Main gun maintenance on submarine
The submarine is thought to be a Type 5 or 6A, and the gun is a 10 centimeter (says "sanchi" in katakana) high-angle gun. You can see the structure of the base (presumably the gun mount).
The rod-shaped object on the right side of the head (starboard bow) is a radio mast that has been overturned (lowered) and a part of the conning tower is in the left-front side.
Dual-purpose gun used only on the I 65 (Type KD 5) class and I 68 (Type KD 6A) class submarines. On 5 May 1942 the I 65 class were redesignated as the I 165 class and the I 68 class redesignated as the I 168 class.
There were two versions of the gun barrel. Model Type I used a radially expanded, removable lining while the Model Type I2 was of monobloc construction. Both types used horizontally sliding breech blocks.
The propellant grain used for this gun was too large and unburnt propellant was present at the muzzle, meaning that the muzzle velocity was unpredictable.
| Designation | 10 cm/50 (3.9") Type 88 (Model 1928) |
|---|---|
| Ship Class Used On | I 65 / I 165 and I 68 / I 168 classes |
| Date Of Design | 1928 |
| Date In Service | 1932 |
| Gun Weight | 6,239 lbs. (2,830 kg) |
| Gun Length oa | 208.7 in (5.300 m) |
| Bore Length | 196.9 in (5.000 m) |
| Rifling Length | 169.1 in (4.295 m) |
| Grooves | (32) 0.049 in deep x 0.219 in (1.25 mm x 5.565 mm) |
| Lands | 0.167 in (4.252 mm) |
| Twist | Uniform RH 1 in 28 |
| Chamber Volume | 488 in3 (8.0 dm3) |
| Rate Of Fire | 6 rounds per minute 1 |
- ^This weapon had a firing cycle of 5 seconds but the pneumatic hoist took 10 seconds to deliver a round.
| Type | Fixed |
|---|---|
| Complete Round Weight | 52.9 lbs. (24 kg) |
| Projectile Types and Weights | HE: 28.7 lbs. (13 kg) |
| Bursting Charge | HE: 2.1 lbs. (1 kg) |
| Projectile Length | 15.0 in (38.0 cm) |
| Propellant Charge | 9.11 lbs. (4.13 kg) 30 DC
Cartridge: 24.2 lbs. (11 kg) |
| Muzzle Velocity | 2,904 to 2,936 fps (885 to 895 mps) |
| Working Pressure | 17.9 tons/in2 (2,820 kg/cm2) |
| Approximate Barrel Life | 400 - 700 rounds |
| Ammunition stowage per gun | N/A |
| Elevation | Range |
|---|---|
| 45 degrees | 17,700 yards (16,200 m) |
| AA Ceiling @ 90 degrees | 36,750 feet (11,200 m) |
| Designation | Single Pedestal
I 65 / I 165 (1): N/A I 168 (1): N/A |
|---|---|
| Weight | N/A |
| Elevation | -10 / +90 degrees |
| Elevation Rate | Hand operated, only |
| Train | about +150 / -150 degrees |
| Train Rate | Hand operated, only |
| Gun recoil | N/A |
"Naval Weapons of World War Two" by John Campbell
"Japanese Warships of World War II" by A.J. Watts
"The Japanese Warships of the Pacific War" by The Koku-Fan
27 August 2007 - Benchmark
27 May 2012 - dated to latest template
16 February 2020 - Added I 168 class, re-scanned photograph, converted to HTML 5 format
31 July 2021 - Minor changes for clarity