Atlanta-class cruiser

USS Atlanta (CL-51)
Class overview
Name:	Atlanta-class cruiser
Operators:	United States Navy
Preceded by:	St. Louis class
Succeeded by:	Cleveland class
Subclasses:	Juneau class
In commission:	1941 - 1949
Completed:	8
Lost:	2
Retired:	6
Preserved:	0
General characteristics
Class & type:	Light cruiser
Displacement:	6,718 long-tons (standard); 7,400 long-tons (loaded)
Length:	541 ft 0 in (164.90 m)
Beam:	52 ft 10 in (16.10 m)
Draft:	20 ft 6 in (6.25 m)
Propulsion:	4 × 665 psi boilers 2 geared steam turbines 75,000 hp (56 MW)
Speed:	32.5 knots (60 km/h)(design), 33.6 knots (62 km/h) (trials)
Range:	8,500 nautical miles (15,700 km) at 15 knots (28 km/h)
Complement:	Officer: 35 Enlisted: 638; Oakland group(CL 95-99) Officer: 47 Enlisted:766
Armament:	As designed 16 × 5 in (127 mm)/38 cal guns 16 × 1.1 in (27 mm)/75 cal guns 6 × 20 mm/70 cal anti-aircraft cannons 8 × 21 in (533 mm) torpedo tubes Oakland group (CL 95-99) 12 × 5 in (127 mm)/38 cal guns 8 × 40 mm/56 cal anti-aircraft guns 16 × 20 mm/70 cal anti-aircraft cannons 8 × 21 in (533 mm) torpedo tubes
Armor:	Belt: 1.1–3.5 in (28–89 mm) Deck: 1.25 inches (32 mm) Turrets: 1.25 inches (32 mm)

The Atlanta-class cruisers were eight United States Navy light cruisers originally designed as fast scout cruisers or flotilla leaders, but later proved to be effective anti-aircraft cruisers during World War II. They were also known as the Atlanta-Oakland class. The four Oakland and later ships had slightly different armament as they were further optimized for anti-aircraft fire. The Atlanta-class had 12 x 5 inch/38 caliber (127 mm) 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"/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 Atlanta-class saw heavy action during World War II, collectively earning 54 battle stars. Two ships of the class were sunk in action: Atlanta and Juneau, both at the Naval Battle of Guadalcanal. The other six were deactivated shortly after the war and were scrapped in the 1960s.

Specifications

As built the original main gun battery of the first quartet of Atlanta-class was composed of eight dual 5 inch/38 caliber (127 mm) gun mounts (8 × 2 5-inch guns). This battery could fire over 17,600 pounds (8,000 kg) of shells per minute, including the radar-fuzed "VT" antiaircraft shells. Fire control was by two Mk 37 fire control systems located on the centerline atop the superstructure. As built these lacked radar but in 1942 radar FD (Mk 4) was fitted. From 1943 this was replaced by the improved Mk 12/Mk 22 combination.

The first four had an original secondary anti-aircraft armament of twelve 1.1 in guns in three quad mountings, initially without directors fitted. By early 1942 as more became available a 4th 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, 4 amidships between the funnels (displacing some of the ships boats) and 2 on the quarterdeck aft. From 1943 onward the number of these mounts increased by adding two more on the forward superstructure and a pair 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 group, sometimes known as the Oakland class was commissioned with only six twin 5"/38 mounts and with Bofors guns from the start, with four additional twin Bofors 40 mm mounts compared to their predecessors: 2 displacing the former 5"/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 20mm Oerlikon's. In addition the battery of 20 mm anti-aircraft cannons was increased with a pair on the bow, 4 on the forward superstructure, 8 amidships arrayed either side of the aft funnel and 2 on the quarterdeck aft for a total of 16.

By the end of the war USS Oakland had been given an anti-kamikaze upgrade which included replacing the 4 aft twin Bofors with quad mountings and greatly reducing the number of 20 mm mounts (possibly as few as 6) while replacing those that remained with twin rather than single guns. Torpedo tubes were removed. Photo evidence show that USS Reno's torpedo tubes had been removed by the time she was torpedoed on 3 November 1944.

The Atlanta-class cruisers were the only class of U.S. Navy cruisers commissioned during World War II to be armed with torpedoes tubes, with eight 21" torpedo tubes in two quad launchers.^[1]

Although ships of the 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 6 depth charge projectors and 2 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.^[2] The Oakland sub-class never received the projectors, getting only two stern tracks, probably due to marginal stability.

Radar was not fitted as built. From spring of 1942 these ships were re-fitted first with SC-1 and SG search and FD (Mk 4) for fire control. As the war progressed additional and more modern radars were added.

The class was powered by four 665 psi boilers, connected to 2 geared steam turbines producing 75,000 hp (56 MW), and the ships could maintain a top speed of 33.6 knots (62 km/h). On trial the Atlanta made 33.67 knots (62 km/h) and 78,985 shp (58,899 kW). The ships of the Atlanta-class had thin armor: a maximum of 3.5 inches (89 mm) on their sides, with the captain's bridge and the 5-inch gun mounts being protected by only 1.25 inches (32 mm).^[2]

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.^[3]

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 Atlantas. Both were sunk in surface combat during the Guadalcanal Campaign.^[4] It should be noted, however, that 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, and throughout World War II and the postwar years, they had problems with topside weight which was addressed by a redesign of the third repeat order which was called the Juneau-class cruiser.^[5][6][7]

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, Atlanta (CL-51), 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 IJN surface warships and USS San Francisco (CA-38) on 13 November 1942 during the Naval Battle of Guadalcanal. USS Juneau (CL-52) was also heavily damaged in surface combat in the same battle and then sunk by Japanese submarine I-26, on 13 November 1942. USS Reno (CL-96) 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.^[4]

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 this ships were recommissioned to serve in an active role; all were ultimately struck and scrapped by 1970.^{[8][9][10][11][12][13]}

Ships in class

See also

• Dido-class cruiser : contemporary British cruiser of similar size, role and configuration

Footnotes

References

• Friedman, Norman (1984), U.S. Cruisers: an illustrated design history, Annapolis, MD: Naval Institute Press, ISBN 0-87021-718-6, OCLC 10949320 

External links

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