Haeju-class destroyer
 4-view of HJ-364 Haeju as built
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| Class overview | |
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| Name: | Haeju class |
| Operators: | Menghe |
| Preceded by: | Pyŏng'an-class destroyer |
| Succeeded by: | Insŏng-class destroyer |
| Subclasses: | Onju-class destroyer |
| Built: | 2003-2017 |
| In service: | 2006-present |
| Planned: | 20 |
| Completed: | 20 |
| Active: | 19 |
| Lost: | 1 |
| General characteristics Haeju, as built | |
| Type: | Guided missile destroyer |
| Displacement: | 7,700 tonnes full load |
| Length: |
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| Beam: |
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| Draught: | 6.08 m to keel, full load |
| Propulsion: | |
| Speed: | 33 knots |
| Range: | 4,600 nm (8,500 km) at 20 knots |
| Boats & landing craft carried: | 2 × RHIB |
| Complement: |
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| Sensors and processing systems: | |
| Electronic warfare & decoys: |
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| Armament: |
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| Aircraft carried: | 2 × GH-28 helicopter |
| Aviation facilities: |
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The Haeju-class are a group of guided missile destroyers built in Menghe during the 2000s and 2010s. Modeled after the Dayashinese Yamazaki-class guided missile cruisers, they incorporate a number of features licensed from Dayashina, including the Suijin Combat System, the Mark 41 Vertical Launching System, and a COGAG powerplant using four Glasic General Electric LM2500 turbines. The ship design, however, is Menghean in origin, and it incorporates a number of Menghean weapons, including the Type 102 130mm gun turret and two Subisu combined gun-and-missile defense systems.
Under the Menghean Navy's hull classification scheme, the Haeju-class are classified as "main escort ships" (주력 호위함 / 主力護衛艦, Juryŏk Howiham). They are primarily tasked with protecting surface formations against air, sub-surface, and surface threats, with a focus on the former two. The multipurpose Mark 41 VLS, however, allows greater flexibility in the range of possible missions, including land attack and anti-shipping attack. The Haeju class also incorporate a small Brigade command facility to direct the operation of two to four smaller ships, such as frigates or anti-surface destroyers.
The last four ships in the class were built to a modified design with a more advanced sonar system, a larger superstructure, and a different hangar arrangement. They are known as the Onju class.
Development
Menghe commissioned its first "modern" guided missile destroyer, the HJ Pyŏng'an, in 1999. While the ship represented a major improvement over previous Menghean naval air defense capabilities, it was still hindered by a number of shortcomings, including poor RCS reduction, inadequate radar systems, and an inflexible vertical launch system which did not allow the loading of different missile types. To correct these issues, the Menghean Navy reduced the original eight-hull order to four hulls and commissioned a series of design studies on a family of next-generation warships. The resulting "21st Century Fleet" resulted in the Haeju-class destroyer, the Yechŏn-class frigate, and, after a longer delay, the Mirun-class corvette.
With the resolution of the Renkaku Islands dispute in 2001, Menghe improved its relations with Dayashina, which agreed to loosen export restrictions on a range of military technologies including the Suijin Combat System and AN/SPY-1 radar family. The Menghean Navy's design team proceeded to incorporate a number of these technologies into the developing 21st-century destroyer, resulting in development delays. The first ship, HJ Haeju, was laid down on 7 December 2003 at the Gyŏngsan Songsu-do shipyard.
Design
Vertical launch system
The main armament of the Haeju-class destroyers is a Mark 41 Vertical Launching System with twelve 8-cell modules, eight forward at deck level and four aft between the hangars. All use strike-length modules, and can accept a wide variety of missile types. The use of a multi-mission hot-launch vertical launch system grants the Haeju-class increased flexibility over the Pyŏng'an-class, which could only carry long-range anti-air missiles in their rotary launch cylinders.
A typical escort loadout in the mid-to-late 2010s might consist of:
- 12 × HŎ-3 Ryongorŭm anti-submarine rocket
- 48 × YDG-60 long-range anti-air missile
- 16 × YDH-28 anti-ship missile
- 8 × SY-28 or SY-52 land-attack cruise missile
- 48 × YDG-64 medium-range anti-air missile (quadpacked, 12 cells)
Other armament
Gun armament consists of a single Type 102 130mm turret forward. While capable of firing timed-fuse anti-air shells, it is most useful in the coastal bombardment role.
Close-range defensive armament consists of two Subisu CIWS mounts, one at each end of the superstructure. Each mount combines two rotary 5-barrel 23mm autocannons with eight YDG-61 infrared-guided missiles, with 24 missile reloads in a below-deck magazine. The Subisu system is also capable of targeting surface ships with its electro-optical camera system, eliminating the need for dedicated anti-surface autocannon armament.
