Built in 1967, by Marinette Marine of Sturgeon Bay, Wisconsin as the YTB-793 (Piqua) for the United States Navy.
Her Keel was laid down on September 29th, 1966. The tug was launched on April 25th, 1967 and delivered to the United States Navy on July 10th, 1967. The tug placed in service at the 1st Naval District at Boston, Massachusetts. She was later reassigned to Holy Loch, Scotland in 1964. Where she served until 1970.
However, she was placed out of service and struck from the Naval Register on March 13th, 2001. The tug was transferred to the Defense Reutilization and Marketing Service (DRMS)
In 2001, she was acquired by McAllister Towing and Transportation of New York, New York. Where she was renamed as the Ellen McAllister.
In 2007, she was rebuilt and reconfigured. Originally powered by a single Fairbanks Morse diesel engine, rated at 2,000 horsepower. The tug was repowered with two Caterpillar 3516B diesel engines. Driving two Schottel SRP 1012 "z-drives" for a rated 4,000 horsepower.
The tug's capacities are 20,000 gallons of fuel oil, 710 gallons of lube oil, and 1,290 gallons of potable water.
She was outfitted with new fire fighting equipment that included a Goulds pump rated at 2,000 Gallons Per Minute. Feeding two fire monitors with a 1,500 Gallon Per Minute foam capacity. Driven by a 6-71 diesel engine.
The towing gear includes a JonRie InterTech 200 series bow winch. Outfitted with 450(ft) of 7(in) Neutron rope. Her original underwater submarine fendering was kept, and refurbished.