidic or basic catalysts and long reaction times. As an alternative, photocuring methods that utilize photoinitiators to trigger rapid organic polymerization under light have gained popularity for enabling fast curing without complex handling or component separation. Moreover, using R-functional trialkoxysilanes with epoxy, amine, thiol, or fluorocarbon side groups allows tailoring of surface adhesion, hydrophobicity, and internal stress relief within the final silsesquioxane-based coating.¹⁷

Bioinspired approaches have further guided the design of antifouling surfaces. Many plants and insects feature microstructured, waxy coatings that combine hydrophobicity with self-cleaning properties. Mimicking these strategies, coatings with nanoscale surface roughness and low-surface-energy materials (e.g., fluoropolymers) have been developed to enhance water repellency and reduce biological adhesion.

By Cynthia A. Gosselin, Ph.D., The ChemQuest Group

As discussed in Part One of this two-part series, it is quite the technical feat to develop marine coatings and methods that keep the submerged portion of the hull free from sea creatures and corrosion without also destroying everything in the vicinity. The many efforts underway to accomplish this are represented in the fact that 64% of the $8.7 billion marine paint market is dedicated to this endeavor. The complex underwater scenario is rarely seen by spectators watching yachts, fishing boats, sailboats, and commercial shipping vessels sail majestically away to their maritime adventures.

What is seen is the part of the boat that is above the waterline. The beauty and majesty associated with boats is represented by topside coatings that impart gleaming paint jobs that are the icon of yacht-quality maintenance—and the goal of all boat owners. Aesthetics are very important and affect the ranking and resale value of a vessel.

Topside paint is, technically speaking, not considered “as important or complex” as bottom boat paint, but it does provide corrosion resistance and significant protection against UV rays. Weeks of sun exposure without “sunscreen” can damage the surface of boat hulls and gunwales just as dramatically as skin can sunburn and blister.

Topside coatings are formulated specifically for the substrate to be painted. Many modern boats have fiberglass hulls, but there remains a significant market for wooden boats among enthusiasts, classic boat owners, and traditionalists.

From Air to the Sea

The genesis of modern topside boat paint occurred in 1973 when two Eastern Airline pilots persuaded Merritt Boat & Engine Works to paint their boats with a coating called Alumigrip that, until now, had only been used on planes flying at 450 knots (517 mph). The coating seemed immune to UV degradation and was extremely hydrophobic. The results were so stunning that US Paints decided to market the product for the marine industry.

Through a series of bar discussions and poor handwriting, Alumigrip became Awlgrip —perfectly (albeit accidentally) named for the marine industry. The new coating process consisted of an epoxy primer and a sprayed linear-polyurethane coating. Ted Turner, winning the 1977 America’s Cup in a record four-race sweep sporting a beautiful Awlgrip topcoat, propelled this coating technology to the top of the marine world. Since then, polyester and acrylic-modified polyurethane topcoats have been added to the product line, providing the same UV and corrosion resistance and hydrophobicity of the original experiment. In the 50 years since the inception of this product, it has become the go-to paint system for the marine and yacht market.¹

Liquid Coatings

Today’s maritime world still has expensive yachts, wealthy boat owners, and less-than-handy boat enthusiasts that commission commercial painting and maintenance for their vessels using only the top-of-the-line coatings. But similar to other industries, the Do-It-Yourself (DIY) philosophy has taken root because of the wildly fluctuating and increasing prices (much to the dismay of boat refurbishing companies).

Paint companies have responded to the DIY demands by simplifying paint systems that provide glossy finishes and decent durability. One-part modified alkyd enamels, urethanes, and two-part simple mix products line marina supply and big box store shelves. If properly applied, the aesthetics are excellent. With some routine maintenance, durability is good enough.

In addition to aesthetics and durability, ease of application is a prime consideration of the DIY consumer. Of course, while the roll-and-tip finish will never rival a PRO-sprayed finish, the results from today’s formulations can be very good.

Several of these formulations generate little sagging and dripping, which is the bane ofĚý improperly applied high-end coatings. The caveat is that the instructions for surface preparation must be carefully followed, the owner has a modicum of sanding and buffing skill with the requisite amount of patience. Boat refurbishing companies hide their grins when someone comes in for a full paint repair because they “knew how to paint and didn’t need directions.”

In fact, many PROs that mentor DIY novices suggest first painting oars with the paint system that will be used on the boat hull. This provides insight into the behavior of the paint and more importantly, the actual skill and ability of the painter.

The chemistries used to either commercially or DIY paint new or refurbished boats include alkyds, epoxies, and polyurethanes for interior and exterior surfaces. Table 1 provides the typical paint systems used for various boat locations with the projected maintenance intervals.

Powder Coatings

Powder coatings are used in a huge variety of applications, including boating and marine equipment. These types of coatings are not as widely used as liquid systems, primarily because they are more difficult, if not impossible to repair without completely removing the existing coating. However, there are some advantages to using powder coatings on metal surfaces—particularly for ladders, stairs, rails, flag poles, and such items. Metal, unlike fiberglass or wood, tends to corrode if there is a poor barrier layer between the surface and the environment. The higher powder coating film thickness, together with complete coverage, provides this advantage.

Salt particles are highly corrosive to common powder coatings. If not formulated specifically for marine applications, salt will permeate the coating over time, causing it to powder and break down. Marine powder coatings are typically made from specialized resins and additives that provide for durability, flexibility, water resistance, UV resistance, and even antifouling properties. In addition, these powders use different media—glass beads, coarse and medium sand, etc.—to generate a variety of textures. Powder coatings also have good chemical resistance to most of the types of exposures that boats can encounter even in relatively clean water.

Powder coatings can be applied to a wide variety of substrates, which helps in reducing corrosion on the metal parts throughout the boat. Epoxy and modified epoxy powder coatings are the oldest and still most widely used for this application. They are considered to be “surface tolerant” by many repair shops because of good adhesion to minimally prepared surfaces.² Many South Florida boat owners choose powder coatings for their metal boat parts because the surfaces maintain their luster and shine without needing constant attention.

Other structures located at or very near the coast or off-shore also benefit from powder coatings. Reliability and durability are critical for metal structures that are exposed constantly to the environmental attack of seaspray, humidity, and sunlight. Powder coatings used for these applications provide protection from these elements.

These coatings are governed by standards such as ISO 12944-5:2019. This standard lists environment classifications and provides guidance as to the types of coatings that have been proven to perform well within those boundaries. Suggestions for testing are also provided. Powder coating chemistries and film thicknesses for metal on boats, shoreline, near shoreline, and sea structures are part of this standard.

Rigorous accelerated and real-time cyclic testing has verified long term durability, corrosion resistance and extended surface aesthetics for marine applications. Marine powder coatings must perform well in Corrosion Classification C5M–Very High Marine, which encompasses on shore and offshore areas of high salinity. Buildings in this classification are almost always subjected to constant condensation and high environmental salt contamination as well.³

Typical accelerated testing for marine products includes ASTM G85 Salt Spray and Salt Fog Testing: Annex 1—Acetic Acid Salt Spray Test (non-cyclic) or Annex 3–Seawater Acidified Test (cyclic).

In addition, real-world testing is also required in order to ensure that the corrosion mechanisms are not artificially test-induced, but actually occur in the ascribed environment. Florida exposure testing includes 72 hours of accelerated UV exposure, 72 hours of neutral salt spray exposure, and 24 hours low temperature testing at -20 °C. This cycle is repeated 25 times (4,200 hours) to ensure that the paint systems on metal substrates ultimately exhibit the necessary durability.⁴

Deck Coatings

A necessary safety feature on boats is a skid-resistant deck. No boat owner wants to take the chance that a purported non-skid deck paint loses gripping power and someone ends up overboard. The substrate determines the decision to prime the deck surface. If the deck is wood or bare metal, a primer is crucial. If the deck is wood, a sealer is required. The best primer is a 2K epoxy because it provides more durability and hardness than a one-part system.

