page_title: USS Lexington (CV-2)
section_title: Armament
hierarchical_section_title: USS Lexington (CV-2) / Design and construction / Armament
caption_attribution_description: The U.S. Navy aircraft carrier USS Lexington (CV-2) firing her 55 caliber eight-inch guns, in 1928.
context_page_description: 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 Lexington class; her only sister ship, Saratoga, 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.
  Lexington was at sea when the Pacific War began on 7 December 1941, ferrying fighter aircraft to Midway Island.
context_section_description: The Navy's Bureau of Construction and Repair was not convinced when the class was being designed that aircraft could effectively substitute as armament for a warship, especially at night or in bad weather that would prevent air operations. Thus the carriers' design included a substantial gun battery of eight 55-caliber Mk 9 eight-inch guns in four twin gun turrets. These turrets were mounted above the flight deck on the starboard side, two before the superstructure, and two behind the funnel, numbered I to IV from bow to stern. In theory the guns could fire to both sides, but it is probable that if they were fired to port (across the deck) the blast would have damaged the flight deck. They could be depressed to −5° and elevated to +41°.
  The ship's heavy antiaircraft (AA) armament consisted of twelve 25-caliber Mk 10 five-inch guns which were mounted on single mounts, three each fitted on sponsons on each side of the bow and stern. No light AA guns were initially mounted on Lexington, but two sextuple .30-caliber (7.62 mm) machine gun mounts were installed in 1929. They were unsuccessful, and they were replaced by two .50-caliber (12.7 mm) machine guns by 1931, one each on the roof of the superfiring eight-inch turrets. During a refit in 1935, platforms mounting four .50-caliber machine guns were installed on each corner of the ship, and an additional platform was installed that wrapped around the funnel. Six machine guns were mounted on each side of this last platform. In October 1940, four 50-caliber Mk 10 three-inch AA guns were installed in the corner platforms; they replaced two of the .50-caliber machine guns which were remounted on the tops of the eight-inch gun turrets. Another three-inch gun was added on the roof of the deckhouse between the funnel and the island. These guns were just interim weapons until the quadruple 1.1-inch gun mount could be mounted, which was done in August 1941.
  In March 1942, Lexington's eight-inch turrets were removed at Pearl Harbor and replaced by seven quadruple 1.1-inch gun mounts. The eight-inch guns and turrets were reused as coast defense weapons on Oahu. In addition 22 Oerlikon 20 mm cannon were installed, six in a new platform at the base of the funnel, 12 in the positions formerly occupied by the ship's boats in the sides of the hull, two at the stern, and a pair on the aft control top. When the ship was sunk in May 1942, her armament consisted of 12 five-inch, 12 quadruple 1.1-inch, 22 Oerlikon cannon, and at least two dozen .50-caliber machine guns.
caption: Lexington firing her eight-inch guns, 1928
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