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Mogami Class, Japanese Heavy Cruisers


Photograph of IJN Mogami

Wikimedia Commons

Schematic of Mogami class

U.S. Navy


Specifications:


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 5x2 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 Type 21 radar and light AA is 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. Type 21 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 to Type 22 and Type 13.


The Mogamis or "B" class cruisers were completed in 1935-37. Opinions on the class are divided: Some writers regard them as probably the finest Japanese cruiser class, while others describe them as a design failure. This may reflect the extensive modifications made to the class just before war broke out. Originally light cruisers with 15 6" (152mm) guns in triple turrets, they shipped 8” (203mm) 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, though Mikuma was lost in the same action.

When first constructed, the ships attracted the attention of foreign observers who suspected (correctly) that they were well over the treaty limit of 10,000 tons. The turret rings for the 6" gun turrets were designed to take 8" gun turrets also so that rapid conversion could take place. When this was carried out in the 1939 refit, the 6" turrets were reused as secondary armament on the Yamatos.

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

Photo Gallery

ONI 41-42 page on Mogami class

U.S. Navy

Forward view of Mogami class cruiser from superstructure

Wikimedia Commons

Stack of Mogami-class cruiser

U.S. Navy

ONI 41-42 page on Mogami class

U.S. Navy


References

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

Whitley (1995)

Worth (2001)



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