20 cm/50 3rd Year Type naval gun: Difference between revisions

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{{Infobox weapon
{{Infobox weapon
|name= 20 cm/50 3rd Year Type naval gun
| name = 20 cm/50 3rd Year Type naval gun
| image=Japanese_heavy_cruiser_Chikuma.jpg
| image = Japanese_heavy_cruiser_Chikuma.jpg
| image_size = 300
| image_size = 300
|caption=''Tone''-class cruiser {{ship|Japanese cruiser|Chikuma|1938|2}} mounted all 4 turrets forward of the bridge.
| caption = ''Tone''-class cruiser {{ship|Japanese cruiser|Chikuma|1938|2}} mounted all 4 turrets forward of the bridge.
|origin= Japan
| origin = Japan
|type= [[Naval gun]]
| type = [[Naval gun]]
<!-- Type selection -->
<!-- Type selection -->
|is_ranged=YES
| is_ranged = YES
|is_bladed=
| is_bladed =
|is_explosive=
| is_explosive =
|is_artillery=YES
| is_artillery = YES
|is_vehicle=
| is_vehicle =
|is_UK=YES
| is_UK = YES
<!-- Service history -->
<!-- Service history -->
|service=1926 - 1945<ref name="Whitley177">Whitley 1995 pp.177</ref>
| service = 1926 - 1945<ref name="Whitley177">Whitley 1995 pp.177</ref>
|used_by= [[Imperial Japanese Navy]]
| used_by = [[Imperial Japanese Navy]]
|wars=[[Second World War]]
| wars = [[Second World War]]
<!-- Production history -->
<!-- Production history -->
|designer=
| designer =
|design_date=
| design_date =
|manufacturer=[[Kure Naval Arsenal]]<br>[[Muroran, Hokkaidō|Muroran]] Ironworks<ref name="Campbell"/>
| manufacturer = [[Kure Naval Arsenal]]<br>[[Muroran, Hokkaidō|Muroran]] Ironworks<ref name="Campbell"/>
|production_date=1 GÔ (Mark 1) : 1923<br> 2 GÔ (Mark 2) : 1932
| production_date = 1 GÔ (Mark 1) : 1923<br> 2 GÔ (Mark 2) : 1932
|number=~300<ref name="Campbell">Campbell 1985 pp.185-187</ref>
| number = ~300<ref name="Campbell">Campbell 1985 pp.185-187</ref>
|unit_cost=
| unit_cost =
|variants=
| variants =
<!-- General specifications -->
<!-- General specifications -->
|weight=1 GÔ (Mark 1) : 17.6 tonnes<ref name="Campbell"/><br>2 GÔ (Mark 2): 18.7 tonnes
| weight = 1 GÔ (Mark 1) : 17.6 tonnes<ref name="Campbell"/><br>2 GÔ (Mark 2): 18.7 tonnes
|length=1 GÔ (Mark 1) : {{convert|10|m|ft}}
| length = 1 GÔ (Mark 1) : {{convert|10|m|ft}}
<br>2 GÔ (Mark 2) : {{convert|10.31|m|ft}}
<br>2 GÔ (Mark 2) : {{convert|10.31|m|ft}}
|part_length=1 GÔ (Mark 1) : {{convert|9.144|m|ft}}<br>2 GÔ (Mark 2) : {{convert|10|m|ft}}<ref name="Campbell"/>
| part_length = 1 GÔ (Mark 1) : {{convert|9.144|m|ft}}<br>2 GÔ (Mark 2) : {{convert|10|m|ft}}<ref name="Campbell"/>
|width=
| width =
|height=
| height =
|crew=
| crew =
<!-- Ranged weapon specifications -->
<!-- Ranged weapon specifications -->
|cartridge=1 GÔ (Mark 1) : {{convert|110|kg}}<br>2 GÔ (Mark 2) : {{convert|126|kg}}
| cartridge = 1 GÔ (Mark 1) : {{convert|110|kg}}<br>2 GÔ (Mark 2) : {{convert|126|kg}}
|caliber= 1 GÔ (Mark 1) : {{convert|20|cm|in|adj=on|sigfig=4}}<br>2 GÔ (Mark 2) : {{convert|8|in|adj=on|sigfig=4}} <ref name="Campbell"/>
| caliber = 1 GÔ (Mark 1) : {{convert|20|cm|in|adj=on|sigfig=4}}<br>2 GÔ (Mark 2) : {{convert|8|in|adj=on|sigfig=4}} <ref name="Campbell"/>
|action=
| action =
|rate=
| rate =
|velocity=835 m/s (2740 ft/sec)<ref name="Campbell"/>
| velocity = {{convert|835|m/s|ft/s|abbr=on}}<ref name="Campbell"/>
|range=
| range =
|max_range= {{convert|29|km|mi}}<ref name="Campbell"/>
| max_range = {{convert|29|km|mi}}<ref name="Campbell"/>
|feed=
| feed =
|sights=
| sights =
<!-- Artillery specifications -->
<!-- Artillery specifications -->
|breech=
| breech =
|recoil=
| recoil =
|carriage=
| carriage =
|elevation=
| elevation =
|traverse=
| traverse =
}}
}}


