 Her clandestine mission was electronic and visual surveillance of Soviet [spy] vessels penetrating U.S. Territorial Waters, including Soviet spy vessels disguised as fishing trawlers and fish factory ships.On 27 May 1957, "Tillamook" was ordered to be decommissioned and placed in reserve.However, that order was rescinded on the following day, and she was reassigned to the Pacific Fleet for duty with the Service Force, United States Pacific Fleet.