View source for Omaha-class cruiser

{{Short description|US Navy light cruiser class}}
{{Use American English|date=October 2024}}
{{Use dmy dates|date=October 2024}}
{|{{Infobox ship begin}}
{{Infobox ship image
|Ship image=File:USS Concord (CL-10) off Balboa 1943.jpg
|Ship caption=USS ''Concord'' in 1943
}}
{{Infobox ship class overview
|Name=''Omaha'' class
|Operators=*{{naval|United States|1949}}
*{{navy|Soviet Union|1935}}
|Class before={{sclass|Chester|cruiser|4}}
|Class after={{sclass|Brooklyn|cruiser|4}}
|Subclasses=
|Cost=
|Built range=1918–1925
|In service range=
|In commission range=1923–1949
|Total ships planned=10
|Total ships completed=10
|Total ships scrapped=10
}}
{{Infobox ship characteristics
|Hide header=
|Header caption=
|Ship type=[[Light cruiser]]
|Ship displacement={{cvt|7050|LT|0|lk=on}} standard, 
{{cvt|9508|LT|0|lk=on}} full
|Ship length=*{{convert|550|ft|abbr=on}} [[Waterline|wl]]
*{{convert|555|ft|6|in|m|abbr=on}} [[Length overall|oa]]
|Ship beam={{cvt|55|ft|4|in}}
|Ship draft={{cvt|20|ft|0|in}}
|Ship power=
*12 × {{cvt|265|psi|lk=in}} [[Yarrow boiler]]s 
*{{cvt|90000|shp|lk=in}}
|Ship propulsion=*4 × [[Westinghouse Combustion Turbine Systems Division|Westinghouse]] reduction geared [[steam turbine]]s
*4 × [[Propeller|screw]]s
|Ship speed={{cvt|35|kn|lk=in}}
|Ship sensors=[[SK-1 radar|SK-1]] [[Radar|air-search radar]]
|Ship endurance={{cvt|9000|nmi|lk=in}} at {{cvt|10|kn}}
|Ship complement=29 officers 429 enlisted (peace time)
|Ship boats= *2 × [[Lifeboat (shipboard)|lifeboat]]s
|Ship armament=
*2 × dual [[6-inch/53-caliber gun|6"/53 cal gun]]s
*8 × single 6"/53 cal guns
*2 × single [[3-inch/50-caliber gun|3"/50 cal gun]]s
*2 × triple [[American 21 inch torpedo|21"]] [[torpedo tube]]s
*2 × dual 21" torpedo tubes
*224 × [[Naval mine|mines]]
|Ship armor=*[[Belt armor|Belt]]: {{cvt|3|in}}
*[[Deck (ship)|Deck]]: {{cvt|1+1/2|in}}
*[[Conning tower|Conning Tower]]: {{fraction|1|1|2}} in
*[[Bulkhead (partition)|Bulkhead]]s: {{fraction|1|1|2}}-3 in
|Ship aircraft=2 × [[floatplane]]s
|Ship aircraft facilities=*2 × [[aircraft catapult]]s
|Ship notes=
}}
|}

The ''' ''Omaha''-class cruisers''' were a class of [[light cruiser]]s built for the [[United States Navy]]. They were the oldest class of cruiser still in active service with the Navy at the outbreak of [[World War II]], being an immediate post-[[World War I]] design.

==History==
[[File:Omaha class cruiser drawing.jpg|thumb|left|1942 ship recognition chart for the ''Omaha'' class]]
Maneuvers conducted in January 1915 made it clear that the [[US Atlantic Fleet]] lacked the fast cruisers necessary to provide information on the enemy's position, deny the enemy information of the fleet's own position, and screen friendly forces. Built to scout for a fleet of [[battleship]]s, the ''Omaha'' class featured high speed ({{cvt|35|kn|lk=in}}) for cooperation with [[destroyer]]s, and {{convert|6|in|mm|adj=on|0}} guns to fend off any destroyers the enemy might send against them. Displacing {{convert|7050|LT|lk=on}}, they were just over {{cvt|555|ft}} long.<ref>US Cruisers: An illustrated design history pg.78</ref>

The ''Omaha'' class was designed specifically in response to the [[Royal Navy|British]] {{HMS|Centaur|1916|2}} subclass of the {{sclass2|C|cruiser}}. Although from a modern viewpoint, a conflict between the US and Great Britain seems implausible, US Navy planners during this time, and up to the mid-1930s, considered Britain to be a formidable rival for power in the Atlantic, and the possibility of armed conflict between the two countries plausible enough to merit appropriate planning measures.

