QF 4.7英寸Mk IX与Mk XII速射舰炮（英语：4.7 inch QF Mark IX and Mark XII）[note 1]是第二次世界大战期间为大多数英国皇家海军和英联邦海军驱逐舰所搭载的45倍径4.7英寸（120毫米）舰载主炮，[1]并且在第二次世界大战以后、随着搭载着它俩的驱逐舰被出售而出口到众多国家，包括巴西、阿根廷与荷兰，发射4.7英寸（120毫米）分装式炮弹。
Quick Facts QF 4.7英寸Mk IX与Mk XII速射舰炮QF 4.7 inch Mark IX & Mark XII, 类型 ...
QF 4.7英寸Mk IX与Mk XII速射舰炮 QF 4.7 inch Mark IX & Mark XII
S级驱逐舰（英语：S and T-class destroyer）为QF Mark XII 4.7英寸舰炮导入了CP（Central Pivot；中央枢轴）Mk XXII单装炮架。这款新型炮架所装有的炮盾（英语：Gun mantlet）的前部倾斜度很高，可将舰炮的仰角从40度增加至55度，[9][10]与以前的CP Mk XVIII的垂直正面形成鲜明对比，并且可轻松地将S级与先前的前型们区分开来。在这方面，野蛮人号（英语：HMS Savage (G20)）却是例外，配备4.5英寸口径速射舰炮；一座前舷的双联炮架与后舷的两座单装炮架。
最终在1943年，4.7英寸口径舰炮被Z级驱逐舰（英语：W and Z-class destroyer）以上的4.5英寸口径速射舰炮所取代。所有新型4.5英寸炮的炮架是英国皇家海军第一款真正的双用炮架，都具有仰角达到55度的炮架，而实际发射的炮弹亦比4.7英寸的Mk IX与XII舰炮稍重，虽然比4.7英寸Mk XI舰炮（英语：QF 4.7-inch Mk XI naval gun）所发射的炮弹稍轻。
3月，英国驱逐舰，P358，金伯利号（英语：HMS Kimberley (F50)），在纳尔维克（March, British Destroyers, P358, Kimberley at Narvik）：“总共齐射了180次…火炮训练非常好，很大一部分的装填动作实现了间隔仅约5秒…”（Salvos fired about 180 in all...drill to guns very good, great part of the action a loading interval of about 5 seconds was achieved...）
原文：It became clear at once that in an attack from the air in narrow waters flanked by mountains, the cards were held by the aircraft. There was too little sea-room for full freedom of manoeuvre, and the aircraft's approach was screened by the rock walls. As often as not, when they did come into view it was at such an angle that our 4.7-inch guns, whose maximum elevation was only forty degrees, could not reach them... Aandalsnes is approached through the Romsdal Fiord, and lies forty miles from the entrance, off which we arrived on the 24th April. The daylight passage of the convoy and escort through this waterway, speed five knots, on a steady course and with mountains rising steeply either side, presented an alluring invitation to enemy aircraft. Junkers attacks persisted to the end, but the fire of the destroyers, although limited to an elevation of forty degrees, was enough to keep the enemy just too high for their standard of marksmanship. Not a ship received a direct hit, though some were damaged by the splinters from near misses.
霍奇斯，部族级驱逐舰，p32：图解高空轰炸机的攻势（Hodges, Tribal Class Destroyers, p32: Diagram of High Level Bomber Attack）：从进入引信保存测定的有效射程之时起，直到它飞至4.7英寸舰炮抬升至仰角55度的最小射程之内以前，高度为12,000英尺、时速为240英里／小时的目标可能会在约58秒以内受到火力打击。相对地，一艘部族级驱逐舰只能使用4.7英寸的Mk XII舰炮抬升至仰角40度，与相同目标交战约37秒。（A 240 mph target, at 12 thousand feet altitude could expect to be under fire for about 58 seconds, from the time it enters the effective range of the FKC until it flies to within the minimum range of a 4.7-inch gun elevated to 55 degrees. A Tribal class destroyer would be able to engage the same target for about 37 seconds with a 4.7-inch Mk XII gun elevated to 40 degrees.）
Campbell, John. Naval Weapons of World War II. Annapolis, Maryland: Naval Institute Press. 1985. ISBN 0-87021-459-4.
Hodges, Peter; Friedman, Norman. Destroyer Weapons of World War 2. London: Conway Maritime Press. 1979. ISBN 0-87021-929-4.
March, Edgar J. British Destroyers: A History of Development, 1892–1953; Drawn by Admiralty Permission From Official Records & Returns, Ships' Covers & Building Plans. London: Seeley Service. 1966. OCLC 164893555.
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