Atlanta-class cruiser

The ''Atlanta''-class cruisers were eight United States Navy light cruisers which were designed as fast scout cruisers or flotilla leaders but which proved to be effective anti-aircraft cruisers during World War II. They were also known as the ''Atlanta''-''Oakland'' class. The ''Atlanta'' class had 12 x /38 caliber guns, mounted in three superfiring sets of two-gun turrets fore and three more aft. The first four ships of the class also had an additional two twin 5-inch/38 mounts, one port and one starboard, giving these first four ''Atlanta''-class cruisers the heaviest anti-aircraft armament of any cruiser of World War II. The last four ships of the class, starting with , had slightly different armament as they were further optimized for anti-aircraft fire.

The ''Atlanta'' class saw heavy action during World War II, collectively earning 54 battle stars. Two ships of the class were sunk in action: and , both at the Naval Battle of Guadalcanal. The other six were decommissioned shortly after the war and were scrapped in the 1960s.

Specifications

As built, the original main gun battery of the first quartet of the ''Atlanta'' class was composed of eight dual 5-inch/38 caliber gun mounts (8 × 2 5-inch guns). This battery could fire over of shells per minute, including the radar-fuzed "VT" anti-aircraft (AA) shells. Fire control was by two Mk 37 fire control systems located on the centerline atop the superstructure. As built, these ships lacked radar but from the spring of 1942 they were re-fitted with FD (Mk 4) fire control radar and SC-1 and SG search radar. From 1943 the FD (Mk 4) radar was replaced by the improved Mk 12/Mk 22 combination.

The first four ''Atlanta'' class cruisers originally had a secondary anti-aircraft armament of twelve /75 caliber guns in three quad mountings, without directors fitted. By early 1942, as more weapons became available, a fourth quad mount had been installed on the quarterdeck and directors were fitted (probably Mk 44). By late 1942 these troublesome and relatively ineffective weapons began to be replaced in the surviving ships by twin mountings for the new and far superior Bofors 40 mm anti-aircraft guns with Mk 51 directors.

Also from early 1942, close-range AA armament was augmented by eight 20 mm rapid-fire anti-aircraft cannons in single Mk 4 mountings disposed two on the forward superstructure, four amidships between the funnels (displacing some of the ship's boats) and two on the quarterdeck aft. From 1943 onward, two more Mk 4 mountings were added on the forward superstructure and a pair on each side of the second funnel to counter the danger of Japanese air attacks (especially ''kamikazes''). From the end of 1943, a quadruple 40 mm Bofors mounting replaced the twin mount on the quarterdeck, with the six depth charge projectors being removed as compensation. The additions of radar, additional close-range anti-aircraft guns and other equipment seriously impaired the stability of these ships as the war progressed and resulted in overcrowding as more ratings had to be added to man them.

The second quartet of the ''Atlanta'' class, sometimes known as the ''Oakland'' class, was commissioned with only six twin 5-inch/38 mounts and with Bofors guns from the start, with four additional twin Bofors 40 mm mounts compared to their predecessors: two displacing the former 5-inch/38 wing turrets (improving both stability and close-range AA firepower while easing congestion) and two between the funnels displacing the previous two pairs of 20 mm Oerlikons. In addition the battery of 20 mm anti-aircraft cannons was increased with a pair on the bow, four on the forward superstructure, eight amidships arrayed on either side of the aft funnel and two on the quarterdeck aft for a total of sixteen.

The ''Atlanta''-class cruisers were the only class of U.S. Navy cruisers commissioned during World War II to be armed with torpedo tubes, with eight torpedo tubes in two quad launchers.

By the end of the war had been given an anti-''kamikaze'' upgrade which included replacing the four aft twin Bofors with quad mountings and greatly reducing the number of 20 mm mounts (to possibly as few as six) while replacing those that remained with twin rather than single guns. The torpedo tubes were removed.

