Built in 1964, by the Albina Machine and Engine Works of Portland, Oregon as the Lassen for River Lines Incorporated of Sacramento, California.
She was then acquired by the Willamette Tug and Barge Company of Portland, Oregon. Where the tug was renamed as the Willamette Mariner.
In 1988, Willamette Tug and Barge was acquired by the Brix Maritime Company of Seattle, Washington. Where she was renamed as the Jim Moore.
In 1993, Brix Maritime was acquired by Foss Maritime of Seattle, Washington. Where the tug retained her name.
In 2011, the tug was acquired by Diversified Marine Incorporated of Portland, Oregon. Where she was renamed as the Mariner.
Her powerplant consists of two CAT D-398 diesels turning two 70" x 59" four-blade propellors. For a rated 1,700 horsepower.
Electrical service is provided by a CAT D-330 75kW and a CAT D-330 90kW generator. Capacities include 14,000 gallons of fuel, 1,000 gallons of water and 200 gallons of lube oil.
Towing equipment consists of a single drum hydraulic winch with 1,200 feet of 1" wire.