In place of the heavy 533mm torpedo tubes present on the Pyŏng'an-class, the Haeju-class carry two twin 350mm torpedo launchers, one on each side. These are located behind metal roll-down doors to protect them from the elements and reduce the ship's radar cross-section. A magazine at the waterline contains 48 YŎ-35/2 torpedoes as reloads. A centerline elevator lifts individual reload torpedoes to deck level on a cart, which the crew can then manuever behind the launchers to reload. Torpedoes from this magazine can also be used to re-arm the helicopters.
Additional anti-submarine armament comes in the form of two HBDJ-21/12 mounts on the forward deck, flanking the pedestal for the Subisu CIWS. Each of these can launch twelve 21cm rocket-propelled depth charges to a range of 4000 or 6000 meters, depending on ammunition type. Both programmed-depth and terminal-homing anti-submarine projectiles can be carried, and later development introduced softkill and hardkill anti-torpedo countermeasures. As the 350mm torpedo tubes and vertically launched anti-submarine missiles are more effective, by the mid-2010s most Haeju-class destroyers only carried torpedo countermeasure ammunition in their HBDJ-21/12 launchers.
Powerplant
For propulsion, the Haeju-class destroyers rely on four LM2500 gas turbines in a COGAG arrangement. Two turbines are connected to each propeller shaft, allowing the ship to run power options that range from a single turbine on one shaft for efficient cruising or all four turbines at once for maximum speed. The paired turbines are located in separate engine rooms forward and aft of a central auxiliary machinery space, and the ship's hull is divided by seven watertight bulkheads consisting of spaced hardened steel plates with flame retardant material in between. These help contain flooding in the event of damage below the waterline, limit the spread of fire through the ship, and reduce the damage to other compartments from shrapnel resulting from a missile impact.
Auxiliary power comes from five Taesan T1SJ diesel generators, each producing 1600 kilowatts of electricity. One auxiliary generator is located in each main engine compartment, one is located far astern under the helicopter hangar, and two are located side-by-side under the bridge area forward of the forward engine room. Like the distribution of the gas turbines, the distribution of the diesel generators across four separate watertight sections limits the probability that a single missile impact will cut power to all areas of the ship. The electrical equipment is also divided across two rooms, each of which can manage all the ship's systems if the other is damaged.
Aircraft facilities
The aft hangar structure can accommodate two GH-28 helicopters. Typically, each ship carries one GH-28R anti-submarine helicopter and one GH-28B airborne early warning helicopter, or even two GH-28Bs with anti-submarine helicopter duties falling to other ships in the formation.
Onju subclass
The last four ships in the class, starting with HJ-380 Onju, were built to a modified design, and the Menghean Navy treats them as a separate ship class. The most prominent change is the rebuilding of the quarterdeck to support the Ŭ-100 variable-depth sonar, also used on the Chunchŏn-class frigates. Because the Ŭ-100 is a variable-depth sonar set with a large finned section, it required the addition of an extra deck in the stern of the ship, as well as more sonar processing equipment.
This, in turn, raised the helicopter landing area by a single deck. Raising the hangars by one deck would have blocked the two aft-facing AN/SPY-1 arrays, and changes to the arrangement of AN/SPY-1 panels, though considered, were deemed too extensive to be feasible within the same class. Instead, the designers revived a solution used on the Ginam-class frigates and Hyŏngnam-class destroyers: a helicopter hangar recessed one deck into the ship, with a retractable roof and an internal ramp leading to the flight deck. Though cramped and inconvenient, this semi-recessed hangar allowed the hangar roof to stay at the same level, and maintained adequate clearance aft of the phased array panels.
The designers also expanded the superstructure to enclose the rigid-hulled boats inside hangar structures. The starboard RHIB bay opens directly over the water, while the port bay has deck rails to move the crane the extra two and a half meters to the edge of the deck. These changes added 600 tonnes to the ship's displacement, so to compensate, the designers added a lipped structure on the rear of the hull to reduce drag. Similar structures were later retrofitted to the other Haeju-class destroyers during scheduled maintenance periods.
Other changes were applied to the ship's electronics mast. In place of the previous JJ-6/7 electronic warfare suite, the designers installed two JJ-9 combined ESM/ECM modules, one on each side. The D-105 datalinks were retained, but relocated. Two JJ-7 ECM antennas were also retained, seemingly confirming that the JJ-7 is compatible with the JJ-9 as well as the JJ-6 ESM dome.
Amidships, the Baram-1 chaff and smoke pods were replaced by Baram-2 modules, which use small pyrotechnic charges rather than solid-fuel rockets to deploy their payloads. This change was also applied to the existing Haejus during refits, though the Baram launchers were kept at their original locations on the smaller asymmetric superstructure.
Operational service
One-Month War
Three Haeju-class destroyers sustained damage during the One-Month War, and one was sunk.