The easiest topcoats to apply are one-part paints containing non-skid additives—with the caveat that they be mixed well for an even application. The 2K linear polyurethanes will last longer and stay cleaner than textured paints or one-part coatings. For higher-end paints to perform better, more care must be taken during application. Professional boat refurbishing shops will generally spray-apply polyurethane. Following the application of the textured layer, multiple thin coats are applied to seal the surface. The 2K linear polyurethanes last at least five years and, in the right environmental conditions (rainy and cloudy versus constant sunshine) can provide good service for up to 10 years.

Wood Coatings

Aluminum is taking over as the preferred mast material for modern sailors. But many classic boat owners, traditionalists, and boat enthusiasts love the aesthetics of a wooden mast—even though it requires much shorter maintenance intervals than all other topside paints. Most topside wood paints lose gloss, color, and durability after only two years—but every sailor should check the mast every year. Furthermore, because masts, spars, and tillers see the most banging of any wood component on a boat, chip- and abrasion-resistance are also important coating characteristics. In fact, clear coatings are preferred on masts because cracks, fungus, wood rot, dings, and chips are visible very early—helping to avoid significant damage or a sailing disaster. Paint tends to hide cracks and seams where water can penetrate, causing unseen deterioration due to moisture ingress. These spar varnishes also tend to be soft and flexible, adapting to the expansion and contraction due to hot, dry, cool, and wet weather cycles without cracking.⁵

There is a one-part, self-crosslinked system with outstanding weathering properties. It is safe for application both above and below deck because there is virtually no odor, it has low VOCs, and it is non-toxic. It contains three UV-stabilizers, does not yellow, and is mold and mildew resistant. It flexes with the wood to prevent cracking—providing longer durability. The formulation allows for cleanup using only water.⁶ Heightened consumer environmental awareness, especially relating to waterways, will spur coatings developers to make more environmentally compatible coatings available in the future.

Topside coatings are a very well-developed genre of marine coatings because serious boat owners understand that the eye-catching, gleaming appearance of a well-maintained boat is really a beautiful cover for a tough preservation imperative for long-lasting enjoyment in the ironically corrosive environment of beautiful lakes and seas.

References

1. Awlgrip website. “1973—From Planes to Boats.” https://www.awlgrip.com/fiftyyears/1973-from-planes-to-boats (accessed September 12, 2023).
2. Coatings Systems Inc. Benefits of Marine Powder Coatings for Boats. November 20, 2017.
3. International Standards Organization. 2019. ISO 12944-5:2019 Paints and varnishes—Corrosion protection of steel structures by protective paint systems—Part 5: Protective paint systems.
4. Northpoint Ltd website. Anti Corrosion. “What Is Marine Grade Powder Coating?”Ěý https://www.northpoint.ltd.uk/2021/08/26/what-is-marine-grade-powder-coating/ (accessed September 24, 2023).
5. The Wood Whisperer.Ěý “Difference Between Spar Varnish and Regular Varnish?” October 20, 2008.

By Cynthia A. Gosselin, Ph.D., The ChemQuest Group

In 2022, marine coatings were an $8.7 billion market, with a growth projection of 5–7% through 2028.¹ However, there is a lot more to marine coatings than great aesthetics. At approximately a 64% share, anti-fouling/fouling release coatings were the largest portion of the marine coating market, followed by anti-corrosion and self-cleaning/self-polishing coatings. In addition, marine coatings have special and specific functionalities to protect watercraft above and below the waterline. Finally, marine coatings are specially formulated to be easily cleaned.

The two most significant drivers for the growth of the marine coatings market are transportation of goods by sea and recreational sailing. Unlike relatively new, speedy, expensive air shipping, transportation of goods by sea is a centuries-old tradition. To this day, it remains the preferred method for heavy or bulk products. Interestingly, it is also the most cost effective and it tends to have a lower carbon footprint and emission standards. Additionally, safe harbors are widely available almost everywhere there is water, making it a practical and accessible choice.

Recreational or leisure boating is the second largest driver of the marine coatings market. Whether for routine maintenance, hull cleaning, racing efficiency, fuel economy, or craft longevity, marine coatings are top-of-mind for large- and small-craft owners. In both the shipping and recreational categories, shipbuilding and repair are enjoying a resurgence in the post-COVID market.

With all these factors contributing to the growing demand for marine coatings, it’s essential to understand what they are and why they’re so vital. Simply put, marine coatings are broadly defined as waterproof protective layers that are applied to surfaces exposed to or immersed in fresh, brackish, or saltwater. Boats, ships, ferries, small watercraft, and marine structures such as offshore oil rigs and bridge structures employ some kind of marine coating both above and below the waterline.

A wide variety of coating chemistries can be used depending upon the specific substrate and service application, with the exception of unsaturated polyester resin (the type often used in fiberglass). Most marine coatings contain varying degrees of volatile organic compounds and can be applied by brush, spray, roller, or any other convenient method.²

Topside boat paints are usually 1K or 2K polyurethanes, buffable 2K polyurethanes, or alkyd marine enamels that protect the boat from UV damage. Bottom boat paints are antifouling coatings designed to reduce the attachment of aquatic organisms to the hull. Bottom paints include ablative and hard coat paints as well as primers. These types of coatings are best removed with paint removers especially designed for these chemistries.

The inability to escape the effects of biofouling beneath the waterline is one of the main reasons for the strength of the antifouling paint sector. Many boats and ships sat idle during the COVID-19 pandemic and exacerbated the problem, especially in relatively still, warm waters. Sitting idle in the harbor allowed the bottom of watercraft to accumulate barnacles, tube worms, algae, sea squirts, and slime.³ While this is a natural aquatic process, it is one of the most significant hurdles for boat and ship owners alike—particularly when speed and fuel economy are compromised. The commercial reason for using antifouling paints is for improving the flow of water passing the hull, and thereby maximizing fuel economy.

When a hull is covered by only 10% barnacle fouling, 36% more power from the engine is required to maintain the same speed through the water and could be responsible for 110 million tons/year of excess carbon emissions and $6 billion of addition fuel cost in the international shipping industry.⁴

Even recreational sailing is affected. Tapio Lehtinen was racing the 2019 Golden Globe non-stop, around-the-world race when he was almost stopped dead in the water. Racing furiously with his rival, he surprisingly noticed that he was being left behind. Thinking something had happened to his propellor, he dived in to check. To his dismay, barnacles were growing all over the hull. He did finish the race, but 110 days behind the winner. Barnacles had encrusted the entire bottom of the hull, stealing his speed. More had colonized on his self-steering blade, causing it to shear off when the load became too massive.⁵ Whether recreational or commercial enterprises, billions of dollars are spent every year to increase the usefulness, fuel economy, and longevity of watercraft by reducing biofouling.

Besides the economic and convenience factors, biofouling presents another important ecological concern. Marine life hitchhiking along the bottom of a boat can be the mechanism for translocating invasive species to the wrong ecosystem, far from natural predators.

