Type 41 12-inch 40-calibre BL 12-inch Mk IX gun
Forward guns of Fuji
Type	Naval gun
Place of origin	United Kingdom, later licence-produced in Japan
Service history
In service	1900–1945
Used by	Royal Navy Imperial Japanese Navy Regia Marina
Wars	Russo-Japanese War World War I
Production history
Designer	Elswick Ordnance Company
Designed	1898
Manufacturer	Elswick Ordnance Company Vickers Woolwich Arsenal
Specifications
Mass	49 long tons (50 t)
Barrel length	40-foot-5-inch (12.32 m) bore (40 calibres)

Shell	850 pounds (390 kg) separate charges and shell
Calibre	12 inches (305 mm)
Breech	Welin interrupted screw
Elevation	−5/+15 degrees
Traverse	+150/−150 degrees
Rate of fire	1 round per minute
Muzzle velocity	Japanese service : 2,400 ft/s (732 m/s) UK service: 2,481 ft/s (756 m/s),^[1] 2,612 ft/s (796 m/s) (King Edward VII class)
Effective firing range	15,000 yards (14 km); 15° elevation

The Armstrong Whitworth 12-inch naval gun of 40 calibres length was designed by and manufactured mainly by Armstrong's ordnance branch, Elswick Ordnance Company. It was intended for the Royal Navy's Royal Sovereign-class battleships, but budgetary constraints delayed their introduction. The first units were instead supplied to Japan. As the Type 41 12-inch (305 mm) 40-calibre naval gun it was the standard main battery on several early United Kingdom-built pre-dreadnought battleships of the Imperial Japanese Navy.

It later entered service with the RN as the 12-inch Mark IX, being fitted to warships of three pre-dreadnought classes prior to World War I. Also, during the war several guns were converted for use as railway guns, and, towards the end of the conflict, for use on the M-class submarine monitors.

The gun also saw service with the Italian Regia Marina, in two classes of pre-dreadnought battleships.

Design and development

The Type 41 12-inch naval gun was produced by Armstrong Whitworth, Elswick, Newcastle upon Tyne, as a slightly modified version of the "EOC G pattern" 12-inch guns used on contemporary Royal Navy battleships.

Japanese service

Japan purchased a total of 44 of these weapons for use on the four ships of the Fuji and Shikishima class, and the battleships Asahi and Mikasa. Each ship carried four guns in twin turrets.

In combat at the Battle of the Yellow Sea in the Russo-Japanese War, the Japanese battleships Asahi, Shikishima and Mikasa all had one of their main guns taken out of action due to premature bore detonations.^[2] The cause was traced to faulty fuses, and the problem was rectified prior to the Battle of Tsushima.

The gun was officially designated as "Type 41" from the 41st year of the reign of Emperor Meiji on 25 December 1908. It was further re-designated in centimetres on 5 October 1917 as part of the standardization process for the Imperial Japanese Navy to the metric system.

The Type 41 12-inch gun fired an 850-pound (390 kg) shell, with either an armour-piercing, high-explosive or general-purpose warhead.

United Kingdom service

Royal Navy service

The gun entered service with the Royal Navy as "BL 12 inch gun Mark IX"^{[note 1]} on the following ships :

Formidable-class battleships: Three ships, laid down 1898 and mounting four guns each.
London-class battleships: Five ships, laid down in 1898–1901 and mounting four guns each.
Duncan-class battleships: Six ships laid down 1899, each mounting four guns.
King Edward VII-class battleships of 1904. Five of the eight ships of this class (HMS King Edward VII, HMS Commonwealth, HMS Hindustan, HMS Dominion and HMS New Zealand) carried the Mark IX gun.

M-class submarine mounting

The gun was in service mounted on the three M-class submarines. HMS M2 and M3 had their guns removed in 1927–28.

Railway gun

Main article: BL 12-inch railway gun

Four guns were mounted on railway carriages and used by the British army in World War I on the Western Front.

United Kingdom ammunition

Cartridge 63½ lb (¼ charge), Cordite M.D. used on King Edward VII-class battleship
Common pointed capped shell, 1912

Italian service

Armstrongs also sold versions of their 12-inch 40-calibre gun to Italy to arm the two Regina Margherita-class (commissioned 1905) and the four Regina Elena-class battleships (commissioned 1908). The version for the Regina Elena class fired a heavier 417 kg (919 lb) shell. The Regina Margheritas were lost during the war, the Regina Elenas scrapped after the war.

Notes

References

Bibliography

External links

British Empire naval weapons of the First World War

British Empire naval weapons of the First World War
Monitor guns	BL 9.2-inch Mk VI BL 9.2-inch Mk VIII BL 9.2-inch Mk X BL 9.2-inch Mk XII BL 12-inch Mk VIII BL 14-inch Mk II (US built) BL 15-inch Mk I BL 18-inch Mk I
Capital ship main armament	Vickers 10-inch 45 cal. EOC 10-inch 45 cal. BL 12-inch Mk VIII BL 12-inch Mk IX BL 12-inch Mk X BL 12-inch Mk XI & XII EOC 12-inch 45 cal. Mk XIII BL 13.5-inch Mk I – IV BL 13.5-inch Mk V BL 13.5-inch Mk VI EOC 14-inch 45 cal. Mk I BL 15-inch Mk I
Armoured cruiser main armament	BL 7.5-inch Mk I BL 9.2-inch Mk X BL 9.2-inch Mk XI
Secondary armament and light cruiser main armament	QF 12-pounder 18 cwt QF 14-pounder Maxim-Nordenfelt QF 14-pounder Mk I & II QF 4-inch Mk III BL 4-inch Mk VII QF 4-inch Mk V BL 4-inch Mk IX BL 5.5-inch Mk I QF 6-inch Mk I – III BL 6-inch Mk VII BL 6-inch Mk XI BL 6-inch Mk XII BL 6-inch Mk XIII-XVIII BL 7.5-inch Mk II – Mk V
Destroyer and small cruiser armament	QF 12-pounder 12 cwt Mk II QF 4-inch Mk III BL 4-inch Mk VIII QF 4-inch Mk IV BL 4.7-inch Mk I
Merchant ship armament	QF 4.7-inch Mk I – IV QF 4.7-inch Mk V*
Submarine guns	BL 4-inch Mk XI QF 4-inch Mk XII
Anti-aircraft guns	QF 2-pounder "pom-pom" Mk II QF 3-inch 20 cwt QF 4-inch Mk V
Light weapons	.303 Vickers machine gun QF 3-pounder Hotchkiss QF 3-pounder Vickers QF 6-pounder Hotchkiss
Torpedoes	18-inch Mk V – VIII 21-inch Mk II 21-inch Mk IV
Mines	Spherical Mk I, II and III Vickers Elia mine Type H mine
Anti-submarine weapons	Type A Depth charge Type B Depth charge Type C Depth charge Type D Depth charge Type E Depth charge Type F Depth charge Type G Depth charge Cruiser Mine 7.5-inch howitzer
Landing guns	QF 12-pounder 8 cwt