Launching a New Era of Great Lakes Freighters with Marine Grade Epoxy Coatings

The Motor Vessel Mark W. Barker – the first Great Lakes freighter built on the Great Lakes in nearly four decades, and The Interlake Steamship Company’s first new build since 1981 – represents a renewal in regional shipping. The vessel also serves as a showcase of advanced coatings that shield the ship from the harsh elements it encounters while navigating a vast network of inland seas and rivers – safeguarding its longevity for years to come.

Measuring 639 feet long and 78 feet wide, the ship’s dimensions set it apart from the typical 1,000-foot-long freighters found on the Great Lakes (Figure 1). Built for The Interlake Steamship Company by Fincantieri Bay Shipbuilding in Sturgeon Bay, Wisconsin, the bulk carrier was designed to navigate the sometimes narrow and winding rivers that feed the freshwater lakes, without compromising shipping capacity.

In fact, the self-unloading bulk carrier is competitive with larger vessels, sporting an impressive cargo capacity of 26,000 tons due to its unique design. The vessel’s square and flat cargo holds – diverging from conventional V-shaped angled bottoms (Figure 2) – feature sliding hatches that maximize available cubic space. Another noteworthy feature of the ship is the forward placement of the unloading boom, which provides greater flexibility for cargo operations in congested ports. This unique arrangement also enables the customized placement of the cargoes for its Great Lakes customers.

The vessel’s unique dimensions and design allow for the transport of a versatile range of cargoes, which informed specifiers on the appropriate coatings systems to use to protect the vessel and ensure durability.

Primarily built to haul salt, the M/V Mark W. Barker has transported bulk cargoes – such as iron ore pellet, limestone, taconite, coal and others – and break-bulk cargoes, including oversized items, such as steel bars and wind turbine parts, since launching in the summer of 2022 (Figure 3).

“This boat will continue to find unique cargoes that haven’t traditionally been moved in the past,” said Rick Hanning, fleet engineer of The Interlake Steamship Company, which operates 10 vessels on the Great Lakes and has headquarters in the Cleveland-area suburb of Middleburg Heights. “Its size and distinctive design give it a special ability to navigate rivers and ports – and its cargo hold is unlike any other in Great Lakes.”

Shielding the Ship
As the first self-propelled vessel built for the Great Lakes by an American company in four decades, the M/V Mark W. Barker required a coatings system as unique as it is. The Interlake Steamship Company created the ship’s coatings specification with the help of the product team at Sherwin-Williams Protective & Marine.

“We were sensitive to where we were having issues on other boats,” said Hanning. “It required deep thought for how protect this exceptional piece of engineering for its decades of service.”

To safeguard the ship’s underwater hull against the many hazards in and around the Great Lakes, the team landed on Sher-Glass® FF.

A high-performance glass flake-reinforced epoxy, the coating was chosen for its added impact and abrasion resistance, as well as improved durability, edge protection and resistance to corrosion in a wide range of environments.

“We wanted the hull to last as long as possible with minimal maintenance in future dry docks, and this product adds to the ship’s life expectancy,” said Hanning. “You never know what you might run into. Shipping on the Great Lakes can be a contact sport.”

In a controlled shipyard environment, applicators started with an SSPC-SP 10 blast before spraying the hull with two coats of Sher-Glass, at an average of 18 mils dry film thickness (DFT) per coat. Applied directly to steel, the coating eliminates the need for a separate primer, simplifying the coating process and saving time. Specifically formulated for immersion service, the coating uses pre-wetted glass flakes to ensure consistent mixing and application reliability to enable long-term exposure to liquids.

The hull of the M/V Mark W. Barker – named for the family-owned Interlake Steamship Company’s president and second-generation leader – has an unmistakable look, featuring the organization’s signature red.

Safeguarding the Interior
For the ship’s uniquely shaped cargo holds, the project team needed a coating system to stand up to a wide variety of materials being shipped.

Starting with an SSPC-SP 10 blast, applicators sprayed a coat of Zinc Clad® III HS – a zinc-rich epoxy primer – to the walls of the cargo holds. A three-component, polyamide epoxy, the coating offers exceptional performance and protection. Its high zinc content provides excellent corrosion protection and cathodic protection to the steel substrate.

