Sŏwicho-class corvette
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| Class overview | |
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| Operators: |
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| Preceded by: | Mugunghwa-class corvette |
| Built: | 1999-2000s |
| In commission: | 2001-present |
| Planned: | 22 |
| General characteristics (Sŏwicho, 2005) | |
| Type: | Anti-submarine corvette |
| Displacement: |
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| Length: |
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| Beam: | 9.95 m at waterline |
| Draught: | 3.05 m to keel |
| Propulsion: | |
| Speed: | 28 knots |
| Range: | 3,200 nautical miles (5,600 km) at 18 knots |
| Complement: |
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| Sensors and processing systems: |
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| Electronic warfare & decoys: |
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| Armament: |
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The Sŏwicho-class corvette is a class of corvette of the Menghean Navy. They were built in the early 2000s as a replacement for the Mugunghwa-class corvettes. They specialize in coastal anti-submarine warfare, though they can also take part in general-purpose patrol missions such as sea policing, fisheries protection, minesweeping, and anti-frogman defense.
Role
In the Menghean Navy's ship classification system, the Sŏwicho-class are classified as small anti-submarine patrol ships (Menghean: 소형 대잠수함 초계함 / 小型對潛水艦哨戒艦, sohyŏng dae-jamsuham chogyeham), abbreviated DChS. This distinguishes them from medium anti-submarine patrol ships (DChJ), like the Ginam-class frigates. It also separates them from the Wang Yŏn-sŏk-class corvettes, which specialize in anti-ship missile attacks and are classifid as large fast missile boats. While Western sources typically group these together as "corvettes," Menghean doctrine assigns each type a different role.
As small anti-submarine ships, the Sŏwicho-class specialize in coastal and inshore anti-submarine warfare. They are designed to operate almost exclusively in the broader littoral zone, only rarely venturing into the open ocean. For this reason, they carry no towed array sonar; at these depths, a towed array has a high probability of becoming snagged on the sea floor. Furthermore, the upper layer of warm water is relatively deep in the tropical waters of the South Menghe Sea, and the East Hemithean continental shelf extends several hundred kilometers out from the shore, creating a large shallow area where the thermocline is not present. Because they mainly operate close to shore, the Sŏwicho-class ships also have relatively low freeboard and a relatively short range.
Sŏwicho-class corvettes are also specialized around anti-submarine missions. They have some anti-ship capability, particularly after the addition of YDH-26 missile boxes, but this armament is only intended for self-defense and pales in comparison to the armament of dedicated fast attack craft. Anti-air armament is also limited to self defense, consisting of a dual-purpose 76mm gun forward and one CIWS mount aft. When operating in high-threat areas, Sŏwicho-class ships are usually paired with anti-air or anti-surface escorts.
Sŏwicho-class corvettes do have limited capability in other undersea roles. Their secondary high-frequency sonar can be used to detect submerged and bottom-profile mines, and their quarterdeck can be modified with minesweeping equipment, including remote-controlled mine disposal drones. Unlike dedicated minesweepers, however, these corvettes have a conventional steel hull. The high-frequency sonar can also be used to detect frogmen and submersibles, both common threats in littoral areas, and the ship can engage these targets with its 220mm and 60mm depth charge launchers.
Design
Sensors
The Sŏwicho-class corvettes are built around a domestic hull sonar, designated Ŭ-19. Little is known about its capabilities, but it is located in a large blister under the superstructure, rather than at the forward end of the hull. There is also a single dipping sonar, of the same type used by the GH-28 helicopter. This is stored behind a spray-proof door in the starboard side of the superstructure when not in use, and can only be deployed when the ship is stationary or moving at a low speed.
Some ships have been spotted with towed array sonar handling equipment on the quarterdeck, with the aft rocket and missile launchers removed to free up space. It is not known whether this is an experimental system, or a purpose-built module which can be installed for deep-water missions.
The built-in sonar array includes a short-range, high-frequency antenna, which can be used to detect mines, divers, small submersibles, and torpedoes.
Air search radar is limited to a single HR-44 antenna in a cylindrical antenna on top of the main mast. This high-resolution I-band antenna is restricted to low-altitude scanning, and can detect surface ships, periscopes, floating mines, sea skimming missiles, and low-flying aircraft. It can also generate firing solutions for the 76mm gun, though the MR-123 fire-control radar over the bridge is more effective for engaging flying targets, especially higher-altitude ones.
Armament
Gun armament consists of a single HP-76/1 gun turret forward. This can engage both surface and air targets. Astern, the ships carry a single GBM-23/5 Bulkkot CIWS turret, making them the first Menghean warships to go to sea with this weapon. The Bulkkot CIWS contains its own target designation radar, with a backup electro-optical targeting system, and can engage surface targets as well as aircraft.
The first group of ships were commissioned with a four-tube YDG-38 missile launcher on the quarterdeck, with 16 missile reloads. This was reportedly uncomfortable to operate in heavy seas, especially as it was manually aimed without assistance from any optics. Ships commissioned from 2006 onward have carried the "Dungji" version of the GBM-23/5 CIWS, with sixteen YDG-61 missiles in non-reloadable boxes. The Dungji-R mount also sports a short-range air search radar, with greater high-angle performance than the sea-level HR-44 on the main mast. Ships completed to this arrangement, or rebuilt to this arrangement, lack the YDG-38 launcher, suggesting that the addition of infrared-homing missiles to the CIWS mount fully replaces it.
Anti-submarine armament consists of two HBDJ-21/12 rocket launchers on the foredeck and two twin 400mm torpedo tubes at the aft end of the superstructure. The HBDJ-21/12 launchers each carry twelve 21cm rockets, which come in unguided depth-charge, guided depth-charge, sonar decoy, and hardkill anti-torpedo countermeasure variants. Each launcher reloads automatically from a below-deck magazine containing 96 rounds in total. The torpedo tubes can also be reloaded at sea, with one source claiming that a total of 8 reloads are carried.
Most ships also sport a removable HB-6/7 60mm rocket-propelled depth charge projector on the quarterdeck. This system is designed to be used against divers, small submersibles, and moored sea mines.
In 2014, during the leadup to the Innominadan Crisis, a number of Sŏwicho-class corvettes were fitted with pintle mounts for 12.7mm or 7.5mm machine guns, to defend against pirates or small craft. These mounts were retained after 2015, though usually only two are fitted with machine guns, and these lack dedicated gunners.
The Sŏwicho-class corvettes are among the last Menghean ships to carry mine rails on the quarterdeck, and can reportedly carry 20 mines without interfering in regular anti-submarine operations. The mine rails also end in mountings for depth charge racks. Sŏwicho-class ships are rarely seen with the depth charge racks installed, even during the Innominadan Crisis.
Propulsion
The ships are driven by a CODOD powerplant, with two diesel engines connected to each shaft via a switchable transmission. The entire powerplant is domestic in design. On cruise diesels, maximum power is 4,400 shaft horsepower, or 3,300 kW. On "sprint" diesels, maximum power is 16,000 shaft horsepower, or 11,900 kW. At this output level, the ships have a top speed of 28 knots.
The powerplant reportedly incorporates some acoustic damping measures, with the engines connected to the hull structure via rubber blocks. While quieter than the Mugunghwa-class corvettes, the Sŏwichos are still noisier than more recent Menghean corvette classes, which incorporate electric transmissions and in some cases battery power.
Ships in the class
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