(SS-111: dp. 876 (surf.), 1,092 (subm.); 1. 231'; b.21'10"; dr. 13'1"; s. 15 k. (surf.), 11 k. (subm.)cpl. 38; a. 4 21" tt., 1 4"; cl. S-3)
S-6 (SS-111) was laid down on 29 January 1918 by the Portsmouth (N.H.) Navy Yard; launched on 23 December 1919, sponsored by Miss Eleanor Westcott and commissioned on 17 May 1920, Lt.Comdr. George B. Junkin in command.
Following trials and outfitting, S-6 departed New London, Conn., on 18 November 1920 to join other "S" boats of Submarine Divisions 12 and 18 for what was to be, at that time, the longest cruise for American submarines on record. The trip, begun with a rendezvous off Portsmouth, N. H., took them through the Panama Canal to Pearl Harbor and then to Cavite Luzon, Philippine Islands. Other submarines had operated out of Cavite prior to this but had been transported there on the decks of colliers.
The two submarine divisions operated from Cavite over the next three years, from the date of their arrival on 1 December 1921 until 29 October 1924. During that time, they frequently visited Chinese ports at Shanghai, Chefoo, Chinwangtao, Tsingtao, Amoy, and Woosung.
On 30 December 1924, S-6 and her division (SubDiv 12) arrived at Mare Island, Calif. They operated along the west coast until 15 February 1927, in the Panama Canal area during March and April; then returned to New London on 3 May to operate along the New England coast. On 17 December, S-4, a unit of SubDiv 12, sank after colliding with the Coast Guard cutter Paulding, off Provincetown, Mass. S-6 then served as a training model to familiarize divers preparing to raise the sunken sub. S-4 was raised on 17 March 1928 and S-6 resumed normal operations with her division. She conducted winter maneuvers in the Panama Canal area in 1929 and 1930, but primarily operated out of New London until decommissioned on 10 April 1931, at Philadelphia.
S-6 was struck from the Navy list on 25 January 1937