St. Louis-class cruiser (1938)

The St. Louis class light cruisers were a pair of warships that served in the US Navy during World War II. The class was a slight modification of the seven-ship Brooklyn-class cruiser that immediately preceded them, incorporating new higher pressure boilers and a new boiler arrangement, with machinery on the "unit system": alternating boiler and engine rooms to prevent a ship from being immobilized by a single unlucky hit. Additionally, AA armament was improved. They were the first US cruisers to be armed with twin five-inch (127 mm) 38-caliber guns. They could be distinguished visually from the Brooklyns by the placement of the after deckhouse, immediately abaft the second funnel, and by the twin 5" mounts.

Both ships were commissioned in 1939, and were active in the Pacific in World War II. Helena was sunk in 1943 during the Battle of Kula Gulf. St. Louis was seriously damaged twice, but survived the war and was transferred to the Brazilian navy in 1951, where she served until 1976.

St. Louis- class ships

 * USS St. Louis (CL-49)
 * USS Helena (CL-50)