|
The ''Implacable''-class aircraft carrier was a class of two aircraft carriers built for the Royal Navy during World War II. Derived from the design of the , they were faster and carried more aircraft than the older ships. They were initially assigned to the Home Fleet when completed in 1944 and attacked targets in Norway as well as the . Subsequently they were assigned to the British Pacific Fleet (BPF). was the first ship to go to the Pacific and attacked Japanese-controlled oil refineries in Sumatra en route. She participated in Operation Iceberg, the invasion of Okinawa in March–April 1945. 's arrival in the Pacific was delayed by a refit and she did not begin operations against the Japanese until June. The sister ships participated in the attacks on the Japanese Home Islands in July and August. ''Indefatigable'' was the only carrier chosen to continue operations after most of the BPF withdrew to prepare for further operations in early August. After the Japanese formal surrender in September, ''Implacable'' ferried Allied troops and prisoners of war back to Australia and Canada for the rest of the year. The sisters returned home in 1946; ''Indefatigable'' was used for the rest of the year to transport troops before being placed in reserve in 1947 and ''Implacable'' became the training carrier for Home Fleet. ''Indefatigable'' was converted into a training ship and reactivated in 1950 for service with the Home Fleet. ''Implacable'' was relegated to the reserve that same year and modified into a training ship in 1952. The sisters were scheduled for modernisation during the mid-1950s, but it was cancelled as the modernisation of the carrier in the queue ahead of them proved to be too expensive and lengthy. The sisters were decommissioned in 1954 and sold for scrap in 1955–56. == Background and description == The ''Implacable'' class had its origin as an improved version of the ''Illustrious''-class aircraft carriers for the 1938 Naval Programme while still remaining within the available from the tonnage allowed by the Second London Naval Treaty. The initial change was to increase the carriers' speed to no less than which required the addition of a fourth steam turbine and associated propeller shaft. Offsetting the additional weight of the machinery meant reductions in armour thicknesses in the hangar deck and the bulkheads at the ends of the hangar. At the same time the Director of Naval Construction (DNC) was developing a different modified ''Illustrious'' design (Design D) to carry an additional dozen aircraft (a total of 48) in a lower hangar that also incorporated the additional machinery of the initial design with the sacrifice of even more armour. Hangar height was initially planned as in the upper hangar to accommodate the new Fairey Albacore torpedo bomber and in the lower hangar to accommodate taller amphibious aircraft, but a later change in policy raised the upper hangar height to . Design D was submitted to the Board of Admiralty on 2 August 1938 and approved on 17 November. In April 1939 the lower hangar's height was reduced to 14 feet to compensate for the thickening of the hangar side armour to and the idea of carrying amphibians in the hangar was abandoned.〔Friedman, pp. 141–44〕 The ''Implacable''-class ships were long overall and at the waterline. Their beam was 〔Friedman, p. 366〕 at the waterline and they had a draught of at deep load. The ships were significantly overweight and displaced at deep load.〔Brown 1977, p. 49〕 Their complement was approximately 2,300 officers and enlisted men in 1945.〔Hobbs, p. 109〕 They had metacentric heights of at light load and at deep load as completed.〔Friedman, p. 151〕 The ships had four Parsons geared steam turbines, each driving one shaft, using steam supplied by eight Admiralty 3-drum boilers.〔Chesneau 1980, p. 20〕 The turbines were designed to produce a total of , enough to give them a maximum speed of .〔Friedman, p. 367〕 On sea trials, the ships reached speeds of with . The ''Implacable'' class carried a maximum of of fuel oil which gave them a range of at .〔 The armoured flight deck had a maximum width of . The arrestor cables, crash barricades, aircraft catapult and lifts were designed to handle aircraft up to in weight. The carriers were fitted with nine arrestor cables aft that were designed to stop landing, at speeds of up to . They were backed up by three crash barricades to prevent landing aircraft from crashing into aircraft parked on the ship's bow. In case of damage to the rear flight deck, the ''Implacable''-class ships also mounted three additional forward arrestor cables to permit aircraft to land over the bow. A single BH3 hydraulic catapult was fitted on the forward part of the flight deck to launch 20,000-pound aircraft at ; lighter aircraft could be launched at a maximum speed of . The ships were equipped with two lifts on the centreline, the forward of which measured and served only the upper hangar, and the aft lift () which served both hangars. The upper hangar was long and the lower hangar was long; both had a uniform width of .〔Roberts, pp. 62-64〕 Both hangars had a height of only 14 feet which precluded storage of Lend-Lease Vought F4U Corsair fighters as well as many post-war aircraft and helicopters. In case of fire the upper hangar could be divided by two fire curtains and the lower hangar had one fire curtain. Designed to stow 48 aircraft in their hangars, the use of a permanent deck park allowed the ''Implacable'' class to accommodate up to 81 aircraft. The crewmen, maintenance personnel and facilities needed to support these additional aircraft were housed in the lower hangar. The ships were provided with of aviation gasoline,〔Brown 1977, pp. 48–49, Friedman, p. 144〕 only enough for approximately five sorties per aircraft.〔Brown 1977, pp. 48–49, Hobbs, p. 108〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Implacable-class aircraft carrier」の詳細全文を読む スポンサード リンク
|