Built in 1979, by McDermott Shipyard of New Iberia, Louisiana (hull #123) as the Ocean Chief for L and L Marine Services Incorporated of St. Louis, Missouri. A subsidiary of the Apex Oil Company of St. Louis, Missouri.
In 1986, the tug was acquired by Weeks Marine Incorporated of Cranford, New Jersey. Where she was renamed as the Katherine.
In 2020, she was acquired by the Pacific Maritime Group of San Diego, California. Where the tug retained her name.
Powered by two, twelve cylinder, EMD 12-645-E6 diesel engines. With Falk 1630 reduction gears, at a ratio of 4.48:1. Turning two, 14(in) by 76(in), four bladed, fixed pitch, stainless steel propellers. She is a twin screw tug, rated at 3,000 horsepower.
Her electrical service is provided by two, Tier II compliant, 99kW, Caterpillar C4.4TA generator sets. The tug's capacities are 62,000 gallons of fuel, 1,100 gallons of lube oil, and 8,800 gallons of water.
The towing equipment consists of a double drum, Markey TDSD-32, towing winch. Outfitted with 2,200(ft) of 2(in) towing wire on each drum. Driven by a single, GM 6-71 diesel engine.