The Japanese considered the Type 89 to be a good AAA weapon and it had a fast rate of fire and excellent elevation and training speeds on the later Mods. Its primary shortcoming was a relatively low muzzle velocity and thus a short range and low AA ceiling. Used a spring rammer cocked by the recoil, similar to other Japanese AAA weapons.
These weapons were of simple construction with autofretted monobloc barrels and breech rings and used horizontal sliding breech-blocks. Total production of Type 89 guns amounted to 1,306 guns, with 836 being manufactured between 1941 and 1945. Of these, 362 were mounted ashore, including 96 in the Yokosuka area and 54 in the Kure area.
Unless otherwise specified, the data that follows is for the Type 89.
12.7 cm (5") twin mount on battleship IJN
12.7 cm (5") twin mount on unidentified
cruiser about 1932
12.7 cm (5") gun mount on IJN Nagato
Tachibana class escort showing single bow and twin stern 12.7 cm/40 mounts
12.7 cm (5") being used to defend an airstrip
12.7 cm/40 (5") gun used as coastal artillery
|Designation||12.7 cm/40 (5") Type 88 (Model 1928)
12.7 cm/40 (5") Type 89 (Model 1929)
|Ship Class Used On||Type 88: Submarines I.5 and I.6
Type 89: Almost all Japanese ships cruiser size and larger, Matsu and Tachibana class escorts
|Date Of Design||1928 / 1929|
|Date In Service||1932|
|Gun Weight||3.05 tons (3.1 mt)|
|Gun Length oa||208 in (5.284 m)|
|Bore Length||200 in (5.080 m)|
|Rifling Length||175 in (4.450 m)|
|Grooves||(36) 0.060 in deep x 0.261 in (1.52 mm x 6.63 mm)|
|Lands||0.175 in (4.45 mm)|
|Twist||Uniform RH 1 in 28|
|Chamber Volume||549 in3 (9.0 dm3)|
|Rate Of Fire||Type 88: 8 rounds per minute
Type 89: 14 rounds per minute initially, 8 rounds per minute sustained
|Weight of Complete Round||Common Type 0 HE - 75.7 lbs. (34.32 kg)
Common Type 3 IS - 77.2 lbs. (35 kg)
Illum - 75.7 lbs. (34.32 kg)
|Projectile Types and Weights
(see Note 1)
|Common Type 0 HE - 51.7 lbs. (23.45 kg)
Common Type 3 IS - 50.7 lbs. (23.0 kg)
ASW - 46.2 lbs. (20.9 kg)
Illum - 51.7 lbs. (23.45 kg)
|Bursting Charge||Common Type 0 HE - 4.2 lbs. (1.88 kg)
ASW - 8.78 lbs. (4.0 kg)
|Projectile Length||Common Type 0 HE - 17.2 in (43.7 cm)
Common Type 3 IS - 17.2 in (43.7 cm)
ASW - 17.2 in (43.7 cm)
|Complete Round Length||38.2 in (97.1 cm)|
|Cartridge Case Type, Size and Empty Weight||Brass, 127 x 583 mm, about 15.23 lbs. (6.9 kg)|
|Propellant Charge||8.77 lbs. (3.98 kg) 21 DC
Cartridge - 26.3 lbs. (12 kg)
|Muzzle Velocity||Common Type 0 HE - 2,360 - 2,379 fps (700
- 725 mps)
Common Type 3 IS - 2,360 - 2,379 fps (700 - 725 mps)
ASW - 820 fps (250 mps)
Illum - 2,362 fps (720 mps)
|Working Pressure||16 tons/in2 (2,500 kg/cm2)|
|Approximate Barrel Life||800 - 1500 rounds|
|Ammunition stowage per gun||Yamato class: 300 rounds
Cruisers with 4 guns: 250 rounds
Cruisers with 8 guns: 200 rounds
1) IS is my abbreviation for the incendiary shrapnel round (sankaidan) intended for AA use.
2) The flat-nosed ASW projectile was issued in 1943 following extensive testing. This is listed in US Naval Technical Mission to Japan report O-19 as being able to penetrate a 9.85 in (25 cm) plate of Ducol Steel (roughly equivalent to USN HTS) at a depth of 26 feet (8 meters). Range for this performance is not given. However, based upon other errors in this document, I would believe this to be an error in metric to english unit conversion and that the actual performance would more likely be 0.985 in (2.5 cm). ASW may have been issued only to escorts.
3) Illumination rounds were rated at 680,000 candle power and had a maximum range of 15,910 yards (14,550 m) and an effective range of 8,750 yards (8,000 m).
4) Common Type 0 HE was considered to have an 62.7 foot (18.8 m) effective radius of destruction.
|Elevation||With 50.7 lbs. (23 kg) IS Shell|
|Range @ 45 degrees||16,185 yards (14,800 m)|
|AA Ceiling @ 75 degrees||30,840 feet (9,400 m)|
|Elevation||With 46.2 lbs. (22.0 kg) ASW Shell|
|Range @ 40 degrees||4,700 yards (4,300 m)|
|Note: Minimum range of ASW shell is given as 875 yards (800 m). Ranges less than this tended to ricochet.|
(see Notes 1 and 5)
|Type 88 Single Mounting
I.5 (1): A
I.6 (1): A mod 1
Type 89 Twin Mounts
Type 89 Single Mount
A and A mod 1: 8.7 tons (8.8 mt)
|Elevation||Type 88: - 7 / +75 degrees
Type 89: -7 / +90 degrees (one source says -8 / +85 degrees)
|Elevation Rate||Type 88
Manual operation, only.
|Train||Amidships Mounts: About -70 / +70
Bow and Stern Mounts: About -150 / +150 degrees
|Train Rate||Type 88
Manual operation, only.
|Gun recoil||17.75 in (45.0 cm)|
1) Single mountings were manually operated. The twin mountings were generally similar and used electrically driven oil hydraulic gear for both training and elevation. A loading platform was attached to the rear of the cradle as the trunnions were 98 inches (249 cm) above the roller path. The A1 mount was unshielded. The A1 Mod 1 added a shield, while the shield for the A1 Mod 2 had a slightly different shape and the A1 Mod 3 had a thicker shield. The B1 mounting had no shield but did have a more powerful electric training motor, giving it faster elevation and training speeds..
2) The battleships Yamato and Musashi had their two amidships 15.5 cm/60 (6.1") triple mountings removed in 1944. Yamato had six twin 12.7 cm/40 (5") mountings installed in their place, giving her a total of twenty-four 12.7 cm/40 (5") guns. Musashi was also to receive six additional twin mountings, but these were not available prior to her loss.
3) Ramming was via a spring-powered mechanism that was cocked by the recoil force when the gun fired. Fuze-setting machines were fixed to the breech faces of the guns. Most ships had one or two hoists per twin mounting.
4) The submarine mountings were supplied ammunition via pneumatic hoists. Twin mountings usually had one or two hoists per mounting, but these were not always located near the guns. For example, the carrier Katsuragi (Unryu class) had one electrical dredger hoist that was located 35 yards (32 m) and two bulkheads away from the mounting.
5) The three submarine depot ships of the Taigei and Tsurugizaki classes and the two seaplane tenders of the Chiyoda class were originally armed with four 12.7 cm (5") guns. All five of these ships were rearmed with eight 12.7 cm (5") guns when converted to aircraft carriers during the war.
03 December 2008 - Benchmark
12 March 2011 - Added gun mounting information
18 December 2011 - Added information for minor Japanese warships