Plan 215 corvette

The Plan 215 corvette was a warship class built in the Democratic People's Republic of Menghe during the 1970s and 1980s. In the West they are generally classified as corvettes, though their official Menghean hull classification is Daehyŏng Yudotan Kwaesokham (대형 유도탄 쾌속전 / 大型誘導彈快速艇), or Large Fast Missile Craft. During the 1990s, many were modernized with newer anti-ship missiles, though the type is still considered largely obsolete today.

Development

Beginning in 1968, Menghe license-built a large number of Osa-class missile boats as Plan 621 KY. While Menghean naval planners were impressed with the type's usefulness in fast sorties from coastal strongholds, eventually producing more than 120 in total, by 1970 there was already some concern over its limitations. It had an at-sea endurance of only 5 days, greatly limiting its sortie range. Once its four anti-ship missiles were expended, it also had little in the way of self-defense armament, leaving it vulnerable to attacks by other corvettes.

To correct these problems, the Menghean Navy began design work on a large missile boat incorporating more supporting systems and defensive weapons. An early prototype design, designated Plan 210, called for a semi-planing hullform with a new combined-gas-and-diesel powerplant, which would have resulted in a ship similar in configuration to Letnia's Tarantul-class corvettes. This was ultimately rejected in favor of the Plan 215 design, which used an older hullform resembling a scaled-down Jangmi-class corvette. The new design also borrowed the Jangmi's entire powerplant, though the sonar and the fuel capacity reduced, allowing for a smaller internal space.

Description

The Plan 215 corvette has the same main armament as the smaller Osa-class missile boat, with four large launch boxes for YDH-20 anti-ship missiles. From 1980 onward, new ships were modified to carry the YDH-22, a solid-fueled derivative of the YDH-20 with improved accuracy, reliability, and readiness. Refits carried out during the 1990s would re-arm most surviving ships with more advanced anti-ship missiles, including the subsonic YDH-24, the supersonic YDH-25, and the lightweight, subsonic YDH-26.

The Plan 215's main advantage over the Osa-class is its improved self-defense armament. Forward of the superstructure, it has two superfiring AK-630 CIWS turrets, both controlled by a single MR-123 radar over the bridge. These can target missiles, aircraft, and other light ships. Facing aft is an AK-726 twin-barrel turret, also with dual-purpose capability. Its rear-facing position allows the ship to engage pursuing warships while retreating after a missile strike. Just forward of the twin 76mm turret, on part of the superstructure, is a mounted launcher for YDG-34 surface-to-air missiles.

Curiously for a light missile craft, the Plan 215 has extensive mine rails on the quarterdeck, running all the way up to the space behind the missile boxes. It is estimated that as many as 80 mines can be carried at full load, though this would require removing the dinghy and likely leaving the missile tubes unloaded and it would most likely prevent safe usage of the missiles.

The powerplant is identical to that of the Project 159 frigates licensed from Letnia, apparently part of an effort to reduce development costs and speed up construction in factories tooled for work on the older class. This CODOG powerplant consists of two 15000-shp gas turbines and a single 6000-shp diesel engine for regular cruising. Because the Plan 215 is a lighter vessel, it is able to achieve a higher top speed on this powerplant, reportedly 34 knots; yet this is still slower than contemporary missile corvettes with semi-planing hullforms or lifting foils. Each engine powers a single propeller shaft, with the variable-pitch diesel propeller trailing in the water during gas turbine operation.

Plan 216 class patrol ship

In 1991, four Plan 215 corvettes which had been under early-stage construction at the time of the Decembrist Revolution were completed to a modified configuration, later revealed to be designated Plan 216. These vessels were officially categorized as Medium Patrol Ships (중형 초계함 / 中型哨戒艦, Junghyŏng Chogyeham), and they served with the Maritime Patrol Forces, which at the time were a paramilitary arm of the Menghean Navy. A dozen more new-build Plan 216 vessels were completed in the early 1990s, possibly as part of a program to keep the military shipyards operational.

The Plan 216 variant removes the missile boxes which flank the bridge, and replaces them with a large deckhouse structure extending out to either side of the deck. This reportedly contains berthing space for additional personnel and a brig for prisoners. The superstructure also follows a slightly different configuration, with a roomier bridge, squared-off side wings, and a lattice mast with a short-range surface-search radar only. Two motor-dinghies are carried, to aid in patrol and boarding operations. Typically these ships are not fitted with the dual YDG-34 launcher, though its base mounting plate is retained. Otherwise, the gun armament is identical across classes, and the mine rails are retained, reflecting the Menghean Navy's requirement that Maritime Patrol Forces vessels be capable of being pressed into service in wartime.

Ships in the class

During the 1970s and 1980s, Menghean Navy ship naming customs held that fast attack craft (missile boats, torpedo boats, and small minesweepers) would be given unique numbers, but not names. As the Plan 215 ships were technically classified as large missile boats, they were initially given numbers as well, though numbering started in the 100s because they were a new type. To confuse Western and Dayashinese intelligence, the first ship was named KYD-107, implying the existence of at least six earlier hulls. Number assignment for the next several ships followed a random order.

In the mid-1990s, the Menghean Navy updated its ship naming conventions, stipulating that KYD-type ships would be named for distinguished individuals. The rules were retroactively applied to the Plan 215 corvettes from 1996 through 1998, with most of the ships still in service given names from an approved Navy register. Ships designated for scrapping or sale within the next few years were not named, and regular naming was not extended downward to smaller missile and torpedo craft.