Editing Brooklyn-class cruiser (section)

===''St. Louis'' subclass===
The last two ships of the class, {{USS|St. Louis|CL-49|2}} and {{USS|Helena|CL-50|2}}, were slightly modified versions of the design with new higher pressure boilers and a [[unit system of machinery]] that alternated boiler and engine rooms to prevent a ship from being immobilized by a single unlucky hit; this system would be used in all subsequent US cruisers. Additionally, [[anti-aircraft|AA]] armament was improved. They were the first US cruisers to be armed with twin [[5"/38 caliber gun|5-inch (127&nbsp;mm)/{{wbr}}38-caliber guns]]. They could be distinguished visually from the other ''Brooklyn''s by the placement of the after deckhouse, immediately abaft the second funnel, and by the twin 5-inch mounts.