40 cm/45 Type 94 naval gun

40 cm/45 Type 94
Yamato under construction.
Type	Naval gun
Place of origin	Empire of Japan
Service history
In service	1940–1945
Used by	Imperial Japanese Navy
Wars	World War II
Specifications
Mass	147.3 tonnes
Length	OA 21.13 m (69 ft 4 in)
Shell	separate charges and shell
Calibre	460 mm (18 in)
Elevation	+45/-5 degrees. 10°/s
Traverse	300°, 2°/s
Rate of fire	2 rounds/min
Muzzle velocity	780 m/s (2,600 ft/s)
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 largest bore gun ever mounted on any warship. 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.

Description

The built-up guns were mounted as the main armament of the Yamato-class battleships that were in service with the Imperial Japanese Navy during World War II. The turrets the guns were mounted in weighed 2,510 tons each, 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".

A Type 91 armour piercing shell at the Yasukuni Shrine in Tokyo.

Drawing showing the internal setup of a Type 91 armour piercing shell.

High explosive shell

See also

• BL 18 inch Mk I naval gun
• List of naval guns
• List of the largest cannons by caliber
• Yamato-class battleships

References

• Scottish History - Mons Meg reportedly mounted at sea
• Nihon Kaigun
• [1]
• PIECES LOURDES : 240 et plus, le.fantasque.free.fr