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The County class was a class of heavy cruisers built for the Royal Navy in the years between the First and Second World Wars. They were the first post-war cruiser construction for the Royal Navy and were designed within the limits of the Washington Naval Treaty of 1922. Such ships, with a limit of 10,000 tons, standard displacement and 8-inch calibre main guns may be referred to as "treaty cruisers" (the term "heavy cruiser" was not defined until the London Naval Treaty of 1930〔). The thirteen Counties were built in three distinct sub-classes: the ''Kent'', ''London'' and ''Norfolk'' classes. They were the only 10,000-ton 8-inch gun, or "A", cruisers that the Royal Navy built. The Counties are remembered for their distinctive three-funnel layout and service in all the major naval theatres of the Second World War. In an attempt to extract more ships from the treaty limits, the navy planned to construct 8,250-ton "B" ships, six of which could be built in place of five Counties. The extra ship that this afforded was an attractive proposition for a navy that had the immense peacetime commitments of empire.〔''British and Empire Warships of the Second World War'', H. T. Lenton, Greenhill Books, ISBN 1-85367-277-7〕〔''Treaty Cruisers: The First International Warship Building Competition'', Leo Marriott, 2005, Leo Cooper Ltd., ISBN 1-84415-188-3〕 In the event, peacetime economies and politics intervened and only two B-type cruisers were built, an 8-inch gun modified County design: the . ==Design & development== The 10,000 ton treaty cruisers were the first type of warships built to internationally agreed restrictions.〔 These restrictions posed new engineering challenges and forced compromises upon designers〔 in how to extract the best balance of speed, armament and protection. The United States Navy adopted a design with triple-gun turrets, allowing the hull to be shortened thus saving weight that could be put into protection. This approach however was at the expense of requiring increased installed power, as the speed of a ship is a function of the ratio of length to beam. The Royal Navy had a requirement for a vessel for colonial trade route defence, which required a good cruising range and speed and independent fighting power. This determined the need for a long hull and the use of four twin-gun turrets, with any remaining displacement invested in protection. The design was conservative in nature, especially when compared to the contemporary ''Nelson''-class battleships built to satisfy the same treaty. The long (630 feet overall) hull was flush decked and with a high freeboard, and was strongly built. This afforded high initial stability,〔〔 which contributed to the protection scheme. The machinery spaces followed the traditional layout of boiler rooms ahead of engine rooms, separated by an amidships magazine. The two boiler rooms exhausted into four uptakes, the central pair being combined to form a thickened central funnel. The three-funnel design was handsome, but somewhat impractical in terms of utilisation of internal space.〔 As had been trialled in the wartime cruiser whose completion had been delayed post-war, the Counties featured a new design of forward superstructure incorporating the navigating bridge, wheelhouse, signalling and compass platforms and gunnery director in a single block. This advance considerably rationalised the separate armoured conning tower and myriad of decks and platforms of older designs. Moving the fire-control equipment from the mast negated the need for a heavy tripod, and light pole masts sufficed for signalling yards and the spread of wireless antennae. 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「County-class cruiser」の詳細全文を読む スポンサード リンク
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