Page 43: of Marine News Magazine (October 2019)

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COATINGS

Copper-Free Antifouling Coating Copper-Free Antifouling Coating

Credit: The Sherwin-Williams Company

Keeps MSC Moving Full Speed Ahead

USNS Millinocket Application Validates Effective Use on High-Speed Vessels

By Michael Manetta and Mark Schultz nsuring that vessels maintain operational ef? ciency is growth. By minimizing this attachment, the coatings help to important to the U.S. Navy’s Military Sealift Com- keep vessel hulls smooth and enable greater fuel ef? ciency.

E mand (MSC). Actually, it is important to ANY boat When evaluating underwater hull coatings for the Millinock- operator; big or small. In the service’s continuous shipbuild- et, MSC opted to test Sherwin-Williams’ SeaVoyage Copper- ing and maintenance operations, effective biofouling control Free Antifouling Paint to ensure the biocide would deliver is a critical aspect of that mission. A recently tested antifoul- the expected performance on the high-speed EPF vessel. Fol- ing coating innovation from Sherwin-Williams Protective & lowing drydocking maintenance after nearly four years at sea,

Marine Coatings may help the MSC maintain advantages MSC has veri? ed the coating’s performance on the Millinock- by effectively preventing biofouling organisms from attach- et and con? rmed its suitability for other vessels of this class.

ing to hulls and thereby hindering vessels’ hydrodynamics.

It turns out that speed is especially important for the MSC’s High Expectations for Coatings

Spearhead-class expeditionary fast transport (EPF) vessels, The unique characteristics of EPFs – their aluminum exte- which provide rapid transport of cargo and personnel. Ca- rior ? nishes and high-speed, shallow-draft performance – re- pable of reaching speeds of 35-45 knots, EPFs can carry com- quire speci? c maintenance techniques and products. In 2015, pany-sized units of the U.S. Army and Marine Corps, includ- MSC wanted to test newer copper-free ablative coatings to ing equipment and vehicles, and even full infantry battalions. ensure they would offer improved durability and a lengthy ser-

The USNS Millinocket is the MSC’s third Spearhead- vice life, particularly on high-speed vessels. The desired coating class EPF, launched in June 2013. The 338-foot-long EPF needed to be suitable for aluminum-hulled vessels like the Mil- is a twin-hull catamaran with four diesel engines, boasting linocket and other Spearhead-class EPFs. The key advantage of a ? ight deck for helicopter operations and capable of car- a copper-free coating on an aluminum hull is that it eliminates rying around 600 tons of troops, vehicles and supplies. To the risk of galvanic corrosion, which occurs between copper save weight and enhance maneuverability, the topside of and aluminum. When copper contacts aluminum, the alumi- the Millinocket isn’t painted; instead, the vessel features a num corrodes preferentially to protect the copper; a copper- corrosion-resistant aluminum exterior ? nish. However, its free antifoulant avoids this reaction on an aluminum hull and underwater hull, waterjet tunnels, generator exhausts and provides a more durable long-term solution.

other submerged and splash zone areas require protective MSC sought to determine whether copper-free ablatives coatings to maintain the vessel’s integrity. This includes would maintain the vessel’s underwater hull more reliably coatings that offer long-term corrosion protection, as well in a smooth, fuel-ef? cient condition, with less dependence as antifouling coatings, which prevent sea life such as algae, on cleaning the vessel while at sea. When the Millinocket barnacles and mollusks from attaching to the vessel. underwent drydock maintenance in early 2019, MSC veri-

Ablative antifouling coatings are designed to release bio- ? ed that Sherwin-Williams’ SeaVoyage Copper Free met cides over time to prevent marine biofouling settlement and the expectations for the Millinocket’s requirements.

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