USS G-4

USS G-4 (SS-26) 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-4 was an attempt to introduce competition to the USN submarine acquisition process. Italian naval architect Cesare Laurenti had been campaigning for permission to build a submarine for the USN and he was granted a contract for one submarine in the Fiscal Year 1909 building program. The contract was approved with the proviso that the boat be built in the United States.

G-4 was built with a radically different hull design. She had a full double hull, with an inner elliptically shaped pressure hull wrapped by a flattened circle shaped outer hull. Electric Boat had built all of their designs up to that point with a circular single hull. The hull design was not entirely successful, as she suffered from stability problems throughout her service. She very nearly capsized during her launch from the building ways. This boat also was the first USN submarine (by date of full commission status) with stern torpedo tubes. G-4 had retractable bow and stern diving planes and two rudders, one ventral and one dorsal both at the stern.

G-4 was named Thrasher when her keel was laid down on 9 July 1910 by William Cramp & Sons in Philadelphia, making her the first ship of the United States Navy to be named for the thresher shark, a shark with a long dorsal tail fin. Thrasher is an outdated spelling. She was renamed G-4 on 17 November 1911, launched on 15 August 1912 sponsored by Ms. Grace Anna Taussig, and commissioned in the Philadelphia Navy Yard on 22 January 1914.