Chŏndong-class destroyer

3-view diagram of Chŏndong as built
Class overview
Builders:	see below
Operators:	Menghe
Preceded by:	Nunbora-class destroyer
Succeeded by:	none
Built:	1982-1995
In commission:	1985-present
Completed:	14
Lost:	2
General characteristics (as built)
Type:	Destroyer
Displacement:	3,300 tons standard 4,540 tons full load
Length:	128.7 m overall 119.1 m at waterline
Beam:	13.1 m at waterline
Draught:	1.73 m
Draft:	4.87 m to keel
Propulsion:	steam turbine propulsion 4 high-pressure boilers 75,000 shp
Speed:	34 knots
Range:	4,000 nautical miles (7,400 km) at 18 knots
Complement:	20 officers 223 enlisted crew
Sensors and processing systems:	2 × HR-210 air-search radar HR-280 surface-search radar Ŭ-12 hull sonar
Electronic warfare & decoys:	2 × JJ-5 ECM antenna
Armament:	1 × HP-130/2 Type 82 dual 130mm turret 8 × YDH-23 anti-ship missile 2 × 8 YDG-36 surface-to-air missile (24 reloads) 4 × GBM-30/6 CIWS 2 × RBU-6000 depth charge launcher 2 × 3 450mm torpedo tube 120 mines

The Chŏndong-class destroyers were a group of fourteen warships built in Menghe during the 1980s and early 1990s. They are designed around anti-surface warfare, carrying a heavy main battery of eight YDH-23 anti-ship missiles and a HP-130/2 Type 82 twin 130mm main gun. Their anti-aircraft armament, however, is limited to short-range point defense, and their anti-submarine armament is also relatively weak. Ships of the class have no helicopter facilities, and are entirely reliant on land-based aircraft or aircraft from nearby warships for targeting.

Owing to their small size and lack of helicopter facilities, the Chŏndong class are sometimes described as frigates. A few foreign intelligence services have remarked that in terms of role, they more closely resemble large corvettes. The Menghean Navy officially classifies them as "missile destroyers" (Yudotan Guchugham), in contrast to the contemporary Yobu-class destroyers, which are classified as "escort ships" (Howiham).

Development

The Chŏndong class are direct successors to the Nunbora-class destroyers, which likewise carried heavy AShM and gun armament but had poor anti-air and anti-submarine capability. Menghean naval planners envisioned sending them out in groups of four, led by a Yobu-class destroyer, to launch coordinated missile strikes against enemy carrier battle groups.

Design

The design was primarily the work of Jin Gi-tae, the chief naval architect at the Naval Design Institute. Rejecting earlier proposals that had called for a large and flexible destroyer, Jin insisted on a compact, efficient warship built around a clear mission. This choice was a function of Menghe's military needs at the time: facing two opponents with greater industrial capacity, Jin Gi-tae believed that the only way to balance in national defense was to create a warship that could be produced in large numbers and easily maintained. This meant restricting features and capabilities superfluous to the core mission's needs.

The design went through several iterations, each time decreasing in tonnage. Even smaller versions were considered, sacrificing, for example, the aft surface-to-air missile mount. Other problems concerned the powerplant. Jin Gi-tae originally hoped to install gas turbine propulsion in a CODOG arrangement, for a high maximum speed and fuel-efficient cruising. Technological constraints, however, limited Menghe to the use of a steam turbine plant, which in turn was derived from that on the Yobu class.

Construction

The final iteration of the design, designated Plan 272, was approved for mass production by the MoND, with the first hull laid down in March 1982. Construction was carried out under conditions of considerable secrecy, with the final fitting-out conducted in the city of Wihae rather than Gyŏngsan where the drydocks were located. For this reason, Dayashinese intelligence officials originally labeled the destroyer as the Wihae class.

Construction work was complicated by Menghe's first nuclear test in November 1984, which officially placed Menghe in violation of the STAPNA agreement. Faced with an embargo with its few remaining trading partners, including Polvokia, Menghe encountered delays in securing key components for the hulls still under construction. Economic dislocation under Ryŏ Ho-jun's ill-conceived reforms also disrupted supply chains, even as the Navy fought to limit interference in shipyard operations.

At the same time, the worsening geopolitical situation led the Menghean Navy to launch the Second Emergency Shipbuilding Program, stepping up new orders of Chŏndong-class warships to confront the increasing risk of an enemy attack. The Gyŏngsan 2 drydock, originally intended for cruisers and large destroyers, was appropriated for Chŏndong construction, and the Kimhae Naval Yard took on additional orders. Some documents from the period suggest that the DPRM intended to build a total of 25 Chŏndong-class warships, more than any postwar destroyer class.

