EOC 12 inch 45-calibre naval gun 12"/45 41st Year Type
41st Year Type on Mikasa
Type	Naval gun
Place of origin	United Kingdom
Service history
In service	1906-1952
Used by	United Kingdom Brazil Empire of Japan
Wars	World War I
Production history
Designer	Elswick Ordnance Company
Specifications
Barrel length	Bore 45 feet (13.716 m) (45 cal)

Shell	850 pounds (385.6 kg)
Calibre	12-inch (304.8 mm)
Muzzle velocity	2,700 feet per second (823 m/s) - 2,800 feet per second (853 m/s)
Maximum firing range	18,850 yards (17,240 m)

The EOC 12 inch 45 calibre gun were various similar 12-inch wire-wound naval guns designed and manufactured by Elswick Ordnance Company to equip ships that the parent company Armstrong Whitworth built and/or armed for several countries before World War I.

History

Brazil service

Elswick supplied its 12-inch 45-calibre guns for the Minas Geraes-class battleships completed by itself and Vickers in 1910 for Brazil.

UK service

When World War I began, Elswick were completing the battleship Sultân Osmân-ı Evvel for the Ottoman Empire, originally begun as Rio de Janeiro for Brazil. It was armed with 14 of a slightly later version of Elswick's 12-inch 45-calibre guns. The battleship was completed as HMS Agincourt and served in the Royal Navy in World War I, with its guns designated BL 12 inch Mk XIII.^[1] The gun's performance was similar to the standard Royal Navy equivalent gun, the BL 12 inch Mk X designed by Vickers.

Japan service

Elswick supplied its 12-inch 45-calibre guns to the Imperial Japanese Navy, and they were also manufactured under licence in Japan. In Japanese service from 1908 they became 12"/45 41st Year Type and later after the navy metricised in 1917, 30 cm/45 41st Year Type. They equipped the following ship classes:

Katori-class battleships commissioned 1906
Ibuki-class battlecruiser commissioned in 1907 & 1911
Tsukuba-class battlecruisers commissioned 1908
Battleship Mikasa as re-gunned in 1908
Satsuma-class battleships commissioned 1910 & 1912
Kawachi-class battleships commissioned 1912

Surviving examples

On the Japanese battleship Mikasa, Yokosuka, Japan

Notes

References

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