(SS56: dp. 340 (surf.), 415 (subm.); l. 155; b. 146; dr. 124; s. 13 k. (surf.), 11 k. (subm.); cpl. 29; a. 4 18 tt.; cl. N4)
N4 (SS56) was laid down 24 March 1915 by Lake Torpedo Boat Co., Bridgeport, Conn.; launched 27 November 1916; sponsored by Miss Dorothy H. Elliott; and commissioned at New York Navy Yard 15 June 1918, Lt. J. R. Mann, Jr., in command.
Departing New York 25 June 1918, N4 proceeded to the New London Submarine Base for outfitting and then she proceeded to the Torpedo Station at Newport, R.I. Returning to New London11 July, she once again departed on the 28th to patrol along the New England Coast and guard coastal shipping against German U-Boats. Alternating out of New London and New York, she continued this duty until 3 November. The signing of the Armistice found this submarine tied up at New London, where, but for a training cruise to Salem, Mass. and Portland, Maine, 14 July to 30 September 1919, she remained until 1920.
During the first half of 1920, N4 made short voyages to New York and Newport before she was placed in reserve at New London 7 June. Taken out of reserve in early September, N4 sailed for Philadelphia 15 September for extensive overhaul until 28 March 1921. Returning to New London in early April, she operated off the New England Coast, out of Newport and New London until she put into New London 6 December to have her main engines removed and transferred to a newer L-class submarine. Sagamore (AT20) then towed the hulk of N4 to Philadelphia. She arrived 13 April 1922, and was decommissioned 22 April. The submarine was sold for scrapping 25 September to Joseph G. Hitner of Philadelphia.