Built in 1957, by Pacific Tow Boat Co at Anacortes, Washington as the Sea Mule for the Pacific Tow Boat Company of Everett, Washington.
In 1969, Pacific Tow Boat and the Foss Launch and Tug Company of Tacoma, Washington were acquired as subsidiaries of the Dillingham Corporation of Honolulu, Hawaii. Operations of the two companies were united under the Foss name, where the tug retained her name.
In 1997 the tug was acquired by Sea and Shore Construction of Seattle, Washington where she was renamed as Kristina H.
After a period in lay-up, she was later acquired by the Fremont Tugboat Company of Seattle, Washington where she was renamed as Yankee.
Powered by a Detroit 8V-92 diesel. The tug's capacities are 1,600 gallons of fuel oil, 18 gallons of lube oil, and 60 gallons of potable water.