40 cm/45 Type 94 naval gun
|46 cm/45 Type 94|
A Type 94 Naval Gun being calibrated on Yamato during construction
|Place of origin||Japan|
|Used by||Imperial Japanese Navy|
|Wars||World War II|
|Designer||C. Hada |
|Manufacturer||Kure Naval Arsenal |
|Barrel length||21.13 m (69 ft 4 in), 46 calibers|
|Diameter||46 cm (18.1 in)|
AP Type 91: 1,460 kg (3,218.7 lb)|
HE Type 0: 1,360 kg (2,998.3 lb)
AA Type 0: 1,360 kg (2,998.3 lb)
|Calibre||46 cm (18.1 in)|
|Breech||Welin breech block|
|Recoil||Hydraulic recoil mechanism|
|Elevation||+45/-5 degrees. 10°/s|
|Rate of fire||1.5 - 2 rounds/min|
|Muzzle velocity||780 m/s (2,600 ft/s)|
|Effective firing range||25 km (16 mi)|
|Maximum firing range||42 km (26 mi) at 45° elevation|
The Japanese "40 cm/45 Type 94 naval gun" (四五口径九四式四〇糎砲 Yonjūgo-kōkei kyūyon-shiki yonjussenchi-hō) was the biggest naval gun used by battleships in World War II. They were actually 46 cm (18.1 in) guns, but were designated 40 cm (15.7 in) in an effort to hide their true size.
The 46 cm (18.1 in) 40 cm/45 Type 94 naval gun was a wire-wound gun. A total of nine in three triple turrets were mounted as the main armament of the Yamato-class battleships that were in service with the Imperial Japanese Navy during World War II. When the turrets and the guns were mounted, each weighed 2,510 tons, which is about the same tonnage as an average sized destroyer of the era.
The Japanese guns were of a slightly larger bore than the three British 18 inch naval guns built during World War I, although the shells were not as heavy. Britain had later designed the N3-class battleship with 18-inch guns but none were built, leaving no Allied naval guns to compare with the Type 94. Unlike the very large guns of other navies they could fire special anti-aircraft shells (Sanshiki) referred to as "beehive".
Some 27 guns were built for the three ships of the Yamato class. Two thirds of the guns were lost with the sinking of Yamato and Musashi. As built, the design of the barrels was complex. A tube was built then auto-frettaged in three stages. A half length tube was fitted over the first tube and shrunk onto it. The assembly was then wire wound and two additional tubes shrunk over the entire length of the gun tubes. A final inner tube was then inserted down the gun and expanded into place. This inner tube was then rifled to finish the gun. As designed this gun could not cost effectively be relined but instead had to have the entire gun tube replaced due to wear.
Unlike previous designs the turrets, when examined by a US naval technical team, were found to have nothing in common with previous British Vickers designs used in other Japanese battleships. The shell hoists and powder rams were found to be ingenious though unduly heavy designs that allowed a relatively rapid rate of reload. Each gun was independently sleeved allowing for separate elevation.
Range and flight time
With Type 91 AP shell
|Elevation||Range||Time of flight|
|10°||18,410 yards (16,830 m)||26.05 sec|
|20°||30,530 yards (27,920 m)||49.21 sec|
|30°||39,180 yards (35,830 m)||70.27 sec|
|40°||44,510 yards (40,700 m)||89.42 sec|
|45°||45,960 yards (42,030 m)||98.6 sec|
Impact angle and velocity
With Type 91 AP shell
|2.4°||5,470 yards (5,000 m)||3.3°||2,264 feet per second (690 m/s)|
|5.4°||10,940 yards (10,000 m)||7.2°||2,034 feet per second (620 m/s)|
|8.6°||16,400 yards (15,000 m)||11.5°||1,844 feet per second (562 m/s)|
|12.6°||21,870 yards (20,000 m)||16.5°||1,709 feet per second (521 m/s)|
|17.2°||27,340 yards (25,000 m)||23°||1,608 feet per second (490 m/s)|
|23.2°||32,810 yards (30,000 m)||31.4°||1,558 feet per second (475 m/s)|
A Type 1 armour-piercing shell at the Yasukuni Shrine in Tokyo.
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- Campbell, Naval Weapons of WWII, p.180.
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- 18.1"/45 caliber, Nihon Kaigun
- Japan 46cm/45 (15.9") Type 94 - Actual Size 46cm (18.1"), Navweaps.com
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- Campbell, John (1985). Naval Weapons of World War Two. Naval Institute Press. ISBN 0-87021-459-4.
Media related to 40 cm/45 Type 94 naval gun at Wikimedia Commons