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==1 GÔ (Mark I) guns==
==1 GÔ (Mark I) guns==
The first model of this gun used a {{convert|32.63|kg|1|abbr=on}} powder charge to fire {{convert|20|cm|in|abbr=on}} projectiles weighing {{convert|110|kg|1|abbr=on}} at a velocity of {{convert|870|m/s|0|abbr=on}}.<ref>Lacroix, ''Japanese Cruisers'', p.61</ref> Useful life was 300 [[List of British ordnance terms#Effective Full Charge|effective full charge]]s (EFC) per gun. These guns were initially installed in type A low-angle (25°) single mounts aboard {{sclass|Furutaka|cruiser|1}}s, in type C (40°) twin turrets in the {{sclass|Aoba|cruiser|4}}, and in type D (40°) twin turrets in the {{sclass|Myōkō|cruiser|4}}. Mark I guns can be visually distinguished from Mark II guns by an abrupt step in the chase diameter which was absent on the latter guns.<ref name="Campbell"/>
The first model of this gun used a {{convert|32.63|kg|1|abbr=on}} powder charge to fire {{convert|20|cm|in|abbr=on}} projectiles weighing {{convert|110|kg|1|abbr=on}} at a velocity of {{convert|870|m/s|0|abbr=on}}.<ref>Lacroix, ''Japanese Cruisers'', p.61</ref> Useful life was 300 [[List of British ordnance terms#Effective Full Charge|effective full charge]]s (EFC) per gun. These guns were initially installed in type A low-angle (25°) single mounts aboard {{sclass|Furutaka|cruiser|1}}s, in type C (40°) twin turrets in the {{sclass|Aoba|cruiser|4}}, and in type D (40°) twin turrets in the {{sclass|Myōkō|cruiser|4}}. Mark I guns can be visually distinguished from Mark II guns by an abrupt step in the chase diameter which was absent on the latter guns.<ref name="Campbell"/>


==2 GÔ (Mark II) guns==
==2 GÔ (Mark II) guns==
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==Aircraft carrier installations==
==Aircraft carrier installations==
[[File:Japanese Navy Aircraft Carrier Kaga 1928.jpg|thumb|right|Starboard quarter of ''Kaga'' with three casemate guns visible.]]
[[File:Japanese Navy Aircraft Carrier Kaga 1928.jpg|thumb|right|Starboard quarter of ''Kaga'' with three casemate guns visible.]]
Mark I guns were installed in [[casemate]]s with a maximum elevation of 25 degrees limiting maximum range to {{convert|22|km|mi|sp=us}}. Aircraft carriers originally had four guns mounted in two type B twin turrets with a maximum elevation of 70 degrees. These were transferred to casemates in ''Kaga'' in 1934 and simply removed from ''Akagi'' in 1936.
Mark I guns were installed in [[casemate]]s with a maximum elevation of 25 degrees limiting maximum range to {{convert|22|km|mi|sp=us}}. Aircraft carriers originally had four guns mounted in two type B twin turrets with a maximum elevation of 70 degrees. These were transferred to casemates in ''Kaga'' in 1934 and simply removed from ''Akagi'' in 1936.


