 "Palos" was built by James Tetlow, Chelsea, Massachusetts, in 1865 and was put into service as yard tug at the Boston Navy Yard the following year.Placed in ordinary in 1869, the tug was converted to a gunboat and commissioned 11 June 1870, Lieutenant C. H. Rockwell in command.Departing Boston 20 June for the Asiatic Station, "Palos" steamed across the Atlantic Ocean and through the Mediterranean Sea, becoming the first American warship to transit the Suez Canal 11–13 August, and arrived at Singapore, via Aden and Ceylon, 25 September.