Tillamook was built as a civilian motorboat or motor yacht of the same name in 1911 by the Matthews Boat Company at Port Clinton, Ohio.

The U.S. Navy purchased her from her owner, Mr. D. C. Whitney of Detroit, Michigan, on 14 May 1917 for World War I service as a patrol vessel.

[3] Assigned to the 9th Naval District—at the time functioning as part of a single administrative entity known as the "9th, 10th, and 11 Naval Districts" -- Tillamook patrolled the waters of Lake Michigan.

According to some sources her name change to USS SP-269 occurred during this time, early in 1918.

Despite her name change, official papers often continued to refer to her as Tillamook (SP-269), particularly those regarding her disposal in 1919.