The NC-4 was one of four NC (Navy-Curtiss) flying-boats, built during World War I, originally to provide patrol cover for American shipping in the Atlantic against the German U-boats but the war was ending even as flight testing began. After the War it was decided to enter the Navy-Curtiss machines for a transatlantic attempt. At 20:01 hours on May 27, 1919, NC-4′ completed the first transatlantic flight.LT. Elmer Stone USCG was the pilot.