USS G-3 (SS-31) 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. G-3 was named Turbot when her keel was laid down on 30 March 1911 by the Lake Torpedo Boat Company in Bridgeport, Connecticut, making her the first ship of the United States Navy to be named for the turbot, a large, brown and white flatfish, valued as a food. She was renamed G-3 on 17 November 1911, transferred to the New York Navy Yard for completion on 17 November 1913 following the cancellation of the Lake contract, launched on 27 December 1913, and commissioned on 22 March 1915 with Lieutenant Felix X. Gygax in command.