Striped zebra mussels are a species native to the Caspian and Black Seas of Russia and Ukraine that have been distributed by ships as invasive species in Ireland, Italy, Sweden, Spain, the United Kingdom, and the United States. Root-like threads of protein called “byssal threads,” enable the zebra mussels to adhere very tightly to hard surfaces (like boat hulls, native mussels, and rocks). They colonize rapidly in the absence of natural predators, filter out algae needed by the “locals,” and are the succubus that attaches to and incapacitates native mussels. The zebra mussels form dense clusters that cut off water flow, clog pipes, and damage equipment. Their sharp edges can injure swimmers, and the infestation may lead to the devaluation of the boat. Since the 1980s, the Great Lakes in the United States have been struggling to eliminate this nuisance that just came along for the ride.⁶

Because of all the ship and yacht traffic, the Mediterranean Sea has more than 800 identified invasive species. In one audit of leisure vessels sailing through that area, 71% of leisure vessels were harboring at least one non-native species.⁷

Despite the problems plaguing biofouling of hulls, the landscape for marine coatings is moving toward sustainability measures and stricter environmental regulations. Copper-based, biocide-boosted antifouling paints have been the dominant performers in reducing biofouling. However, the effect of these paints does not segregate itself to affecting only those aquatic hitchhikers that attach themselves to the hull. Rather, cuprous oxides carrying biocides leach into the water, where they ultimately settle at the bottom of the sea or lake, also poisoning oysters, welk, clams, and other bottom-dwelling organisms.

Marine coatings manufacturers are now emphasizing improved sustainability along with operational performance factors of reduced power demand, lower fuel consumption, and carbon emissions. Manufacturers have had to become more cognizant of the environmental effects of biofouling agents because of the push by the regulatory agencies resulting from harbor contamination studies conducted during pandemic idle time.

Earlier, paints that contained the organitin biocide tributyltin (TBT) were banned on January 1, 2008, by the International Maritime Organization. For more than 40 years, TBT had been used successfully to boost the performance of cuprous oxide through controlled release. The problem with this effective method was that TBT would leach out of the paint, damaging the aquatic hitchhikers and contaminating the surrounding water. Once there, it would accumulate at the bottom, affecting the endocrine systems of shellfish. This led to abnormal developments, such as female snails taking on male sex characteristics, and severe deformities in oyster shells, making some beds almost extinct.

Since the TBT biocide ban, the number of effective biocides that meet regulatory requirements has decreased substantially. As a result, self-polishing copolymers (SPC), controlled depletion polymers (CPD), and foul release (FR) coatings are gaining popularity. Right now, the biocides in SPC and CPD are evenly dispersed in the matrix and not bound to anything. Release occurs when the matrix erodes (polishes) or by dissolution when water penetrates the paint film. These reactions are relatively uncontrolled and could lead to premature dissolution or over-leaching. Research is underway to find a way to attach the biocide molecules to a polymer carrier. Using hydrolysable covalent bonds could control the release rate of the antifouling constituents— mimicking the long-lived controlled performance of TBT.³

It is clear that a totally different strategy will be needed in the future to satisfy ultimate environmental concerns and regulations in harmony with antifouling performance characteristics. On the one hand, something is needed that will keep marine organisms from damaging and compromising marine craft below the waterline. On the other hand, even the most hardened industrialist agrees that the solution must keep from damaging everything else in its wake.

Nanotechnology that mimics the surface texture of algae that inhibits attachment of marine organisms is one outside-the-box thought. But this is still in the research stage and not yet available for mass production.⁸

There is one other approach that uses a totally different point of view and has proven commercially and environmentally successful. Ninety studies have been completed that pass the EU regulation Biocides Product Directive 98/8/EC (BPD) governing “biocides.” Regulating bodies in Japan (CSCL and JPMA), Korea (NIER), and China (MEP, Order 7) have also approved this material, and notifications have been provided to other relevant shipping regions.

Rather than using the typical paradigm of killing off the barnacle hitchhiker (and ultimately everything in the vicinity), an attempt was made to modify the attachment mechanism of the larvae.

Instead of using metal oxide biocides, medetomidine, a mammal anesthetic, was added to bottom paint. When exposed to medetomidine leaching out from a wet coating, the cyprid larvae of the barnacle species Balanus improvises were repelled from the surface. How? Medetomidine in tiny concentrations stimulates a receptor in the larvae causing hyperactive swimming behavior. Instead of settling down on the surface, the legs move at 100 kicks/minute, forcing it to swim away from the bottom of the boat. The effect is reversible. As the barnacle larvae move away, the kicking stops. This makes it impossible for the organism to attach to the surface.⁹

Since 2016, a thousand governing-body-approved commercial ship applications of this “biocide” were used successfully in several different biofouling paint formulations. This may be the first marriage of true environmental sustainability through benign influence on organisms and the desired performance from an antifouling marine paint.

About the Author

Cynthia A. Gosselin, Ph.D., is director at The ChemQuest Group, ChemQuest Technology Institute, ChemQuest Powder Coating Research. Email: cgosselin@chemquest.com.

References

1. IMARC Impactful Insights. “Antifouling Paints and Coatings Market: Global Industry Trends, Share, Size, Growth, Opportunity and Forecast 2023-2028.”
2. “Marine Coatings Selection Guide: Types, Features, Applications | GlobalSpec.” https://www.globalspec. com/learnmore/materials_chemicals_ adhesives/industrial_coatings_ sealants/marine_coatings#.
3. Koch, S. “Invasive Zebra Mussels.” National Park Service, April 2, 2021. https://www.nps.gov/articles/ zebra-mussels.htm (accessed July 27, 2023).
4. “Sustainable Antifouling by Controlled Release from Polymer-Bound Selektope.” ITECH-Technical-Paper_ November-2022-1.pdf, November 2022, selektope.com (accessed July 27, 2023).
5. Strickland, K. “Tapio Lehtinen’s Barnacle Blight.” Yachting Monthly, May 22, 2019.
6. “The 5 Most Common Marine Fouling Organisms and the Effect They Can Have on Your Boat.” Electronic Fouling Control, Antifouling Tips, June 21, 2023.
7. Rotter, A.; et al. “Non-indigenous Species in the Mediterranean Sea: Turning from Pest to Source by Developing the 8Rs Model, a New Paradigm in Pollution Mitigation.” Front. Mar. Sci., 2020, 7, Marine Pollution Section, March 24, 2020.
8. Kumar, S.; et al. “Nanocoating is a New Way for Biofouling Prevention.” Front. Nanotechnol., 2021, Environmental Nanotechnology Section, Nov. 22, 2021.
9. “About Selektope® – A Sustainable Biocide Used in Antifouling Coatings.” https://selektope.com/ about-selektope/ (accessed July 27, 2023). When exposed to medetomidine leaching out from a wet coating, the cyprid larvae of the barnacle species Balanus improvises were repelled from the surface.

One recent example is a new marine coating primer developed by Norway coating manufacturer Jotun. Primers make up 70–80% of the total amount of paint applied to a ship, according to the company. The new technology, which was developed over a period of 13 years, yields a solvent-free marine primer that provides better corrosion protection than previous systems while reducing the total solvent release by 80–90%, according to Erik Risberg, one of the scientists at Jotun whose efforts led to the new product. Solvent emission reduction is not the only benefit of the new primer. Shipyards do not have to invest in facilities to burn the collected VOC emissions, leading to a savings of hundreds of millions of dollars and a reduction in CO₂ emissions. The enhanced corrosion protection also helps extend the life of the vessels and reduces the need for maintenance.

Risberg has worked in Korea for years, and he and his colleagues at Jotun developed the new primer in close collaboration with Samsung Heavy Industry (SHI), a Korean shipyard. Those cooperative efforts have paid off in a big way. In June 2019 during a state visit to Norway by South Korea’s President Moon Jae-In, Jotun signed a memorandum of understanding with Hyundai Heavy Industries (HHI), one of the world’s largest shipbuilders. The agreement was signed by Jotun’s chairman Odd Gleditch and HHI’s chief executive Ka Sam-Hyun and includes a commitment to closer cooperation and the use of the new primer. The partnership, according to Sam-Hyun, will allow HHI to be better equipped to meet the new environmental requirements that are aimed at reducing solvent emissions. Added Jotun CEO Morten Fon: “We are, of course, very pleased with the agreement with the world’s largest shipyard, but even more satisfied that our innovation is contributing to a better environment.”

