200mm L/50 Type 25 naval gun
| 200mm L/50 Type 25 | |
|---|---|
| Type | Naval gun Coastal defense gun |
| Place of origin | Menghe |
| Service history | |
| In service | 1930-1945 |
| Used by | Menghe |
| Wars | Pan-Septentrion War |
| Production history | |
| Designed | 1925 |
| Produced | 1926-1931 |
| Specifications | |
| Weight | 27.9 metric tons |
| Length | 10.367 m (34 ft 0.1 in) |
| Barrel length | 10 m (32 ft 10 in) 50 caliber |
| Shell weight | 117.2 kg (258 lb) |
| Caliber | 200 mm (7.9 in) |
| Breech | Welin breech block |
| Rate of fire | 3 rpm |
| Muzzle velocity | 895 m/s (2,940 ft/s) |
| Maximum firing range | 29.8 km (18.5 mi) at +45° |
The 200mm L/50 Type 25 naval gun was a Menghean naval gun designed in the early 1920s. Initially intended for a class of 4-gun scout cruiser which never materialized, it was later carried by the Ryangju- and Madaesan-class heavy cruisers, and by coastal batteries on land. Subsequent Menghean heavy cruisers used the 200mm L/55 Type 32 naval gun.
Description
These guns used built-up construction and a Welin breech block. The breech block was manually operated and swung to the side, outward from the centerline of the turret. The charge consisted of two cloth bags of smokeless powder loaded separately from the projectile. Barrel life was approximately 300 rounds.
Ammunition
| Designation: | Type 25 200mm AP | Type 25 200mm HE |
|---|---|---|
| Type | Armor piercing | High-explosive |
| Projectile weight | 117.2 kg (258 lb) | 102.6 kg (226 lb) |
| Bursting charge | 2.2 kg (4.9 lb) | 7.4 kg (16 lb) |
| Muzzle velocity | 895 m/s (2,940 ft/s) |
Turret mountings
The Ryangju-class cruisers used compact twin mountings, with the guns mounted close together in a shared cradle to reduce weight and save space. This was found to increase dispersion, as the muzzle blast from each gun interfered in the adjacent shell's trajectory. It also somewhat complicated loading procedures. The Madaesan class introduced the larger Type 29 twin mounting, which increased the distance between guns by 40cm and allowed for separate elevation and firing of each barrel. The Type 29 mounting also incorporated improved ammunition handling equipment, resulting in a faster rate of fire. Because both turrets loaded at a fixed angle, rate of fire was lower at high elevations. Another difference between these mountings was their maximum elevation, 35 degrees on the Ryangju class and 40 degrees on the Madaesans. This resulted in the Madaesans having a slightly longer maximum range. Neither turret was designed for anti-aircraft use.
| Designation: | Type 26 twin | Type 29 twin |
|---|---|---|
| Used on classes | Ryangju | Madaesan |
| Guns per turret | 2 | 2 |
| Cradle | Shared | Separate |
| Elevation | -7 to +35° | -5 to +40° |
| Elevation rate | 6°/s | 12°/s |
| Train | ±150° | A,X,Y: ±150° B: ±146° |
| Train rate | 6°/s | 4°/s |
| Loading angle | Fixed; +7° | Fixed; +5° |
| Rate of fire | 1.5-2.5 rpm | 3-5 rpm |
| Rounds per gun | 140 | 160 |
| Armor | Face: 100mm Sides: 75mm Roof: 75mm Rear:75mm Barbette:75mm |
Face: 175mm Sides: 75mm Roof: 75mm Rear: 75mm Barbette: 150mm |
| Local rangefinder | 6 m (20 ft) | 7 m (23 ft) |
Coastal defense battery
The Menghean Navy initially planned to procure a large number of these guns for use in coastal defense batteries along Menghe's east coast facing Dayashina. After relations with Dayashina improved in the late 1920s, however, most of these orders were cancelled. Guns already purchased were either placed in storage as spares or installed in a small number of emplacements around naval bases on the south coast.
The coastal defense mounting was a single gun on a rotating platform, intended for use in caves or concrete bunkers. Loading was by manual ramming, with a small crane on the base platform to lift the shells and charges onto the loading tray. Traverse and elevation controls were also manual. These mounts were manpower-intensive but relatively inexpensive to install and maintain.