USS Atlanta (CL-51)
under construction,
1 October 1941
USS San Juan (CL-54)
and
USS San Diego (CL-53)
under construction
|
|
The Atlanta class light cruisers were the lightest and most lightly armed cruisers to see service with the US Navy during the Second World War and were a product of the London Naval Treaty of 1936. Armed with 5in guns, they found a use during the Second World War as anti-aircraft cruisers, but the US Navy hadn't really wanted to build them, and they were only ordered because of problems with a new dual purpose 6in gun.
USS San Juan (CL-54)
and
USS San Diego (CL-53)
under construction
The previous Brooklyn class cruisers had been built under the terms of the London Naval Treaty of 1930, which allowed 10,000 ton cruisers armed with 6in guns. They had carried the 6in gun as their main armament and a dual purpose 5in gun as their main anti-aircraft weapon. The 1936 treaty reduced the weight limit to 8,000 tons, but kept the 6in gun.
USS Reno (CL-96) at sea, late 1943 or early 1944
The US Navy took some time to decide what sort of ships it wanted to build under the new rules. Work began in December 1936 with the aim of building ten ships of between 5,000 and 7,000 tons. A number of designs were produced, armed with a mix of 6in and 5in guns. The favoured option was to use the new dual purpose 6in/47 gun, but this gun was still under development, and wasn't really ready for use until 1945. The massive Cleveland class of light cruisers was built after the end of treaty limitations, and reverted to a mix of 6in and 5in guns. One of the possible Atlanta designs was similar, with nine 6in and six 5in guns, but it was very hard to fit these guns into 8,000 tons.
Eventually the navy settled on using the dual purpose 5in gun as the main armament and long range anti-aircraft gun. The new cruiser carried eight twin 5in gun houses, for a total of sixteen guns. Six of these turrets were mounted on the centre line and two by the side of the rear superstructure. As a result only seven turrets could fire on the broadside. The first batch of Atlanta class ships carried all eight turrets, with the six centre line turrets carried on three levels, making the ships look somewhat like large destroyers. On the second batch the side guns were removed and replaced with 40mm anti-aircraft guns. On the third batch the middle four turrets were all dropped one level to reduce top weight.
The new ships were significantly smaller than the preceding Brooklyn class. They had a standard displacement of 9,767 tons, were 608ft 4in long and 61ft 9in wide. The new Atlanta class ships displaced 6,718 tons, were 541ft 6in long and 53ft 2in wide.
The basic shape was similar to that of the earlier cruisers, including the fantail stern, even though the Atlanta class ships didn't carry any aircraft. The superstructure looked more bulky, although that was partly because of the reduced length.
The Atlanta class ships were designed with an immune zone against a 5.1in shell hitting at 60 degrees of between 6,000 and 16,000 yards. The main armoured belt was 3.75in thick and was a structural part of the hull instead of being attached to a steel shell. Deck armour was 1.25in thick, the bulkheads at the end of the belt 3.75in thick. The guns were weakly armoured, with only 1.25in of protection. A total of 585.5 tons of armour was carried, a much lower proportion than on the Brooklyn class ships.
The Atlanta class cruisers were the only American cruisers of the Second World War to have a two-shaft turbine. There were four boilers in two fire rooms, with the turbine room between them. They had a top speed of 32.5kts, although some contemporary publicity claimed they could reach 40kts.
Unusually for American cruisers the Atlanta class ships were armed with eight torpedo tubes, in two quadruple mountings taken from Sims class destroyers. They were also the only American cruisers to carry depth charges and sonar, but they were poor anti-submarine vessels and the depth charges were later removed.
The light anti-aircraft provision changed over time. The first batch were built with three quad 1.1in mountings, one behind the after control station and two by the sides of the bridge. A fourth mounting was later added on the fantail. These were all replaced by 40mm Bofors guns when they became available.
On the second batch the side 5in gun houses were replaced with twin 40mm Bofors mountings. This gave them a total of eight twin 40mm mountings. They also carried as many as eighteen 20mm guns.
The third batch was built with four quad and six twin 40mm and twenty 20mm guns. The torpedo tubes were later removed and the AA firepower increased to six quad and six twin 40mm, twenty single and two twin 20mm guns. The 20mm guns were later replaced by eight twin 20mm mountings.
The London Naval Treaty of 1930 allowed countries to replace ships that were judged to be 'over-age'. Ships laid down after the start of 1920 were judged to be overage twenty years after they had been completed. For the United States this applied to the Omaha class cruisers. The first two members of the class had been laid down in 1919 and would become over-age in 1939, allowing work to begin on their replacements in 1936. The next four ships were laid down in 1920 and completed between July 1923 and February 1924, so could be replaced in 1943-44.
The tonnage to build the first four Atlanta class ships was a mix of spare treaty capacity and the space available to replace the first four Omaha ships.
The first batch of four Atlanta class ships was ordered on 25 April 1939 (CL-51 to CL-54). These ships were laid down between April and May 1940 and all completed by February 1942. Somewhat ironically the outbreak of the Second World War meant that the naval treaties that had limited their design were no long in force by the time work on them began.
