Built in 1966, by Gulfport Shipbuilding Company of Port Arthur, Texas (hull #671) as the Libby Black for the Gulfcoast Transit Company of Tampa, Florida. A subsidiary of the Tampa Electric Company of Tampa, Florida.
In 2002, the Gulfcoast Transit Company became the TECO Ocean Shipping Company of Tampa, Florida. Where the tug retained her name.
In 2003, the tug was acquired by the McAllister Towing and Transportation Company of New York, New York. Where she was renamed as the Katie G. McAllister.
In 2016, she was acquired by the Port City Tug Company of Muskegon, Michigan. Where the tug retained her name and was "laid up" at Muskegon, Michigan.
Powered by two, twelve cylinder, EMD 12-645-E5 diesel engines. With Falk reduction gears, at a ratio of 4.27:1. Turning two, cast steel, fixed pitch, propellers. She was a twin screw tug, rated at 4,300 horsepower.
Her electrical service is provided by two, 125kW generator sets. The tug's capacities are 70,378 gallons of fuel oil, 1,440 gallons of lube oil, and 2,467 gallons of potable water.
The towing gear consists of a Markey TYS 36 single drum towing winch equipped with 2,200(ft)of 2.25(in)towing wire. The winch can be run at two speeds. At high speed, which is rated at 25,000(lbs) or 100(ft) per minute or at low speed, which is rated at 50,000(lbs) or 5(ft) per minute.