HJ-370 Ranju, approaching the north coast of Isla Diamante as the lead ship of the 41st Escort Brigade, was one of the first Menghean warships to see action in the conflict. Mere minutes after the outbreak of hostilities, she came under attack from eight subsonic anti-ship missiles fired by an Avante 2200 frigate, intercepting all of them with a mix of YDG-66 and YDG-61 missiles. She also contributed to the interception of cruise missiles and Lancea SRBMs fired from Isla Diamante at Menghean naval installations in Quang Pha. After fending off these attacks, Ranju moved closer to Isla Diamante to provide naval gunfire support while also searching the area for suspected Sieuxerrian submarines.
HJ-366 Dongchŏn and HJ-376 Pungsu both accompanied the Insŏng-class destroyer Chilsan on her failed raid against Portcullia, along with the Chŏndong-class destroyers Josu, Dolpung, Ho-u, and Ilchul. Dongchŏn was hit by a torpedo at 2011 hrs Menghean time on 11 April 2022, but her crew were able to contain the flooding to her forward compartments, and she limped back to Puerto Alegre under her own power. HJ-376 Pungsu suffered a torpedo hit from a different submarine several hours later at 2355, splitting in two amidships and sinking rapidly. The destroyers Josu and Dolpung both came alongside the wreckage to pick up survivors; Josu herself was later sunk with the loss of all hands.
HJ-365 Anchŏn was part of the engagement known as the Battle of Cape Valdes on 12 April 2022, the second day of the war. At 1032 hrs Menghean time Anchŏn detected a SLAM missile passing nearby and engaged with a YDG-60 missile. Either the SLAM datalink or the SAM launch revealed Anchŏn's location, and at 1218 hrs four Typhoon GR4 fighters released MM80 missiles against Anchŏn from low altitude. Anchŏn detected the incoming missiles at 1229 using passive sensors and was able to engage, claiming six shootdowns with YDG-64 missiles, seven with YDG-61 missiles, and one by CIWS fire. Possibly due to jamming or guidance error, one MM.90 overshot the ship's bow, and another, cruising at 10 meters above the waterline, impacted the aft funnel and exploded after punching through. This ruptured the uptakes and disabled the aft STIR 2.4 guidance unit, but otherwise left the ship operational. A damage control report filed at 1240 hours reported that the powerplant, hangar, armament, and sensors were all operational, but recommended powering down the aft turbines and generators to reduce smoke ingestion into the intakes. Later in the afternoon, Anchŏn shot down a Sieuxerrian Rafale fighter using a salvo of two YDG-62N missiles, but only after the Rafale shot down one of Anchŏn's GH-28M1 airborne early warning helicopters.
On 13 April 2022 at 1754 hrs Menghean time, still patrolling north of Isla Diamante, HJ-370 Ranju detected a seabed anomaly and conservatively identified it as a bottomed-out submarine. The captain of the Ranju, expecting a short-range search with a fast reaction time, had earlier ordered that the ship's HBDJ-21/12 launchers be loaded with H-21NS anti-submarine homing projectiles, and Ranju engaged the target with a focused barrage. For unknown reasons, the fast-sinking projectiles did not destroy the submarine, possibly because they were unable to distinguish it from the seabed on which it rested. The submarine reacted by firing a heavyweight torpedo against Ranju. Detecting the torpedo launch, Ranju fired a YŎ-35/2 torpedo at the submarine and began evasive maneuvers. With her HBDJ-21/12 launchers loaded with anti-submarine munitions, she was unable to fire torpedo countermeasures, and several minutes later she sustained heavy damage from a torpedo blast. A damage control report filed at 1908 reported that the forward engine compartment was flooding, but other watertight compartments were intact; to avoid worsening the flooding with fast movement, she proceeded north to Quang Pha at a reduced speed of 6 knots, arriving in port on April 16th in the early hours of the morning.
In Quang Pha, HJ-370 was taken into a reserve drydock, where engineers drained the flooded compartments and confirmed the extent of the damage. The Navy's initial plan was to keep the ship in drydock until the end of the war, or perhaps arrange for a heavy-lift ship to transport her to another location; but as Maverican forces closed in on Quang Pha in the following days, Navy leaders decided to change their plans and bypass normal procedure to get the ship out of harm's way. With no time to patch the breaches in the hull, base workers instead rushed to weld shut any doors or vents into the breached spaces, and on April 22nd, HJ-370 Ranju was released from her drydock on a voyage east at reduced power. She arrived in Dongchŏn on April 26th, and was again drydocked for maintenance. This time, inspection revealed that several joints around the watertight double bulkheads had cracked while the ship was flooded and underway, and ruptures at any of the stressed areas could have flooded the aft engine compartment and sunk the ship. Subsequent repairs were put on hold.
Ships in the class
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