The Pacific War Online Encyclopedia

Tonnage	6590 tons standard displacement
Dimensions	541'6" by 53'2" by 26'6" 165.05m by 16.21m by 8.08m
Maximum speed	33 knots
Complement	623
Armament	8x2 5"/38 dual-purpose guns 4x4 1.1"/75 AA guns 2x4 21" torpedo tubes 2 depth charge racks
Protection	3.75" (95mm) belt (machinery and after magazine) 1.1" (28mm) belt (forward magazine) 3.75" (95mm) bulkheads 1.25" (32mm) armored deck 1.25" (32mm) turret 2.5" (64mm) enclosed bridge
Machinery	2-shaft Westinghouse geared turbines (75,000 shp) 4 Babcock & Wilcox boilers
Bunkerage	1360 tons fuel oil
Range	8500 nautical miles at 15 knots
Sensors	Sonar, most likely QC
Modifications	1942-10: Removed antisubmarine gear. Added SC, SG, and 2 Mark 12/22 radars 1943-12: Replaced all 1.1" guns with 1x4, 3x2 40mm Bofors AA guns. Added 7x1 20mm Oerlikon AA guns. 1945: Added 2x2 40mm guns.

The Atlantas were completed in 1942-45. They were the first cruisers laid down by the United States Navy since late 1936 and their design was a departure from previous cruiser designs, being influenced by the proposed limitations of the Second London Conference. They retained antisubmarine capability and one of the heaviest torpedo armaments in the fleet long after other American cruisers had discarded them. They had a main armament of relatively light guns, but in great numbers: sixteen of the 5"/38 dual-purpose guns that proved to be the best heavy naval antiaircraft guns produced by any nation in the war. In fact, they resembled nothing so much as armored super destroyers, optimized for escort duty or as destroyer flotilla leaders. However, their crowded fantails aggravated a lack of maneuverability that made them useless as submarine trackers, and they were never employed in the flotilla leader role. Instead, they were employed primarily as antiaircraft escorts.

Their rather meager armor protection (just 9% of displacement) was compensated somewhat by good machinery dispersal and toughness in their design. The belt was an integral part of the hull, which made for considerable strength. However, in the desperate early days of the war, the ships were sometimes employed in surface actions for which they were unsuited. Atlanta absorbed hits by a Long Lance and 49 shells off Guadalcanal yet survived for twelve hours before finally being scuttled. Juneau nearly made it from Guadalcanal to Espiritu Santo with a broken keel, but was torpedoed and suffered a magazine explosion that killed almost all her crew, including five brothers named Sullivan who had enlisted together.

The first four Atlantas lacked stability, and their wing turrets were of limited usefulness. Both problems were remedied in the next four ships, which replaced the wing turrets with twin 40mm mounts. These are listed as a separate class (Oakland class).

They were expensive ships at $27 million apiece.

Units in the Pacific:

Atlanta	arrived 1942-1-24	Sunk by torpedoes and gunfire 1942-11-13 off Savo Island
San Diego	arrived 1942-5-10
San Juan	arrived 1942-6-10
Juneau	arrived 1942-8-27	Torpedoed by I-26 1942-11-13 while en route Noumea from Guadalcanal