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Nagato 1920

Ships

Name	No	Yard No	Builder	Laid down	Launched	Comp	Fate
長門 [Nagato]			Kure K K	28.8.1917	9.11.1919	25.11.1920	surrendered 9.1945, sunk as target 29.7.1946
陸奥 [Mutsu]			Yokosuka K K	1.6.1918	31.5.1920	22.11.1921	internal explosion 8.6.1943

Technical data

Data variant	as completed	1938, after modernization
Displacement standard, t	---	39120
Displacement normal, t	33800
Displacement full, t	38500	42850
Length, m	213.3 wl 215.8 oa	221.1 wl 224.9 oa
Breadth, m	29.0	33.0
Draught, m	9.10	9.49
No of shafts	4	4
Machinery	4 sets Gihon geared steam turbines, 21 Kampon boilers	4 sets Kampon-Parsons geared steam turbines, 10 Kampon boilers
Power, h. p.	80000	82000
Max speed, kts	26.5	25
Fuel, t	coal 1600 + oil 3400	oil 5600
Endurance, nm(kts)	5500(16)	8560(16)
Armour, mm	belt: 305 - 102, bulkheads: 330 - 254, deck: 51 + 70, barbettes: 305 - 229, turrets: 356 - 127, casemates: 152 - 19, CT: 356 - 102	belt: 305 - 102, bulkheads: 330 - 254, deck: 127 + 70, barbettes: 457 - 356, turrets: 457 - 127, casemates: 152 - 19, CT: 356 - 102
Armament	4 x 2 - 410/45 3-shiki, 20 x 1 - 140/50 3-shiki, 4 x 1 - 76/40 3-shiki, 8 - 533 TT (beam)	4 x 2 - 410/45 3-shiki, 18 x 1 - 140/50 3-shiki, 4 x 2 - 127/40 89-shiki, 10 x 2 - 25/60 96-shiki, 1 catapult, 3 seaplanes (E7K2)
Complement	1333	1368

Standard scale images

Graphics

Project history

In reply to accepted in the USA in 1916 ambitious shipbuilding program Japanese parliament has approved the so-called "8-4" program, which else since 1914 was tried to conduct by Naval staff. According to it, in addition to ships of classes already ready or being built (Kongo, Fuso and Ise classes) it was provided to build four more battleships. Nagato and Mutsu should become the first Japanese battleships not only built, but also completely designed in Japan. 410mm guns have been developed in Japan in 1914 in reply to occurrence of RN 381mm guns, and also taking into account hearings about works in the USA with heavier guns. Nagato and Mutsu were formed according to the concept of the fast battleship, British Queen Elizabeth class battleships were unique embodiment of this concept at that time, as has predetermined some likeness of these ships though structurally new Japanese battleships "have grown" from Ise class (the same as British from Iron Duke class super-dreadnoughts). The hull, in comparison with previous class, became on 7.6m longer and on 0.3m wider. Abandoning from amidships turrets allowed to place almost twice more powerful machinery, that increased a speed, in comparison with Ise, by 3kts, to 26.5kts.

Already after start of building both ship have moved to the program "8-8", becoming the first of eight battleships and eight battlecruisers with guns in not less than 410mm calibre provided to building. And the last: the Washington conference of 1922 cancelled this program realisation. The fate of Mutsu hung by a thread: it was offered to hand over already ready ship on demolition, but Japanese managed to defend her (in particular, one of arguments was that the part of means for her building was collected by schoolchildren).

Ship protection

Main belt extended from No1 to No4 barbettes and had 305mm thickness between barbettes, tapering to 76mm at lower edge. It closed by 330-254mm fore and 254mm aft bulkheads abreast end barbettes. Hull outside end barbettes was protected by 203mm belt tapered to 76mm at lower edge, thickness of this belt decreased to 102mm near ship ends. Upper 203mm belt extended from main belt to upper deck and from No2 to No3 barbette (110m). It was closed by 203mm angled bulkheads. Lower casemate had 152mm armor. Upper casemate had only 25mm protection. Flat main 70mm deck connected with upper edge of main belt. Lower deck had 51mm thickness in flat part and connected with lower edge of main belt by 76mm slopes. Forecastle deck over casemate was 38-25mm. Turrets had 356mm faces, 280mm sides and 127mm crowns. CT had 356mm sides and 102mm roof. Underwater protection was 6.5m deep and content 76-51mm longitudinal bulkhead.

Ship protection after modernization: 134x3.5m main belt extended from No1 to No4 barbettes and had 305mm thickness between barbettes, tapering to 76mm at lower edge. It closed by 330-254mm fore and 254mm aft bulkheads abreast end barbettes. Hull outside end barbettes was protected by 203mm belt tapered to 76mm at lower edge, thickness of this belt decreased to 102mm near ship ends. Upper 203mm belt extended from main belt to upper deck and from No2 to No3 barbette (110m). It was closed by 203mm angled bulkheads. Lower casemate had 152mm armor. Upper casemate had only 25mm protection. Flat main 70mm deck connected with upper edge of main belt. Lower deck had 127mm thickness in flat part and connected with lower edge of main belt by 76mm slopes. Forecastle deck over casemate was 51mm. Turrets had 457mm faces, 280mm sides and 127mm crowns. CT had 356mm sides and 102mm roof. Underwater protection was 6.5m deep and content 76-51mm longitudinal bulkhead.

Modernizations

1925, Nagato: + 3 x 1 - 76/40 3-shiki

1932 - 1933, Nagato: - 7 x 1 - 76/40; + 4 x 2 - 127/40 89-shiki, 2 x 1 - 40/62 "HI" 91-shiki

1932 - 1933, Mutsu: - 4 x 1 - 76/40; + 4 x 2 - 127/40 89-shiki, 2 x 1 - 40/62 "HI" 91-shiki

(8/1933 - 1.1936, Kure K K) Nagato; (9/1934 - 9.1936, Yokosuka K K) Mutsu: bulges were fitted, hull was lengthened, new boilers were fitted and turbines modernized. Superstructure was reconstructed, fore funnel removed. Maximal angle of main guns elevation increased to 43°, secondary guns from 15° to 35°. 2 140mm guns and all TT were removed, catapult was installed. Protection was partially strengthened.

1938, both: - 2 x 1 - 40/62; + 10 x 2 - 25/60 96-shiki. Data was as given in the table.

6/1943, Nagato: + 1 x 2 - 25/60 96-shiki, 1-shiki 2-go radar

7/1944, Nagato: - 2 x 1 - 140/50, 1 x 2 - 25/60; + 16 x 3 - 25/60 96-shiki, 28 x 1 - 25/60 96-shiki, 2x 3-shiki 1-go, 2x 2-shiki 2-go radars

11/1944, Nagato: - 4 x 1 - 140/50; + 2 x 2 - 127/40 89-shiki, 9 x 3 - 25/60 96-shiki

6/1945, Nagato: - 12 x 1 - 140/50, 6 x 2 - 127/40

Naval service

On Mutsu 8.6.1943 in the Hiroshima bay there was an aft magazines explosion. The principal cause of the explosion which has caused loss of the ship, often a crew negligence is specified.

Nagato during battle in Sibuyan Sea 24.10.1944 has received hits of three bombs which have put out of action one main turret. Next day she was damaged by two more bombs, partially repaired in Yokosuka in the beginning of 1945. The Unique Japanese battleship which has got to winners. 20.9.1945 she was transferred to the USA, used at nuclear tests off the Bikini atoll. 25.7.1946 she was hard damaged by explosion of a 40kt bomb in 1km from the ship and sunk in 4 days.