The Pacific War Online Encyclopedia

Brooklyn Class, U.S. Light Cruisers

Schematic diagram of Brooklyn class light cruiser

ONI 222

Tonnage	9767 tons standard
Dimensions	608'4" by 61'8" by 21'6" 185.42m by 18.82m by 6.93m
Maximum speed	33.7 knots
Complement	868
Aircraft	2 catapults 4 seaplanes
Armament	5x3 6"/47 guns 8 5"/25 AA guns 8 0.50 machine guns
Protection	1798 tons: 5.625" (15.88mm) belt tapering to 3.7" (83mm) backed by 25lb STS steel 5" (127mm) machnery bulkheads tapering to 2" (51mm) 2" (51mm) internal longitudinal magazine protection 3.7" (93mm) magazine bulkheads 2" (51mm) armor deck 6.5"/2"/1.25" (165mm/51mm/38mm) turret front/roof/sides and rear 6" 152mm) barbettes 5" (127mm) conning tower
Machinery	4-shaft Parsons geared turbine (100,000 shp) 8 Babcock & Wilcox boilers
Bunkerage	1982 tons fuel oil
Range	10,000 nautical miles at 15 knots
Sensors	Mark 3 radar
Modifications	1942: Added 2 3"/50 AA guns 1942-8: Light antiaircraft armament of 4x4, 4x2 40mm Bofors AA guns. SG, SC, and two Mark 4 radar sets installed. 1943: SC and Mark 3 radars replaced with (typically) SK and Mark 8. 1945: Light antiaircraft armament typically 4x4, 6x2 40mm guns and 10x2 20mm Oerlikon AA guns.

The Brooklyns were completed during 1938-1939 and were the most modern and powerful light cruisers with which the U.S. Fleet began the war. The design arose out of the London Conference of 1930, where the U.S. reluctantly agreed to a freeze on further heavy cruiser construction. This forced the U.S. Navy to turn to light cruiser construction. Though design studies began as soon as the London Treaty was ratified, a final design was not accepted until 1934, due to increased awareness of the need for antiaircraft protection and the appearance of the Japanese Mogamis with their (initial) armament of 15 6" guns.

The final design matched the enormous number of guns on the Mogamis and used a protection scheme similar to that of the New Orleans-class heavy cruisers, making them the best-protected modern light cruisers in the world (only the Mogamis came close). However, the Brooklyns proved somewhat structurally weak, and their machinery was not well dispersed. They could carry up to six seaplanes in their large hangers, but the usual complement was four.