The new primer is currently available for Korean shipyards and selected shipbuilders in Europe who have experience applying single-coat primers that require careful application techniques.

One recent example is a new marine coating primer developed by Norway coating manufacturer Jotun. Primers make up 60–70% of the total amount of paint applied to a ship, according to the company. The new technology, which was developed over a period of 13 years, yields a solvent-free marine primer that provides better corrosion protection than previous systems while reducing the total solvent release by 80–90%, according to Erik Risberg, one of the scientists at Jotun whose efforts led to the new product. Solvent emission reduction is not the only benefit of the new primer. Shipyards do not have to invest in facilities to burn the collected VOC emissions, leading to savings of hundreds of millions of dollars and a reduction in CO₂ emissions. The enhanced corrosion protection also helps extend the life of the vessels and reduces the need for maintenance.

Risberg has worked in Korea for years, and he and his colleagues at Jotun developed the new primer in close collaboration with Korean shipyards. Those cooperative efforts have paid off in a big way. In June 2019 during a state visit to Norway by South Korea’s president Moon Jae-In, Jotun signed a memorandum of understanding with Hyundai Heavy Industries (HHI), one of the world’s largest shipbuilders. The agreement was signed by Jotun’s chairman Odd Gleditch, Jr. and HHI’s chief executive Ka Sam-Hyun and includes a commitment to closer cooperation and the use of the new primer. The partnership, according to Sam-Hyun, will allow HHI to be better equipped to meet the new environmental requirements that are aimed at reducing solvent emissions. Added Jotun CEO Morten Fon: “We are, of course, very pleased with the agreement with the world’s largest shipyard, but even more satisfied that our innovation is contributing to a better environment.”

The new primer is currently available for Korean shipyards and selected shipbuilders in Europe who have experience applying single-coat primers that require careful application techniques.

“From the beginning, we knew this project would require looking beyond the usual horizons— not just in terms of engineering a strategy, but in effectively communicating our innovations and ideas, and collaborating with the right teams,” said Mark Schultz, government marine manager for Sherwin-Williams Protective & Marine Coatings.

Development of new technologies designed to increase efficiency and reduce the environmental impact of the project began two years in advance of the initiation of work.

The first innovation was the use of vapor blasting to prepare the surface of the hull for recoating. Traditional sandblasting on an aircraft carrier creates massive amounts of waste and dust, requiring containment and significant time-consuming clean-up. Sherwin-Williams worked with Greener Blast Technologies and introduced the Naval contractors to vapor blasting, which uses a water-like medium to reduce dust levels during surface prep and minimize the waste and time required to clean up following blasting—while providing a similar blast profile as traditional blasting. This technique was used as the first blast to remove exterior built-up materials, such as biofouling and the outermost coatings, before the secondary direct-to-steel blasting, which was completed more quickly and with far less debris due to the first round of vapor blasting. Impressed by the process, the Navy created a new SSPC/NACE specification for vapor blasting. Further reducing waste, the surface preparation crew cleaned and recycled slurry from the vapor blasting process and also used recycled steel grit for the subsequent abrasive blasting step. In addition, all blasting was completed using water-powered pressure washers instead of gas-powered washers, which decreased fuel emissions for the project.

Sherwin-Williams Fast Clad^® ER, a single-coat, high-solids solution that cures in four hours, was used on about 70% of the freeboard instead of a traditional two-coat system. This choice allowed applicators to accelerate the coating schedule and eliminate the possibility of missing recoat windows, which can lead to delamination issues—without sacrificing durability, according to Schultz. The remaining 30% of the freeboard was coated with Sherwin Williams SeaGuard^® 5000HS Epoxy, with Sherwin-Williams Polysiloxane XLE-80 HAPS Free Epoxy Siloxane applied as a topcoat on the entire area. The Polysiloxane XLE-80 coating included a newly designed and approved Naval Research Lab low solar absorption (LSA) pigment package, which enhances the paint’s signature “Navy Gray” color stability and reduces the solar temperature load on the vessel. Within the ship, more than 100 tanks designed to hold ballast, chemicals, fuel, water, and waste were also coated with Fast Clad ER, which offers long-term immersion service for up to 15 years.

The coatings were applied using plural-component sprayers. A new cartridge technology from V.O. Baker Company was employed that enabled precise measurements for dispensing small batches of plural-component coatings, which helped reduce the chance of mixing errors and allowed teams to work longer for touchup and repair work. More than 95% of the touchup and repair work following the initial spray application was completed exclusively with cartridges.

The USS George Washington restoration project is an example of Sherwin-Williams’ unwavering commitment to improving the coatings selection and application techniques for the U.S. Navy, helping the organization enhance efficiencies, and realize life cycle improvements throughout its operations. “We always aim to take steps that improve sustainability and reduce environmental impact, especially on projects of this scope,” Schultz said. “The results across the board couldn’t have been achieved without the intense cooperation of our dedicated teams and partners, or the support of the Navy when we suggested new solutions for the future.”

One recent example can be seen with the Maiden yacht, which was originally built in 1979 as the DISQUE D’OR 3 by boat designer Bruce Farr for the Swiss Ocean Racing Club. Skippered by Pierre Fehlmann, the yacht finished 4th overall in the 1981–82 Whitbread Round the World Race (Race (now the Volvo Ocean Race). In 1986 the 58-ft boat, now renamed Stabilo Boss, was sailed by Bertie Reed in the BOC Single Handed Round the World Race. After that race, the racing yacht was renamed again—as the Prestige—and was left to languish in Cape Town, South Africa.

Tracy Edwards, who was a cook on a South African boat in the 1986 Whitbread Round the World Race, decided she wanted to take the trip again. This time, she was committed to sailing with an all-female crew—something unheard of at the time. The “Maiden Great Britain” project, supported by King Hussein I of Jordan, purchased the Prestige and had it repaired and refitted and renamed the Maiden.

The all-women crew competed in their first race in December 1988, winning the Route of Discovery Race from Cadiz to Santa Domingo. In 1989, they participated in the Whitbread Round the World Race, finishing 2nd place overall in their class—at the time the best result for a British boat in 17 years. After the race, Maiden was sold, and the crew dispersed to pursue their own lives.

Photo credits: The Maiden Factor

Fast-forward to 2016, when Edwards found the Maiden, much damaged, in a marina in The Seychelles. She purchased the boat, and it was brought back to Hamble Yacht Services Refit and Repair in the UK in 2017. The yacht’s restoration has been supported by Princess Haya Bint Al Hussein, the daughter of King Hussein I. The completely refurbished Maiden set sale in October 2018 on a three-year voyage with planned stops in 22 countries where the crew will deliver a message of hope and solidarity from school children in the UK to girls around the world.

The funds raised on this trip will support the Maiden Factor Foundation, which works with charities that empower/teach/mentor girls and/or promote, facilitate, and lobby for or provide solutions that enable the education of girls not currently afforded this basic human right.

Refurbishing the Maiden required replacement of several segments of its aluminum structure, reconfiguration to meet new safety and environmental regulations and refitting as a sailing yacht (rather than a racing boat).Ěý The paints and coatings used in the restoration—from topcoat through to tank coatings—were provided by AkzoNobel. Analysis of samples from the original boat made it possible for the company to provide paints that matched the original colors used on the 1989 Maiden, which were, interestingly enough, also supplied by AkzoNobel.