After the Decembrist Revolution, the Second Emergency Shipbuilding Program was slowed down, and the military budget was decreased. The eight ships which remained in various states of construction in 1988 were completed on a reduced schedule, and three additional ships were laid down after 1989, all of them at Gyŏngsan. Later construction included careful inspections for faulty parts installed during rushed building, and both Chŏndong and Swaejŏn were drydocked in 1989-1990 to identify and replace faulty parts and welds. The basic design, however, was not modified during this stage, though there was some discussion of building the last two ships with helicopter facilities.

Description (as built)

Main armament

As built, the Chŏndong-class destroyers carried a powerful forward-facing battery of eight YDH-23JG "Yusŏng" anti-ship missiles. A surface-launched derivative of the Letnian KSR-5, the YDH-23 follows a quasi-ballistic trajectory toward the target, climbing to an altitude of 25 to 30 kilometers before descending at a terminal speed of Mach 4. While it has a maximum range of 280 kilometers when air-launched (500 kilometers for improved variants), the surface-launched variant has a range of only 200 kilometers due to the loss of fuel while ascending through denser low-altitude air.

Readying these missiles for launch could take over two minutes, a longer time than on Letnian warships, with an additional 15 seconds between ready status and launch. The launchers themselves could only fire missiles at 10-second intervals, but this could be reduced to 5 by alternating between port and starboard batteries. Total time to fire a full salvo was in theory just 40 seconds, but could be longer with a less prepared crew. The missiles could only engage targets 30 degrees to either side of the bow, requiring the ship to face toward its target during the launch phase.

Other armament

Gun armament consists of a single HP-130/2 Type 82 twin 130mm gun mount. This weapon system was designed specifically for the Chŏndong class, and boasts improved traverse performance and a higher rate of fire than the SM-2-1 mount on the Nunbora class. It is capable of engaging ships, land targets, aircraft, and incoming anti-ship missiles, using contact, timed, or proximity fuses. Special guided rounds and submunition rounds were also later introduced.

Close-range gun armament consists of four AK-630 CIWS guns, two on each side. The forward pair are slightly further outboard than the aft pair, allowing both mounts to fire directly aft. Combined with the superstructure layout, this arrangement also creates a blind spot in CIWS coverage at 15 degrees to either side of the ship's prow. Air defense over this arc depends entirely on the main gun and surface-to-air missiles.

The surface-to-air missile armament, like the gun mount, was designed specifically for the Chŏndong class. Originally, it consisted of two launch modules for the YDG-36 surface-to-air missile. Each module consists of an eight-box launch unit, plus 24 reload missiles stored below deck. Each mount can cover a 270-degree arc, resulting in full 360-degree coverage with overlapping coverage to either side. Each mount carries a combination of radar-guided and infrared-homing missiles, for greater redundancy against countermeasures, jamming, and poor atmospheric conditions, and each of the four radar illumination antennas can guide two missiles toward one target at maximum. Post-launch trials and operational service revealed that the YDG-36 had very poor accuracy and reliability, and during refits these mounts were replaced with the Subisu combined-gun-and-missile CIWS.

Anti-submarine armament consists of two three-tube 450mm torpedo launchers, one on either side of the forward funnel. Sources disagree on whether reloads are usually carried. Further aft are two RBU-6000 depth charge rocket projectors, which can also throw sonar decoys to distract incoming homing torpedoes. Because the ships lack any kind of variable depth sonar, they cannot detect submarines below the thermocline except at very short ranges, and their anti-submarine weapons are purely intended for self-defense.

Sensors and electronics

The first group of Chŏndong-class destroyers (Chŏndong through Bŏmram) were fitted with two HR-210 3D air search radars, one on each mast. The two-radar layout, also present on the Nunboras, was intended to provide a measure of redundancy in the event that one radar is damaged in battle or taken down for maintenance. On Hongsu onward, these are replaced by HR-270 3D search radars, a licensed version of the MR-710 Fregat ("Top Plate") radar on Letnian ships. The new radar type was also fitted to the early-production hulls during their mid-life refits.

Atop the bridge is a more impressive HR-280 surface search radar, located inside a large radio-transparent dome. This J-band system exploits atmospheric ducting to detect surface targets beyond the regular radar horizon, and has both active and passive modes. Its long range allows the Chŏndong class to generate firing solutions for the YDH-23 anti-ship missile even without support from aerial reconnaissance aircraft, though such aircraft would normally be part of a coordinated strike operation.

The ships' only sonar equipment is a single "Plamina-S" antenna in a bulge under the bow. The ships carry no variable-depth or towed-array sonar, and cannot embark helicopters for area search operations.

A modest electronic warfare suite with two active jamming antennas provides defense against incoming anti-ship missiles. There are also two amidships chaff-and-smoke projectors to interfere in missile guidance systems; these were upgraded during refits as well.