==Ammunition==
==Ammunition==
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!Impact velocity
!Impact velocity
|-
|-
|{{convert|5|km|mi|abbr=on}}
|5&nbsp;km (3 miles)
|2°&nbsp;24{{prime}}
|2°&nbsp;24{{prime}}
|3°&nbsp;
|3°&nbsp;
|2133&nbsp;ft/s (650&nbsp;m/s)
|{{convert|2133|ft/s|m/s|abbr=on}}
|-
|-
|{{convert|10|km|mi|abbr=on}}
|10&nbsp;km (6 miles)
|5°&nbsp;18{{prime}}
|5°&nbsp;18{{prime}}
|7°&nbsp;30{{prime}}
|7°&nbsp;30{{prime}}
|1634&nbsp;ft/s (498&nbsp;m/s)
|{{convert|1634|ft/s|m/s|abbr=on}}
|-
|-
|{{convert|15|km|mi|abbr=on}}
|15&nbsp;km (9 miles)
|10°&nbsp;30{{prime}}
|10°&nbsp;30{{prime}}
|15°&nbsp;48{{prime}}
|15°&nbsp;48{{prime}}
|1299&nbsp;ft/s (396&nbsp;m/s)
|{{convert|1299|ft/s|m/s|abbr=on}}
|-
|-
|{{convert|20|km|mi|abbr=on}}
|20&nbsp;km (12 miles)
|18°&nbsp;
|18°&nbsp;
|29°&nbsp;
|29°&nbsp;
|1194&nbsp;ft/s (364&nbsp;m/s)
|{{convert|1194|ft/s|m/s|abbr=on}}
|-
|-
|{{convert|25|km|mi|abbr=on}}
|25&nbsp;km (15 miles)
|30°&nbsp;
|30°&nbsp;
|47°&nbsp;
|47°&nbsp;
|1247&nbsp;ft/s (380&nbsp;m/s)
|{{convert|1247|ft/s|m/s|abbr=on}}
|}
|}


==Gun mounts==
==Gun mounts==
===Type A===
===Type A===
Only Mark I guns were installed in type A mounts. Maximum elevation was 25°&nbsp; in the six single mounts installed aboard ''Furutaka''-class cruisers in 1926, in the six casemate mountings installed on aircraft carriers ''Akagi'' in 1927 and ''Kaga'' in 1930, and in the four casemate mountings added to ''Kaga'' in 1934.
Only Mark I guns were installed in type A mounts. Maximum elevation was 25°&nbsp;in the six single mounts installed aboard ''Furutaka''-class cruisers in 1926, in the six casemate mountings installed on aircraft carriers ''Akagi'' in 1927 and ''Kaga'' in 1930, and in the four casemate mountings added to ''Kaga'' in 1934.


===Type B===
===Type B===
Only Mark I guns were installed in type B mounts. Maximum elevation was 70°&nbsp; in the two twin turrets installed aboard ''Akagi'' in 1927 and ''Kaga'' in 1930. These turrets were removed from ''Kaga'' in 1934 and from ''Akagi'' in 1936. Guns removed in 1934 were transferred to additional casemates aboard ''Kaga'', but those removed in 1936 were not replaced.
Only Mark I guns were installed in type B mounts. Maximum elevation was 70°&nbsp;in the two twin turrets installed aboard ''Akagi'' in 1927 and ''Kaga'' in 1930. These turrets were removed from ''Kaga'' in 1934 and from ''Akagi'' in 1936. Guns removed in 1934 were transferred to additional casemates aboard ''Kaga'', but those removed in 1936 were not replaced.


===Type C===
===Type C===
Three twin turrets with maximum elevation of 40°&nbsp; were installed only aboard ''Aoba''-class cruisers. The Mark I guns installed in 1927 were replaced by Mark II guns in 1937 and 1938.
Three twin turrets with maximum elevation of 40°&nbsp;were installed only aboard ''Aoba''-class cruisers. The Mark I guns installed in 1927 were replaced by Mark II guns in 1937 and 1938.


===Type D===
===Type D===
Five twin turrets with maximum elevation of 40°&nbsp; were installed only aboard ''Myōkō''-class cruisers. The Mark I guns installed in 1928 and 1929 were replaced by Mark II guns between 1931 and 1934.
Five twin turrets with maximum elevation of 40°&nbsp;were installed only aboard ''Myōkō''-class cruisers. The Mark I guns installed in 1928 and 1929 were replaced by Mark II guns between 1931 and 1934.


