Japan 12.7 cm/40 (5") Types 88 and 89

Japan
12.7 cm/40 (5") Type 88
12.7 cm/40 (5") Type 89
Updated 18 December 2011

The Type 88 was used only on two submarines in single mountings. The very similar Type 89 was the first Japanese AAA weapon designed for the purpose and was used in twin mountings on most World War II warships cruiser size and larger as well as on small destroyers and some auxiliaries. The Type 89 was also used to replace many of the 12 cm/45 (4.7") AA guns on older cruisers. The Type 89 prototype was proved in 1931 and adopted for service use on 6 February 1932.

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 Musashi
Detail from U.S. Naval Historical Center Photograph # NH 73091

12.7 cm (5") twin mount on unidentified cruiser about 1932
In the background is IJN Haguro
Detail from U.S. Naval Historical Center Photograph # NH 88373

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 on Guam
National Archive Photograph No. SC 360857 Book 3
National Park Service WAPA Photograph No. 52 antiaircft.jpg

Images at Australian War Memorial

12.7 cm/40 (5") gun used as coastal artillery
Search via "018852"

Gun Characteristics .

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

Ammunition .

Type	Fixed
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 Others: N/A
Notes: 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.

Range .

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.

Mount / Turret Data .

Designation (see Notes 1 and 5)	Type 88 Single Mounting I.5 (1): A I.6 (1): A mod 1 Type 89 Twin Mounts Kongô (4), Fuso (4), Ise (4), Nagato (4), Aoba (2), Furataka (2), Takao (4), Atago (4) and Maya (4): A₁ Myôkô (4), Mogami (4), Tone (4), Akashi (2), Ashizuri (2) and Hayasui (2): A₁ Mod 1 Kaga (8), Ryûjô (4), Shôkaku (8), Hiryû (6), Shoho (4), Hiyo (6), Ryûhô (ex-Taigei) (4), Shoho (ex-Tsurugizaki) (4), Chiyoda (4), Kaiyo (4), Shinyo (4), Shinano (8), Unryu (6), Hiyo (6), Ryuho (4), Kaiyo (4), Shinyo (4), Shinano (8), Unryu (6), Mizuho (3) and Tsugaru (2): A₁ Mod 2 Yamato (6): A₁ Mod 3 Matsu (1) and Tachibana (1): B₁ Type 89 Single Mount Matsu (1) and Tachibana (1): B₁ Mod 4
Weight	Type 88 A and A mod 1: 8.7 tons (8.8 mt) Type 89: A₁: 20 tons (20.3 mt) A₁ Mod 1: 24 tons (24.5 mt) A₁ Mod 2: about 24 tons (24.5 mt) A₁ Mod 3: 28.5 tons (29 mt) B₁: N/A B₁ Mod 4: N/A
Elevation	Type 88: - 7 / +75 degrees Type 89: -7 / +90 degrees (one source says -8 / +85 degrees)
Elevation Rate	Type 88 Manual operation, only. Type 89 A₁ (all): 12 degrees per second B₁: 16 degrees per second
Train	Amidships Mounts: About -70 / +70 degrees Bow and Stern Mounts: About -150 / +150 degrees
Train Rate	Type 88 Manual operation, only. Type 89 A₁ (all): 6 to 7 degrees per second B₁: 16 degrees per second
Gun recoil	17.75 in (45.0 cm)
Loading Angle	Any
Notes: 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.

Data from
"Naval Weapons of World War Two" by John Campbell
"Battleships: Axis and Neutral Battleships in World War II" by W.H. Garzke, Jr. and R.O. Dulin, Jr.
"The Japanese Ships of the Pacific War" by The Koku-Fan
"Japanese Cruisers of the Pacific War" by Eric Lacroix and Linton Wells II
"Anatomy of the Ship: The Heavy Cruiser Takao" by Janusz Skulksi
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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-47(N)-1: Japanese Naval Guns and Mounts-Article 1, Mounts Under 18"

Page History

03 December 2008 - Benchmark
12 March 2011 - Added gun mounting information
18 December 2011 - Added information for minor Japanese warships