The coating exhibits excellent stability and durability, even in demanding environments where mechanical stress or movement may occur – such as the front-end loaders that are active in the M/V Mark W. Barker’s cargo holds (Figure 4). The coating’s self-healing properties give it the ability to reseal and recover its protective properties when minor abrasions or scratches occur, further enhancing its longevity.

Finally, applicators spray-applied SeaGuard 6000 to the walls of cargo holds for added protection.

A versatile anti-corrosive two-component, modified epoxy coating, SeaGuard 6000 is formulated for immersion and atmospheric service in both saltwater and freshwater marine environments. Its self-priming qualities eliminate the need for a separate primer application, which helps streamline the coating process. Surface tolerant, the coating adheres well even in challenging conditions, such as in the presence of moisture and at low temperatures – which can be expected when performing ship maintenance activities during cold-weather months on the Great Lakes.

“We’re happy this system provides a bit of cathodic protection,” said Hanning. “We know we’ll need a maintenance coating from time to time, because it’s a tough environment for coatings to thrive, especially with the heavy equipment moving around down there and the impacts and contact abrasion that come from loading cargoes from 50-foot heights (Figure 5).”

SeaGuard 6000 was the “workhorse on the remainder of boat,” said Hanning, “especially the areas not exposed to major UV light,” which included common spaces, habitability areas and floors – with SeaGuard 1000 serving as the topcoat throughout.

SeaGuard 1000 is a single-component, fast-drying, rust-inhibitive, high-gloss marine enamel coating with long-lasting color stability – even when sometimes exposed to exterior conditions. Specifically formulated to withstand the challenges of marine and coastal environments, including humidity and other corrosive elements, the coating provides a protective barrier that prevents the deterioration of the substrate and resists yellowing – keeping parts of the vessel looking whiter and cleaner.

Another distinctive feature of the ship is a tunnel below its cargo holds that runs nearly the length of the entire ship. Through small channels in the bottom of holds, cargoes enter the tunnel and are pulled along by a rubber belt to the top of the freighter to be unloaded.

In this area of the vessel, the project team needed to create a unique coatings system that could stand up to corrosive bulk cargoes – especially salt.

Though normally used for tank linings, Nova-Plate® 360 was chosen to protect the tunnel’s floors and walls.

“Cargoes are introduced into a very small area that’s incredibly hard to fix once corrosion starts, so it’s important to keep this area as intact as possible,” said Hanning. “We’ve seen the issue on other boats, so we had to find a hard coating that can withstand moisture and salt – plus the constant impacts of people working down there.”

A versatile flake-reinforced novolac-based coating, Nova-Plate 360 offers exceptional performance in abrasive environments and is specifically designed for applications that require robust corrosion protection. Incorporating PTFE, commonly known as Teflon – which enhances abrasion resistance – Nova-Plate 360 provides an extra layer of protection against wear and tear, extending the service life of coated surfaces.

Starting with an SSPC-SP 10 blast, applicators first sprayed zinc primer for extra protection and added stripe coating, with Nova-Plate 360, where necessary. Next, the application team used single-leg sprayers to apply a single coat between 20 to 25 mils DFT. Aluminum oxide was added to the coating for slip resistance, providing texture to the flooring, which is often wet.

Exhibiting low surface energy, which makes it easier to clean and maintain, Nova-Plate 360 allows for effective removal of contaminants during shutdown periods – promoting the longevity of the coating.

“The shipyard loved the coating’s ease of application,” said Hanning. “It’s self-leveling, cleans up nicely and is extremely hard to scratch – so it was the right product for this application.”

Given the freshwater environment of the Great Lakes, freighters operating there generally do not feature ballast tank coatings. However, given the corrosive nature of some cargoes – namely, salt, which could enter a ballast tank if spilled in a dock during unloading – the project team specified SeaGuard 6000 for these components.

“Salt can work its way in anywhere. We wanted to make sure the whole square footage of the boat was protected from corrosion,” said Hanning. “The coating puts us in a position to win against corrosion.”

Applicators sprayed the two coats over an SSPC-SP 10 blast to the tanks. After a one-year survey, no signs of rust or failure had occurred.

