Built in 1929 at Portland, Oregon as the Wilavis for the Smith Transportation Company of Portland, Oregon.

In 1930, the Smith Tranportation Company was consolidated into the Shaver Transportation Company of Portland, Oregon. Where the tug retained her name.

Eventually the tug was renamed as the Cowlitz.

In 1977, she was acquired by the Knappton Towboat Company of Astoria, Oregon. Where the tug retained her name.

The tug was later acquired by the Jay Towing Company Incorporated of Tacoma, Washington. Where she was renamed as the Mystery.

In 1997, she was acquired by an individual named John E. Eilertsen of Wrangell, Alaska. Where the tug retained her name.

The tug's documents expired on March 31, 2000. Her current and/or final fate is not known.

She was a single screw tugboat with 750 horsepower.