swilliam@dtoa1.dt.navy.mil (Williams) (12/28/90)
From: swilliam@dtoa1.dt.navy.mil (Williams) This is in response to one posting saying that catapults were not needed on WWII carriers. I see the need for clarification on the use of catapults on the aircraft carriers. The original purpose of catapults was to launch the floatplanes (in the 1920's), and the current purpose of catapults is to launch heavier aircrafts with minimum takeoff distance. Let us go to the early years of the aircraft carriers, around 1920's. The aircraft carriers, at that time, were highly valued first for the reconnaissance and artillery spotting their aircrafts could provide the battle fleet, and for the denial of these advantages to an enemy. The strike power of the carriers, at first, was very much a secondary asset. This thinking continued through the beginning of World War II. Strategic reconnaissance can be defined as providing intelligence about the approximate position, speed, course, and composition of enemy naval formations, information a distant fleet commander might use to seek or avoid action. During World War I, German Zeppelins performed this function, and the British placed fighters aboard their battleships to deny the Germans such information. The Zeppelins were effective. The British came up short here because of their failure (despite considerable effort) to develop a successful long-endurance aircraft. A cruiser/battleship had only a very limited radius of vision, hardly encompassing the entire battle view. Navagational errors often created considerable confusion. A single observor high above the battle area could probably form a much better idea of the relative positions, courses, speeds, and even identities of approaching and engaging forces. This led to proposals for the earliest aircraft carriers. The battleship gun was unquestionably the most effective naval offensive weapon during World War II. Moreover, the battleship gun had a longer maximum range than the torpedo. Here an aircraft played a vital role. An observor on an aircraft could observe the fall of shot, even well beyond the horizon, and radio down corrections. At very long ranges most ships could be penetrated through their deck armor, whereas at shorter ranges, conventional battle ranges recent battleships would enjoy the protection of their vertical (belt) armor. The fleet that could use extreme ranges effectively would have a decisive advantage. This was clear to the U.S. Navy by the early twenties, when it agitated for increased elevation (range) for the guns of its older battleships and rapidly developed spotting aircraft. Moreover, aircraft might well be able to derange the fire control of enemy battleships by strafing their relatively vulnerable fire-control positions aloft. This was the strategy that was developed for naval aircraft at sea before aircraft could directly damage ships in a battle. Thus, the aircraft carrier was an important part of the battleship group. The carriers initially functioned as depot ships for battleship and cruiser float planes. The first U.S. carrier designs had incorporated facilities to service floatplanes that the battleships and cruisers might launch earlier in a battle, but that they would be unable to recover during the battle. The maintenance facilities aboard the carriers might also be used by those float-planes. USS Lexington and USS Saratoga each had a flywheel catapult on the flight deck in the twenties for the purpose of launching float-planes in the twenties. Don't ask what a flywheel catapult is - I don't know. At least, it looks just like any catapult; it consists of tracks down the flight deck. The value of the catapult was limited, particularly when the role of float-planes depot ship waned as the large carriers became separated from close cooperation with the battle line. However, the catapult was important in the Ranger design, just completed when the Lexington and Saratoga entered service. The Ranger was not as big as the Lexington class carriers. The catapult was removed from the Lexington class carriers in 1934 after relatively little use. In 1936 the Lexington had her flight deck widened at the bow during a refit; no catapult was added. In a 1944 refit, the Saratoga was fitted with a pair of the standard H Mk II hydraulic catapults. They were considered essential for night operation because of the guidance they provided for an airplane taking off in total darkness. The Saratoga was designated a night carrier then. The Yorktown class carriers were completed with both hanger and flight deck catapults. The prototype H Mk I was tested in 1935; it could launch a 5,500 lb aircraft at 45 mph in a length of 45 feet. Its success lead to the H Mk II of the Yorktown and Wasp classes, which could launch a 7,000 lb aircraft at 70 mph; it was later developed into the H 2-1 (11,000 lb at 70 mph in 73 feet) for escort carriers and also for the Enterprise as refitted in wartime. The hanger deck H Mk II was seldom used. CinC U.S. Fleet authorized the removal of the hanger-deck catapults from the carriers on February 17, 1942, in view of their unnecessary weight and their inability to launch the heavy aircraft then in service (flight-deck catapults of equal capacity could launch much heavier aircraft because they benefitted from "wind-over-the-deck" generated by the carrier's forward motion). The catapults that became surplus would be valuable for the escort carrier program. Pearl Harbor Navy Yard reported the removal of the hanger-deck catapults from the Enterprise and Hornet on June 26, 1942. The Yorktown had already been sunk with her hanger-deck catapult aboard. Early war experience suggested that catapults were not worth their weight, and on April 29, 1943, the captain of the Enterprise asked to have his remaining flight-deck catapults removed. However, by that time, the CVEs (escort aircraft carriers) had shown how valuable the catapults could be, and when the Enterprise was rebuilt at Puget Sound that summer, two redesigned H 2-1 catapults were fitted. The Essex class carriers had H 4B catapults.