===Type E===
===Type E===
Only Mark II guns were installed in type E twin turrets. Maximum elevation was 70° in the five turrets installed aboard ''Atago'', ''Takao'', and ''Chōkai'' in 1932. Early recognition of the impracticality of using these guns for anti-aircraft fire caused reduction of maximum elevation to 55° in all subsequent installations. ''Maya'' received five 55° turrets as original equipment in 1932. Three new turrets with Mark I guns from ''Myōkō''-class cruisers re-bored to Mark II replaced the original type A mounts aboard ''Furutaka''-class cruisers in 1936 and 1937. ''Tone''-class cruisers were completed with four type E turrets in 1937 and 1938. Five new turrets replaced the original triple 6-inch turrets aboard ''Mogami'' class cruisers between 1939 and 1941.
Only Mark II guns were installed in type E twin turrets. Maximum elevation was 70° in the five turrets installed aboard ''Atago'', ''Takao'', and ''Chōkai'' in 1932. Early recognition of the impracticality of using these guns for anti-aircraft fire caused reduction of maximum elevation to 55° in all subsequent installations. ''Maya'' received five 55° turrets as original equipment in 1932. Three new turrets with Mark I guns from ''Myōkō''-class cruisers re-bored to Mark II replaced the original type A mounts aboard ''Furutaka''-class cruisers in 1936 and 1937. ''Tone''-class cruisers were completed with four type E turrets in 1937 and 1938. Five new turrets replaced the original triple 6-inch turrets aboard ''Mogami'' class cruisers between 1939 and 1941.


