(SS-25: dp. 287; l. 135'3"; b. 14'7"; dr. 11'8"; s. 14 k.; cpl. 20; a. 4 18" tt; cl. E)
Sturgeon (SS-25) was launched 15 June 1911 by Fore River Shipbuilding Co., Quincy, Mass.; sponsored by Miss Margaret Nelson Little; renamed E-2, 17 November 1911; and commissioned 14 February 1912, Ensign C. N. Hinkamp in command.
Serving in the Atlantic Submarine Flotilla, E-2 sailed out of Newport for developmental exercises and training. Between 5 January and 21 April 1914, she cruised to Guantanamo Bay and the Gulf of Mexico. She returned to Newport, 27 July, for training operations for the remainder of the summer and from February to May 1915 off Florida.
Entering New York Navy Yard 19 June 1915 for overhaul, E-2 was victim of a violent explosion and fire 15 January 1916 when hydrogen gas was ignited by a spark. Four men were killed and seven injured. On 13 March, E-2 was placed out of commission for use as a laboratory, for exhaustive tests of the Edison storage battery.
Recommissioned 25 March 1918, E-2 served in training and experimental work at New London until 16 May. Two days later she arrived at Norfolk to operate against enemy submarines off Cape Hatteras. Between 21 May and 27 August, she made four war patrols, sighting a large enemy submarine for which she made extended submerged search on her last patrol. E-2 was commended by the Chief of Naval Operations for two of these antisubmarine patrols, which were exceptionally long for a submarine of her size.
Returning to New London, 31 August 1918, E-2, made two more patrols before the end of the war, then returned to training student officers and qualifying men for duty in submarines. She sailed from New London 19 April 1920 for Norfolk, arriving 2 days later. There she was placed in commission in ordinary, 18 July 1921. On 17 September, she sailed for Philadelphia Navy Yard where she was decommissioned 20 October 1921 and sold 19 April 1922.