Koos No. 2 was the second of several tugboats bearing the Koos name to work for the Knutson Towboat Company. Built in 1924 by Frank Lowe at his Marshfield shipyard, she went to work with her sister tug Koos. The original Koos had been used as a travel boat by the Simpson family to get from their estate at Shore Acres to the Coos Bay waterfront before its conversion to a tug. The name Coos was given to the Native Americans who lived in this area, and the Lewis and Clark expedition of 1804 to 1807 first recorded them as Cook-Koo-Oose, followed later by the spellings Cahoose, Koo-as, Kowes, Koos, Coose, and finally Coos.