The importance of paints and coatings to the Navy was highlighted in early September 2018 when Under Secretary of the Navy, Thomas Modly, visited the Sherwin-Williams research and development lab in Warrensville, OH as part of Cleveland Navy Week—a week-long celebration that brought the Navy closer to the people it protects. Members of the Sherwin-Williams Protective & Marine Coatings division and the company’s research and development (R&D) leadership teams met with Naval officials to discuss the role protective coatings play in helping to ensure the readiness of the Navy’s fleet around the globe.

Sherwin-Williams marine group offers fast-drying, general maintenance coatings for quick return-to-service to high-solids coatings designed for long-term asset protection. Of particular note is the close collaboration between the company and the Navy to develop novel coating solutions including Fast Clad^® ER, an ultra-high-solids, rapid cure, single-coat epoxy that replaced the Navy’s traditional three-step coating practice to enable faster maintenance and a 24-hour return-to-service for ballast and fuel storage tanks and other vessel assets.

In addition, Sherwin-Williams is the primary paint supplier for the new USS Gerald R. Ford (CVN-78) aircraft carrier and for restorations being performed on the USS George Washington (CVN-73) aircraft carrier. The Navy is currently using the company’s SeaVoyage® Copper Free antifoulant coating on the USS Nimitz (CVN-68) to deter fouling of its underwater hull. In addition, Sherwin-Williams has a five-year just-in-time (JIT) coatings contract with four public naval shipyards in Norfolk, Portsmouth, Puget Sound, and Pearl Harbor. The JIT contract enables Sherwin-Williams to manage the shipyards’ coatings inventory and deliver supplies as needed to not only ensure a steady delivery of coatings from local inventory but also reduce onsite storage challenges for the shipyards.

Meanwhile, ONR is sponsoring efforts by Dr. Anish Tuteja, an associate professor of materials science and engineering at the University of Michigan, to develop an omniphobic coating. The clear coating, which can be applied to many different surfaces, has been shown to be durable and repel most types of liquids, from oil to water to peanut butter. The coating has significant potential to reduce friction drag on ships, submarines, and unmanned underwater vessels. Because up to 80% at lower speeds and 40–50% at higher speeds of a ship’s fuel consumption goes toward maintaining its speed and overcoming friction drag, significantly reducing friction drag would result in reduced fuel consumption or required batter power, saving money and also extending the potential range of operations, according to Dr. Ki-Han Kim, a program officer in ONR’s Sea Warfare and Weapons Department.

The challenge has been to develop an omniphobic coating that is durable enough for use on ship hulls and capable of repelling all of the types of liquid a ship might come in contact with. Simply mixing polymers and fillers with the right properties does not provide the best coating. Tuteja’s team searched through large databases of known chemical substances and evaluated their performance in mixtures using computer models that considered a wide rage of molecular properties. The right combination was identified after investigating hundreds of combinations.

The rubber-like formulation is optically clear and binds tightly to many different types of surfaces. It can be applied by spraying, brushing, dipping or spin-coating and has excellent resistance to scratching and denting. In addition to its potential for reducing friction drag, Tuteja believes the coating could also be used to protect high-value equipment like sensors, radars, and antennas from damage due to harsh weather. Tuteja expects to have the coating available for small-scale military and civilian use within the next couple of years.

ONR is also sponsoring research into other types of protective coatings, from anti-corrosion systems to coatings that prevent biofouling (the buildup of marine organisms) and ice buildup on ship hulls.

The efficacy of the active biocide ingredients used in antifouling bottom paint to contain and impede the growth of biofouling on boat hulls is of global economic concern, given that costs associated with mitigating the damage caused by invasive species are escalating, especially in coastal waters where fouling nutrients are concentrated. The efficacy of an antifouling coating depends on site-specific fouling pressure where the vessel operates, which biocide(s) are used in the formulation, and the biocidal release rate from the painted surface to the ambient water. Coatings formulated with cuprous oxide have been around for at least 100 years, and are applied to an estimated 90% of the world’s vessels whose hulls are protected with biofouling control coatings. Historically, copper has been repeatedly challenged and subsequently reviewed for its risk and effectiveness, and is arguably the most researched substance for toxicity in the marine environment. Likewise, copper-based antifouling paint has been repeatedly tested for efficacy in hundreds of coatings formulations by multiple manufacturers. Therefore, it is not unreasonable to characterize copper-based antifouling coatings as proven technology.

Yet, the sale and use of copper-based antifouling paints formulated to protect recreational boat hulls in the United States is under closer scrutiny than ever before. Recent proposals submitted by the U.S. Environmental Protection Agency (U.S. EPA) have expanded the focus of restricting the use of copper, while such restrictions have heretofore been confined to the states of Washington and California, and a handful of municipalities in the United States. This trend, should it continue, threatens the use of proven antifouling technology on recreational boats—posing larger economic questions not only for the boating public whose vessels require effective antifouling bottom paint to curtail higher fuel consumption and hull maintenance costs linked to friction and drag as the result of biofouling accumulation—but also for port districts, municipalities, and marinas that must bear the cost of containing invasive species.

Manufacturers continue in their efforts to provide effective (and compliant) copper and copper-free antifouling bottom paint products to meet customer requirements in an ever-changing regulatory environment.

As a sequel to the September 2016 CoatingsTech article entitled, “Marine Coatings: Making Sense of U.S., State, and Local Mandates of Copper-Based Antifouling Regulations,” this article reviews recent legislative actions, explaining the ramifications of new and pending legislation from various perspectives. The authors conclude with what the future holds for antifouling bottom paint.

RECENT DEVELOPMENTS

Copper-based antifouling paint came under scrutiny by regulatory authorities in San Diego, CA, when the Shelter Island Yacht Basin was found to have levels of copper exceeding the 3.1 mg/L limit permitted under The Clean Water Act (CWA). Numerous actions have been instituted or investigated, including requiring hull cleaning divers to use best management practices, encouraging and testing the use of alternative coatings, and establishing alternative but environmentally protective water quality standards, as part of the solution toward bringing the harbor into regulatory compliance for copper by 2022. Nevertheless, the use of copper-based antifouling bottom paint for recreational vessels has been under further scrutiny by Washington, California, and the U.S. EPA.

The State of Washington—Ssb 5436 (April 2011)

Biocidal paints must be registered with the U.S. EPA and the Washington State Department of Agriculture (WSDA). WSDA staff review labels and documents from manufacturers for compliance with state law. Selected data are stored in the Pesticide Information Center Online (PICOL) Database (Washington State University, 2017). In 2011, the Washington State Legislature passed the Recreational Water Vessels—Antifouling Paints Law, Revised Code of Washington (RCW) Chapter 70.300, to phase out the use of copper-based antifouling paints on recreational boats. A recreational vessel is defined in the law as being no more than 65 feet in length, and used primarily for pleasure boating. As of JanuaryĚý1, 2018, Washington law bans the sale of new boats with copper-based antifouling paint. However, the state of Washington has proposed legislation—to be considered in the legislative session that began January 8, 2018—which would delay this ban until January 1, 2021. While the bill is being considered by the Legislature, state resources will not be dedicated to enforcement. If the Legislature chooses to leave the ban in place, state officials have indicated they will “reprioritize and start enforcing the ban as needed and as resources permit.”

>Why has the state of Washington delayed the ban?

State officials concluded there is not a proven, superior biocide alternative to copper. While the state of Washington’s Department of Ecology seeks to reduce copper pollution found in its marinas that state officials have attributed to copper leaching from copper-based antifouling bottom paints, they fear any alternate biocide used in bottom paint as an active ingredient may cause more environmental damage than copper, threatening water quality and damaging Washington’s environment. Therefore, state officials have recommended delaying the ban of copper-based bottom paint, so they may have ample time to study the relative impacts of copper versus non-copper biocides, using models based on Puget Sound marina designs and water quality conditions.

