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The ''Mahan''-class destroyers of the United States Navy were a series of 18 destroyers of which the first 16 were laid down in 1934. The last two of the 18, ''Dunlap'' and ''Fanning'' (this pair laid down in 1935), are sometimes considered as a separate ship class. All 18 were commissioned in 1936 and 1937. was the lead ship, named for Rear Admiral Alfred Thayer Mahan, an influential historian and theorist on sea power. The ''Mahan''s featured improvements over previous destroyers, with 12 torpedo tubes, superimposed gun shelters, and generators for emergency use. Standard displacement increased from 1,365 tons to 1,500 tons. The class introduced a new steam propulsion system that combined increases in pressure and temperature with a new type of lightweight steam turbine, proving simpler and more efficient than the ''Mahan''s' predecessors—so much so that it was used on many subsequent wartime US destroyers. All 18 ships saw action in World War II, entirely in the Pacific Theater, including during the Guadalcanal Campaign, and the battles of the Santa Cruz Islands, Leyte Gulf, and Iwo Jima. Their participation in major and secondary campaigns included the bombardment of beachheads, amphibious landings, task force screening, convoy and patrol duty, and anti-aircraft and submarine warfare. Six ships were lost in combat and two were expended in the postwar Operation Crossroads nuclear tests. The remainder were decommissioned, sold, or scrapped after the war; none remain today. Collectively, the ships received 111 battle stars for their World War II service. ==Design== The ''Mahan''-class destroyers emerged as improved versions of the ''Farragut''s,〔Reilly p. 28〕 incorporating the most up-to-date machinery available.〔Reilly p. 28〕 The Navy's General Board had been wrestling with proposed design changes, first considering 12 torpedo tubes with one fewer 5"/38 caliber gun,〔Friedman p. 86〕 and then proposing to retain all five guns with the 12 torpedo tubes, but configuring those guns only for surface targets, not air targets. The Chief of Naval Operations objected, recommending against "subordinating the gun to the torpedo", and a compromise was struck that included a new engineering plant and a new battery arrangement for the ''Mahan'' class and others.〔Friedman pp. 87 & 88〕 In the final design, No. 3 gun was moved to the aft deckhouse (just ahead of No. 4) to make room for the third quadruple torpedo tube; the two middle torpedo tubes were moved to the sides, releasing the centerline space for extension of the aft deckhouse. All five 5"/38s were kept and remained dual purpose guns, able to target aircraft as well as ships, but only No. 1 and No. 2 had gun shields. The traditional destroyer machinery was replaced with a new generation of land-based machinery. This change ushered in a new steam propulsion system that combined increases in pressure and temperature with a new type of lightweight steam turbine, which proved simpler and more efficient to operate. Double reduction gearing also reduced the size of the faster-turning turbines and allowed cruising turbines to be added. These changes led to a ten percent increase in displacement over the ''Farragut''s.〔Friedman p. 88〕 The ''Mahan''s typically had a tripod foremast with a pole mainmast.〔 To improve the anti-aircraft field of fire, their tripod foremast was constructed without nautical rigging.〔 In silhouette, they were similar to the larger s that immediately preceded them.〔Reilly p. 28〕 The ''Mahan''s were fitted with the first emergency generators, replacing the storage batteries of earlier classes. Gun crew shelters were built for the superimposed weapons, one shelter before the bridge and one atop the shelter deck aft.〔 The ''Mahan''s displaced at standard load and at deep load. The overall length of the class was , the beam was , and the draft . They were powered by General Electric geared steam turbines, driving two shafts that developed a total of for a maximum speed of . Four Babcock & Wilcox or four Foster Wheeler water-tube boilers generated the superheated steam needed for the turbines. The ''Mahan''s carried a maximum of of fuel oil, with a range of at . Their peacetime complement was 158 officers and enlisted men.〔Friedman p. 465〕 The wartime complement increased to approximately 250 officers and enlisted men.〔Roscoe p. 20〕 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「Mahan-class destroyer」の詳細全文を読む スポンサード リンク
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