Type 051 destroyer

The Type 051 destroyer (NATO code name Luda class) missile destroyer was the first surface warfare oriented vessel ever designed and built in China, and the first Chinese ship to be fitted with an integrated combat direction system. It was based on the Soviet Neustrashimy class destroyer design, with some design influences from the Kotlin class destroyer design.

History
In the late 1960s, China began testing its long-range rockets for the Chinese space program, as well as the ICBM program. The People's Liberation Army Navy operated only four ex-Soviet Gnevny class destroyers (Anshan class in PLAN service) at the time, which were unsuitable for long-range ocean recovery missions. The 701 institute was instructed to develop China's first indigenous guided missile destroyer, modelled after the Soviet Kotlin class. The design was approved in 1967, and construction of the first Type 051 Luda class destroyer began in 1968.

A total of 16 Type 051 destroyers were built between 1968 and 1991. 9 remain in service today. Major refit for ships of this class began in the 1990s, replacing the old HY-1/HY-2 with YJ-83 (C-803) missile, and manual guns with automatic guns. For air-defense, an 8-cell HQ-7 Surface-to-air missile system is also installed with the upgrade.

Ships
The general designers of Luda class destroyer were Mr. Li Fuli (李复礼) and Mr. Pan Jingfu (潘镜芙) of the 701st (Research) Institute of the 7th Academy. A total of 732 types of material, and 1240 kinds of equipment (include over 110 brand new ones needed to be developed from scratch) were tasked to over a dozen establishments under Ministry of Industry in 22 provinces and municipalities. A total of 16 ships were constructed, consisted of 7 ships of the Type 051, 6 ships of Type 051D, and32 ships of Type 051Z. Later versions are the subsequent upgrade of earlier units.

Luda I (Type 051/051D/051Z)
This is the original configuration of the design, albeit with equipment inconsistencies among the units. Three shipyards built the original 16 vessels of this group: units #106-109/133/134/165/166 in Dalian, #131-132/110 in Shanghai (the Zhonghua Shipyard), and #160-164 in Guangzhou. Of these, Units Nos. 105 were converted into Luda II type, 109 and 110 were converted into Luda III type, while Unit No. 160 suffered an explosion in August, 1978 and was eventually scrapped. She is listed as decommissioned.

The original Luda destroyer was equipped with 2 x triple HY-1 or HY-2 missile launchers, 2 x 130 mm guns, plus an assortment of manual 25 mm, 37 mm, and 57 mm AA guns. Two of the Luda I destroyers were converted into command-variant, with enlarged superstructure for air defense C3I center, ZKJ-1 combat data system, and Type 381A Rice Shield 3-D long-range air search radar.

Type 051
This initial batch is the first Chinese surface warship to have a bow mounted sonar. Initial proposal of adopting Soviet Tamir-11(MG-11, NATO reporting name Stag Hoof) search light sonar was rejected, because it was not considered adequate enough due to its single beam search capability, which means the low speed of search cycle would easily lose targets. A more capable indigenous Chinese sonar was ordered to be developed, with Mr. Huo Guozheng (霍国正) named as the general designer. The resulting indigenous Chinese domestic sonar was SJD-1 low frequency (LF), high power, large aperture sonar with a cylindrical array (designated as Type 601 sonar array), which was accepted into service after eleven major trials at the sea. Type 601 sonar array of SJD-1 sonar has a diameter of 2 meters, height of 1 meter and weight of 4 tons, and the range is in excess of 6 nautical miles (nm), more than twice the range of Soviet Tamir/MG-11 search light sonar originally proposed. SJD-1 sonar was jointly developed by 706th Research Institute, 726th & 461th Factories, and it is the first bow mounted sonar adopted by Chinese navy. SJD-1 is frequently confused with its successor SJD-2, more commonly referred as SJD-II, whose design started in the 1970s, but was not completed until the 1980s due to major redesign.

Anti-ship missiles (AShM)s of Type 051 was HY-1. A joint team of 713th and 701st Research Institutes and the 3rd Academy of 7th Ministry was tasked to develop the ship-launched version of HY-1, with Mr. Xie Xianzhang (谢宪章) and Mr. Yao Yuebin (姚跃滨) as the general designers. To save space, the design team went against the common practice of separate launching and loading systems, but instead, integrated the launching and reloading systems into a single container, a first in China. This launcher / container /reloading system is designated as Type 7222. Electromagnetic compatibility proved to be a major difficulty which caused AShM to be potentially detonated and launched, and this problem was not solved until the early 1980s. As a result, when Luda I class ships were deployed in 1982 to escort the convoy of submarine-launched ballistic missile testing, none of those ships were armed with AShM.

