USS G-2's crew out getting some fresh air after World War I
History
United States
Name	USS G-2
Builder	Lake Torpedo Boat, Bridgeport, Connecticut
Laid down	20 October 1909, as USS Tuna
Launched	10 January 1912
Commissioned	1 December 1913 6 February 1915 (Full commissioned)
Decommissioned	2 April 1919
Renamed	USS G-2, 17 November 1911
Stricken	11 September 1919
Fate	Sank at her mooring, 30 July 1919
General characteristics
Class and type	G-class submarine
Displacement	375 long tons (381 t) (surfaced) 516 long tons (524 t) (submerged)
Length	161 ft 3 in (49.15 m)
Beam	13 ft 1 in (3.99 m)
Draft	12 ft 6 in (3.81 m)
Propulsion	Gasoline-electric
Speed	14 kn (16 mph; 26 km/h) (surfaced) 10 kn (12 mph; 19 km/h) (submerged)
Complement	26 officers and men
Armament	4 × 18-inch (450 mm) torpedo tubes, (2 internal in the bow, 1 external in bow, one external stern), 8 torpedoes

USS G-2 (SS-27) was a G-class submarine of the United States Navy. While the four G-boats were nominally all of a class, they differed enough in significant details that they are sometimes considered to be four unique boats, each in a class by herself. A Simon Lake design, G-2 was named Tuna when her keel was laid down on 20 October 1909 by Newport News Shipbuilding in Newport News, Virginia (a contractor for Simon Lake). She was the first ship of the United States Navy to be named for the tuna, a large, vigorous, spiny-finned fish highly esteemed for sport and food. She was renamed G-2 on 17 November 1911, launched on 10 January 1912 sponsored by Ms. Marjorie F. Miller, towed to the New York Navy Yard after the termination of the Lake contract on 7 November 1913 where she was completed, and placed in reduced commission on 1 December 1913.

Departing New York City under tow of submarine tender Ozark (ex-Arkansas) the submersible torpedo boat arrived at the torpedo station, Newport, Rhode Island, on 28 February 1914. Attached to the Atlantic Submarine Flotilla, G-2 spent the next five months conducting dive training and engineering exercises with G-1 in Long Island Sound and Narragansett Bay. During these trials the boat made six submerged runs to a maximum depth of 37 ft (11 m). Her engines proved troublesome, however, and after the port armature shaft failed on 31 March, the boat was towed to New York for repairs. While there, financial considerations led to G-2 being put in reserve commission on 15 June 1914.

G-2 was placed in full commission at New York City on 6 February 1915. Attached to Division Three, Submarine Flotilla, Atlantic Fleet, the boat joined G-1, tender Fulton and tug Sonoma, for a cruise to Norfolk, Virginia on 25 March. Arriving there two days later, the submersible conducted maneuvers in Hampton Roads before proceeding to Charleston, South Carolina in April, arriving there on 17 April. Following a short yard period for repairs, the division proceeded back to New York, mooring alongside the 135th Street pier on 9 May.

On 18 May G-2 joined other warships and passed in review before President of the United States Woodrow Wilson, who looked on from the yacht Mayflower. The boat then sailed to Nantucket, Massachusetts, to participate in a war problem off Block Island, before unloading her torpedoes at Newport on 25 May. Ordered back to New York for an overhaul, the submersible again transited the familiar waters of Long Island Sound before arriving at the mouth of the East River on 22 June. While standing down the river with G-4, however, the two boats collided with submarine K-2, in an unusual three-boat accident. Fortunately, none of the boats suffered any damage. G-2 entered the Navy Yard there for an extended overhaul later that day.

Escorted to Provincetown, Massachusetts, by Ozark and tug Iwana, G-2 commenced final acceptance trials from 1–10 December. Following those successful evolutions, during which the Trial Board noted numerous items requiring modernization, the boat moved back to New York for an overhaul on 14 January 1916. Six months later, G-2 shifted to the Lake Torpedo Boat Company yard for completion, receiving new diving rudder gear, hydroplanes, electrical wiring and a new crankshaft. This yard work required extensive alterations and the boat did not return to service until convoyed to New London, Connecticut, by Sunbeam II on 28 June 1917.

On 21 August G-2 sailed to Boston, Massachusetts via the Cape Cod Canal to operate with the destroyer Aylwin, submarine chaser SC-6, and steam yacht Margaret. There, the boat helped a Navy Experimental Board embarked in Margaret carry out various sound detector tests in nearby waters. The submarine also conducted practice approaches and served as an instruction platform for officer and enlisted submarine students.

Shifting back to New London on 20 October, G-2 combined work on sound detection devices with training for the newly established Submarine School off Block Island and in Long Island Sound. During seven months of operations, she experimented with magnetic detectors and dragging devices and tried out new periscopes and other submarine equipment. The boat carried out these tests with section patrol boats Wacondah and Thetis, as well as numerous subchasers. Learning of the possible proximity of German U-boats, she conducted four-day patrols off Block Island in late June 1918 and again in mid-July.

G-2 continued schoolship duty out of New London through the end of World War I, testing listening and flare signaling devices (including the Very System Signal) among other pieces of equipment. On 30 August, for example, her crew tested the strength of the pressure hull, and the reliability of electric equipment, against depth charge explosions. On 12 September, Thetis experimented with a magnetic detector while G-2 lay on the bottom in 86 ft (26 m) of water and, in November, G-2 even conducted experimental work with patrol seaplanes. This duty ended in January 1919 when she was scheduled for inactivation.

Decommissioned on 2 April, the boat was designated as a target for testing depth charges and ordnance nets in Niantic Bay, Connecticut. During inspection by a six-man maintenance crew on 30 July, the boat suddenly flooded and sank at her moorings in Two Tree Channel near Niantic Bay. She went down in 81 ft (25 m), drowning three of the inspection crew. Too deep and too old to salvage, the submarine was struck from the Naval Vessel Register on 11 September.

 This article incorporates text from the public domain Dictionary of American Naval Fighting Ships. The entry can be found here.

• Friedman, Norman US Submarines through 1945: An Illustrated Design History, Naval Institute Press, Annapolis:1995, ISBN 1-55750-263-3.
• PigBoats.COM G-2 page

• Photo gallery of USS G-2 at NavSource Naval History
• On Eternal Patrol: USS G-2