==Wartime installations of ''3 Nendo Shiki'' 20 cm/50 caliber guns==
==Wartime installations of ''3 Nendo Shiki'' 20 cm/50 caliber guns==
Line 123: Line 123:
|-
|-
|{{ship|Japanese aircraft carrier|Akagi||2}}
|{{ship|Japanese aircraft carrier|Akagi||2}}
|6 Mark I guns in type A casemates with 25°&nbsp; elevation<ref>Brown 1995 pp.15</ref>
|6 Mark I guns in type A casemates with 25°&nbsp;elevation<ref>Brown 1995 pp.15</ref>
|-
|-
|{{ship|Japanese cruiser|Aoba||2}}
|{{ship|Japanese cruiser|Aoba||2}}
|3 type C twin turrets with 40°&nbsp; elevation<ref name="Whitley170"/>
|3 type C twin turrets with 40°&nbsp;elevation<ref name="Whitley170"/>
|-
|-
|{{ship|Japanese cruiser|Ashigara||2}}
|{{ship|Japanese cruiser|Ashigara||2}}
|5 type D twin turrets with 40°&nbsp; elevation<ref name="Whitley174">Whitley 1995 pp.174</ref>
|5 type D twin turrets with 40°&nbsp;elevation<ref name="Whitley174">Whitley 1995 pp.174</ref>
|-
|-
|{{ship|Japanese cruiser|Atago||2}}
|{{ship|Japanese cruiser|Atago||2}}
|5 type E twin turrets with 70°&nbsp; elevation<ref name="Whitley178"/>
|5 type E twin turrets with 70°&nbsp;elevation<ref name="Whitley178"/>
|-
|-
|{{ship|Japanese cruiser|Chikuma|1938|2}}
|{{ship|Japanese cruiser|Chikuma|1938|2}}
|4 type E twin turrets with 55°&nbsp; elevation<ref name="Whitley185">Whitley 1995 pp.185</ref>
|4 type E twin turrets with 55°&nbsp;elevation<ref name="Whitley185">Whitley 1995 pp.185</ref>
|-
|-
|{{ship|Japanese cruiser|Chōkai||2}}
|{{ship|Japanese cruiser|Chōkai||2}}
|5 type E twin turrets with 70°&nbsp; elevation<ref name="Whitley178">Whitley 1995 pp.178</ref>
|5 type E twin turrets with 70°&nbsp;elevation<ref name="Whitley178">Whitley 1995 pp.178</ref>
|-
|-
|{{ship|Japanese cruiser|Furutaka||2}}
|{{ship|Japanese cruiser|Furutaka||2}}
|3 type E twin turrets with 55°&nbsp; elevation<ref name="Whitley170">Whitley 1995 pp.170</ref>
|3 type E twin turrets with 55°&nbsp;elevation<ref name="Whitley170">Whitley 1995 pp.170</ref>
|-
|-
|{{ship|Japanese cruiser|Haguro||2}}
|{{ship|Japanese cruiser|Haguro||2}}
|5 type D twin turrets with 40°&nbsp; elevation<ref name="Whitley174"/>
|5 type D twin turrets with 40°&nbsp;elevation<ref name="Whitley174"/>
|-
|-
|{{ship|Japanese aircraft carrier|Kaga||2}}
|{{ship|Japanese aircraft carrier|Kaga||2}}
|10 Mark I guns in type A casemates with 25°&nbsp; elevation<ref>Brown 1995 pp.16</ref>
|10 Mark I guns in type A casemates with 25°&nbsp;elevation<ref>Brown 1995 pp.16</ref>
|-
|-
|{{ship|Japanese cruiser|Kako||2}}
|{{ship|Japanese cruiser|Kako||2}}
|3 type E twin turrets with 55°&nbsp; elevation<ref name="Whitley170"/>
|3 type E twin turrets with 55°&nbsp;elevation<ref name="Whitley170"/>
|-
|-
|{{ship|Japanese cruiser|Kinugasa||2}}
|{{ship|Japanese cruiser|Kinugasa||2}}
|3 type C twin turrets with 40°&nbsp; elevation<ref name="Whitley170"/>
|3 type C twin turrets with 40°&nbsp;elevation<ref name="Whitley170"/>
|-
|-
|{{ship|Japanese cruiser|Kumano||2}}
|{{ship|Japanese cruiser|Kumano||2}}
|5 type E twin turrets with 55°&nbsp; elevation<ref name="Whitley182">Whitley 1995 pp.182</ref>
|5 type E twin turrets with 55°&nbsp;elevation<ref name="Whitley182">Whitley 1995 pp.182</ref>
|-
|-
|{{ship|Japanese cruiser|Maya||2}}
|{{ship|Japanese cruiser|Maya||2}}
|5 type E twin turrets with 55°&nbsp; elevation<ref name="Whitley178"/>
|5 type E twin turrets with 55°&nbsp;elevation<ref name="Whitley178"/>
|-
|-
|{{ship|Japanese cruiser|Mikuma||2}}
|{{ship|Japanese cruiser|Mikuma||2}}
|5 type E twin turrets with 55°&nbsp; elevation<ref name="Whitley182"/>
|5 type E twin turrets with 55°&nbsp;elevation<ref name="Whitley182"/>
|-
|-
|{{ship|Japanese cruiser|Mogami|1934|2}}
|{{ship|Japanese cruiser|Mogami|1934|2}}
|5 type E twin turrets with 55°&nbsp; elevation<ref name="Whitley182"/>
|5 type E twin turrets with 55°&nbsp;elevation<ref name="Whitley182"/>
|-
|-
|{{ship|Japanese cruiser|Myōkō||2}}
|{{ship|Japanese cruiser|Myōkō||2}}
|5 type D twin turrets with 40°&nbsp; elevation<ref name="Whitley174"/>
|5 type D twin turrets with 40°&nbsp;elevation<ref name="Whitley174"/>
|-
|-
|{{ship|Japanese cruiser|Nachi||2}}
|{{ship|Japanese cruiser|Nachi||2}}
|5 type D twin turrets with 40°&nbsp; elevation<ref name="Whitley174"/>
|5 type D twin turrets with 40°&nbsp;elevation<ref name="Whitley174"/>
|-
|-
|{{ship|HTMS|Sri Ayudhya||2}}
|{{ship|HTMS|Sri Ayudhya||2}}
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|-
|-
|{{ship|Japanese cruiser|Suzuya|1934|2}}
|{{ship|Japanese cruiser|Suzuya|1934|2}}
|5 type E twin turrets with 55°&nbsp; elevation<ref name="Whitley182"/>
|5 type E twin turrets with 55°&nbsp;elevation<ref name="Whitley182"/>
|-
|-
|{{ship|Japanese cruiser|Takao|1930|2}}
|{{ship|Japanese cruiser|Takao|1930|2}}
|5 type E twin turrets with 70°&nbsp; elevation<ref name="Whitley178"/>
|5 type E twin turrets with 70°&nbsp;elevation<ref name="Whitley178"/>
|-
|-
|{{ship|HTMS|Thonburi||2}}
|{{ship|HTMS|Thonburi||2}}
|2 type D twin turrets with 40°&nbsp; elevation<ref name="DiGiulian"/>
|2 type D twin turrets with 40°&nbsp;elevation<ref name="DiGiulian"/>
|-
|-
|{{ship|Japanese cruiser|Tone|1937|2}}
|{{ship|Japanese cruiser|Tone|1937|2}}
|4 type E twin turrets with 55°&nbsp; elevation<ref name="Whitley185"/>
|4 type E twin turrets with 55°&nbsp;elevation<ref name="Whitley185"/>
|}
|}


Line 192: Line 192:
** till 1937: 6 7.9-inch type A 25°
** till 1937: 6 7.9-inch type A 25°
** from 1937: 3 twin 8.0-inch type E 55°
** from 1937: 3 twin 8.0-inch type E 55°