Type 051D
Type 051D is the 2nd batch of Luda I class, with D stands for Dingxing (定型), meaning finalized design. The primary difference between Type 051D and earlier Type 051 is in electronics. During deployment of Type 051, it was discovered that SJD-1 sonar cannot provide accurate locations of targets, and the error was too great to be adequate enough to provide fire solutions to on board ASW weapons. Therefore, the design of Type 051D incorporated an additional high frequency (HF) active attack sonar designated as SJD-N (with Type 675 sonar transducer array) to provide fire solutions, and this attack sonar was subsequently fitted on all Luda class ships.

To save valuable space, depth charge racks on Type 051 were eliminated. Instead, the two mine rails for mine laying were modified to also function as depth charge racks. A total of 20 - 28 mines or up to 42 depth charge can be carried (depending on types).

To better utilize on board ASW weaponry, a specialized ASW fire control system was developed for Type 051D, designated as SIASWFCS, or Shipborne Integrated Anti-Submarine (Warfare) Fire Control System (Chinese: 舰载综合反潜火控系统 Jian-zai Zong-he Fan-qian Huo-kong Xi-tong), the first kind in Chinese service. SIASWFCS links up on board sensors and ASW weaponry, and once top priority targets are identified, SIASWFCS would be able to simultaneously engage two targets by automatically providing fire solutions from any of the following ASW weaponry: torpedo tubes, ASW rocket launcher, ASW mortar, mine laying rails, and later, ASW missiles as well. Up to two types of ASW weapons can be simultaneously used, either against the same target, or two targets independently. SIASWFCS would become a standard equipment on all Chinese warships and later models would expand capability by increasing targets can be attacked simultaneously and types of weaponry used.

Type 051Z
Type 051Z is the 3rd batch of Luda I class, with Z for Zhihui (指挥), meaning command. Design work begun in April 1977, and completed in September, 1978. The primary external difference between these two ships and earlier ships is that they are equipped with the first Chinese indigenously developed passive phased array radar, Type 381 Radar.

Type 051Z ships are also among the first Chinese warships to be equipped with a combat data system, which is designated as ZKJ-1. Developed by a joint team of 724th Research Institute (later reorganized as Nanjing Marine Radar Research Institute 南京船舶雷达研究所) as the primary contractor, and 709th Research Institute as the secondary contractor, the system took 13 years to complete, because there was absolutely not any outside information that can be referenced. The general designer was Mr. Qin Xuechang (秦学昌, born in 1940 in Chongming County), the future head of 724th Institute. Tests for subsystems of ZKJ-1 combat data system were completed in 1978, system test was completed the following year. Land tests against aerial targets begun in November 1979 and completed four months later, and finally in July 1980, the system was installed on board ships and completed its final tests. The combat information center centered around ZKJ-1 was Type 672-II, with three electronics cabinets and six display consoles, and it is also known as Poseidon-1. However, due to the technological backwardness of Chinese microelectronics industry at the time, the computational power of ZKJ-1 was not strong enough, and the speed of information processing was not fast enough for emerging threats in the 1980s. As a result, ZKJ-1 was only installed on board one of the Type 051Z ships, No. 110 Dalian while the second ship of this class was equipped with a combat data system of British origin.

The second unit of Type 051Z, No 132 Hefei, was equipped with ZKJ-2 combat direction system, which is a very simple combat data system of British origin. This combat data system is frequently but erroneously referred by many as ZKJ-3, but in reality, it ZKJ-2 instead, because ZKJ-3 is actually the Chinese version of Italian IPN-10 combat data system used on some of the Luda III ships. ZKJ-2 is based on Racal Marine Radar CTC-1629 (CTC: Command Tactical Console) combat direction system, which can simultaneously track 20 targets. However, UK had its own electrical/electronics standard, and ZKJ-2 is basically the same CTC-1629 converted to internationally accepted IEEE/ITU standard.

