USN Carriers vs IJN Carriers

US NAVY CARRIER DOCTRINE

Following World War I, during which the British Royal Navy had demonstrated the utility of embarking aircraft on ships, including aircraft carriers, the US Navy realized that naval aviation was an instrumental part of modern naval operations. Fearful of falling farther behind the British, the US Navy received funding for the conversion of a collier into an aircraft carrier in July 1919. This experimental carrier was followed by the first fleet carriers in 1927. Upon first entering service, US Navy carriers' primary task was to support the battle fleet. Carrier aircraft would provide reconnaissance and spotting for the battle fleet while denying those advantages to the enemy. Spotting was viewed as especially important as aircraft could observe the fall of fire and radio corrections. Carriers were also expected to protect the airspace over their own fleet, thus denying the enemy the advantages of long-range spotting and scouting.

Gradually, the US Navy developed the carrier's role into an independent offensive platform. Early carrier aircraft were unable to carry torpedoes large enough to cripple or sink a capital ship, and although bombs could be carried, they posed no real threat to ships maneuvering at speed to avoid attack. However, in the 1920s, the offensive capability of carrier aircraft was greatly increased by the development of dive-bombing, which for the first time, allowed maneuvering ships to be struck with some degree of accuracy. Capital ships with heavy deck armor were still immune from attack, but carriers, with their unarmored flight decks, had now become very vulnerable to aerial attack.

Reflecting the premise that carriers could not withstand significant damage, US Navy doctrine increasingly separated the carriers from the battle fleet to prevent their early detection and destruction by the enemy. The primary task of the carrier was now to destroy opposing carriers as soon as possible, thus preventing their own destruction and setting the stage for intensive attack on the enemy battle fleet. To maximize the carrier's striking power, standard US Navy doctrine called for the launch of an entire air group at one time. In order that an entire “deck load” strike be launched quickly, it was necessary to have the entire strike spotted on the flight deck.

Early in the war, US Navy carriers each had a permanently assigned air group. Each of the assigned squadrons carried the hull number of the ship it was assigned to. For example, Lexington's fighter squadron was numbered VF-2, her dive-bombers VB-2, her scout bombers VS-2, and her torpedo squadron VT-2. After July 1938, air groups were known by the name of the ship. Thus, the squadrons listed above comprised the Lexington Air Group. By mid-1942, the entire air group was numbered to match its parent ship's hull number. With few exceptions, the permanence of the squadrons within an air group lasted through the battle of Midway. After that, due to carrier losses or squadron exhaustion, carriers could have a mix of squadrons from two or three air groups. As such, when Enterprise engaged in the battle of the Eastern Solomons in August 1942, her air group had its original fighter and dive-bomber squadrons as well as the scouting squadron from the sunken Yorktown and the torpedo squadron from the damaged Saratoga.