GBM-30/6
| GBM-30/6 | |
|---|---|
| File:Parts Sheet GBM-30-6.png Diagram of the main GBM-30/6 variants. | |
| Type | Close-in weapon system |
| Place of origin |  Menghe |
| Service history | |
| In service | 1975-present |
| Production history | |
| Manufacturer | Haeju Naval Artillery Plant |
| Produced | 1973-present |
| Variants | GBM-30/6SH, GBM-30/6TH |
| Specifications (GBM-30/6) | |
| Weight | 1,800 kg (gun and mount) 1,918 kg (2,000-round belt) 5,700 kg (fire-control radar) |
| Height | 2.28 meters deck to roof |
| Diameter | 2.21 meters below deck |
| Crew | automated with oversight |
| Shell | 30x165mm |
| Shell weight | 832 g |
| Barrels | 6 |
| Elevation | -15° to +80° |
| Traverse | ±180° |
| Rate of fire | 4,000 rpm (maximum) 300 rpm (reduced) |
| Muzzle velocity | 880-900 m/s |
| Effective firing range | 4,000 m |
| Feed system | Belt, 2000 rounds |
| Sights | fire-control radar electro-optical sight |
The GBM-30/6 (abbr. from Menghean 근접 방어 무기, Gŭnjŏb Bang-ŏ Mugi, "Close-range Defensive Weapon," 30mm x 6) is a family of close-in weapon systems developed in Menghe for the Menghean Navy and offered for export in Septentrion. The mounts in the family differ somewhat in their supporting electronics and configuration, and by extension in their range and capabilities, but all are built around a shared 30mm, six-barreled rotary autocannon.
Description
Compared to other close-in weapon systems, the GBM-30/2 is a relatively heavy weapon, in part due to its large caliber, high rate of fire, and large magazine. It also requires below-deck space some 2.59 meters deep for stored ammunition and other supporting systems, in contrast to "bolt-on" CIWS types used by the OSN.
The core of the system is a rotary six-barreled 30mm autocannon. This weapon weighs some 150 kilograms by itself. It can achieve a maximum rate of fire of 4,000 rounds per minute, relying on the ship's own power source to spin up the gun. To reduce overheating, the rotating barrel assembly is encased in an outer cylinder and cooled by water circulated from internal tanks or from the ocean itself. The cartridge fired is an electrically-primed 30x165mm round, license-produced from a round designed in the Federation of Socialist Republics.
Most GBM-30/6 variants, with the exception of the GBM-30/6TH, rely on a separate fire-control system mounted elsewhere on the ship, usually on a mast or platform one or more decks above the mount itself. As on other CIWS weapons, this consists of a radar dish which tracks the targeted missile and the outgoing rounds and adjusts the gun's aim until the two intersect. As a backup measure in environments with heavy electronic warfare, and to allow the targeting of small boats where surface clutter is an issue, the mount itself also incorporates an electro-optical fire-control system in both visual and infrared frequencies. This can either provide video feed to a control screen within the ship, allowing crew members to manually aim the weapon, or automatically produce a firing solution, albeit with less accuracy than the radar-based system would allow.
From 1993 onward, GBM-30/6 systems were refitted to incorporate a second firing mode, in which the gun fires at 300 rounds per minute. This mode is used when engaging surface targets, such as small boats approaching the ship. It eliminates the need for separate autocannon mounts around the deck, though Menghean warships often carry two to four GCh-75 12.7mm heavy machine guns for defense against light craft at the closest of ranges.
Variants
GBM-30/2
Though in many respects a different weapon, the GBM-30/2 served as the origin for the later GBM-30/6, and shares some similarities. Its main armament was a twin-barrel 30mm autocannon using a Gast-style action to achieve a combined rate of fire of 3,800 rpm. A modernized version of this same weapon was later used on the DGJP-230 Jaebongtul. All ammunition and supporting systems were stored within the above-deck turret unit, though additional bracing systems were needed to support the mount's recoil and weight. The mount could be manually operated, with a crew of 2, but it usually relied on a radar-based fire-control system mounted elsewhere on the ship.
The GBM-30/2 was pioneered aboard the first Danhohan-class frigate in 1975.
GBM-30/6
While the GMB-30/2 offered impressive improvements over previous manually aimed Menghean anti-air guns, the Menghean People's Navy nevertheless pursued a new weapon with a faster traverse time and an increased rate of fire, with the aim of improving effectiveness against anti-ship missiles. The result was the first true member of the GMB-30/6 family, with a six-barreled 30mm water-cooled autocannon and extensive below-deck supporting systems.
First introduced in 1978 aboard the first Angae-class destroyer, it was initially seen as a complement for the GMB-30/2, serving only on heavier ships. The GMB-30/2 remained standard on the Dandohan-class frigates until 1983, when the Mussanghan was commissioned with a modified superstructure to support the heavier mount.
GBM-30/6TH
The leading GBM-30 variant currently in widespread production, the GBM-30/6TH (통합된, Tonghabdoen, "integrated") directly integrates the fire-control radar onto the roof of the turret. This eliminates the need for a separate fire-control unit elsewhere on the ship, freeing up more space for other electronics. In all other respects, it is identical to the baseline GBM-30/6, though it mounts the electro-optical camera alongside the radar dish rather than alongside the gun.
Notably, the GBM-30/6TH system still lacks an independent air-search radar of its own, and must instead rely on data fed from the ship's own radar systems to acquire targets.
GBM-30/6SH
This variant, with the suffix SH for Sohyŏng (소형), "compact," is a lighter, more compact version of the GBM-30/6 for use on light vessels such as missile boats and corvettes. It features a reduced-RCS covering and incorporates extensive use of composite materials, as well as a more compact turret and below-deck structure. One sacrifice in this system is a reduced ammunition load, with total stowage decreasing to 1,200 rounds, and a less powerful water-cooling system for the barrels.
