Power, guns, and seaplanes for a long-range scout

Eight boilers supplied four Parsons turbines, producing 107,000 horsepower and a top speed of 32.5 knots. The ships were deliberately kept near 9,000 tons even though the Washington Treaty imposed no aggregate cruiser-tonnage ceiling, leaving roughly 800 to 950 tons of potential capacity unused. As built, the main and secondary armament comprised nine 8-inch/55 guns, four 5-inch/25 guns, two 3-pounder saluting guns, and six 21-inch torpedo tubes. The wartime antiaircraft battery grew substantially, though the final 40 mm Bofors arrangement remains uncertain: most sources give six quadruple mounts, while two accounts suggest a transitional mix of four quadruple and four twin mounts. Four seaplanes, two catapults, and a hangar gave the class its own long-range search capability.