Although ships of this class were planned as destroyer flotilla leaders, the original design did not include anti-submarine armament such as sonar or a depth charge battery. In early 1942, along with anti-aircraft and radar upgrades, these ships were fitted with sonar and the standard destroyer battery of six depth charge projectors and two stern mounted tracks. When the vessels were determined to be more valuable as protection against aircraft, the projectors were removed but the tracks were retained. The ''Oakland'' sub-class never received the projectors, getting only two stern tracks, probably due to marginal stability.

The class was powered by four 665 psi boilers, connected to two geared steam turbines producing , and the ships could maintain a top speed of . On trial the ''Atlanta'' made and . The ships of the ''Atlanta'' class had thin armor: a maximum of on their sides covering machinery and magazines, with the 5-inch gun mounts being protected by only and the conning tower by .

The ships were originally designed for 26 officers and 523 men, but this increased to 35 officers and 638 men with the first four ships, and 45 officers and 766 men with the second group of four ships beginning with ''Oakland''. The ships were also designed as flagships with additional space for a flag officer and his staff but the additional space was used for additional crew necessary to man anti-aircraft weapons and electronics.

Criticisms

Although very formidable as anti-aircraft ships, the ''Atlanta''-class cruisers did not fare well in surface combat. The only two cruisers of the class that engaged in surface combat were sunk: ''Atlanta'' and ''Juneau''. The U.S. Navy lost three light cruisers during World War II, two of which were ''Atlanta''s. One was sunk in surface combat during the Guadalcanal Campaign while the other was heavily damaged in the same battle and sunk by on her way back for repairs. Both of these vessels received their fatal blows from Japanese torpedoes, and gunfire from larger, more heavily armed ships. The unique armament of the ''Atlanta'' class did not contribute to their loss.

The ''Atlanta''-class design was also criticized for its shortage of gunfire directors for the main 5-inch gun battery, which reduced its effectiveness. Initially there were not enough intermediate anti-aircraft guns (i.e. 1.1 in guns, Bofors 40 mm and the Oerlikon 20 mm rapid-fire cannons). These problems were somewhat corrected in naval shipyards by the end of 1942, but the ''Atlanta''-class warships were thereafter overloaded with weight, compared to the size of their hulls. Throughout World War II and the postwar years, they had problems with topside weight; this was addressed by a redesign of the class which was then constructed as the three s.Naval marine archive.com - cruiser roles and missions page 55
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Service history

All eight ships in this class served during World War II, and six ships survived the war. The lead ship of this class, , was laid down on 22 April 1940 and launched on 6 September 1941. ''Atlanta'' was commissioned at the New York Navy Yard on 24 December 1941, just a few weeks after the Japanese attack on Pearl Harbor of 7 December. ''Atlanta'' participated as an anti-aircraft cruiser in the decisive American victory at the Battle of Midway in June 1942 before she was sent south to fight in the Solomon Islands. ''Atlanta'' was scuttled after receiving a torpedo hit and heavy gunfire damage from Japanese surface warships and on 13 November 1942 during the Naval Battle of Guadalcanal. was also heavily damaged in surface combat in the same battle and then sunk by the , on 13 November 1942. was torpedoed off Leyte on 4 November 1944 resulting in a large fire and significant flooding, but was saved from sinking by the damage control efforts of the crew.

After the war, the six surviving ships in this class were decommissioned between 1947 and 1949 and placed in the reserve fleet. The ships received a new type designation of CLAA in 1949. None of these ships were recommissioned to serve in an active role; all were ultimately struck and scrapped by 1970.

Ships in class

See also

*The Cruiser-Destroyer and the CL-154 class cruiser, attempts to create a "super-''Atlanta''" by replacing the ''Atlantas 5-inch/38-caliber gun with the longer-range and faster firing 5-inch/54-caliber Mark 16 gun
*, a contemporary British cruiser of similar size, role and configuration
*List of cruisers of the United States Navy
* List of ship classes of World War II

Footnotes

References

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External links

{{WWII US ships

Cruiser classes