* {{sclass|Aoba|cruiser|0}} heavy cruisers: {{ship|Japanese cruiser|Aoba||2}}, {{ship|Japanese cruiser|Kinugasa||2}}
* {{sclass|Aoba|cruiser|0}} heavy cruisers: {{ship|Japanese cruiser|Aoba||2}}, {{ship|Japanese cruiser|Kinugasa||2}}
** till 1938: 3 twin 7.9-inch type C 40°
** till 1938: 3 twin 7.9-inch type C 40°
** from 1938: 3 twin 8.0-inch type C 40°
** from 1938: 3 twin 8.0-inch type C 40°

* {{sclass|Myoko|cruiser|0}} heavy cruisers: {{ship|Japanese cruiser|Myoko||2}}, {{ship|Japanese cruiser|Nachi||2}}, {{ship|Japanese cruiser|Ashigara||2}}, {{ship|Japanese cruiser|Haguro||2}}
* {{sclass|Myoko|cruiser|0}} heavy cruisers: {{ship|Japanese cruiser|Myoko||2}}, {{ship|Japanese cruiser|Nachi||2}}, {{ship|Japanese cruiser|Ashigara||2}}, {{ship|Japanese cruiser|Haguro||2}}
** till 1934: 5 twin 7.9-inch type D 40°
** till 1934: 5 twin 7.9-inch type D 40°
** from 1934: 5 twin 8.0-inch type D 40°
** from 1934: 5 twin 8.0-inch type D 40°

* {{sclass|Takao|cruiser|0}} heavy cruisers
* {{sclass|Takao|cruiser|0}} heavy cruisers
** {{ship|Japanese cruiser|Takao||2}}, {{ship|Japanese cruiser|Atago||2}}, {{ship|Japanese cruiser|Chokai||2}}
** {{ship|Japanese cruiser|Takao||2}}, {{ship|Japanese cruiser|Atago||2}}, {{ship|Japanese cruiser|Chokai||2}}
Line 206: Line 203:
** {{ship|Japanese cruiser|Maya||2}}
** {{ship|Japanese cruiser|Maya||2}}
*** 5 twin 8.0-inch type E 55°
*** 5 twin 8.0-inch type E 55°

* {{sclass|Mogami|cruiser|0}} heavy cruisers: {{ship|Japanese cruiser|Mogami|1934|2}}, {{ship|Japanese cruiser|Mikuma||2}}, {{ship|Japanese cruiser|Kumano||2}}, {{ship|Japanese cruiser|Suzuya|1934|2}}
* {{sclass|Mogami|cruiser|0}} heavy cruisers: {{ship|Japanese cruiser|Mogami|1934|2}}, {{ship|Japanese cruiser|Mikuma||2}}, {{ship|Japanese cruiser|Kumano||2}}, {{ship|Japanese cruiser|Suzuya|1934|2}}
** till 1939: 5 triple 6.1-inch 55° (classified as light cruiser)
** till 1939: 5 triple 6.1-inch 55° (classified as light cruiser)
** from 1939: 5 twin 8.0-inch type E 55°
** from 1939: 5 twin 8.0-inch type E 55°

* {{sclass|Tone|cruiser|0}} heavy cruisers: {{ship|Japanese cruiser|Tone|1937|2}}, {{ship|Japanese cruiser|Chikuma|1938|2}}
* {{sclass|Tone|cruiser|0}} heavy cruisers: {{ship|Japanese cruiser|Tone|1937|2}}, {{ship|Japanese cruiser|Chikuma|1938|2}}
** 4 twin 8.0-inch type E 55°
** 4 twin 8.0-inch type E 55°
Line 236: Line 231:
* Tony DiGiulian, [http://www.navweaps.com/Weapons/WNJAP_8-50_3ns.htm Japanese 20 cm/50 (8") 3rd Year Type No. 2]
* Tony DiGiulian, [http://www.navweaps.com/Weapons/WNJAP_8-50_3ns.htm Japanese 20 cm/50 (8") 3rd Year Type No. 2]
{{WWIIJapaneseNavalWeapons}}
{{WWIIJapaneseNavalWeapons}}



{{DEFAULTSORT:20 cm 50 3rd Year Type naval gun}}
{{DEFAULTSORT:20 cm 50 3rd Year Type naval gun}}

