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fighting ships of the world

IMPERIAL JAPANESE NAVY (JAPAN)

CRUISERS

NACHI heavy cruisers (1928-1929)

Nachi 1941

Myoko 1945

Project history: First real Japanese "Washington" cruisers. Under the 1922-1929 Programme in addition to 7100t "scouts" (Aoba class) building of four 10000t cruisers was provided. According to the technical project prepared by Naval Staff, eight 200mm guns in four turrets (three in a fore end pyramidally, as on Furutaka class, one in aft end) and eight fixed TT were provided. Under the insisting of chief of Naval technical department a number of serious changes has been brought in the task. So, at the expense of abandoning from TT number of main gun turrets has been increased to five, and protection against underwater explosions was strengthened by introduction of longitudinal bulkheads.

Early 1924 designing work has been completed (standard displacement was 10000t, speed 35.5kts, armament included 5x2 200mm/50 and 4х1 120mm/45 guns, 1 catapult and 2 seaplanes, the basic hull form and protection scheme as on 7100t cruisers), however before laying down of already ordered ships under the insisting of the Naval Staff armament was increased by four triple fixed 610mm TT, and number of 120mm AA guns had increased to six. By calculations, it increased a loads approximately on 500t, however actual standard displacement after completion has reached 10980t.

Though protection scheme essentially did not differ from applied on Furutaka class, its some elements have been notably strengthened: the thickness of a belt has increased to 100mm, its length to 123.6 m, angle of its inclination (outside on an upper edge) has made 12°. The thickness of an armour deck was stored unchanged (32-35mm), but over machinery it reached 70-89mm. Thickness of an upper deck has raised to 25mm. Total armour weight was 2052t. 58mm longitudinal anti-torpedo bulkhead with 93m length became the important innovation, in comparison with previous cruisers, it had the curvilinear form and formed an internal plating of bulges, being dipped from lower edge of main belt to a double bottom. Depth of underwater protection was 2.5m and, by calculations, should ensure protection of the hull against explosion of 200kg TNT.

Because of increased displacement and the sizes for reaching of 35kt speed it was required to raise engine power to 130000hp. All boilers initially were planned for oil-firing.

In 1939-1941 Myoko class cruisers have passed next modernization: the torpedo armament (4x4 610mm TT and eight spare torpedoes), light antiaircraft armament was strengthened. Machinery has passed capital repairs and modernization that has allowed to lower fuel stowage from 2472 to 2214t. For improvement of stability and underwater protection bulges were fitted during the previous update have replaced by new, hull beam has increased to 20.7m. By calculations, new underwater protection ensured protection against explosion of 250kg TNT. Displacement growth has led to decrease in speed to 33.3kts.

Ship protection: 102mm main belt of 123.2m length protected machinery and magazines and was lightly inclined outside (12°). Its height was 3.5m abreast machinery (82.6m part) and 2.0m abreast magazines. Belt was closed by 102-38mm bulkheads abreast end barbettes. Medium part of belt was connected with 35mm main deck by upper edge, thickness of main deck decreased to 32mm near center line. Horizontal protection was strengthened by 40-25mm construction steel plating of upper deck. Underwater protection consisted of bulges and 58mm thick and 93m long longitudinal bulkhead, its deep was 2.5m. Guns had only 25mm protection.

Modernizations: early 1932, Myoko, Nachi; early 1934, Haguro, Ashigara: - 5 x 2 - 200/50; + 5 x 2 - 203/50 3-shiki 2-go

2/1935, Ashigara; 3.1935, Myoko; 6.1935, Nachi, Haguro: - 6 x 1 - 120/45, 12 - 610 TT, 1 catapult, hangar; + 4 x 2 - 127/40 89-shiki, 2 x 4 - 610 TT (16), 2 new catapults (3 seaplanes); new additional bulges were fitted, breadth was increased to 19.0m. Full displacement was 15313-15391t. Maximal speed was 34kts.

10/1935, all: + 2 x 4 - 13.2/76

(1 - 12.1939) Haguro; (1/1939 - 3.1940) Nachi; (6/1939 - 6.1940) Ashigara; (3/1940 - 4.1941) Myoko: - 2 x 4 - 13.2/76, 2 x 1 - 7.7/80; + 4 x 2 - 25/60 96-shiki, 2 x 2 - 13.2/76, 2 x 4 - 610 TT (totally 24); catapults were replaced by new ones, fuel stowage decreased to 2214t. Bulges were replaced by new ones, breadth increased to 20.7m, deep of underwater protection to 4.2m and draught to 6.40m. Displacement was 12071-12342 / 15840-16007t, maximal speed fell to 33.3kts.

4 - 7.1942, all: - 2 x 2 - 13.2/76; + 4 x 2 - 25/60 96-shiki, 4 DCR (12), 1-shiki 2-go radar

11/1943 - 3.1944, Myoko, Haguro: + 8 x 1 - 25/60 96-shiki

11/1943 - 3.1944, Nachi, Ashigara: + 8 x 1 - 25/60 96-shiki, 2-shiki 2-go radar

6/1944, Haguro, Myoko: - 2 x 4 - 610 TT (total 16); + 4 x 3 - 25/60 96-shiki, 16 x 1 - 25/60 96-shiki, 2-shiki 2-go, 3-shiki 1-go radars

9/1944, Ashigara, Nachi: - 2 x 4 - 619 TT (total 16); + 2 x 2 - 25/60 96-shiki, 20 x 1 - 25/60 96-shiki, 3-shiki 1-go radar

Naval service: Ashigara 22.4.1945 was damaged by Dutch submarine О19. 8.6.1945 she was sunk by torpedoes (5 hits) from British submarine Trenchant in Bangka Strait (Java sea).

Haguro 25.10.1944 in battle at Samar was damaged by US carrier aircraft, 16.11.1944 again damaged by US aircraft. 15.5.1945 she was sunk in strait of Malacca by torpedoes (3 hits) from British destroyers Saumarez, Venus, Virago, Verulam and Vigilant.

Nachi 5.11.1944 was sunk in Manila Bay by USN carrier aircraft of TF.38 (she received hits of 10 air torpedoes, 21 bombs and 16 rockets).

Myoko 25.10.1944 was damaged by US air torpedo; temporary repaired in November, 1944. 13.12.1944 she was again damaged by a torpedo from US submarine Bergall, her stern was broken while ship was towed to repair 17.12.1944. She passed temporary repair and was used as AA floating battery in Singapore where has surrendered to British troops 21.9.1945, used as barrack ship and scuttled in strait of Malacca 8.6.1946.

Ashigara 1937

Nachi

Many thanks to Wolfgang Stöhr for additional information on this page.

© Ivan Gogin, 2008-14