Nunbora-class destroyer

The Nunbora class were a group of destroyers built in the Democratic People's Republic of Menghe during the 1960s and 1970s. They were designed for anti-surface warfare, and carried only minimal anti-air and anti-submarine weaponry. A total of 24 Nunbora-class ships were built, making them Menghe's most numerous destroyer class. As of 2020, all have been retired from service.

Development

The Nunbora-class destroyers are derived from the plans for the Letnian Project 56 destroyer. While the interior is largely identical, the Nunbora design incorporates a number of changes and modernizations, particularly in the area of armament. The use of an existing design helped expedite the development process, allowing Menghe to rush the ships into large-scale production just a few years after the end of the Menghean War of Liberation.

At the time of the ships' construction, Menghean naval commanders considered anti-ship missiles to be a secondary weapon in naval combat, owing to their poor reliability and large size in the 1960s. As a result, they stressed that the Nunbora class should be able to launch a salvo of anti-ship missiles first, and then close with the enemy to initiate a gun engagement.

Characteristics (as built)

The Nunbora-class destroyer resembles a late-PSW destroyer in layout, but with triple AShM boxes in place of the torpedo tubes. In the as-built configuration, all ships carry YDH-20 missiles; during the 1980s, however, several were refitted with modified launchers to support the improved YDH-22. The launchers are carried in a forward-facing position for regular travel, but can traverse 90 degrees port or starboard to fire. To reduce the risk of damage to the superstructure, the missiles are only fired directly to either side.

Gun armament consists of two SM-2-1 turrets, each carrying two 130mm guns. These use Letnian 130mm ammunition, which is not compatible with the 130mm guns on the Taepung-class destroyers. The guns have a rate of fire of 11-15 rounds per minute with automated loading, depending on elevation; with manual loading this falls to 8-9 rounds per minute. The turrets are stabilized in two axes, and have a train rate of 18 degrees per second. Menghean and Letnian sources cite a maximum range of 27 kilometers. In contrast to the Letnian Project 56, which had one fire-control tower, the Nunboras were all built with two, to improve aiming arcs aft of the ship and increase redundancy in the event of damage.

Beyond the dual-purpose guns, anti-air armament on all ships of the class is limited to close-in weapon systems, though with six mounts arranged in three pairs this armament is relatively strong. The first sixteen ships carried AK-230 turrets, though from Haejilnyŏk onward the remaining eight used the more capable AK-630. Ships in the later group also had an improved air search radar on a rebuilt aft mast.

Anti-submarine armament is the most minimal, consisting of three sixteen-tube depth charge rocket launchers. These are further constrained by an obsolte "Pegas-2" sonar of 1950s vintage. The last eight ships, of the Haejilnyŏk subclass, deleted these weapons altogether in favor of chaff and smoke launchers.

Refits and upgrades

Haejilnyŏk and the seven ships which followed her represent a distinct subclass of the Nunbora series, with modestly improved air defense capabilities. Menghean sources, however, do not treat them as a separate ship class, as they do with the Hyŏngnam-class destroyers.

Over the course of the 1980s, several ships in the class were refitted to support the YDH-22 missile. The most visible change is a "bulged" door on the launch tubes, to accommodate missiles roughly half a meter longer. Onboard electronics were also upgraded as part of the refit process. Haejilnyŏk subclass ships were given priority in these refits, but a few early hulls were also modified. No new refits to this standard were made after 1990, likely in anticipation of the more capable YDH-24 missile which would soon enter service.

The arrival of the YDH-24 brought a new round of refits. This rebuild involved stripping off the traversing missile launchers and installing two fixed quad-missile boxes in place of each. This increased the number of missiles to 16. The aft radar mast was also rebuilt to support a HR-280 surface-search radar, which exploits atmospheric ducting to detect surface targets at longer ranges. On early-hull ships given this conversion, the anti-submarine weapons were replaced with smoke and chaff launchers, as on the Haejilnyŏk subclass. New ESM and ECM antennas were added to improve electronic warfare capability, and radio communication systems were upgraded. On two ships the aft fire-control tower was replaced by a four-tube YDG-38 missile launcher, with reload tubes stored in the former fire control room below it.

