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.

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.

The Mahans carried a maximum of 523 long tons (531 t) of fuel oil, with a range of 6,940 nautical miles (12,850 km; 7,990 mi) at 12 knots (22 km/h; 14 mph).

[19] As weight compensation, the bridge wings were cut back, tripod foremast replaced by a pole mast, and several other elements eliminated, including the mainmast, torpedo tube blast shields, gun shelter on the after deckhouse, and the potato locker.

[21] In January 1945, as part of the anti-Kamikaze refit program, removal of the two waist torpedo tubes was authorized, providing enough weight margin to replace the two 40 mm twin mounts with quads.

[24] These rebuilt ships retained only two quadruple torpedo tubes (both mounted on the centerline above the main deck) and had six rather than five Oerlikons (four rather than three on the bridge), but otherwise had the same four 5-inch/38s and two twin Bofors of a typical Mahan in 1943/1944.

[27][28] Dunlap and Fanning were the first US destroyers to use enclosed forward gun mounts rather than shields; their light pole foremast and lack of a mainmast visibly distinguished them from the Mahans.

[31] This included a cheaper, faster and more efficient propulsion system, which combined increases in steam pressure and temperature with a new type of lightweight, fast-running turbine and double reduction gears.

At sea when the Japanese attacked Pearl Harbor on 7 December 1941, Mahan participated in the initial post-attack efforts in search of the strike force.

In the months to follow, Mahan escorted convoys between New Hebrides and the Fiji Islands, performed patrol assignments off New Caledonia and engaged in operations in Australian waters.

On 7 December 1944 while patrolling the channel between Leyte and Ponson Island, a group of Japanese suicide aircraft overwhelmed Mahan at Ormoc Bay.

[33] By July she was back in San Francisco to escort the heavy cruiser Baltimore, the ship that carried President Franklin D. Roosevelt to Pearl Harbor.

In December 1944, while screening a convoy to San Pedro Bay in the Philippines, a Japanese bomber attacked the ship, killing two men and wounding seven.

[63] After extensive repairs in the Puget Sound Naval Shipyard, she returned to the Pacific and operated off Iwo Jima, then sailed to the United States in November 1945.

Late in May 1942, Reid steamed north from Pearl Harbor to bombard the Japanese positions in Kiska and supported landings at Adak, Alaska.

[37] While conducting an anti-submarine patrol in August, she brought a Japanese submarine to the surface with a heavy depth charge barrage, and opened fire on it until it capsized and sank.

[70] Following repair work at Eniwetok, the ship resumed operations with the task group, screening for air strikes in July and for attacks on the Bonin Islands in August and September.

[39] In March 1941, Conyngham left Pearl Harbor on a goodwill tour to Samoa, Sydney and Brisbane in Australia, and Suva in Fiji, returning in April 1941.

[43] Afterward, Downes took part in the bombardment of Marcus Island to create a diversion and destroy Japanese installations, an action that Admiral Halsey later commended.

Downes served in Iwo Jima from June 1944 until the end of the war, when the ship was ordered to return to the United States, arriving at Norfolk in November 1945.

In the fighting that followed, she sustained several hits amidships and slowly began to lose power, but was able to fire six torpedoes by local control at the Hiei.

She operated in the eastern Pacific prior to World War II, and was at the Mare Island Navy Yard when the Japanese struck Pearl Harbor.

Docking at San Diego on 19 November, she remained there until ordered to Pearl Harbor on 28 December, arriving there on 3 January 1946 and assumed an inactive status.

In the ensuing skirmish, Preston was hit by a salvo from a Japanese cruiser that put both fire rooms out of commission and toppled the aft stack.

Afterward, Dunlap patrolled Hawaiian waters, escorted convoys between various ports on the west coast, and returned to Pearl Harbor in October 1942.

In United States Destroyer Operations in World War II (1953), Theodore Roscoe wrote: "In the Battle of Vella Gulf, as this engagement was called, the enemy had not laid a hand on the American ships.

"[94] After overhaul in San Diego, Dunlap performed patrol duty out of Adak, Alaska, in November and December 1943 and sailed to Pearl Harbor.

In July, she sailed to San Francisco to join the screen for the heavy cruiser Baltimore, which carried Roosevelt for conferences and inspections with top Pacific commanders of Pearl Harbor and Alaskan bases.

In March she reported to the Eastern Fleet (British units, reinforced with Australian, Dutch and French warships), participating in strikes against Sabang, Indonesia, the next month.