Jangsu-class frigate
| File:ISS Gimonbyun.png FFG Jangsu in 2014 during the Innominadan Crisis
| |
| Class overview | |
|---|---|
| Name: | Jangsu-class |
| Operators: |
 Menghe |
| Preceded by: | Yŏngbok-class frigate |
| Succeeded by: | Yŏngtae-class frigate |
| Cost: | ₩3.9bn ($176 million) |
| Built: | 2009-2016 |
| In service: | 2012-present |
| Planned: | 20 |
| Building: | 8 |
| Completed: | 11 |
| Cancelled: | 9 |
| General characteristics | |
| Type: | frigate |
| Displacement: | 3200 tonnes fully loaded |
| Length: |
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| Beam: | 14.5 m |
| Draught: |
list error: <br /> list (help) 4.42 m to keel, full load |
| Propulsion: |
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| Speed: | 32 knots |
| Range: | 5,000 nm (15,000 km) at 16 knots |
| Complement: | 180 |
| Sensors and processing systems: |
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| Electronic warfare & decoys: |
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| Armament: |
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| Aircraft carried: | 2 × GHJ-28 helicopter |
| Aviation facilities: | hangar and landing pad |
The Jangsu-class is a series of modern frigates designed in Menghe for the Menghean Navy. They are among the most advanced frigates in Menghean service, with state-of-the-art electronics and a reduced-RCS hull design. Although primarily intended to serve in the anti-surface and anti-submarine roles, they also have a fairly resilient self-defense capability in the form of the "Dando" anti-air system which fires the YDG-64 surface-to-air missile.
In 2013, new construction of Jangsu-class frigates was cancelled in favor of the Yŏngtae-class design, a modified Jangsu hull incorporating more capable weapon systems.
Design and Development
The Jangsu is part of the Menghean Navy’s "Fleet for the 21st Century" program. Published in 2000, this project reviewed the MN’s doctrinal design practices and determined that the past decision to focus on overly specialized vessels and neglect RCS reduction had hampered the MN’s combat effectiveness. New warships, the plan suggested, should place a greater emphasis on multipurpose capability while pursuing low-RCS profiles to improve survivability. A new class of warship was to be planned in each major classification category, beginning with the Ri Sun-hŭi class corvette.
In the frigate category, naval designers faced a difficult task. The preceding Yŏngbok-class frigate specialized in air defense and left much to be desired even in that category. Rather than pursuing the narrower goal of a Yŏngbok replacement, however, they instead focused on a new role of outer fleet defense. In this capacity, the new frigate class would not only take on the ASW role of other past frigates, but would also be able to supplement fleet firepower with its own anti-ship missiles, in some respects taking over the anti-surface role of the Chŏndong-class destroyer.
Design
Sensors
Like any modern warship, the Jangsu-class relies heavily on its radar to fight effectively. Initial design studies considered fitting the 21st-century frigate with an AESA radar system, possibly even a multipurpose one which could handle missile guidance as well as detection. In the end, however, this was passed up in favor of a conventional rotating array in light of the ships’ intended role. The main radar chosen for the ship is the HR-2000, common on newer Menghean naval vessels. It is mounted atop a mainmast 24 meters above the waterline, extending the radar horizon out to 26 kilometers against an anti-ship missile skimming two meters above the surface. Above the radar horizon, it is rated as having a 280-kilometer detection range against fighter-sized targets. A secondary radar system, MTH-1200, improves detection at closer ranges and can serve as a backup system if the MTH-2000 is damaged.
For anti-submarine warfare, the Jangsu sports a highly sensitive sonar bulge under the bow, with a longer towed sonar array carried in the stern to detect targets below the thermocline. Both of these sonar sets incorporated Dayashinese electronic manufacture experience, and the Menghean Navy rates them as much more effective than previous Menghean sonar sets in both active and passive detection.
In the area of electronic warfare, the class sports two J220 ESM domes and four J250 ECM domes, as well as four smoke and chaff dispensers to shield the ship from radar and infrared seekers. In continuation of earlier practice, it is also equipped with signal lights and microwave-band antennas to allow more secure communication while operating under radar and radio silence.
