Rolls-Royce Commercial Marine has been contracted to upgrade Interlake Steamship Company’s Tug Dorothy Ann. The 124-foot, 7,200-horsepower Z-drive tug is the largest Z-drive ATB tug built to date in North America and is mated to the barge Pathfinder. The duo is engaged in hauling bulk commodities on the Great Lakes.
The upgrade will convert the Dorothy Ann’s Rolls-Royce/Ulstien azimuth thrusters from fixed-pitch to controllable-pitch propellers. The project will include replacement of the lower drive units as well as all thruster control systems on the vessel. This conversion will improve the reliability of the vessel’s propulsion system equipment and reduce overall maintenance costs. Great Lakes Shipyard will perform the work under its new affiliation as the Rolls-Royce Regional Service Center on the Great Lakes. This contract is the first to take place since Great Lakes Shipyard and Rolls-Royce Commercial Marine Inc. teamed up to create the Marine Service Center.
Great Lakes Shipyard, a division of The Great Lakes Towing Company, operates a full-service shipyard specializing in all types of vessel new construction, repairs, and modifications. A major Shipyard expansion project at its Cleveland location is now well-underway and includes a new state-of-the-art 770-ton Marine Travelift; the largest on the Great Lakes, second largest in the Western Hemisphere, and the third largest in the World. Current projects include the complete construction and delivery of a work boat for the Port of Milwaukee and contracts with SEACOR Holdings, Inc. to build two tugs for operation at the Hovensa Oil Refinery in St. Croix, U.S. Virgin Islands.