The second phase of the bill, slated to go into effect January 1, 2020, would ban the sale of antifouling paints for recreational boats if the paints contain more than 0.5% copper.

Section 2a of the bill sought industry comments through 2017, following a survey of manufacturers of antifouling paints to determine the types of antifouling paints that are available in the state of Washington. The Department of Ecology stated it would also study how antifouling paints affect marine organisms and water quality. All study findings were promised to be reported to the Legislature, consistent with RCW 43.01.036, by December 31, 2017.

The survey of manufacturers identified the following formulation types of antifouling paints registered for use in Washington State. Note that the following figures are not adjusted for double counting of toll-manufactured store brands:

• 123 antifouling paints containing some form of copper

— Of the 123, 90 paints were based on copper alone, mostly in the form of cuprous oxide.

— None of the copper-containing paints meet the 0.5% copper maximum limit described in RCW 70.300.020. Therefore, they would all be subject to the law’s 2020 ban on use and sale.

• A total of 11 biocides are registered for use (as shown in Table 1).
• 30 non-copper biocidal antifouling paints (as shown in Table 2).
• Several types of non-biocidal paints.

The non-copper biocides identified in the survey include six different types, based on the use of a single non-copper biocide or a combination of two non-copper biocides. According to unspecified studies conducted by other countries, any of these non-copper biocides “may pose” a significant risk to marine life and water, according to the Washington Department of Ecology. However, the conditions found in Washington’s waters reportedly differ from conditions studied outside the United States. The impact of non-biocidal paints on marine life is unknown, as it has never been studied. Moreover, the Department of Ecology would require aquatic toxicity testing
to determine the effects (if any) of non-biocidal antifouling paints on marine life.

Washington State’s criteria for the “ideal biocide” specifies that the biocide’s lifecycle in the environment should be short in duration, with low bioaccumulation, and low toxicity to non-fouling species, albeit what they consider to be “short” and “low” is not included.

For more details on the state of Washington Department of Ecology’s risk assessment models and benchmarks, results for non-copper biocidal paints, and additional study findings, are published online in their December 2017 report entitled, Report to the Legislature on Non-copper Antifouling Paints for Recreational Vessels in Washington, go to .

A summary of Washington State’s recommendations includes:

• Collect additional scientific data and information about biocides.ĚýBiocide assessments conducted by governments in other countries suggest that the use of paints with certain non-copper biocides may have an adverse effect on water quality and marine life in the Puget Sound. The Department of Ecology recommends working with the U.S. EPA, other regulatory authorities, paint manufacturers, and other interested parties to collect scientific data and information on the use and safety of these biocides.
• Investigate and model biocide risk based on Washington State data.ĚýHigh quality scientific models are available that can quantify the risk of biocides in marina environments. The Department of Ecology recommends using these models with data for Washington State water conditions and marina characteristics to validate whether the high risk estimated in other countries is relevant to marinas here. These models can also be used to address sediment impacts and freshwater marina considerations.
• Evaluate efforts by U.S. EPA and other states to adopt leach rate limits.ĚýTo mitigate the effects of copper, the state of California has recently implemented a leach rate limit for copper-based antifouling paints used on recreational vessels. Interim reports from the registration review of copper at the U.S. EPA suggest that similar leach rate limits may be proposed nationally for saltwater recreational antifouling applications. The Department of Ecology intends to evaluate these regulatory actions for applicability in Washington State.
• Incorporate findings from recent antifouling paint assessments.ĚýNorthwest Green Chemistry (NGC), a nonprofit organization, worked with the Department of Ecology, industry, and other organizations to conduct research and publish an alternatives assessment of copper-based antifouling paints. Washington State will integrate the results from their analysis of copper-free alternative paints into ongoing work to determine whether there are safer options.
• Establish a public-private partnership to assess the performance of antifouling paints.ĚýNGC assessments of the performance of antifouling paints rely on limited data, mostly from warm-water locations. The Department of Ecology recommends forming a public-private partnership to conduct performance field tests of antifouling paints in Washington waters to assess whether performance data from other jurisdictions is relevant to Washington waters and fouling species.
• Collaborate with the private sector to promote safer alternatives and best practices.ĚýThe Clean Boating Foundation’sĚýClean Boatyard Program works to disseminate best management practices for boatyards to reduce the impact of toxic substances on nearby waters (Clean Boating Foundation, 2017). The Department of Ecology recommends working with this program to promote source control and reduction strategies and to share current and future findings on the safest available antifouling paint alternatives.
• Promote the use of alternatives assessments.ĚýThe Department of Ecology recommends promoting ongoing alternatives assessments of new paint technologies as they are developed, but also for innovative technologies such as boat washing stations. Efforts in this area can help avoid the use of regrettable substitutes and, where possible, identify non-chemical solutions to our environmental challenges.

California’s AB 425—2013

Senate Bill 623, introduced by Senator Christine Kehoe in February 2011, would have, as written, banned the use of copper in antifouling coatings on recreational vessels in the state of California. However, SB 623 was not passed into law. The additional cost to the recreational boat owner of alternatives, the unproven efficacy of alternatives, and the concern of additional transport and introduction of invasive species due to biofouling on recreational vessels, were three reasons a different approach was instituted.

Assembly Bill 425 was passed and included a mandate for the hull cleaning study, which was later used to determine the leach rate. As noted in our September 2016 CoatingsTech article, the state of California’s antifouling registration renewal program notified antifouling coatings manufacturers in March 2011 that they were required to fund a comprehensive study to evaluate the contribution underwater hull cleaning made to copper in water coves. Study findings indicated that underwater hull cleaning contributed up to 50% of copper detected in the water. Earley, Swope, Barbeau, Rundy, McDonald, and Rivera-Duarte’s acclaimed paper, “Life Cycle Contributions of Copper from Vessel Painting and Maintenance Activities,” puts that study finding into proper perspective by concisely characterizing the chemistry of copper levels that exceed water quality criteria. (Note: Earley’s full paper is available on the NIH.gov website. The study was conducted under requirements established by the DPR.)

Moreover, AB 425 stated “no later than February 1, 2014, the Department of Pesticide Regulation shall determine a leach rate for copper-based antifouling paints used on recreational vessels and make recommendations for appropriate mitigation measures.”Ěý The result of this calculation is a leach rate effective January 1, 2018 equal to or less than 9.5 ÎĽg/cm²/day, resulting in loss of registrations of antifouling products above that leach rate on July 1, 2018. In addition, a key strategy that the California Department of Pesticide Regulation (DPR) is counting on is improved in-water hull cleaning best management practices to mitigate against spikes in dissolved copper concentration levels.

California’s Marina Del Rey Total Maximum Daily Load (TMDL)

The Los Angeles Regional Water Quality Control Board has approved the development of a site-specific objective (SSO) for dissolved copper in the Marina del Rey Harbor. Simply put, rather than using one-size-fits-all dissolved copper levels called out in the Clean Water Act to regulate Marina del Rey, a designated scientific group will scientifically quantify the actual toxicity limit of copper in that water body. Site-specific objectives for dissolved copper are, by far, the most accurate implementation method of protective standards and actions while preventing the waste of resources in attempting to meet standards that are not appropriate for a given water body. These benefits have been demonstrated in other water bodies such as San Francisco Bay.¹

Once the SSO is determined, it will be presented to the LA Regional Water Quality Control Board for approval as the new objective for that water body (i.e., it will become a new scientifically established environmentally protective concentration limit for copper specific to the site of Marina del Rey Harbor). Moving forward, it would serve as the newly established goal or standard.

