Built in 1970, by McDermott Shipyard Incorporated of Morgan City, Louisiana (hull #167) as the Ocean Star for the L and L Marine Service Incorporated of St. Louis, Missouri. A subsidiary of the Apex Oil Company of St. Louis, Missouri.
In 1975, she was acquired by the Foss Maritime Company of Seattle, Washington. Where she was renamed the Agnes Foss.
In 2004, the tug was acquired by the SeaCoast Transportation Company of Seattle, Washington. Where she was renamed as the Pacific Raven.
In 2007, Sea Coast Transportation was acquired by the K-Sea Transportation Partnership Incorporated of East Brunswick, New Jersey. Where the tug retained her name.
In 2011, the K-Sea Transportation Partnership Incorporated was acquired by the Kirby Corporation of Channelview, Texas. Where the tug retained her name.
In 2017, she was phased out of active service and was "laid up" at Seattle, Washington.
In 2018, the tug was acquired by the Curtin Maritime Company of Long Beach, California. Where she was renamed as the Shirley C.
Powered by two, twelve cylinder, EMD 12-645 diesel engines, Falk 1235 RM reduction gears. Turning two, 48(in) by 48(in), four bladed bronze, fixed pitch propellers. She was a twin screw tug rated at 3,000 horsepower.
Her electrical service was provided by two, 110kW, John Deere 6068, generator sets. The tug's capacities are 96,000 gallons of fuel, 1,700 gallons of lube oil, 236 gallons of hydraulic oil, and 3,000 gallons of water.
The towing equipment consists of a double drum, Markey TDSD 32 towing winch. Outfitted with 2,000(ft) of 2(in) towing wire one the port drum. And, 2,000(ft) of 2(in) towing wire on the starboard drum.
(Kyle Stubbs, Captain Russell Shrewsbury)