20 cm/50 3rd Year Type naval gun
Naval gun / From Wikipedia, the free encyclopedia
Third year type 20 cm/50 caliber guns (五十口径三年式二〇糎砲, gojūkōkei sannenshiki ni-maru centi-hō) formed the main battery of Japan's World War II heavy cruisers. These guns were also mounted on two early aircraft carriers, the Kaga and the Akagi before their 1935 reconstruction.[2] The typical installation was ten 20 cm/50 guns; although Tone-class cruisers carried eight while Furutaka and Aoba-class cruisers carried six. After modernization, Akagi and Kaga carried only six, divided in three casemates per side, after the removal (during the 1935 reconstruction) of the four guns in two turrets on both ships placed on the second deck.
20 cm/50 3rd Year Type naval gun | |
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Type | Naval gun |
Place of origin | Japan |
Service history | |
In service | 1926 - 1945[1] |
Used by | Imperial Japanese Navy |
Wars | Second World War |
Production history | |
Manufacturer | Kure Naval Arsenal Muroran Ironworks[2] |
Produced | 1 GÔ (Mark 1) : 1923 2 GÔ (Mark 2) : 1932 |
No. built | ~300[2] |
Specifications | |
Mass | 1 GÔ (Mark 1) : 17.6 tonnes[2] 2 GÔ (Mark 2): 18.7 tonnes |
Length | 1 GÔ (Mark 1) : 10 metres (33 ft)
2 GÔ (Mark 2) : 10.31 metres (33.8 ft) |
Barrel length | 1 GÔ (Mark 1) : 9.144 metres (30.00 ft) 2 GÔ (Mark 2) : 10 metres (33 ft)[2] |
Shell | 1 GÔ (Mark 1) : 110 kilograms (240 lb) 2 GÔ (Mark 2) : 126 kilograms (278 lb) |
Calibre | 1 GÔ (Mark 1) : 20-centimetre (7.874 in) 2 GÔ (Mark 2) : 8-inch (203.2 mm) [2] |
Muzzle velocity | 835 m/s (2,740 ft/s)[2] |
Maximum firing range | 29 kilometres (18 mi)[2] |
These were built-up guns with an inner A tube, encased by a second tube, encased by a full length jacket. Early guns were partially wire-wound, but later guns dispensed with the wire winding. The guns were breech loaded with two cloth bags of smokeless powder.[2] Third year type refers to the Welin breech block on this gun. Breech block design began in 1914 AD, the third year of the Taishō period. This breech block design was also used on Japanese 41 cm (16.1 inch), 15.5 cm (6 inch), 14 cm (5.5 inch), 12.7 cm (5 inch), and 12 cm (4.7 inch) naval guns.[3]