IJN Furutaka (CL-CA-1926+)


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First cruisers designed after WW1 under the new Washington treaty conditions. The main armament was improved from the 5.5" of the Sendais' to the new 7.9" weapon, which turned out to be a disappointment in service. Also all that could be managed for the original layout was six single guns. An unwieldly and awkward armament for servicing the guns with shells. So why were the Japanese always willing to keep with single and twin 7.9" and 8" turrets while the rest of the world went to triples? The only thought I could come up with was that the hulls of the cruisers could be kept finer with better length to breadth ratios. The twins did not need as much breadth of hull as the triple. Easier to make the hulls go faster.

The next trial was with twin 7.9" which also proved a problem. Not with the twin turret but the 7.9" weapon. At one stage the four ships had all been completed with different classes of armament from the 7.9" to the 6.1".

The ships served for ten years in their original configurations but the ships were always due to be rebuilt. Thought was given to keeping with the larger 8" gun in 3 twin turrets but the number of guns worked against this. These were to be modern cruisers and the enemies they would fight in the same category would outgun them. Then the new 6.1" guns manufactured for the Mogami and Yamato class were eminently suitable for these ships. The guns fired almost as far as the 8", but they did fire faster. The secondary armament also went through various changes till it ended with four twin 5" mountings from the original 4 single 4.7". The best of the armament fitting was the two quadruple sets of 24" Long Lance torpedoes mounted on each beam. As with most Japanese cruisers of the time the four ships were fitted with aircraft handling facilities for up to 3 aircraft.

One problem all Japanese cruisers (and destroyers) had was: stability. All were overweight for the hull ratios. Most required remedial action for this in some form or another. Mostly by the fitting of bulges. Which of course slowed the ships down several knots and defeated the object of the very fine hulls. Japanese designers had a lot to learn. They designed very good looking and well armed ships but ton for ton they were not as good as their competitors.

(My job, should I choose to accept it, is to improve the Japanese ships to a point where every class does not require immediate remedial action to stop them joining the submersible fleet.)


Displacement 8,500 tons std, 10,550 tons full load
Length 581 ft
Breadth 62 ft
Draught 19 ft
Machinery 4 shaft Steam turbines, 110,000shp
Speed 33 knots
Range 6,500 miles at 18 knots
Armour 3" side, 2" deck, 2" turrets.
Armament 9 x 6.1" (3x3)

8 x 5" (4x2)

33 x 25mm (9x3 6x1)

Aircraft 3
Torpedoes 8 x 24" (2x4)
Complement 640
Notes IJN Furutaka (1922-1926)

IJN Kako (1922-1926)

IJN Aoba (1924-1927)

IJN Kinugasa (1924-1927)



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