page_title: USS Omaha (CL-4)
section_title: Construction and design
hierarchical_section_title: USS Omaha (CL-4) / Construction and design
caption_attribution_description: English: A U.S. Navy Vought UO-1 observation plane (BuNo A-67??) at a naval air station, circa in the mid-1920s. The aircraft was assigned to the light cruiser USS Omaha (CL-4).
context_page_description: USS Omaha (CL-4) was the lead ship of the Omaha-class light cruiser of the United States Navy. She was originally classified as a scout cruiser. She was the second US Navy ship named for the city of Omaha, Nebraska, the first being Omaha, a screw sloop launched in 1869.
  Omaha spent most of her career in the Pacific. At this time her primary mission was training, and she proved to be very capable by consistently winning fleet awards in gunnery and communications. She made many ports-of-call throughout the Pacific, Mediterranean and Caribbean during her peacetime cruises, displaying the Stars and Stripes. In 1941, prior to the US entering the war, she was assigned to Neutrality Patrol in the Atlantic, based in Recife, Brazil. Nearly a month before the US entered the war she captured the German blockade runner SS Odenwald, for which she holds the claim as being the last US Navy ship to be awarded "prize" money.
  After the US entered the war she continued her activities of guarding convoys in the Atlantic between South America and Western Africa.
context_section_description: Omaha's keel was laid down by the Todd Dry Dock & Construction Company of Tacoma, Washington, on 6 December 1918. She was launched on 14 December 1920. Omaha was sponsored by Louise Bushnell White, a descendant of David Bushnell, the inventor of the first documented submarine to be used in combat, Turtle. She was commissioned on 24 February 1923, with Captain David C. Hanrahan in command.
  Omaha was 550 feet (170 meters) long at the waterline with an overall length of 555 ft 6 in (169.32 m), her beam was 55 ft 4 in (16.87 m) and a mean draft of 14 ft 3 in (4.34 m). Her standard displacement was 7,050 long tons (7,163 t) and 9,508 long tons (9,661 t) at full load. Her crew during peacetime consisted of 29 officers and 429 enlisted men.
  Omaha was powered by four Westinghouse geared steam turbines, each driving one screw, using steam generated by 12 Yarrow boilers. The engines were designed to produce 90,000 ihp (67,000 kW) and reach a top speed of 35 kn (65 km/h; 40 mph). Though the ship's design was intended to provide a range of 10,000 nmi (19,000 km; 12,000 mi) at a speed of 10 kn (19 km/h; 12 mph), she only delivered 8,460 nmi (15,670 km; 9,740 mi) at that speed.
  Omaha's main armament went through many changes while she was being designed. Originally she was to mount ten 6-inch (150 mm)/53 caliber guns; two on either side at the waist, with the remaining eight mounted in tiered casemates on either side of the fore and aft superstructures. After the United States entry into World War I the US Navy worked alongside the Royal Navy and it was decided to mount four 6-inch/53 caliber guns in two twin gun turrets fore and aft and keep the eight guns in the tiered casemates so that she would have an eight gun broadside and, due to limited arcs of fire from the casemate guns, four to six guns firing fore or aft. Her secondary armament consisted of two 3-inch (76 mm)/50 caliber anti-aircraft (AA) guns in single mounts. She carried two triple and two twin, above-water, torpedo tube mounts for 21-inch (533 mm) torpedoes. The triple mounts were fitted on either side of the upper deck, aft of the midships catapults, and the twin mounts were one deck lower on either side, covered by hatches in the side of the hull. Omaha was also built with the capacity to carry 224 mines.
  The ship lacked a full-length waterline armor belt. The sides of her boiler and engine rooms and steering gear were protected by three inches (76 mm) of armor. The transverse bulkheads at the end of her machinery rooms were one and a half inches (38 mm) thick forward and three inches thick aft. The conning tower and the deck over the machinery spaces and steering gear had one and a half inches of armor. The gun turrets were not armored and only provided protection against muzzle blast and splinter damage.
  Omaha carried two floatplanes aboard that were stored on the two catapults. Initially these were Vought VE-9s, then Vought UO-1s, the ship then operated Curtiss SOC Seagulls from 1935, and Vought OS2U Kingfishers after 1940.
caption: Omaha's #1 Vought UO-1
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