Mogami Class, Japanese Heavy Cruisers

Photograph of IJN Mikuma, a Mogami-class heavy cruiser

Tonnage	12,400 tons standard displacement
Dimensions	661'1" by 66"4" by 19'5" 201.5m by 18m by 5.5m
Maximum speed	34.9 knots
Complement	896
Aircraft	2 Kure Type 2 Model 3 catapults 3 seaplanes
Armament	4x2 8"/50 Mark 2 guns 4x2 4.7"/45 dual-purpose guns 4x2 25mm AA guns 4 13mm AA guns 4x3 Long Lance torpedo tubes (24 torpedoes)
Protection	2028.7 tons 4" to 1" (100mm to 25mm) maximum NVNC/CNC machinery belt sloped 20 degrees 5.5" to 1.2" (140mm to 30mm) NVNC magazine belt sloped 20 degrees Torpedo bulges (tapered belt serving as holding bulkhead) 2.4" to 1.4" (60mm to 35mm) CNC middle deck 4" (100mm) sides/2" (50mm) overhead NVNC conning tower 3.7" (95mm) uptakes 2.6" (65mm) to 5.5" (140mm) NVNC bulkheads 4" (100mm) side/1.4" (35mm) end/1.2" (30mm) top NVNC steering spaces 4" to 3" (100mm to 75mm) barbettes 1" (25mm) NVNC turret
Machinery	4-shaft Kanpon geared turbines (152,000 shp) 10 Kanpon boilers
Bunkerage	2389 tons fuel oil
Range	7500 nautical miles (14,000 km) at 14 knots
Modifications	1943-2: Kumano and Suzuya receive radar and light AA altered to 4x3, 4x2 25mm guns. 1943-4: Mogami converted "aircraft cruiser" after severe damage at Midway. One 8" turret removed and replaced with aircraft deck capable of operating 11 E16A1 float planes. Light AA armament changed to 10x3 25mm guns. Radar was installed. Early 1944: Mogami has 10x3, 8x1 25mm guns and the other units 4x3, 4x2 and 8x1 25mm guns. 1944-6: Mogami: Light AA is 14x3, 8x1 25mm guns; Kumano: 8x3, 4x2, 24x1 25mm guns; Suzuya: 8x3, 4x2, 18x1 25mm guns. Radar upgraded.

The Mogamis were completed in 1935-37 and were probably the finest Japanese cruiser class. Originally light cruisers, they took on 8” guns in their 1939 refit, at which time their hulls were also reinforced and their stability improved. This yielded very powerful and tough ships; Mogami was badly chewed up at Midway but somehow made it to Truk for repairs.

When first constructed, the ships attracted the attention of foreign observers who suspected (probably correctly) that they were well over the treaty limit of 10,000 tons. The turret rings for the 6" gun turrets were allegedly deliberately designed to take 8" gun turrets also so that rapid conversion could take place.

The second pair of ships in the class (Suzuya and Kumano) differed in some details from Mogami, such as having ten large boilers instead of twelve, which reduced the length of the machinery spaces slightly.

The ships were designed with deck stowage for four seaplanes, but never carried more than three.

These ships cost ¥24,833,950 apiece.

Units in the Pacific:

Kumano	Main Body (Ozawa) in South China Sea	Sunk by aircraft 1944-11-25 in Santa Cruz Harbor, Luzon
Mikuma	Main Body (Ozawa) in South China Sea	Sunk by aircraft 1942-6-6 west of Midway
Mogami	Main Body (Ozawa) in South China Sea	Crippled by gunfire 1944-10-25 at Surigao Strait and scuttled
Suzuya	Main Body (Ozawa) in South China Sea	Sunk by aircraft 1944-10-25 off Samar

References

CombinedFleet.com (accessed 2007-12-7)
Lacroix and Wells (1997)

Whitley (1995)

Worth (2001)

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