The ''Omaha'' class mounted four smokestacks, a look remarkably similar to the {{sclass|Clemson|destroyer|1}}s (a camouflage scheme was devised to enhance the resemblance). Their armament showed the slow change from [[casemate]]-mounted weapons to [[Gun turret|turret]]-mounted guns. They carried twelve [[6-inch/53-caliber gun|{{cvt|6|in|adj=on}}/53]] [[caliber (artillery)|caliber]] guns, of which four were mounted in two twin turrets, one fore and one aft, and the remaining eight in casemates; four on each side, at the corners of the superstructure. This gave them a broadside of eight guns. Launched in 1920, {{USS|Omaha|CL-4|2}} (designated C-4 and later CL-4) had a displacement of 7,050 long tons. The cruisers emerged with a distinctly old-fashioned appearance owing to their World War I-type stacked twin casemate-mount cannons and were among the last broadside cruisers designed anywhere.<ref>US Cruisers: An illustrated design history pg.80</ref>

Additional torpedo tubes and hydrophone installation was ordered. As a result of the design changes placed on the ship mid-construction, the vessel that entered the water in 1920, was a badly overloaded design that, even at the beginning, had been rather tight. The ships were insufficiently insulated, too hot in the tropics and too cold in the north. Sacrifices in weight savings in the name of increased speed led to severe compromise in the habitability of the ship. While described as a good ship in a seaway, the low freeboard led to frequent water ingestion over the bow and in the torpedo compartments and lower aft casemates. The lightly built hulls leaked, so that sustained high-speed steaming contaminated the oil tanks with sea water.<ref>US Cruisers: An illustrated design history pg.80</ref>

A serious flaw in these ships' subdivision was the complete lack of watertight bulkheads anywhere above the main deck or aft on the main deck.<ref>US Cruisers: An illustrated design history pg.77</ref>

These drawbacks notwithstanding, the US Navy took some pride in the ''Omaha'' class. They featured improved compartmentalization; propulsion machinery was laid out on the unit system, with alternating groups of boiler rooms and engine rooms, to prevent immobilization by a single torpedo hit. Magazines were the first to be placed on centerline, below the waterline. These were also the first U.S. Navy cruisers designed after the switch from coal to oil-fired boilers.

Originally designed to serve as [[Scout cruiser|scouts]], they served throughout the interwar period as [[Flotilla leader|leaders of fleet flotillas]], helping them resist enemy destroyer attack. Tactical scouting became the province of cruiser aircraft, and the distant scouting role was taken over by the new heavy cruisers spawned by the [[Washington Naval Treaty]]. Thus, the ''Omaha'' class never performed their designed function. They were relegated to the fleet-screening role, where their high speed and great volume of fire were most appreciated.<ref>US Cruisers: An illustrated design history pg.81</ref>

===Armament changes===
During their careers the ''Omaha''s went through several armament changes. Some of these changes were to save weight, while others were to increase their AA armament. On 8 September 1926, the [[Chief of Naval Operations]], [[Admiral (United States)|Admiral]] [[Edward W. Eberle]], along with the Commanders in Chief of the [[United States Fleet]] and [[Battle Fleet]], and their subordinate commanding officers, the [[Secretary of the Navy]], [[Curtis D. Wilbur]], ordered that all mines and the tracks for laying the mines be removed from all of the ''Omaha''-class cruisers, as the working conditions had been found to be very "wet". In 1933–1934, their 3-inch AA guns were increased from two to eight, all mounted in the ship's waist.{{sfn|Watts|2017}} The lower torpedo tube mounts, which had also proved to be very wet, were removed and the openings plated over before the start of World War II. After 1939, the lower aft 6-inch guns were removed from most of the ''Omaha''s and the casemates plated over for the same reason as the lower torpedo mounts. The ships' AA armament was first augmented by three quadruple [[1.1"/75 caliber gun|{{convert|1.1|in|adj=on}}/75 gun]] mounts by early 1942, however, these did not prove reliable and were replaced by twin [[Bofors 40 mm Automatic Gun L/60|{{convert|40|mm|2|adj=on|sp=us}} Bofors guns]] later in the war. At about the same time they also received [[Oerlikon 20 mm cannon|{{convert|20|mm|2|adj=on|sp=us}} Oerlikon cannons]].{{sfn|Terzibashitsch|1988}}

==World War II service==
Both {{USS|Detroit|CL-8|2}} and {{USS|Raleigh|CL-7|2}} were at [[Pearl Harbor]] during the Japanese surprise attack, with ''Raleigh'' being torpedoed. ''Detroit'', along with {{USS|St. Louis|CL-49|2}} and {{USS|Phoenix|CL-46|2}}, were the only large ships to get out of the harbor during the attack.

