Pyŏng'an-class destroyer

The Pyŏng'an-class destroyers are a group of four guided missile destroyers built for the Menghean Navy. They are armed with the Letnian S-300FM long-range surface-to-air missile, giving them a much longer surface-to-air engagement range than any previous Menghean destroyer class. This made them the first Menghean warship class to use a vertical launching system for its missiles, albeit in an inefficient revolver-type cold launch configuration. Later, in 2001, Menghe obtained a license to produce the Mark 41 VLS, making the Pyŏng'ans the first and last Menghean warship class to carry the YDG-39.

Development

Area Air Defense Ship program

During the 1980s and 1990s, Menghe's main air defense ship was the Yobu-class destroyer (along with its Hyŏngnam subclass). These ships were armed with the YDG-32 surface-to-air missile, a licensed derivative of the S-125 Neva/Pechora. In its upgraded 1990s model, this missile had a range of 40 kilometers, relatively short compared with more modern systems elsewhere. These ships also carried their YDG-32s on twin-arm mounts, limiting their rate of fire, and had only 16 missiles per magazine for a total of 32. Given that many Menghean warship classes carried either no radar-guided SAMs (Nunbora, Mugunghwa, Ginam) or relatively ineffective ones (Chŏndong), this was seen as a serious problem.

In response, the Menghean Navy launched a design competition for an Area Air Defense Ship specialized in protecting surface ships against aerial attack. Anti-submarine capabilities were added to the requirements list as well. The new ships would be given the hull type juryŏk howiham (주력 호위함 / 主力護衛艦), or "main force escort ship," to contrast them with the Yobu and Hyŏngnam-class escort ships and the Ansa-class outer escorts (wichung howiham). These main force escort ships would accompany the aircraft carrier Haebang and escort surface action groups composed of anti-shipping destroyers or anti-submarine warships.

Competition with Plan 351

Cross-section drawing of the Plan 351 design.

Initially, the Navy responded with a modified version of the Chanjok Jachido-class cruisers, modified with S-300FM launch cylinders in place of the helicopter hangar. The radar masts were also replaced with solid pyramid structures containing boiler exhaust pipes and electronics, and a smaller hangar structure for two helicopters was added aft, though the powerplant and the forward one-third remained unchanged. The command deck was retained, allowing these ships to operate as command centers for a formation of surface ships. Previously, the Yobu-class destroyers had been used as destroyer squadron leaders, but their makeshift command facilities were not adequate for coordinating large groups of ships. This design was designated Plan 351, and given the name Yerihan ("Keen"), though this was only a codename for the project rather than a prospective ship name, as sometimes erroneously reported.

The Yerihan design initially received a favorable evaluation from the Navy's general staff, and Choe Sŭng-min personally endorsed the design. A model was unveiled at a domestic defense exposition in 1994, and Dayashinese satellite intelligence mistakenly reported that the first ship in the class was laid down the following year (in fact, it was the Kungnaejok Jachido, third ship in the Chanjok Jachido class). Further evaluation, however, began to tip the balance against the Plan 351 design. The added superstructure aft and heavier pyramid masts added considerably to the ship's weight and shifted the center of gravity, requiring new structural bracing. This eliminated many of the expected benefits of using an existing hull. The Navy also projected that the operating costs of these ships would be relatively high, due to their large crewing requirements and inefficient steam turbine machinery.

As debate on the viability of the Plan 351 continued, the Navy commissioned a separate design team to draw up a more compact, less expensive alternative. This prototype, designated Plan 332, became the basis for the Pyŏng'an class. To reduce space, the 8-tube S-300 launch cells were replaced by 6-tube cells with outward-angled launch points, and the total number of missiles was reduced. The intermediate-range SAM battery was also removed, in favor of the short-range YDG-61, still in early development. The overall layout was more conventional, resembling foreign destroyers such as the Yakaze class.

Another breakthrough in the Plan 332 design came in 1995, when representatives of the Hallian Navy offered to covertly transfer LM2500 gas turbine engines to Menghe under the guise of a private ship-scrapping contract. Menghean engineers used these to achieve further reductions in powerplant mass, making the design more compact while retaining an adequate top speed.

See also

• Plan 351 "Yerihan," a competing design for Menghe's next-generation air defense ship
• Yakaze-class destroyer