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The 4.7 inch QF Mark XI〔Mark XI = Mark 11. Britain used Roman numerals to denote Marks (i.e. models) of ordnance until after World War II. Hence this article covers the eleventh model of British QF 4.7-inch gun.〕 was a 120-mm 50-calibre naval gun deployed on Royal Navy (RN) and allied destroyers during World War II.〔Campbell, p. 46〕 ==Description and history== The QF 4.7-inch Mk XI gun, on the Mk XX twin mounting, was introduced to the RN aboard the L and M class destroyers, in commission from 1941 onwards. It featured a 62 lb (28.1 kg) shell fired at 2538 ft/second (774 m/s) to a maximum range of 21,240 yards (19,420 m) at 45 degrees of elevation.〔 The Mk XX mounting was fully enclosed, but the hoists did not revolve with the turret. The gun's firing cycle was six seconds〔Campbell, p. 47〕〔March, p. 507: "The guns in the Mk XI mounting in the "L"s fired 12 rounds per minute, as each shell or cartridge was taken from the top of the hoist another automatically took its place." 〕 and the separate shell and cordite hoists for each gun provided shells and cartridges at a rate of 10 per minute. The shells and cartridges were transferred from the hoists to the tilting tray of the fuze-setting machine by hand. Once the fuzes were set, they slid forward to the loading tray from which they were rammed forward into the breech by a hydraulic rammer.〔Smith, p. 206〕 The horizontal sliding-block breech opened semi-automatically after the guns fired.〔 The guns could be loaded at any angle of elevation. The Mk XX mounting could elevate to a maximum of 50° and depress to −10°. The turret had a maximum powered training rate of 10° per second, but was manually elevated. Including the crew and ammunition, the revolving weight of the mounting was . It was protected by a gun shield thick.,〔 too thin to hold a direct hit, but still appreciable versus small splinters, explosions, small caliber rifles. With a shell 24% heavier, the new gun was far more powerful than the previous 45 calibre long 4.7 inch gun making it a match for a weapon such as the Italian 120/50 mm,〔(italian 120/50 guns )〕 whilst also improving the air defence role. It could now penetrate 3 inches (76.2 mm) of armour at a range of 10 km rather than 5.9 km. In the Battle of Pantelleria on 15 June 1942), HMS ''Marne'' and ''Matchless'' engaged a superior Italian task force. ''Marne'' fired 704 shells, ''Matchless'' 746, while HMS ''Ithuriel'' (with four 4.7 /45) managed to fire only 246. ''Marne'' hit with a single shell the cruiser RN ''Eugenio di Savoia'' at around 5.50 AM. Matchless failed to hit the other cruiser, RN ''Montecuccoli'', but later hit the large destroyer ''Ugolino Vivaldi''. The new 120/50 mm shell was heavy and powerful, and the Italian destroyer was soon laying dead in the water, with a furious fire at midship. That destroyer was saved only towing her to a near naval base, where the fire was finally extinguished.〔Cernuschi, p. 10-12〕 In the worlds of Tony di Giuliano, the 120/50 Mark XI gun was the perhaps the finest destroyer gun made by British during the World War II, but it was also heavy and costly, as were the ships equipped with it. Wartime production required a much greater production of ships and guns, so cheaper weapons were installed in many other classes, like the 'O' and 'P' (102 mm) and furthers (with the old 120 mm), until the 114 mm (4.5 in) started to replaced them, as the first, powerful dual purpose destroyer gun.() 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「QF 4.7 inch Mark XI gun」の詳細全文を読む スポンサード リンク
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