Most ships of the ''Omaha'' class spent the war deployed to secondary theaters and in less vital tasks than those assigned to more recently built cruisers. The ''Omaha'' class were sent to places where their significant armament and speed might be useful if called upon, but where their age and limited abilities were less likely to be tested. These secondary destinations included patrols off the east and west coasts of South America, convoy escort in the South Pacific far from the front lines of battle, patrols and shore bombardment along the distant and frigid [[Aleutians]] and [[Kuril Islands]] chains, and bombardment duty in the [[Operation Dragoon|invasion of Southern France]] when naval resistance was expected to be minimal. {{USS|Marblehead|CL-12|2}} participated in early war actions around the [[Dutch East Indies]] (most notably, the [[Battle of Makassar Strait]]), and {{USS|Richmond|CL-9|2}} would engage in the [[Battle of the Komandorski Islands]]. The most significant action that any of the ships of the class would see during the war was {{USS|Detroit|CL-8|2}} during her time in the pacific theater. {{USS|Detroit|CL-8|2}} would see action in [[Battle of Iwo Jima|The Battle of Iwo Jima]] and [[Battle of Okinawa|The Invasion of Okinawa]] being assigned to the fifth fleet and serving as the flag ship of the Logistics Support Group (TF 50.8). 

None of the ships were wartime losses. ''{{USS|Raleigh|CL-7|2}}''{{'}}s torpedo damage at Pearl Harbor and ''{{USS|Marblehead|CL-12|2}}''{{'}}s damage at Makassar Strait were the only significant wartime combat damage suffered by the class.

The ships of the class were considered obsolete as the war ended, and were decommissioned and scrapped within seven months of the [[surrender of Japan]] (with the exception of {{USS|Milwaukee|CL-5|2}}, which had been loaned to the Soviet Navy, and was scrapped when returned to US Navy control in 1949).

==Ships in class==
The following ships of the class were constructed.<ref>{{cite web |url=http://www.ibiblio.org/hyperwar/USN/ships/ships-ca.html |title=U.S. Navy Cruisers 1940–1945 |access-date=18 September 2011 }}</ref>