Exterior Defense
The vessel’s freeboard – the part of the hull above the water – features The Interlake Steamship Company’s signature brown coloring, which comes from a topcoat of Acrolon® 218 HS. In fact, most areas of the M/V Mark W. Barker exposed to exterior conditions above the waterline received a coat apiece of SeaGuard 6000 and the Acrolon 218 HS topcoat (Figure 6).

A fast-drying polyester-modified, acrylic polyurethane coating, Acrolon 218 HS exhibits excellent application properties – providing smooth and uniform coverage – offering exceptional long-lasting performance and durability. Formulated to provide excellent color and gloss retention, the coating protects against weathering, UV radiation and other environmental factors – helping maintain the appearance and aesthetics of coated surfaces over time.

While the M/V Mark W. Barker is notably a new construction, its unloading boom has seen many thousands of nautical miles. Removed from a retired freshwater shipping vessel, the boom was rehabilitated – receiving a coat of SeaGuard 6000 and a coat of SeaGuard 1000 – keeping alive a piece of Great Lakes maritime history. 

A tech support team from the marine team at Sherwin-Williams Protective & Marine was heavily involved throughout the coatings portion of the three-year build, working with the shipyard to offer assistance and enhance the project’s timeline by ensuring all coatings were available without delays or concerns.

“At the shipyard, we worked on boat in a controlled environment – and knew we could put the best foot forward with these first coats,” said Hanning. “Everybody worked together to make sure we got things just right.”

Notably, in some areas of the ship, crew are using new burst pouch technology from Sherwin-Williams Protective & Marine for repairs. The utilization of this system offers ease of application, simplifies maintenance and reduces associated waste – making it easier to preserve the ship for years to come.

“We are very cognizant of our environmental footprint,” said Hanning, “and very much appreciate not having to mix up a gallon when we really only need a pint.”

Charting a New Course
The project team anticipates the vessel can operate for a decade before dry docking, a period nearly twice as long as what’s expected for most hulls, given new regulations and the durability of coatings systems.

In the meantime, the M/V Mark W. Barker will call the waters of the Great Lakes home (Figure 7), hauling essential cargoes and components that support a range of domestic industries.

“This boat is going to be a gamechanger in American freshwater shipping and offers a glimpse into the maturation of our industry,” said Hanning. “I’m incredibly confident this vessel will have a very long life and proud to say the coatings are a part of that.”

ABOUT THE AUTHORS
Justin Peare is the Marine Coatings Representative for the Great Lakes Region at Sherwin-Williams Protective & Marine. He has served the coatings industry for over 20 years. Contact: Justin.L.Peare@sherwin.com

Matt Heffernan is the Commercial Marine Business Manager of North America with Sherwin-Williams Protective & Marine. He is a NACE III-Certified industrial coatings inspector and has been supporting the paint and coatings industry for over 20 years. Contact: Matt.T.Heffernan@sherwin.com

Figure 1. Seeking a modern, nimble vessel to haul a range of unique cargoes, The Interlake Steamship Company built the M/V Mark W. Barker to navigate the sometimes-narrow rivers and tight ports along the Great Lakes. Image courtesy of The Interlake Steamship Company.

Figure 2. The vessel’s square-shaped cargo holds are unique for a Great Lakes vessel and allow it to carry more freight than some ships larger in size. Image courtesy of The Interlake Steamship Company.

Figure 3. With a traditional bottle-smashing ceremony, representatives from The Interlake Steamship Company christen the M/V Mark W. Barker in Cleveland in September 2022. Image courtesy of The Interlake Steamship Company.

Figure 4. The flat bottoms of the vessel’s cargo holds allow the use of heavy machinery – necessitating advanced coatings systems to protect the areas from damage. Image courtesy of The Interlake Steamship Company.

Figure 5. A zinc-based coating on the walls of the cargo holds offers durability in an area subject to many stressors, including loose cargo loaded from dozens of feet above the floor. Image courtesy of The Interlake Steamship Company.

Figure 6. The M/V Mark W. Barker features exterior topcoats of The Interlake Steamship Company’s signature red (hull) and brown (freeboard). Image courtesy of The Interlake Steamship Company

Figure 7. The M/V Mark W. Barker – designed to navigate the rivers and ports of the Great Lakes while carrying unique cargoes – is docked at a shipyard. Image courtesy of The Interlake Steamship Company.