Japan
4.7"/45 (12 cm) 3rd Year Type
12 cm/45 (4.7") 3rd Year Type
12 cm/45 (4.7") 11th Year Type
Updated 14 July 2014

Simple hand-worked guns used on destroyers of the World War I era and on small escort vessels and submarines of the World War II era.  Many 3rd Year Type guns were used in coastal defense batteries during World War II.

The majority of these guns were of built up construction but a few had monobloc barrels with breech rings and some may have been wire wound.  3rd Year and 11th Year types differed in the type of breech mechanism.

Most of these guns used a screw-breech, but 11th Year Type Models "J" and "K" for submarines had horizontal sliding breech-blocks and were slightly shorter than the other models.

3rd Year Type guns were produced for Britain during World War I and designated as the 4.7" (12 cm) Mark V* gun.

Redesignated in centimeters on 5 October 1917.

WNJAP_47-45_11ns_Etorofu_pic.jpg

Japanese Escort Etorofu in May 1943 showing her three 12 cm guns
CPL photograph

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Gun Characteristics
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Designation 4.7"/45 (12 cm) 3rd Year Type (Model 1914)
12 cm/45 (4.7") 3rd Year Type (Model 1914)
12 cm/45 (4.7") 11th Year Type (Model 1922)
Ship Class Used On 3rd Year Type:  Momi, Minekaze, Wakatake, Kamikaze, Mutsuki, Shumushu and Etorofu classes
11th Year Type Marks J and L:  I.153 and I.171 classes
11th Year Type Mark M:  Ootori class and used to rearm Tomodzuru class
Date Of Design 1914 / 1922
Date In Service about 1920
Gun Weight about 3 tons (3.1 mt)
Gun Length oa Most models:  218.5 in (5.550 m)
Models J and L:  212.6 in (5.400 m)
Bore Length Most models:  212.6 in (5.400 m)
Models J and L:  207.5 in 5.270 m)
Rifling Length Most models:  181.1 in (4.601 m)
Models J and L:  176.0 in (4.471 m)
Grooves Model Type V:  (36) 0.040 in deep x 0.253 in (1.02 mm x 6.43 mm)
Model Type VII:  (34) 0.057 in deep x 0.263 in (1.45 mm x 6.68 mm)
Others:  N/A
Lands 0.173 in (4.40 mm)
Twist Uniform RH 1 in 28
Chamber Volume 637 in3 (10.44 dm3)
Rate Of Fire about 5 rounds per minute
Note:  Model M may have been of the same dimensions as Models J and L.  This model may have been different only in that it was designed to be used at higher elevation than the other guns in this series.
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Ammunition
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Type Separate
Projectile Types and Weights Common Type 0 HE - 44.9 lbs. (20.3 kg)
Common Type 1 HE - 44.9 lbs. (20.3 kg)
ASW - 36.3 lbs. (16.4 kg)
Illum - about 44.9 lbs. (20.3 kg)
Bursting Charge Common Type 0 HE - 3.75 lbs. (1.7 kg)
Common Type 1 HE - 4.07 lbs. (1.9 kg)
ASW - 7.19 lbs. (3.8 kg)
Projectile Length Common Type 0 HE - 16.0 in (40.8 cm)
Common Type 1 HE - 16.0 in (40.8 cm)
ASW - 16.4 in (41.5 cm)
Propellant Charge 11.6 lbs. (5.27 kg)
Muzzle Velocity 2,707 fps (825 mps)
Working Pressure 17.5 tons/in2 (2,750 kg/cm2)
Approximate Barrel Life 700 - 1000 Rounds
Ammunition stowage per gun N/A
Notes:

1) The flat-nosed ASW projectile was issued in 1943 following extensive testing.

2) Illumination rounds were rated at 600,000 candle power and had a maximum range of 15,310 yards (14,000 m).

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Range
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Elevation 45.0 lbs. (20.41 kg) HE Shell
Range @ 33 degrees (M1914) 16,400 yards (15,000 m)
Range @ 33 degrees (M1922) 17,500 yards (16,000 m)
Elevation With 36.3 lbs. (16.4 kg) ASW Shell
Range @ 40 degrees 4,375 yards (4,000 m)
Note:  Minimum range of ASW shell is given as 750 yards (820 m).  Ranges less than this tended to ricochet.
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Mount / Turret Data
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Designation Single Mounts
   3rd Year Type:  Momi (3), Minekaze (4), Wakatake (3), Kamikaze (4), Mutsuki (4), Shumushu (3) and Etorofu (3):  G
   11th Year Type - Submarine:  I.153 (1) and I.171 (1):  N/A
   11th Year Type - Torpedo Boat:  Ootori (3) and Tomodzuru (2):  N/A
Weight  8.76 tons (8.9 mt)
Elevation G:  -7 / +33 degrees

Submarine I.171 Mountings:  -10 / +33 degrees

Torpedo Boat Mountings:  -10 / +55 degrees

Elevation Rate Manual operation, only (about 5 degrees per second)
Train About +/- 120 degrees
Train Rate Manual operation, only (about 4 degrees per second)
Gun recoil N/A
Loading Angle +10 to +15 degrees
Notes:

1) Submarines used pneumatic hoists while other ships had a dredger hoist for every one or two mountings.

2) Torpedo boats had "X" 12 cm gun removed in 1942 and replaced with additional AA weapons.

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Data from
"Naval Weapons of World War Two" by John Campbell
"Japanese Kaibokan Escorts - Part 1" in "Warships Volume VIII" by Hans Legerer
"Japanese Kaibokan Escorts - Part 2" in "Warships Volume VIII" by Hans Legerer and Tomoko Rehm-Takahara
"Japanese Warships of World War II" by A.J. Watts
"Cruisers of World War Two" by M.J. Whitley
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US Naval Technical Mission to Japan report O-19:  Japanese Projectiles General Types
US Naval Technical Mission to Japan report O-54(N):  Japanese Naval Guns
Page History

22 November 2006 - Benchmark
27 May 2012 - Updated to latest template
14 July 2014 - Added information on Shumushu and Etorofu escort classes