The were a series of four

heavy cruisers The heavy cruiser was a type of cruiser, a naval warship designed for long range and high speed, armed generally with naval guns of roughly 203 mm (8 inches) in caliber, whose design parameters were dictated by the Washington Naval Tr ...

built for the

Imperial Japanese Navy The Imperial Japanese Navy (IJN; Kyūjitai: Shinjitai: ' 'Navy of the Greater Japanese Empire', or ''Nippon Kaigun'', 'Japanese Navy') was the navy of the Empire of Japan from 1868 to 1945, when it was dissolved following Japan's surrender ...

in the late 1920s. Three were lost during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

. The ships of this class displaced 11,633 tons (standard), were long, and were capable of steaming at . Their main

armament A weapon, arm or armament is any implement or device that can be used to deter, threaten, inflict physical damage, harm, or kill. Weapons are used to increase the efficacy and efficiency of activities such as hunting, crime, law enforcement, s ...

were ten

20 cm/50 3rd Year Type naval gun formed the main battery of Japan's World War II heavy cruisers. These guns were also mounted on two early aircraft carriers. The typical installation was ten 20 cm/50 guns; although s carried eight while and -class cruisers carried six. A ...

s in five twin turrets which were complemented by a heavy torpedo armament; at the time, this was the heaviest armament of any

cruiser class A cruiser bicycle, also known as a beach cruiser or (formerly) motobike, is a bicycle that usually combines balloon tires, an upright seating posture, a single-speed bicycle, single-speed drivetrain, and straightforward bicycle frame#Frame ma ...

in the world. They were also the first cruisers the Japanese Navy constructed that exceeded the (10,000 ton) limit set by the

Washington Naval Treaty The Washington Naval Treaty, also known as the Five-Power Treaty, was a treaty signed during 1922 among the major Allies of World War I, which agreed to prevent an arms race by limiting naval construction. It was negotiated at the Washington Nav ...

Design

The ''Myōkō'' class displaced , with a hull design similar to the preceding . The displacement was substantially more than the designed 2/3 trial displacement of , a consequence of the demand to put as much as possible on a hull limited by the

, and were likely unintentional as it adversely affected the seakeeping qualities and endurance of the class. They were long with a

beam Beam may refer to: Streams of particles or energy *Light beam, or beam of light, a directional projection of light energy **Laser beam *Particle beam, a stream of charged or neutral particles **Charged particle beam, a spatially localized grou ...

of , and a

draft Draft, The Draft, or Draught may refer to: Watercraft dimensions * Draft (hull), the distance from waterline to keel of a vessel * Draft (sail), degree of curvature in a sail * Air draft, distance from waterline to the highest point on a vessel ...

of . Propulsion was by 12 Kampon boilers driving four sets of single-impulse geared turbine engines, with four shafts turning three-bladed propellers propelling the ship to . Design endurance was 8,000 nautical miles; however, the increased weight issues reduced it to 7,000. Protection was superior to the preceding ''Aoba''-class and accounted for about 16 percent of trial displacement. A side belt that ran along of the ship's length and armored deck protected the magazine and machinery spaces and protected the turret barbettes; however, the turrets had only 25mm splinter protection and the

bridge A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually somethi ...

was unarmored. Following innovations pioneered in ''Yubari'', the armor belt was made an integral part of the hull structure to reduce weight. A torpedo bulkhead consisting of two plates with a total thickness of extended inwards from the bottom of the armor belt and curved to meet the bottom of the double hull. It was calculated that it was sufficient to withstand an explosion of of TNT. As originally constructed, the class was armed with a main battery of ten 20 cm/50 3rd Year Type ''1 GÔ'' naval guns mounted in 5 twin turrets, the heaviest armament of any heavy cruiser in the world at the time. Secondary armament initially were 12 cm/45 10th Year Type dual purpose guns in six single mounts. Short-range anti-aircraft defense was provided by two 7.7mm machine guns. Torpedo armament was unusually heavy compared to the cruisers of other nations at the time, with 12 carried in fixed single launchers inside the hull. They were also equipped with a single aircraft catapult and aircraft for scouting purposes.

Modernizations

The class was modernized twice before the outbreak of the Pacific War. The first modernization program, carried out between 1934 and 1936, was the most extensive. The main armament was upgraded to the ''2 GÔ'' versions and the 120mm guns replaced with eight 12.7 cm/40 Type 89 dual purpose guns in twin mounts. The single catapult was replaced with an aircraft deck that could accommodate three aircraft and two catapults. The fixed torpedo tubes in the hull were removed and two quadruple launchers carrying the Type 93 Long Lance torpedo were installed under the aircraft deck. The torpedo bulges were extended to increase stability. The modifications added 680 tons of displacement and reduced speed to . Anti-aircraft protection was increased to eight 13mm machine guns in two quadruple mounts. The second modernization in 1939 added an additional two quadruple torpedo launchers and enhanced light anti-aircraft armament with the introduction of the Type 96 25mm gun. The aircraft catapults were upgraded to handle heavier floatplanes and the torpedo bulges were enlarged to increase stability. The class would receive upgrades during the Second World War to reflect the growing threat of aircraft in the form of numerous Type 96 25mm gun and air and surface search radar, ''Myōkō'' eventually receiving 52 25mm autocannons in various single, double, and triple mounts. The two aft quadruple torpedo mounts were removed in 1944 to allow for the growing number of anti-aircraft armament.

Ships in class

The ships in the class were:

References

Notes

Books

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External links

CombinedFleet.com: ''Myōkō'' class cruisersWW2 Cruisers: Myoko Class Heavy Cruiser
{{DEFAULTSORT:Myoko-class cruiser Cruiser classes Ships built in Japan Cruisers of the Imperial Japanese Navy