(SS-37: dp. 392 (surf.), 521 (subm.); l. 153'7"; b. 16'8"; dr. 13'1"; s. 14 k. (surf.), 10.5 k. (subm.); cpl. 28; a. 4 18" tt; cl. K-1)
K-6 (SS-37) was launched 26 March 1914, by the Fore River Shipbuilding Co., Quincy, Mass., under a subcontract from the Electric Boat Co., Groton, Conn.; sponsored by Mrs. Thomas Gaines Roberts; and commissioned 9 September at Boston, Lt. J. O. Fisher in command.
Steaming to Newport, R.I., 16 November, K-6 joined the 4th Division, Atlantic Torpedo Flotilla, for shakedown and training. For almost 3 years she conducted experimental and development operations along the Atlantic coast and in the Gulf of Mexico. She underwent diving tests off Cape Cod and Long Island; practiced firing torpedoes in Chesapeake Bay; and participated in tactical submarine exercises out of New London, Key West, and Pensacola. Following overhaul at Philadelphia, she departed New London 12 October 1917, and steamed via Halifax, N.S., for patrol duty in the Azores.
K-6 arrived Ponta Delgada, Azores, 27 October in company with three other K -class submarines. For more than a year they patrolled the surrounding ocean, searching for German submarines and surface raiders and preventing them from using the islands as a haven. After the surrender of Germany, K-6 sailed for the United States 21 November arriving Philadelphia via Bermuda 13 December. After overhaul K-6 preceded to New London 28 May 1919, to resume development and tactical operations along the New England coast.
During the 4 years of service that followed, K-6 ranged the Atlantic from New England to the Caribbean. Operating primarily out of New London, Hampton Roads, and Key West, she trained prospective submariners, conducted experimental dives and underwater maneuvers, and proved the value of submarines as an effective part of the mighty Navy. Arriving Hampton Roads from New London 21 March 1923, K-6 decommissioned 21 May. Subsequently, she was towed to Philadelphia 13 November 1924. Her name was struck from the Navy List 18 December 1930. She was broken up and sold for scrapping 3 June 1931.