The Pacific War Online Encyclopedia

Northampton Class, U.S. Heavy Cruisers

Schematic diagram of Northampton class heavy cruiser

ONI 222

Tonnage	9000 tons standard displacement
Dimensions	600' by 66'1" by 18'11" 182.88m by 20.14m by 5.77m
Maximum speed	32.8 knots
Complement	621
Aircraft	2 catapults 4 seaplanes
Armament	3x3 8"/55 guns 8x1 5"/25 AA guns 4x1 3"/50 AA guns 4x4 1.1"/75 AA guns 8x1 0.50 machine guns
Protection	1057 tons: 3" (76mm) machinery belt 3.75" (95mm) magazine belt 1" (25mm) machinery bulkheads 2.5" (64mm) magazine bulkheads 1" (25mm) machinery armor deck 2" (51mm) magazine armor deck 1.5" (38mm) barbettes 2.5"/2"/1"/0.75" (64mm/51mm/25mm/19mm) turret faces/roofs/sides/rears 1.25" (38mm) conning tower
Machinery	4-shaft Parsons geared turbine (107,000 shp) 8 White-Forster boilers
Bunkerage	2108 tons fuel oil
Range	10,000 nautical miles (18,500 km) at 15 knots
Sensors	CXAM air search radar (Northampton, Chester, Chicago)
Modifications	1942: 0.50 machine guns replaced by 14x1 20mm Oerlikon AA guns. Mark 3 and Mark 4 radars added. 1943: 1.1" guns replaced with 4x4 40mm Bofors AA guns and CXAM1 replaced with SG, SK, and SP radars. By war's end the standard light antiaircraft outfit was 4x4, 2x2 40mm Bofors AA guns and 31x1 20mm guns. There continued to be considerable variation from unit to unit.

The Northamptons were completed in 1930-31. The design dated back to 1926 and was a modification of the preceeding Pensacola class, with slightly heavier armor and slightly reduced armament. Instead of ten 8" guns mounted in four turrets, the Northamptons had nine 8" guns in three turrets, allowing a shorter and therefore heavier armor belt. However, it was ruled impractical to provide protection against 8" shells and the protection scheme was designed against 6" shells only. The weight saved was used to improve overall survivability and increase the aircraft handling capability.

Originally equipped with torpedoes, the ships landed their tubes prior to the war in exchange for improved antiaircraft protection. This was probably a good decision given the miserable quality of U.S. torpedoes.

The aircraft handling facilities included a proper hangar around the aft funnel, which protected the seaplanes from gun blast and the elements. In principle, six aircraft could be carried (four in the hangars and two on the catapults) but in practice only four were carried.

The ships cost about $12 million apiece.

These powerful units greatly concerned the Japanese, who feared their use as screening vessels in the ring formation the Americans were expected to use if war broke out. They could foil Japanese plans to break through the American screen with light forces to attack the American battle line with torpedoes.The Japanese responded by turning to night combat tactics.

Units in the Pacific:

Houston	Iloilo	Sunk by gunfire and torpedoes 1942-2-28 off Sunda Strait
Northampton	Task Force 8 (Halsey, Enterprise) en route Oahu from Wake	Torpedoed 1942-12-1 off Guadalcanal
Chester	Task Force 8 (Halsey, Enterprise) en route Oahu from Wake
Chicago	Task Force 12 (Newton, Lexington) en route Midway from Oahu	Sunk by aircraft 1943-1-30 off Rennell Island
Louisville	Off Rennell Island with convoy returning from Philippines