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, and (this pair laid down in 1935), are sometimes considered 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 Mahans featured improvements over previous destroyers, with 12 torpedo tubes, superimposed gun shelters, and generators for emergency use. The 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, which proved simpler and more efficient than the Mahans' predecessors—to such an extent that it was used on many subsequent wartime US destroyers.
All 18 ships saw action in World War II, entirely in the Pacific Theater, which included 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 ,
which incorporated the most up-to-date machinery available. and then proposed to retain all five guns with the twelve torpedo tubes, but configure those guns only for surface targets, not air targets. The Chief of Naval Operations objected, and recommended 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. 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, and released the centerline space for extension of the aft deckhouse. All five 5 in/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 Farraguts.