Built in 1957, by Todd Shipyards Incorporated of Seattle, Washington (hull #14) as the Shannon Foss for the Foss Tug and Launch Company of Tacoma, Washington.
In 1997, the tug was acquired by the Manke Tug and Barge Company of Shelton, Washington. Where she was renamed as the Judi M.
In 2002, she was acquired by ForeWest Maritime Incorporated of Bainbridge Island, Washington. Where the tug was renamed as the Shannon.
Re powered in 1977, with a single EMD-645 diesel engine. Turning a single, propellor mounted in a kort nozzle. She is a single screw tug, rated at 1,500 horsepower.