In addition, by June 2018, the State Implementation Plan (SIP) has approved that 25 recreational vessels be painted with alternatives to copper-based antifouling coatings (and 100 recreational vessels painted with copper alternatives by 2020). Their intent is to make the boating public aware of non-copper-based coatings that may meet the needs of the recreational boater in terms of efficacy and economic viability (e.g., life-
cycle coatings costs) benchmarked against copper-based antifouling coatings. The ultimate goal of the actions being taken in Marina Del Rey is to bring that water body into copper concentration compliance by 2024.

Amendment to the California State Lands Commission’s Biofouling Management Regulations for Vessels Arriving at California Ports

As of October 1, 2017, an amendment to the California State Lands Commission biofouling management regulation (title 2, California Code of Regulations section 2298.1 et seq.) requires all vessels capable of carrying ballast water to submit the Marine Invasive Species Program Annual Vessel Reporting Form to the California State Lands Commission’s Marine Environmental Protection Division 24 hours in advance of the first arrival at a California port for each calendar year.

If a vessel arrived at a California port in 2017 prior to October 1, this form is not required for 2017, but rather, the vessel must submit the now-repealed Hull Husbandry Report Form and the Ballast Water Treatment Technology Annual Reporting Form (if applicable). Beginning on January 1, 2018, the requirement for completing the commission’s Hull Husbandry Report Form, the Ballast Water Treatment Technology Annual Reporting Form (and the Ballast Water Treatment Supplemental Report Form) has been repealed to streamline reporting requirements for ship operators.

According to the commission’s Initial Statement of Reasons, this amendment is intended to “encourage the use of best management practices, including the appropriate use of antifouling or foul-release coatings (i.e., using coatings aged within their effective coating lifespan).”

Biofouling management regulations require ocean-going vessels entering the ports of California to have minimum biofouling on the underwater portion of their hulls and niche areas. Ships having a hull husbandry report that verifies the coating on the hull is still within the specified lifetime will be presumed to be in compliance. A ship whose coating is beyond its life span, or is not using an antifouling coating at all, will be inspected and must not exceed 5% biofouling on the hull and not more than 15% in niche areas, albeit several niche areas are exempted for safety reasons. The American Coatings Association (ACA) expressed support for the streamlined reporting measure that lessens the burden on ship operators, and encourages the use of efficacious antifouling coatings.

ACA, which is both a member and Secretariat for the International Paint and Printing Ink Council (IPPIC), also offered the commission use of an IPPIC-developed template for the completion of a biofouling management plan. IPPIC worked with IMarEST (The Institute of Marine Engineering, Science and Technology) to develop the template, which can be used as a tool for the implementation of the International Maritime Organization’s 2011 Guidelines for the Control and Management of Ships’ Biofouling to Minimize the Transfer of Invasive Aquatic Species. This template was recently submitted by IPPIC and IMarEST (a major maritime NGO) to the International Maritime Organization at the 70th Session of the Marine Environment Protection Committee that met in London in October 2016.

Â鶹ĘÓƵbelieves this template meets the California commission’s objectives, and urged the commission to consider accepting the IPPIC template in lieu of the proposed SLC form. Given that vessels can operate in a wide variety of regulatory environments, allowing operators to use a consensus document such as the IPPIC document could be a sensible alternative to the proposed form, according to Â鶹ĘÓƵ

Details on this amendment can be found online at.

U.S. EPA ACCEPTING COMMENTS ON DRAFT COPPER RISK ASSESSMENT

The U.S. EPA periodically reviews pesticide registrations under the Federal Insecticide, Fungicide, and Rodenticide Act “to ensure that each pesticide continues to satisfy the statutory standard for registration, that is, the pesticide can perform its intended function, without unreasonable adverse effects on human health or the environment (based on current scientific and other knowledge).” To that end, the U.S. EPA had accepted public comments on its Registration Review: Draft Ecological and/or Human Health Risk Assessments for copper. While the agency’s risk assessment does not address organic copper registrations, it does include copper sulfate, copper group II, copper salts, complexes, hydroxides, and oxides. U.S. EPA had previously completed comprehensive draft human health and/or ecological risk assessments for all chemicals listed in the Table of Unit III (Figure 1).

The agency’s subsequent risk assessment (with a recreational vessel focus) is considering copper leach-rate limits for antifouling coatings such as those imposed in the state of California.

During the public comment period ending December 22, 2017, in the agency’s Interim Report, the copper antifouling coating registrants (that includes the copper active ingredients’ registrants as well as the paint formulators) submitted comments on the data the U.S. EPA is considering collecting. Registrants suggested the agency collect a smaller data set. Registrants also volunteered to work with the agency to collect coatings’ use and existing toxicity data.

Currently, the copper antifouling coating registrants are in discussion with the U.S. EPA about the most effective action plan to mitigate U.S. EPA concerns related to copper concentrations found in recreational marina waters. In a conference call scheduled for early February 2018, registrants had an opportunity to discuss the specifics of the action plan with the U.S. EPA, including how best to proceed, given that U.S. EPA has now had time to review registrants’ submitted comments.

U.S. EPA INVESTIGATING AN IMPROVED METHOD TO ESTABLISH SITE-SPECIFIC OBJECTIVES

In the September 2016 CoatingsTech article, we reported that the Recreational Boaters of California (RBOC) had been urging the U.S. EPA’s Office of Water to approve the Marine Biotic Ligand Model for Copper in salt water to ensure that more accurate marine and estuarine water quality criteria was developed. The BLM will allow for for more scientifically objective benchmarks as the basis for SSO for use in TMDL regulations versus the current one-size-fits-all methods. At the time of publication of this article, the U.S. EPA has not yet completed its work on the BLM to scientifically determine SSOs.

REGULATORY DISPARITY

Several studies conducted in Shelter Island Yacht Basin (SIYB), determined that the majority of the basin had dissolved copper concentrations that exceeded the U.S. EPA Clean Water Act and California Toxics Rule (CTR) criteria, but also determined that there was only one spot in the marina (at the farthest distance inside the basin) in which statistically significant effects on mussel larvae were reported.² Neal Blossom, Â鶹ĘÓƵMarine Coatings Committee Chair, contends that when it comes to achieving a goal of non-toxicity for non-target species, establishing an SSO will provide reasonable assurance of environmental protection. Put another way, exceeding criteria that is set forth in the Clean Water Act and observing actual toxicity in the environment are disparate.

In fact, agencies attempting to work in tandem with one another can find themselves working at cross purposes due to their incongruent goals.

Consider the U.S. EPA Organization Chart: The Office of Water (OW) is responsible for implementing the Clean Water Act, and similar statutes designed to maintain aquatic ecosystems to protect human health; support economic and recreational activities; and provide healthy habitat for fish, plants, and wildlife. Copper-based antifouling coatings registrants must obtain approval from the U.S. EPA’s Office of Pesticide Programs (OPP), which oversees periodic pesticide registrations and reviews, and regulates pesticide use to prevent significant adverse effects on non-target organisms. The state of California’s organizational chart and regulatory objectives are nearly identical to the U.S. EPA’s two offices. In theory, both offices can concurrently meet their regulatory goal. However, a third agency responsible for a given water body, such as the San Diego Regional Water Quality Control Board that is responsible for the SIYB, may be required by the Clean Water Act or the California Toxics Rule to meet a water quality standard when no significant adverse effects to non-target organisms have been measured. Therefore, an action of meeting a water quality goal must be taken by the agency responsible for a water body, even in the absence of measurable toxicity (or measured at minimal levels in a small geographic area of the water body in question).