Refits

Several major refit configurations exist for the Chŏndong-class destroyer, depending on the year in which they were rolled out. All share certain characteristics, but others differ between ships. Some ships, such as the early group, also went through multiple rounds of refits.

First round: YDH-25

Chŏndong entered refits in early 2000, fifteen years after her commissioning. In addition to an overhauled powerplant, new air-search radars, and new electronics, she also received YDH-25 missile launch tubes in place of her initial missile armament. Though it has a shorter range, a lower speed, and a smaller warhead, the YDH-25 can follow a sea skimming trajectory all the way to the target, making it harder to detect and intercept. Later Menghean variants of the YDH-25 would also boast improved performance, including the ability to perform pseudo-random evasive maneuvers on the final approach.

Apart from these revisions, the ships' basic armament remained unchanged. The Subisu CIWS system, while in development, was not yet operational, nor was the YDG-61 short-range point defense missile. While Tír Glas had recently authorized the sale of the Mk 41 VLS to Menghe, the Chŏndong's guidance radars lacked the range to support the YDG-60 or YDG-62 SAMs, and the ship's short-range sonar would have limited the effectiveness of the HŎ-3 Ryongorŭm rocket-deployed torpedo. The YDG-36 missile launcher did receive new ammunition (YDG-36D and YDG-36R), though these missiles are reverse-compatible with the existing launcher's electronic systems and were reportedly deployed aboard other ships in 1996.

The following ships were refitted to this standard, listed by the year they completed their refits:

• Chŏndong (2001)
• Donghan (2002)
• Swaejŏn (2003)
• Pado (2004)

Second round: YDH-25 and Subisu

In 2003, the Subisu CIWS completed at-sea evaluation and was approved for operational service. This prompted the Navy to modify its refit plans for the next group of vessels. Pado was already too close to completion to be fitted with Subisu mounts, so the next ship to begin rebuilding, Pungrang, became the first hull completed in the new arrangement.

In addition to the installation of YDH-25 launch boxes, Pungrang and the ships that followed her were refitted with Subisu CIWS mounts fore and aft, in place of the YDH-36 SAM launchers. The Subisu system was designed to take up the same amount of volume below deck as the YDH-36 magazine, allowing for easy installation. In the course of this refit program, the port and starboard GBM-30/6 mounts and their fire directors were removed, as they had become redundant. The newly acquired space was converted into crew quarters, improving morale on what was originally a cramped design.

The following ships were refitted to this standard, listed by the year they completed their refits:

• Pungrang (2004)
• Bŏmram (2004)
• Hongsu (2005)
• Josu (2006)
• Ubak (2006)
• Ilchul (2006)

Service

During the Ummayan Civil War, Chŏndong-class destroyers played a prominent role in the Battle of the Aqaba Sea.

In the fighting that followed, two Chŏndong-class destroyers in the task force were lost. The Bŏmram succumbed to air-launched anti-ship missiles on the afternoon of the 14th, while the Noesŏng was damaged in the aerial attack yet remained afloat. Despite damage to the rear superstructure, she was able to retreat under its own power, but began experiencing engine problems overnight. During the early dawn hours of March 15th, Noesŏng was struck by a torpedo from an Anglian submarine, and split in half directly beneath the funnel. As all ships in the formation were maintaining radio silence, and the captain had no time to send a distress signal, the ship's loss went unnoticed among the ships further ahead until 1103 hours when a patrol helicopter sent from the Migi failed to locate her.

Later on the 15th, a Dayashinese destroyer arrived to pick up the survivors. This move was a major step in cementing Menghe-Dayashinese relations. A monument to the Noesŏng was built in the city of Yanggang in 2008, and the captain of the Dayashinese ship was invited to the unveiling ceremony, where he was greeted by the survivors.

The wreck of the Noesŏng today lies within Ummayah's exclusive economic zone, but as a signal of gratitude, the Ummayan government in 2010 allowed Menghean salvage vessels to conduct dives over the ship's hull. The helm, recovered intact from the bridge, was brought to the surface and transported to the monument at Yanggang, after serving as a two-year temporary display in Gyŏngsan. The recovery team also claimed to have brought up the remains of Captain Ho Tae-su, cremating them for use at a Sŏngindan in his hometown of Hwasŏng. Some skeptics have questioned the official explanation of the recovery, charging that the description of Captain Ho "still standing at the helm" was unlikely and that the ashes used were not his.

Ships in the class

Ships in the Chŏndong class are named after weather systems, in keeping with ship naming conventions in the Menghean People's Navy. This again contrasts them with the Yobu-class destroyers (officially escort ships), which were named after Menghean prefectures, and the Pyŏng'ans and their successors, which were named after Menghean cities.