Built in 1969, by Diesel Shipbuilding Incorporated of Jacksonville, Florida as the Radrala III.
The tug was later sold, and renamed as the Sugar C.
She was then acquired by R.J. Casho Marine Towing Corporation of Wilmington, Delaware. Where she was renamed as the Mister Jim.
The tug was eventually acquired by River Associates Incorporated of Philadelphia, Pennsylvania. Where she was renamed as the Jimmy III.
In 2007, River Associates Incorporated was acquired by K-Sea Transportation Partnership Incorporated of East Brunswick, New Jersey. Where the tug retained her name.
In 2009, the tug was acquired by Cyr's Marine Construction Incorporated of Millersville, Maryland. Where she was renamed as the Karen C.
She is a single screw tug, rated at 365 horsepower.