Revision as of 10:23, 28 April 2024

20 cm/50 3rd Year Type naval gun
Tone-class cruiser Chikuma mounted all 4 turrets forward of the bridge.
TypeNaval gun
Place of originJapan
Service history
In service1926 - 1945[1]
Used byImperial Japanese Navy
WarsSecond World War
Production history
ManufacturerKure Naval Arsenal
Muroran Ironworks[2]
Produced1 GÔ (Mark 1) : 1923
2 GÔ (Mark 2) : 1932
No. built~300[2]
Specifications
Mass1 GÔ (Mark 1) : 17.6 tonnes[2]
2 GÔ (Mark 2): 18.7 tonnes
Length1 GÔ (Mark 1) : 10 metres (33 ft)
2 GÔ (Mark 2) : 10.31 metres (33.8 ft)
Barrel length1 GÔ (Mark 1) : 9.144 metres (30.00 ft)
2 GÔ (Mark 2) : 10 metres (33 ft)[2]
Shell1 GÔ (Mark 1) : 110 kilograms (240 lb)
2 GÔ (Mark 2) : 126 kilograms (278 lb)
Calibre1 GÔ (Mark 1) : 20-centimetre (7.874 in)
2 GÔ (Mark 2) : 8-inch (203.2 mm) [2]
Muzzle velocity835 m/s (2,740 ft/s)[2]
Maximum firing range29 kilometres (18 mi)[2]

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.

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]

1 GÔ (Mark I) guns

The first model of this gun used a 32.63 kg (71.9 lb) powder charge to fire 20 cm (7.9 in) projectiles weighing 110 kg (242.5 lb) at a velocity of 870 m/s (2,854 ft/s).[4] Useful life was 300 effective full charges (EFC) per gun. These guns were initially installed in type A low-angle (25°) single mounts aboard Furutaka-class cruisers, in type C (40°) twin turrets in the Aoba class, and in type D (40°) twin turrets in the Myōkō class. Mark I guns can be visually distinguished from Mark II guns by an abrupt step in the chase diameter which was absent on the latter guns.[2]

2 GÔ (Mark II) guns

Second model guns used a 33.8 kg (74.5 lb) powder charge to fire 8 in (203.2 mm) projectiles weighing 125.85 kg (277.5 lb) at a velocity of 835 m/s (2,740 ft/s).[5] These guns had a useful life expectancy of 320 to 400 EFC (Effective/Equivalent Full Charge). Rate of fire varied from four rounds per minute firing at low angles diminishing to two or three rounds per minute firing at maximum elevation.[2] These guns and the type E twin turret with 70-degree elevation installed on Takao-class cruisers were influenced by Royal Navy County-class cruisers.[1] Type E turrets were promptly redesigned to limit elevation to 55 degrees when 70-degree elevation proved impractical. Modified type E turrets were installed as original equipment aboard Maya and the Tone-class cruisers, and replaced the original turrets aboard Furutaka and Mogami-class cruisers. Mark II guns replaced the original Mark I guns in type C and D turrets so all Japanese heavy cruisers carried Mark II guns in twin turrets by December 1941.

Aircraft carrier installations

Starboard quarter of Kaga with three casemate guns visible.

Mark I guns were installed in casemates with a maximum elevation of 25 degrees limiting maximum range to 22 kilometers (14 mi). Aircraft carriers originally had four guns mounted in two type B twin turrets with a maximum elevation of 70 degrees. These were transferred to casemates in Kaga in 1934 and simply removed from Akagi in 1936.

Ammunition

Shell weights and muzzle velocities for high explosive or San Shiki incendiary shrapnel are specified for each of the Marks above. Infobox muzzle velocity applies to type 91 armor-piercing (AP) shells with trajectory information below. Illuminating shells were fired with a reduced charge at a muzzle velocity of 710 meters per second (2330 ft/sec).[2]

Type 91 AP shell trajectory

Range[2] Elevation Descent Impact velocity
5 km (3.1 mi) 2° 24′ 3°  2,133 ft/s (650 m/s)
10 km (6.2 mi) 5° 18′ 7° 30′ 1,634 ft/s (498 m/s)
15 km (9.3 mi) 10° 30′ 15° 48′ 1,299 ft/s (396 m/s)
20 km (12 mi) 18°  29°  1,194 ft/s (364 m/s)
25 km (16 mi) 30°  47°  1,247 ft/s (380 m/s)

Gun mounts

Type A

Only Mark I guns were installed in type A mounts. Maximum elevation was 25° in the six single mounts installed aboard Furutaka-class cruisers in 1926, in the six casemate mountings installed on aircraft carriers Akagi in 1927 and Kaga in 1930, and in the four casemate mountings added to Kaga in 1934.