{| class="sortable wikitable plainrowheaders"
|+ Construction data
|-
! scope="col" | Ship name
! scope="col" | {{abbr|Hull no.|hull number}}
! scope="col" style="max-width: 10em;" | Builder
! scope="col" | Laid down
! scope="col" | Launched
! scope="col" | {{abbr|Comm.|commissioned}}
! scope="col" | {{abbr|Decomm.|decommissioned}}
! scope="col" | Fate
|-
! scope="row" | {{USS|Omaha|CL-4|2}}
| CL-4
| rowspan=3 | [[Todd Dry Dock and Construction Company]], [[Tacoma, Washington]]
| style="text-align: right;" | 6 Dec 1918
| style="text-align: right;" | 14 Dec 1920
| style="text-align: right;" | 24 Feb 1923
| style="text-align: right;" | 1 Nov 1945
| Struck 28 Nov 1945; Scrapped Feb 1946
|-
! scope="row" | {{USS|Milwaukee|CL-5|2}}
| CL-5
| style="text-align: right;" | 13 Dec 1918
| style="text-align: right;" | 24 Mar 1922
| style="text-align: right;" | 20 Jun 1923
| style="text-align: right;" | 16 Mar 1949
| Struck 18 Mar 1949; Sold for scrap, 10 Dec 1949
|-
! scope="row" | {{USS|Cincinnati|CL-6|2}}
| CL-6
| style="text-align: right;" | 15 May 1920
| style="text-align: right;" | 23 May 1921
| style="text-align: right;" | 1 Jan 1924
| style="text-align: right;" | 1 Nov 1945
| Scrapped Feb 1946
|-
! scope="row" | {{USS|Raleigh|CL-7|2}}
| CL-7
| rowspan=2 | [[Bethlehem Shipbuilding Corporation]], [[Fore River Shipyard]], [[Quincy, Massachusetts]]
| style="text-align: right;" | 16 Aug 1920
| style="text-align: right;" | 25 Oct 1922
| style="text-align: right;" | 6 Feb 1924
| style="text-align: right;" | 2 Nov 1945
| Struck 28 Nov 1945; Scrapped, Feb 1946
|-
! scope="row" | {{USS|Detroit|CL-8|2}}
| CL-8
| style="text-align: right;" | 10 Nov 1920
| style="text-align: right;" | 29 Jun 1922
| style="text-align: right;" | 31 Jul 1923
| style="text-align: right;" | 11 Jan 1946
| Struck 21 Jan 1946; Scrapped, Feb 1946
|-
! scope="row" | {{USS|Richmond|CL-9|2}}
| CL-9
| rowspan=5 | [[William Cramp & Sons]], [[Philadelphia]]
| style="text-align: right;" | 16 Feb 1920
| style="text-align: right;" | 29 Sep 1921
| style="text-align: right;" | 2 Jul 1923
| style="text-align: right;" | 21 Dec 1945
| Struck 21 Jan 1946; Sold for scrap, 18 Dec 1946
|-
! scope="row" | {{USS|Concord|CL-10|2}}
| CL-10
| style="text-align: right;" | 29 Mar 1920
| style="text-align: right;" | 15 Dec 1921
| style="text-align: right;" | 3 Nov 1923
| style="text-align: right;" | 12 Dec 1945
| Struck 8 Jan 1946; Sold for scrap, 21 Jan 1947
|-
! scope="row" | {{USS|Trenton|CL-11|2}}
| CL-11
| style="text-align: right;" | 18 Aug 1920
| style="text-align: right;" | 16 Apr 1923
| style="text-align: right;" | 19 Apr 1924
| style="text-align: right;" | 20 Dec 1945
| Struck 21 Jan 1946; Sold for scrap, 29 Dec 1946
|-
! scope="row" | {{USS|Marblehead|CL-12|2}}
| CL-12
| style="text-align: right;" | 4 Aug 1920
| style="text-align: right;" | 9 Oct 1923
| style="text-align: right;" | 8 Sep 1924
| style="text-align: right;" | 1 Nov 1945
| Struck 28 Nov 1945; Sold for scrap 27 Feb 1946
|-
! scope="row" | {{USS|Memphis|CL-13|2}}
| CL-13
| style="text-align: right;" | 14 Oct 1920
| style="text-align: right;" | 17 Apr 1924
| style="text-align: right;" | 4 Feb 1925
| style="text-align: right;" | 17 Dec 1945
| Struck 8 Jan 1946; Sold for scrap, 18 Dec 1947
|}

==''Omaha'' alternatives==
Two other ''Omaha'' versions were also designed. The first, intended to function as a monitor, had two 14-inch guns in 2 single turrets, while the other design had four 8-inch guns in two twin turrets. The second design eventually evolved into the {{sclass|Pensacola|cruiser|1}}. Furthermore, in 1928 after seeing the successes of ''[[USS Langley (CV-1)|Langley]]'' a proposed carrier alternative was designed, featuring none of her 2 × twin 6 in/53 caliber turrets, and only including 4 of the original single 6 in/53 caliber turrets. {{citation needed|date=October 2023}} 

==See also==
* [[List of cruisers of the United States Navy]]

==Citations==
{{Reflist}}

==References==
* {{cite book 
  | title=Cruisers of the US Navy 1922–1962 
  | publisher=[[Naval Institute Press#Naval Institute Press|Naval Institute Press]] 
  | last= Terzibashitsch
  | first= Stefan 
  | year= 1988 
  | isbn= 0-87021-974-X
  }}
* {{cite DANFS
  |last= Watts
  |first= John W.
  |url= https://www.history.navy.mil/research/histories/ship-histories/danfs/o/omaha-ii.html
  |title= Omaha II (CL-4)
  |publisher= [[Naval History and Heritage Command]]
  |date= 7 April 2017
  |access-date= 4 November 2019
  }}{{PD-notice}}

==External links==
{{Commons category|Omaha class cruiser}}
* http://www.avalanchepress.com/OmahaAlternatives.php
* http://www.avalanchepress.com/AmericanCruisers.php

{{Omaha class cruiser}}
{{WWII US ships}}

[[Category:Cruiser classes]]
[[Category:Omaha-class cruisers| ]]
[[Category:World War II cruisers of the United States| ]]