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 design of their Welin breech mechanisms.

Most of these guns used a Welin screw-breech, but 11th Year Type Models "J" and "K" used on submarines had horizontal sliding breech-blocks and these 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.

Gun Characteristics

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 1: Ootori class and used to rearm Chidori 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
  • ^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.


Type Separate 1a
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 2a : 36.3 lbs. (16.4 kg)
Illum 3a: 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) 4a
Working Pressure 17.5 tons/in2 (2,750 kg/cm2)
Approximate Barrel Life 700 - 1000 Rounds
Ammunition stowage per gun N/A
  • ^Although these guns used a brass cartridge case to hold the propellant, all guns except the 11th Year Type Marks J and L used Welin screw breeches.
  • ^The flat-nosed ASW projectile was issued in 1943 following extensive testing.
  • ^Illumination rounds were rated at 600,000 candle power and had a maximum range of 15,310 yards (14,000 m).
  • ^A Note on Sources: In USNTMTJ report O-54(N), it is stated that the MV for the 3rd Year Type was 780 mps (2,560 fps) while for the 11th Year Type the MV is stated as 825 mps (2,700 fps). In "Naval Weapons of World War Two" by Campbell, both guns are stated as having a MV of 780 mps (2,707 fps). In examining O-54(N) more closely, it can be seen that both Year Types have the same ammunition and propellant weights, the same rifling twist, depth and length, and the same bore pressure. So, it is difficult to see how they could have such different MVs. In further examining the very similar 12 cm/45 10th Year Type we again see very similar ammunition, propellant, twist and bore pressures, again for a stated MY of 825 mps (2,700 fps). From this, it appears that Campbell considered O-54(N) to be in error for the MV of the 3rd Year Type, a conclusion that I support.


Range with 45.0 lbs. (20.41 kg) HE
Elevation Model Range
33 degrees M1914 16,400 yards (15,000 m)
M1922 17,500 yards (16,000 m)
Range with 36.3 lbs. (16.4 kg) ASW
Elevation Range
40 degrees 4,375 yards (4,000 m)

Minimum range of ASW shell is given as 750 yards (820 m). Ranges less than this tended to ricochet.

Mount/Turret Data

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) 1b: N/A
   11th Year Type - Torpedo Boat: Ootori (3) and Chidori (3) 2b: 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
  • ^Submarines used pneumatic hoists while other ships had a dredger hoist for every one or two mountings.
  • ^Torpedo boats had "X" 12 cm gun removed in 1942 and replaced with additional AA weapons.


"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
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
24 August 2020 - Added Note on Sources, converted to HTML 5 format
18 May 2022 - Minor changes