Luda II
Two Luda class destroyers were modified for ASW and C3I duties. The aft 130 mm gun and AAA guns were removed, and replaced with a helicopter deck, hangar space for 2 helicopters. See this pic for example. ZKJ-1 combat data system was upgraded by adopting new electronics, including Type 911 computer developed by 709th Research Institute, and multiple distributed and ruggeddized Type 991 microprocessors, also developed by the same institute. This upgraded ZKJ-1 would be a standard equipment that was used to modernize other Luda ships. ZKJ-1 was later replaced by a more advanced version of combat data system, ZKJ-4, a Chinese copy of Thomson-CSF TAVITAC combat data system, for the more capable C3I duties during later upgrades.

Luda III (Type 051G/051G1/G2)
Although designated as Luda III, the first batch, Type 051G, consisted of a single ship, was actually put into service before Luda II. None of the Luda III's are identical, each had their own subsystems, and these ships are mainly used to compare and evaluate different systems developed.

Type 051G
In the early 1980s, decision was made to upgrade the obsolete ASW systems on board Luda class by introducing foreign equipment, and Italy was selected as the contractor to provide such systems. Reportedly (yet to be confirmed), No. 105 was selected as a testbed for these Italian systems, including a more capable combat data system than the simple CTC-1629/ZKJ-1 used on Luda I's. This Italian combat data system is SADOC 2 (SADOC = systema dirizione della Operazioni di combattimento), which is the export version of IPN-10 combat data system used by Italian navy, but with data links deleted. SADOC 2 combat data system was delivered to China in 1985.

Another very important piece of Italian systems introduced was the DE-1164 integrated sonar system, which is the Italian version of Raytheon AN/SQS-56 sonar. DE-1164 is consisted of 2 subsystems using the same electrical cabinet, DE-1160 hull mounted sonar (HMS, with a maximum range around 20 km) and DE-1163 variable depth sonar (VDS, with a maximum range in excess of 50 km). DE-1164 is the first sonar in Chinese service to have integrated the HMS & VDS. Because externally, DE-1164 looks identical to its successor DE-1167, some western sources have claimed that China might have DE-1167 sonar as well, but this does not appear to be true, because the HMS of DE-1167 has twice the range over its predecessor, around 40 km, but Chinese sources have confirmed that HMS of Italian sonar in Chinese service only has a maximum range around 20 km, which is exactly what DE-1164 has. Italian ILAS triple torpedo tubes were also purchased by China, in conjunction with A244-S light weight ASW torpedoes, 40 of which were subsequently delivered to China.

Trials revealed that the performance of DE-1164 sonar was disappointing, with a huge gap between the actual performance and what was specified in documents. However, this was not due to sonar, but the ship itself. Due to the inherent flaws of an old design, the ship is not an ideal ASW platform for advanced ASW system. The steam propulsion system proved to be the major hindrance preventing DE-1164 reaching its full potential. The noise and vibration generated by the steam boilers simply created too much interference with the sensitive sonar that it could only reach its full potential at very low speed. However, at such low speed, target would easily evade and escape Luda's attempt to attack. Another problem is the lack of helicopter carrying capability of Luda class, so that even when the full potential of DE-1164 is reached, it could not be fully exploit, because the on board ASW weaponry does not have enough range to reach the edge of the envelop of the sonar performance. Lack of helicopters carrying capability meant that the ASW defense perimeter could not be extended to the maximum range of on board sonar. After nearly two years of trials, most of the Italian system on board was removed for reverse engineering, and installation on later Type 052 destroyer, with No. 105 itself would be converted to Luda II with capability to carry two helicopters soon after. Testing experience would greatly help China to develop similar domestic systems later, such as ZKJ-3 combat data system and SJD-7 sonar, and upgrade existing systems such as SIASWFCS.

Type 051G1
Program originally started in November 1983, but experience gained from testing Italian equipment on board Type 051G revealed many inherent design flaws of Luda class, and efforts were made to reduce the negative impacts, causing major redesign, so the construction did not begun until 1986. Type 051G1 consisted of a single unit, No 165 Zhanjiang, which was launched on Aug 1, 1988 and entered service on December 30, 1989, in South Sea Fleet. Two parallel approaches were adopted in attempt to solve the problem of the role of an ASW platform, and one of these two approaches is to upgrade the original Chinese sonar with Italian DE-1164 sonar technology. This resulted in a major redesign of SJD-2 (SJD-II), the successor of SJD-1 that was almost completed, which inevitably, caused the delay of the program, but the performance of the sonar was greatly improved: SJD-1 was replaced by SJD-II, and SJD-N was replaced by SJD-4, and these sonar systems allowed submarine detections up to 18 kn in harsh sea states. However, Type 051G1 originally lacked VDS.