Type B

Only Mark I guns were installed in type B mounts. Maximum elevation was 70° in the two twin turrets installed aboard Akagi in 1927 and Kaga in 1930. These turrets were removed from Kaga in 1934 and from Akagi in 1936. Guns removed in 1934 were transferred to additional casemates aboard Kaga, but those removed in 1936 were not replaced.

Type C

Three twin turrets with maximum elevation of 40° were installed only aboard Aoba-class cruisers. The Mark I guns installed in 1927 were replaced by Mark II guns in 1937 and 1938.

Type D

Five twin turrets with maximum elevation of 40° were installed only aboard Myōkō-class cruisers. The Mark I guns installed in 1928 and 1929 were replaced by Mark II guns between 1931 and 1934.

Type E

Only Mark II guns were installed in type E twin turrets. Maximum elevation was 70° in the five turrets installed aboard Atago, Takao, and Chōkai in 1932. Early recognition of the impracticality of using these guns for anti-aircraft fire caused reduction of maximum elevation to 55° in all subsequent installations. Maya received five 55° turrets as original equipment in 1932. Three new turrets with Mark I guns from Myōkō-class cruisers re-bored to Mark II replaced the original type A mounts aboard Furutaka-class cruisers in 1936 and 1937. Tone-class cruisers were completed with four type E turrets in 1937 and 1938. Five new turrets replaced the original triple 6-inch turrets aboard Mogami class cruisers between 1939 and 1941.

Wartime installations of 3 Nendo Shiki 20 cm/50 caliber guns

Ship Gun Installation[2]
Akagi 6 Mark I guns in type A casemates with 25° elevation[6]
Aoba 3 type C twin turrets with 40° elevation[7]
Ashigara 5 type D twin turrets with 40° elevation[8]
Atago 5 type E twin turrets with 70° elevation[9]
Chikuma 4 type E twin turrets with 55° elevation[10]
Chōkai 5 type E twin turrets with 70° elevation[9]
Furutaka 3 type E twin turrets with 55° elevation[7]
Haguro 5 type D twin turrets with 40° elevation[8]
Kaga 10 Mark I guns in type A casemates with 25° elevation[11]
Kako 3 type E twin turrets with 55° elevation[7]
Kinugasa 3 type C twin turrets with 40° elevation[7]
Kumano 5 type E twin turrets with 55° elevation[12]
Maya 5 type E twin turrets with 55° elevation[9]
Mikuma 5 type E twin turrets with 55° elevation[12]
Mogami 5 type E twin turrets with 55° elevation[12]
Myōkō 5 type D twin turrets with 40° elevation[8]
Nachi 5 type D twin turrets with 40° elevation[8]
Sri Ayudhya 2 type D twin turrets with 40°  elevation[13]
Suzuya 5 type E twin turrets with 55° elevation[12]
Takao 5 type E twin turrets with 70° elevation[9]
Thonburi 2 type D twin turrets with 40° elevation[13]
Tone 4 type E twin turrets with 55° elevation[10]

See also

Weapons of comparable role, performance and era

Notes

  1. ^ a b Whitley 1995 pp.177
  2. ^ a b c d e f g h i j k l m n Campbell 1985 pp.185-187
  3. ^ Campbell 1985 pp.173&183
  4. ^ Lacroix, Japanese Cruisers, p.61
  5. ^ Lacroix, Japanese Cruisers, p.97
  6. ^ Brown 1995 pp.15
  7. ^ a b c d Whitley 1995 pp.170
  8. ^ a b c d Whitley 1995 pp.174
  9. ^ a b c d Whitley 1995 pp.178
  10. ^ a b Whitley 1995 pp.185
  11. ^ Brown 1995 pp.16
  12. ^ a b c d Whitley 1995 pp.182
  13. ^ a b DiGiulian, Tony. "20 cm/50 (7.9") 3rd Year Type". NavWeaps. Retrieved 4 September 2017.

References

  • Brown, David (1977). Aircraft Carriers. Arco Publishing Company. ISBN 0-668-04164-1.
  • Campbell, John (1985). Naval Weapons of World War Two. Annapolis, Maryland: Naval Institute Press. ISBN 0-87021-459-4.
  • Whitley, M.J. (1995). Cruisers of World War Two. Brockhampton Press. ISBN 1-86019-874-0.
  • Lacroix, Eric; Wells, Linton (1997). Japanese Cruisers of the Pacific War. Naval Institute Press. ISBN 0-87021-311-3.
allikas: https://en.wikipedia.org/wiki/Special%3ADiff%2F1221180653