All internal electronics in the Jangsu are hardened against the induced voltage forces from an electromagnetic pulse, ensuring that ships of the class will suffer only brief electronic inactivity if subjected to a high-altitude nuclear detonation over or near the fleet.
Armament
Jangsu’s main armament consists of thirty VLS cells, twenty in a 5x4 aft array and ten in a 5x2 forward array. Unlike previous Menghean VLS systems, which were specialized around a single missile family, these VLS systems are designed for compatibility with multiple missile loads, depending on the depth of the cell array. They are also hot-launch rather than cold-launch; while previous Menghean warships used pressurized air to propel the missile from its tube, in the Jangsu the missile is launched under its own thrust, with the exhaust vented down a central hatched shaft running between rows of missiles.
Due to their 4.1-meter depth, the forward VLS cells are thus far only compatible with the YDG-64 surface-to-air missile or the DJSH-4 anti-submarine standoff weapon. In practice, however, they are almost always used with the YDG-64, as longer ASW standoff missiles can be launched from the aft VLS cells. The YDG-64 has a maximum range of 28 kilometers, more than twice the range of the YDG-33 it replaced. It can also be quadpacked into the VLS cells, allowing for a load of 40 missiles when all forward cells are used. The ship is built with four radar illuminators for this system, one at each corner of the main superstructure; each uses an AESA array for beam steering and can guide up to four missiles at once.
In addition to carrying the anti-submarine DJSH-4, the 6.1-meter-deep aft cells can also carry the YDH-29 anti-ship missile or the YJJ-52 land-attack cruise missile, both of which have a maximum range of 500 kilometers. On most ships, eight additional box launchers for the YDH-28 AShM are also fitted, allowing the frigate to engage lighter vessels while reserving the YDH-29s for more valuable targets. Likewise, the DJSH-4 is supplemented by six 400mm torpedo tubes in three fixed mounts on each side, which can be used to engage submarines at close range. These tubes can be reloaded from inside the ship. The final line of anti-submarine defense comes from two DJSR-300 launchers, each with six 300mm tubes for rocket-propelled depth charges. Ammunition options include homing charges and noisemaker torpedo decoys.
Gun armament consists of a single 100mm gun in a low-RCS automated turret. This weapon can engage surface targets out to a range of 20 kilometers, and aircraft and missiles out to a range of 7 kilometers. It has a rate of fire of 60 rounds per minute, with a total of 350 rounds stored in the magazine. Fire control is provided by a radar set just above the bridge, though there is also a backup electro-optical targeting system on the gun turret itself.
For close-range protection from anti-ship missiles that have not been intercepted by the YDG-64 system, the Jangsu class carries two 30mm CIWS guns, designated GBM-30/6TH. Both of these are fully self-enclosed systems, with the fire control radar mounted atop the gun turret. They also have electro-optical aiming systems, which can be used as a backup option in situations of heavy radar jamming. In the event of a swarming attack by light craft, the electro-optical cameras can also be used in manual mode to engage surface targets, in which case the rate of fire is reduced to 300 rounds per minute from its standard level of 4,000. Additional close-in missile defense is provided by two "Bŏdŭl" SAM systems, each carrying twelve YDG-61 IIR-guided missiles.
In the event that the 30mm guns are insufficient or restricted by rules of engagement, defense against light craft and boarding attempts is provided by four 12.7mm GCh-75 machine-guns, one at each corner of the superstructure.
Two projected sound systems are also mounted, to hail other vessels at range or repel light craft without resorting to gunfire. Counter-piracy efforts along the coast of the Republica Innominada prior to the Menghean invasion found that the Menghean-designed model of projected sound system was less effective than had been expected, and in early 2016 it appeared that the device had been removed from several Menghean warships including Jangsu-class frigates. Speculation exists that the Menghean Navy is developing a larger and more capable array.
