Onward II was built as a civilian motorboat of the same name by Defoe Boat and Motor Works at Bay City, Michigan. The U.S. Navy acquired her from her owner, W. S. Forsythe, on 23 June 1917 for World War I service as a patrol vessel and commissioned her on 25 June 1917 as USS Onward II (SP-728). For the rest of World War I, Onward II performed rotuine harbor patrol duties at Newport, Rhode Island. In 1918 she was renamed USS SP-728. SP-728 was returned to her owner on 2 December 1918. Onward II should not be confused with the patrol vessel USS Onward (SP-311), in commission from 1917 to 1919.