Built in 1981, by the Marinette Marine Corporation of Marinette, Wisconsin (hull #ATF 171) as the ATF-171 (Sioux) for the United States Navy.
Her keel was laid on March 22nd, 1979, she was launched on November 15th, 1980. And the tug was delivered to the United States Navy on May 1st, 1981. Where she was allocated to Military Sealift Command and designed the T-ATF-171 (USNS Sioux).
Powered by two, twenty cylinder, EMD 20-645F7B diesel engines. Turning two, stainless steel, controllable, reversible pitch propellers, mounted in kort nozzles. With a single, 300 horsepower bow thruster. She is a twin screw towing vessel rated at 7,200 horsepower.
Her electrical service is provided by three, 400kW generator sets. Driven by four DD 8v-71 diesel engines. The tug's capacities are 206,714 gallons of fuel oil, 6,100 gallons of lube oil, 5,800 gallons of potable water, 6,000 gallons of drinking water.
The towing equipment consists of a single drum, SMATCO66 DTS-200, towing winch, with a level wind. Outfitted with 2,500(ft) of 2.5(in) towing wire. With a Lake Shore traction winch, outfitted with 15(in) towing hawser. A direct drive capstan, as well as two sets of hydraulic towing pins. And two electro hydraulic mooring winches.