Built in 1975, by Main Iron Works Incorporated of Houma, Louisiana (hull #289) as the Tara Lynn S. for Nolty J. Theriot Offshore Incorporated of Golden Meadow, Louisiana.
In 1984, the tug was sold and renamed as the Polar 2.
In 1985, she was acquired by the Great Lakes Dredge and Dock Company of Oak Brook, Illinois. Where she was renamed as the William L. Colnon.
In 2003, the tug was acquired by the McAllister Towing and Transportation Company of New York, New York. Where she was renamed as the Christine M. McAllister.
Powered by two, EMD 16-645-E5 diesel engines. With Lufkin reduction gears, at ratio of 4.98:1. Turning two, cast steel, fixed pitch propellers. She is a twin screw tug, fitted with kort nozzles. She is a twin screw tug, rated at 6,000 horsepower.
Her electrical service is provided by two, 99kW, generator sets. The tug's capacities are 184,000 gallons of fuel oil, 5,086 gallons of lube oil, and 14,244 gallons of potable water.
Her towing equipment consists of an INTERcon double drum towing winch. Outfitted with 3,500(ft) of 2.25(in) towing wire on one drum. And 2,500(ft) of 2.25(in) towing wire on the second drum. As well as a QMC 5555 PED deck crane with a Safe Working Load (SWL) of 38,000(lbs) at 10(ft) to 55(ft).