Propulsion
Like many Menghean warships, the Jangsu is propelled by a combined gas-diesel powerplant, to balance efficient cruising with high-speed sprints. At full speed it can reach 32 knots, faster than many other contemporary frigates, an important feature when relocating quickly to keep up with a new threat axis. While running on the diesels alone it can reach 18 knots.
Unlike most of its predecessors, however, it uses a CODLAG rather than a CODOG arrangement: at these high speeds, the diesel-electric drive runs in tandem with the gas turbines rather than switching off. In the past this option was avoided where possible because it required a complex and potentially unreliable gearing system, but on the Jangsu designers chose it in order to save weight, space, and gas turbine fuel. Furthermore, rather than being directly hooked up to the propeller shafts, the diesel engines are mounted separately on generators which power a pair of electric motors.
One advantage of this diesel-electric drive is that it allowed the designers to decouple the diesel engines from the driveshaft, mounting them instead on submarine-type mounts to reduce the amount of vibration transmitted to the rest of the hull. This allows the ship to operate at a greatly reduced noise level while cruising, making it harder for submarines to track it on passive sonar during ASW patrols. An active noise-masking system is also fitted on the hull sides and propeller to reduce cavitation noise and impede classification by enemy submarines.
Aircraft
First-batch Jangsus have an aft landing pad with side-by-side hangar facilities to house and service two small helicopters. Normally this consists of the GHJ-28, the Navy’s multipurpose helicopter, which can perform surface scans with a nose-mounted radar set or anti-submarine patrols with a dipping sonar and a sonobuoy dispenser in the rear hull. It is fitted with two side pylons on stub wings, which are typically used to carry 400mm torpedoes taken from the same magazine as the ship’s fixed torpedo tubes. Depending on the mission, other possible loads include rocket-launched standoff ASW torpedoes, anti-ship missiles, anti-ship missiles, a 32mm autocannon, or standard depth charges.
The landing pad itself was built large enough to support the Dym-38 tiltrotor, which is used for larger-area ASW work. The Dym-38 is too large to fit within the small GHJ-28 hangars, however, and it can only perform rearming, refueling, and basic repair aboard the Jangsu’s landing pad. Typically, these frigates would be used as range-extending stops for Dym-38s based off of a larger ASW carrier or cruiser.
Role
Although it is officially described as a "multirole" frigate, the Jangsu-class is actually designed around a more limited spectrum of capabilities. In general, it is intended to serve as the outermost ring of defenses for a larger surface battlegroup, which could be centered around an aircraft carrier, a landing ship, or a pair of offensive guided-missile cruisers. Its main duty in this role would be to screen for submarines attempting to infiltrate the battlegroup defenses. It can also supplement fleet missile strikes from its aft VLS tubes, which are deep enough to carry the intermediate-range YDH-29 and its land-attack cousin YJJ-52. Its anti-air suite is formidable from a self-defense perspective, in anticipation of the likelihood that the fringe of the fleet will come under attack first, but at 28 kilometers the range of the YDH-64 SAM is still too short for the area defense needed to protect an aircraft carrier.
Service
Multiple Jangsu-class frigates took part in Menghean operations during the Innominadan Crisis in the late summer and early fall of 2014. They played a pivotal role in Operation Mist Lake, the Menghean Navy’s campaign to render the remaining portion of the Innominadan navy ineffective early in the war. During this operation, two Jangsu-class frigates were subjected to Anti-Ship Missile attack, and both managed to intercept the missiles from range using their YDG-64 SAM systems. After this initial operation, Jangsu-class frigates took part in cruise missile strikes on high-value targets in support of Army forces moving up the coast and Marine Infantry task forces landing further south.
In a comprehensive report published in the summer of 2015, the Menghean Navy reviewed all naval engagements in the wartime period and concluded that the Jangsu-class frigate had performed its tasks effectively in operations against the old Innominadan regime. Critics allege that the report distorted many of its findings as part of the Navy’s effort to secure funds for more warships, and that the state of the Republica Innominada after its government’s collapse but before the invasion prevented hostile warships from making a coordinated response.