Classification

When they were first built, the Nunbora class were classified as destroyers (guchugham), or to translate the term more literally, "pursuers." This was the same classification used for the postwar Taepung-class destroyers, and for Menghean destroyers in the Pan-Septentrion War. With the introduction of the Chŏndong-class destroyers, however, both the Nunbora and Chŏndong classes were reclassified as "missile destroyers" (yudotan guchugham). This aimed to distinguish them from the older Taepung class, which relied on torpedoes instead of anti-ship missiles as its main long-range armament.

This distinguishes the Taepung, Nunbora, and Chŏndong classes from other Menghean "destroyers," such as the Yobu and Hyŏngnam classes. These are classified as howiham, or "escort ships." This distinction refers to their different roles on the maritime battlefield: gughugham are designed to pursue, engage, and destroy enemy surface ships, while howiham are intended to escort landing ships, cruisers, and surface-to-surface combatants.

Ships in the class

In keeping with the postwar Menghean nomenclature tradition, the Nunbora-class destroyers are named for weather conditions. The first 19 were named for weather conditions in northeastern Menghean vocabulary, that is, terms without corresponding Gomun characters. The remaining 5 ships, from Ubing onward, reverted to weather terms with corresponding Gomun characters.

Name	Meaning	Builder	Laid down	Launched	Commissioned	Status
Nunbora	Snowstorm	Gyŏngsan	1969 May 01	1970 Aug 05	1972 Oct 03	--
Gurŭm	Cloud	Kimhae	1969 Jul 14	1970 Oct 11	1973 Jan 29	--
Angae	Mist	Gyŏngsan	1969 Nov 28	1971 Jan 19	1973 Feb 20	--
Baram	Wind	Gyŏngsan	1970 Aug 12	1971 Dec 04	1974 Jan 26	--
Sonagi	Shower	Kimhae	1970 Oct 20	1971 Nov 05	1973 Mar 11	--
Bi	Rain	Gyŏngsan	1971 Jan 28	1972 Mar 21	1973 Dec 13	--
Ryŏngorŭm	Waterspout	Kimhae	1973 Nov 13	1973 Jan 14	1974 May 07	--
Jangma	Monsoon	Gyŏngsan	1971 Dec 18	1973 Jan 31	1974 Sep 04	--
Bŏngae	Lightning	Gyŏngsan	1972 Apr 29	1973 Apr 02	1974 Sep 13	--
Saebyŏk	Daybreak	Kimhae	1973 Jan 26	1974 Feb 04	1975 May 15	--
Noŭl	Sunset	Gyŏngsan	1973 Feb 06	1974 Mar 21	1975 Oct 03	--
Kŭnbi	Heavy rain	Gyŏngsan	1973 Apr 10	1974 Jun 17	1975 Dec 16	--
Mulgyŏl	Current	Kimhae	1974 Feb 08	1975 Mar 29	1976 Jul 23	--
Haessal	Sunshine	Gyŏngsan	1974 Mar 27	1975 May 10	1976 Oct 16	--
Orora	Aurora	Gyŏngsan	1974 Jun 29	1975 Aug 06	1977 Mar 03	--
Sŏri	Frost	Kimhae	1975 Apr 03	1976 Mar 28	1977 Oct 22	Sunk 1985 Jul 14 due to an onboard fire which broke out while at sea.
Haejilnyŏk	Nightfall	Gyŏngsan	1975 May 17	1976 Jun 24	1977 Dec 17	--
Achimdŭm	Morning Calm	Gyŏngsan	1975 Aug 12	1976 Oct 02	1978 Apr 19	--
Mudŏwi	Heat Wave	Kimhae	1976 Apr 04	1977 Apr 30	1978 Nov 09	--
Ubing	Sleet	Gyŏngsan	1976 Jun 30	1977 Jul 14	1979 Jan 14	--
Sŏlpok	Snowstorm	Gyŏngsan	1976 Oct 10	1977 Dec 07	1979 Jul 14	--
Roe-u	Thunderstorm	Kimhae	1977 May 09	1978 Jun 20	1979 Dec 23	--
Ryŏmyŏng	Dawn light	Kimhae	1978 Jun 26	1979 Jun 14	1980 Nov 07	--
Janpung	Storm	Kimhae	1979 Jun 19	1980 Jul 01	1982 Jan 06	--