Other improvements of Type 051G1 over earlier units included using HY-1J AShM to replace HY-1 AShM, with the latter incorporating following improvement: lower cruise altitude achieved with radio altimeter, higher accuracy and better jamming resistance achieved with mono-pulse seeker. The range also increased to 10 km to 95 km. Other weaponry improvement included using enclosed Type 76A twin 37 mm naval guns to replace the open mounted Type 76 twin 37 mm naval guns originally mounted on earlier ships. Type 76A can be used as a CIWS. An enclosed bridge of the ship is replaced the open bridges of earlier ships.

Other improvements were mainly in the electronics, such as radars. Type 381 passive phased array radar on Type 051Z was added, and Type 347 fire control radar was also added to meet the need for Type 76A used in CIWS role. Chinese version of Racal RM-1290 navigational radar replaced Type 751 navigational radar, and frequency hopping Type 352III radar replaced Type 352I radar for surface search. Also added was Type 825 electronic warfare system. A new combat data system of French origin was installed, with capability to automatically tracking 60 targets and an additional 60 more tracked manually. The exact type of this combat data system is subject to debate, some sources claim it's the French Thomson-CSF TAVITAC combat data system (two systems purchased from France in 1985 and delivered sometimes later), while others claim it's the Chinese equivalent of TAVITAC, ZKJ-4. The overall capability of Type 051G1 improved greatly, but the advanced electronic and weaponry of western origin was not what Chinese sailors used to, and it took about four years for the crew to become fully skilled and finally in 1993, the ship reached its full potential.

Type 051G2
Design of Type 051G2 was approved in February 1987, and work begun in October of the same year at Dalian Shipyard, the same builder of Type 051G1. No. 166 was completed in November 1991 and handed to Chinese navy in the same year. Zhuhai (166) was equipped with 4 x twin YJ-8 (C-801) AShMs. 2 ASW mortars in stern are replaced by 2 x triple Whitehead ILAS torpedo launchers at both sides of the bridge, which can launch western torpedoes and their Chinese equivalents. The size of Type 051G2 is slightly different than all other Luda class ships, with draught increased to 4.66 meter, but length reduced by 4 meters to 128.6 meters, and the total number of crew was reduced to 280 due to automation. The new derivative of Type 347 radar, EFR-1 Rice Lamp fire-control radar, was more capable and Type 352 radar was thus not need and hence removed. Type 517 Radar replaced Type 515 radar for long range air search. Type 344 fire-control radar is used for naval guns.

Type 051G2 is used to test out the other approach to solve the problem of noise and vibration generated by steam boilers of the propulsion system interfering with sonar. No. 166 is equipped with SJD-7 sonar. SJD-7 is frequently but erroneously claimed by many as the Chinese version of the French Thomson-CSF DUBV-23/43 HMS/VDS, but in reality, SJD-7 is actually the Chinese version of Italian DE-1164 sonar instead, and the Chinese version of French DUBV-23/43 is actually SJD-9. SJD-7 is basically a DE-1164 incorporating measures to reduce the negative effects of vibration and noise generated by steam boiler and other old propulsion systems. The Chinese equivalent of DE-1160 HMS portion of DE-1164 is rumored to be ESS-2 HMS, and DE-1163 VDS portion of the DE-1164 is ESS-1 VDS towed sonar, but this is challenged by some sources which claims that ESS-1/2 are the Chinese copies of French DUBV-23/43 respectively.

