SP-237 was transferred to the Department of Commerce for use by the Coast and Geodetic Survey on 28 April 1919. Named USC&GS Ranger in Coast and Geodetic Survey service, she operated along the United States East Coast and in the Atlantic Ocean during her entire career with the Survey.
On 28 June 1922, Ranger joined the Coast and Geodetic Survey launchUSC&GS Marindin in searching for survivors of the schoonerRose Standish, which had burned off Morro Point Light, Puerto Rico, although none were found. On 29 August 1924, she performed rescue work in the United States Virgin Islands—primarily by transporting rescue personnel to outlying islands from St. Thomas—after a hurricane passed through the area; she received a letter of thanks for her efforts from Philip Williams (1869-1942), the Governor of the U.S. Virgin Islands. On 28 February 1928, she assisted a gasoline launch on fire off Miami, Florida, putting out the fire so that the launch could be salvaged.
Ranger was transferred back to the Navy on either 26 November 1930[3] or 31 January 1931.[4] The Navy sold her on 21 December 1931, and she was registered in Panama in 1932.