The ten cruisers of the Omaha (CL-4) class were authorized during World War I and were originally conceived as “scout cruisers”—hence their high speed of 34 knots and their 90,000 shaft horsepower propulsion plants. Commissioned in 1923-25, they were originally armed with 12 6-inch guns in two twin gunhouses and eight single mountings, ten 21-inch torpedo tubes in two triple and two twin mountings, and four single 3-inch antiaircraft guns. They were the first U.S. Navy cruisers to be equipped with trainable aircraft catapults. Two of the class—the Marblehead (CL-12) in the Dutch East Indies in early 1942 and the Richmond (CL-9) at the Battle of the Komandorski Islands in March 1943— saw action with Japanese surface forces, but the class in general was retained in relative backwater areas on prosaic convoy escort duties because of their inadequate armament and protection. In April 1944, the Milwaukee (CL-5) was Lend-leased to the Soviet Union, which did not return her until 1949.
The Richmond (CL-9) is pictured at top travelling at a speed of 30 knots during builder’s trials in May 1923. Note the opening in the ship’s side for the portside twin torpedo tubes, which were soon removed, as were the low- mounted single 6-inch guns at the break of the forecastle deck aft. At this stage, the aircraft catapults had yet to be installed.
The Marblehead (CL-12) is pictured at center in the early 1930s, with mine- rails in place down the sides of the narrow fantail. Note the single, superfiring 6-inch gunmount substituted atop the after superstructure, a short-lived experiment to replace the pair removed. A Vought biplane scout is atop the portside catapult, which is swung out for launching.
The Trenton (CL-11) is pictured at bottom painted in wartime camouflage while in the Gulf of Panama in July 1944. By this time, the number of 3-inch guns abreast the distinctive four stacks had been doubled, and additional antiaircraft protection was provided in the form of three twin 40-millimeter and a dozen 20-millimeter guns. By late in the war, the Detroit (CL-8) had also had the upper single 6-inch guns forward replaced by two additional twin 40-millimeter mounts, and several others had lost their remaining torpedo armament in favor of single 40-millimeter antiaircraft guns. None ever carried antisubmarine weapons.