CONCLUSION

Copper-containing antifouling coatings are a proven efficacious technology to reduce biofouling on recreational and commercial vessels, as shown by their overwhelming market share. This efficacy is critical to provide the vessel owner with a clean hull that travels well through the water with limited drag and lower fuel usage. It is also critical to minimize the extremely detrimental and long-term environmental damage caused by the introduction of invasive species. However, recreational marinas by their very design for berthing a multitude of vessels in a small area with low flushing can create conditions whereby copper concentration exceeds existing water quality standards. The use of new studies to determine more appropriate and protective standards for each water body can ensure that the environment is protected while preventing the waste of resources and effort to achieve nonproductive outcomes. As regulators have determined, there is no risk-free, simple answer to the biofouling challenge. Federal and state regulators are working with industry and recreational boaters to allow efficacious coatings that protect the environment from invasive species and excessive fuel use while minimizing negative consequences in recreational marinas from copper and other antifouling coating biocide and chemical inputs to the environment. Copper continues to prove itself to be an effective active ingredient in antifouling coatings with limited negative effects. Where those effects are found to be of concern, copper leach-rate limits, best hull management practices, and alternatives coatings, have been proposed to environmentally protect recreational marinas.

Endnotes

1. The necessity of SSOs, including substantial reductions achieved in copper wastewater loading to the Bay over the past two decades, are presented by Richard Looker in the California Regional Water Quality Control Board’s Copper Site-Specific Objectives in San Francisco Bay—A Proposed Basin Plan Amendment and Draft Staff Report (dated June 6, 2007, 107 pp).
2. 2. The Copper Bioavailability and Toxicity to Mytilus galloprovincialis in Shelter Island Yacht Basin, San Diego, CA study, prepared by Casey Bosse, Ignacio Rivera-Duarte, Gunther Rosen, Marienne Colvin, Brandon Swope, and Patrick Earley (representing the University of San Diego, SPAWAR System Center Pacific, and the San Diego State University Research Foundation, respectively) findings: “Although copper in SIYB are elevated in comparison to the main body of San Diego Bay, the ambient water is generally not toxic to mussel embryos (1 out of 62 samples somewhat toxic), and that dissolved copper as high as 8.8 μg L-1 were not toxic to mussel embryos.” The Final 2014 Shelter Island Yacht Basin Dissolved Copper TMDL Monitoring and Progress Report, prepared by AMEC Environment & Infrastructure, Inc., findings: “Consistent with the 2013 monitoring event, the 2014 results indicate that only one station (SIYB-1, the station farthest inside the basin) had a statistically significant effect on developing mussel larvae.”

RCW Chapter 70.300

The full text and history of RCW Chapter 70.300, which was originally written as Senate Bill 5436, modified as Substitute Senate Bill 5436, and amended by the House, can be found online at

Washington State’s notice on the existing ban’s delay can be read online at .

Questions pertaining the proposed legislation, the existing ban (and the delay), or other related issues can be directed to Kimberly Goetz at (360) 407-6754 or kimberly.goetz@ecy.wa.gov

*This article is an update to the American Coatings Association (ACA) Industry Market Analysis, 9th Edition (2014-2019).

CoatingsTech | Vol. 15, No. 3 | March 2018

Estimated overall cost associated with hull fouling for the Navy’s coating, cleaning, and fouling level in 2011 to be $56 million for the entire DDG-51 class of naval vessels, or $1 billion over 15 years.

Once microorganisms, most often marine crustaceans such as barnacles and tubeworms, settle on the walls of a ship, the originally smooth surface becomes rough. In addition, a ship can add barnacle weight at 150 kgs per square meter in as little as six months, according to Office of Naval Research (ONR) within the U.S. Navy. The increased weight and greater frictional resistance due to surface roughness leads to a decrease in the speed of the vessel, which must be overcome by burning more fuel. The Naval Surface Warfare Center, Carderock, estimates that vessel speed is reduced by up to 10% from biofouling, which can require up to a 40% increase in fuel consumption to counter the added drag. Importantly, marine transport accounts for approximately 90% of global freight forwarding, according to Evonik. The International Maritime Organization estimates that annual biofouling costs lie in the billion-dollar range. Economic losses are not the only negative impact of biofouling, however.Ěý Increased fuel consumption by ocean-going vessels results in more carbon dioxide (CO₂) emissions by these ships.

To address this problem, the ONR has developed the Sharklet™ coating in partnership with researchers at the University of Florida. This coating mimics the inherent texture and antimicrobial properties of shark skin. In cooperation with scientists at the University of Washington, they have also developed a coating that incorporates zwitterionic, or mixed charge compounds, to manipulate surface environments at the molecular level to prevent proteins from binding to the ship’s surface. “By reducing microorganism build-up, both coatings stand to substantially improve ship performance and fuel efficiency while dramatically cutting fuel and maintenance costs. These coatings may also reduce the transport of invasive species via ship hulls and eliminate the discharge of biocides into surrounding environments,” says an ONR spokesperson. The ONR-funded marine biofouling prevention technologies have an added feature: they have been shown to also inhibit the growth of disease-causing bacteria. As a result, these coatings might have applications in the design of medical devices or hygienic surfaces found in hospitals and food preparation areas.

Evonik is tackling this issue by bundling the expertise of all its technology platforms at the new Smart Surface Solutions Competence Center, where scientists seek to find new solutions related to anti-icing coatings, anti-corrosion coatings, anti-microbial coatings, and dirt-repellent surfaces, in addition to marine biofouling, according to Stefan Silber, head of Innovation Management Coating Additives in Evonik’s Resource Efficiency Segment. “Biofouling is one of the last unsolved problems in the coatings industry. Until recently, we had not succeeded in finding the optimal solution for ship coatings that is both efficient and eco-friendly. That is why antifouling coatings are a core topic for us,” he says. The Resource Efficiency segment supplies high-performance materials for environmentally friendly and energy-efficient systems to the automotive, paints and coatings, adhesives, construction, and many other industries, according to the company.

One new raw material concept for biofouling coatings under development by Evonik combines water-repellent (hydrophobic) silicones with water-loving (hydrophilic) polymers to form amphiphilic polymers with alternating hydrophilic and hydrophobic domains, according to Silber. The coatings, as a result, trick microorganisms into perceiving plain water in front of them, rather than ship hulls, and therefore the organisms often do not attempt to settle on the walls. “The hydrophilic domains attract water to the ship’s hull, building a layer of water around the polymers, camouflaging the hull from the organisms,” Silber explains. “The alternation of the hydrophilic domains with the water-repellent domains further confuses the organisms, preventing them from being able to clearly recognize the surface and distinguish the hull unambiguously from the surrounding sea water,” he adds. As a result of this uncertainty, microorganisms usually stay away from the coated hulls altogether.

The coating also has properties that make it difficult for microorganisms that are not tricked to settle on ship hulls. The hydrophobic, silicone-based portions of the block polymers have very low surface tension, imparting a smooth, easy-to-clean surface with anti-adhesion properties, according to Silber. “The organisms cannot readily adhere to the hull, and the few that do succeed should be dislodged by the water stream, even at low ship speeds,” he observes. Silber adds that the new coating technology is attractive because it protects ships against biofouling without directly attacking the organisms or releasing any active agents into the water.

Field tests conducted by Evonik under real conditions have demonstrated the basic efficacy of the new hybrid binder system, according to Silber. The company is currently working with customers to formulate coatings based on the new resins. Further work is ongoing to reduce the frequency at which the coatings must be reapplied in order to reduce maintenance costs.

CoatingsTech | Vol. 15, No. 1 | January 2018

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