The combat data system of Type 051G2 is ZKJ-3 (ZKJ-III), which is a Chinese equivalent of Italian IPN-10 combat data system. IPN-10 and its export version SADOC 2 is capable of simultaneously tracking 200 targets, but such capability cannot be fully utilized in SADOC 2 due to lack of data link, because the maximum number of 200 can seldom be reached either due to the fact that there are not enough targets within the vicinity, or the on board sensors are not capable of tracking that many targets. Data link is critical in that it allows target information from other platforms to be transmitted and integrated to the combat data system, fully utilizing its potential. Furthermore, being able to receive additional information on targets detected by other platforms and integrated to one's own combat data system would result in extending the defense perimeter beyond the range of on board sensors, thus greatly improving situation awareness. Such advantages did not exist for SADOC 2 combat data system due to lack of data link, and China had to come up with its own data link for SADOC 2 system. The resulting domestic Chinese system is ZKJ-3, which is essentially a SADOC 2 with indigenous domestic Chinese data link added, along with some other improvements, thus bring ZKJ-3 to the Chinese equivalent of the original IPN-10 combat data system, fully utilize its potential. Designed by the 724th Research Institute, ZKJ-3 entered service in 1988, and experience gained had helped the development of ZKJ-4 series combat data system, the Chinese version of French TAVITAC combat data system by bring the total number of targets that can be simultaneously and automatically tracked to two hundred. During the mid-life upgrade, Zhuhai (166) was upgraded with HQ-7 SAM, 4 x YJ-83 (C-802a) SSMs.

The HQ-7 SAM system is reported to be equipped with "semi-automatic reloader" system with 16 spare missiles. The same system is also used on the Type 052 destroyer, bringing the total number of air-defense missiles to 24: 8 (ready to fire) plus 16 (stored).

Luda IV (Type 051DT)
The PLAN has performed mid-life upgrades on several of its Luda class destroyers. Some ships have been upgraded with a new ZKJ-4A-3 combat data system (C3I), HQ-7 SAM, manual AA guns replaced by Type 76A dual-37 mm automatic AA guns, and HY-1/HY-2 missiles replaced by 16 YJ-83 (C-802a) anti-ship missiles, with two of the launchers can also be used for CY series ASW missiles. The upgraded ships are sometimes referred to as the Type 051DT. At least 2 ships (109 & 110) are reported to have been upgraded to the Type 051DT standard, with more expected to follow.

Luda S (Type 051S)
Proposed variant, equipped with Sea Dart missile, but cancelled for lack of funds and other factors.

Type 051DT (mid-life upgrade) Specs
For comparison, please see this pic of Luda prior to modernization, and this pic of Luda with modernization.


 * Displacement 3,250 tons (empty), 3,670 tons (loaded)
 * Length 433.1 ft / 132 meters
 * Beam 42 ft / 12.8 meters
 * Draft 15.3 ft
 * Speed ~30+ kts
 * Endurance 2970 nmi at 18 kn
 * Crew 280 (45 officers)
 * Propulsion 2 boilers 2 turbines 72,000 hp(m) (53 MW) 2 shafts
 * C3I System: combat data systems of ZKJ series (ZKJ = Zidong Kongzhi Jiqi: automatic control machines)
 * ZKJ-1 for Luda I
 * ZKJ-4 for Luda II
 * Thomson-CSF TAVITAC for Luda III (051G1/G2)
 * ZKJ-4A-3 for Luda mid-life upgrade (051DT)
 * Data link: HN-900 (Chinese equivalent of Link 11A/B, to be upgraded)
 * Radar/Sonar
 * Type 517A Knife Rest, or Cross Slot 3-D long-range air search, A-band
 * Type 515 Bean Sticks or Pea Sticks air search radar, E/F-band
 * Rice Screen 3-D early warning lon-range radar, G-band
 * Square Tie air/surface-search radar, I-band
 * TSR 3004 (DRBV-15 Sea Tiger) or Eye-Shield air/surface search radar (E-band)
 * Type 343G fire-control radar (for 100 mm gun)
 * Type 347 fire-control radar (for automatic 37 mm guns)
 * Racal RM-1290 navigation radar (J-band)
 * High pole IFF
 * Pegas 2M & Tamir 2 medium-frequency hull-mounted sonar
 * Armament 
 * 16 x YJ-83 (C-803) anti-ship missiles in 4 x quad launcher boxes
 * 1 x 8-cell HQ-7 Surface-to-air missile launcher + 16 spare missiles
 * 2 x twin 100 mm guns
 * 4 x Type 76A dual-37 mm automatic AA guns
 * 2 x Type 75 (FQF-2500) 12 barrel 240 mm ASW rocket launchers (120 rockets)
 * 2 x triple 324 mm Yu-7 torpedo launchers
 * 4 x DC projectors + 4 DC racks
 * 2 x Chaff/decoy rocket launchers