Built in 1945 by Commercial Iron Works at Portland, Oregon as the Sassaba-class district harbor tug YTB-507 "Mimac" (hull #239) for the United States Navy.
In 1966, she was redesignated by the United States Navy as the YTM-770 "Mimac."
In 1985, the tug was placed out of service and struck from the Naval Register.
In 1987, she was acquired by the Island Tug and Barge Company of Seattle, Washington. Where the tug was renamed as the Paula S.
In 2012, the tug was acquired by the Northwest Marine Equipment Leasing Company of Anacortes, Washington. At that time she was redocumented as the Ambitious and work began to convert the tug into a fishing tender.
As of 2017, she is laid-up at Lovric's Marine in Anacortes, Washington.