(SS58: dp. 340 (surf.), 415 (subm.); l. 155; b. 146; dr. 124; a. 13 k. (surf.), 11 k. (subm.); cpl. 29; a. 4 18 tt.; cl. N4)
N6 (SS58) was laid down 15 April 1915 by Lake Torpedo Boat Co., Bridgeport, Conn.; launched 21 April 1917; sponsored by Mrs. John A. Kissick; and commissioned 9 July 1918, Lt. Comdr. Herbert R. Hein in command.
After outfitting at New London, she commenced patrolling off the New England Coast to protect coastal shipping from German submarines. She alternated operating out of New London and New York until she put into the former port 13 October for upkeep. With the exception of a training cruise up the New England coast from 14 to 19 July 1919, and a voyage to New York Navy Yard 29 September to 9 October, N6 remained at New London until sailing in early May 1920 for Annapolis, arriving 27 May. There she was used to indoctrinate midshipmen of the Naval Academy in submarine warfare.
Departing Annapolis 3 June, she returned to New London where she was placed in reserve on 7 June. Remaining in reserve until 15 September, she sailed to Philadelphia for an extensive overhaul, returning to New London 25 March 1921. She operated out of New London, making several training cruises, until October, when her engines were transferred to a new L-Class submarine. Departing New London 2 February 1922, under tow of Lykens (AT56), she sailed to Philadelphia where she was decommissioned 16 February and was sold for scrap to Joseph G. Hitner of Philadelphia, 31 July.