USS '' Lexington '' ( CV-2 ) , nicknamed " Lady Lex " , was an early aircraft carrier built for the United States Navy . She was the lead ship of the ; her only sister ship , , was commissioned a month earlier . Originally designed as a battlecruiser , she was converted into one of the Navy 's first aircraft carriers during construction to comply with the terms of the Washington Naval Treaty of 1922 , which essentially terminated all new battleship and battlecruiser construction . The ship entered service in 1928 and was assigned to the Pacific Fleet for her entire career . '' Lexington '' and '' Saratoga '' were used to develop and refine carrier tactics in a series of annual exercises before World War II . On more than one occasion these included successfully staged surprise attacks on Pearl Harbor , Hawaii . The ship 's turbo-electric propulsion system allowed her to supplement the electrical supply of Tacoma , Washington , during a drought in late 1929 to early 1930 . She also delivered medical personnel and relief supplies to Managua , Nicaragua , after an earthquake in 1931
earthquake in 1931
1931 Nicaragua earthquake
USS Lexington (CV-2)