The second batch was ordered on 9 September 1940, probably in order to use slipways that weren't big enough to take the better Cleveland class cruisers. These ships were built in two batches at the Bethlehem shipyard, San Francisco. Oakland (CL-95) and Reno (CL-96) were laid down on 13 July 1941 and 1 August 1941 and launched on 23 October 1942 and 23 December 1942. On the same days Flint (CL-97) and Tucson (CL-98) were laid down.
The third batch was ordered from Bethlehem, San Francisco on 7 August 1942. On 27 September 1943 the order was transferred to Federal, Kearny, and they were laid down between September 1944 and February 1945.
The third batch was built to a modified design (the same was done with the Cleveland and Baltimore classes). The main change was to lower four of the six 5in gun houses to lower locations. Gun houses 2 and 5 were dropped to the main deck, putting them on the same level as Gun houses 1 and 6. Gun houses 3 and 4 were dropped one level to the first superstructure level, putting them on the same level previous used by Nos.2 and 5. Plans to replace the original two funnels with a single funnel were abandoned. Light anti-aircraft firepower was boosted to four quad 40mm mountings, six twin 20mm and twenty single 20mm mountings in the design and to six quad 40mm, six twin 40mm and eight twin 20mm mountings as built.
The intention was to use these ships with the destroyers, to protect the flanks of the battle line against air or surface threats. They thus had to have good anti-aircraft fire and be capable of defeating enemy destroyers. They weren't popular with the fleet commanders who preferred the 6in cruisers, but they did turn out to be effective anti-aircraft cruisers and were used to protect the vital aircraft carriers. After the war most were decommissioned very quickly. The Juneau was the last in service, but she was decommissioned in 1956.
Ship Histories
USS Atlanta (CL51) served in the Solomon Islands, fighting at the battles of the Eastern Solomon Islands, Santa Cruz and Savo Island. She was damaged by a Japanese torpedo at the naval battle of Guadalcanal and had to be scuttled.
USS Juneau (CL52) also served in the Solomon Islands. She was hit by a torpedo at the naval battle of Guadalcanal, and by a second torpedo while attempting to reach safety. This second torpedo caused a magazine explosion which destroyed her.
USS San Diego (CL53) fought off Guadalcanal and during the advance west up the Solomon Islands to Bougainville. From 1943 to the end of the war she operated with various carrier task forces. She was present at the battles of the Philippine Sea and Leyte Gulf and became the first US warship to enter Tokyo Bay after the Japanese surrender.
USS San Juan (CL54) survived the battle of Savo Island undamaged. She was hit by a bomb during the Battle of Santa Cruz. She spent the rest of the war with the carrier task forces, and was present at the Battle of the Philippine Sea.
USS Oakland (CL95) entered service during the invasion of the Gilbert Islands. During 1944-45 she acted with the carrier task groups and was present at the battle of Leyte Gulf.
USS Reno (CL96) entered combat with the carrier task force in May 1944 and was with them until she was badly damaged during the Leyte campaign. She didn’t return to service until the end of the war.
USS Flint (CL97) arrived in time to support the landings on Luzon at the start of 1945. For the rest of the war she supported the carrier task force in its raids on Iwo Jima, Okinawa and the Japanese Home Islands.
USS Tucson (CL98) arrived just in time to take part in the last attacks on the Japanese Home Islands. She remained in service until 1949.
USS Juneau (CL119) was the longest serving member of the class, remaining in the post-war fleet until 1956.
USS Spokane (CL120) was decommissioned in 1950. In 1966 she was selected for conversion into an experimental ship, but the work was never carried out and she was struck off the Navy List in 1972.
USS Fresno (CL121) was in service for two and a half years before being decommissioned in May 1949.
Displacement (standard) |
6,718t |
Displacement (loaded) |
8,340t |
Top Speed |
32.5kts |
Range |
8,500 nm @ 15kts |
Armour – belt |
3.75in |
- bulkheads |
3.75in |
- armour deck |
1.25in |
- gunhouses |
1.25in |
- deck over underwater magazines |
1.25in |
Length |
541ft 6in oa |
Armaments (Batch One) |
Sixteen 5in/38 guns (eight two-gun turrets) |
| Armaments (Batch Two) | Twelve 5in/ 38 guns (six two-gun turrets) |
| Armaments (Batch Three) | Twelve 5in/ 38 guns (six two-gun turrets) Modified to: |
Crew complement |
623 |
Ships in Class |
Fate |
Sunk 13 November 1942 |
|
Sunk 13 November 1942 |
|
Broken up 1960 |
|
Broken up 1962 |
|
Broken up 1962 |
|
Broken up 1962 |
|
Broken up 1966 |
|
Stricken 1966 |
|
Broken up 1961 |
|
Sold for break up 1973 |
|
Broken up 1966 |
US Navy Light Cruisers 1941-45, Mark Stille.
Covers the five classes of US Navy light cruisers that saw service during the Second World War, with sections on their design, weaponry, radar, combat experience. Nicely organised, with the wartime service records separated out from the main text, so that the design history of the light cruisers flows nicely. Interesting to see how new roles had to be found for them, after other technology replaced them as reconnaissance aircraft [read full review]
