Type 912 degaussing/deperming ship

Type 912 degaussing/deperming ship is a class of degaussing/deperming ship of the People's Liberation Army Navy (PLAN) with many derivatives. Type 912 is also the most numerous degaussing/deperming ship in PLAN (as of 2014).

Sea Fish 16 class
The origin of Type 912 degaussing/deperming ship can be traced all the way back to Sea Fish (Hai-Yu or Haiyu, 海鱼) 16 class, which is a class of degaussing/deperming ship converted from US Landing ship, infantry (Large), or LSIL for short. Molded after Soviet SR barges, these converted degaussing/deperming ships carried sixty KSM-type accumulator batteries providing ten-volt external and a hundred ten-volt or two hundred twenty-volt for internal coils and cable reels for two hundred forty-millimeter diameter cables. Additional equipment needed for degaussing/deperming duties such as magnetometer to measure horizontal and vertical magnetic field is also carried on board.

Originally, some of the LSILs were sold/transferred to ROCN as part of military assistance program, but many more were sold to China after World War II as excess material for civilian use with armament removed, and some Chinese enterprises purchased them as fishing / processing vessels, and hence the name Sea Fish from its original name in civilian service. Other LSILs commercially sold to China for civilian use were used by Chinese shipping companies as cargo ships or passenger ferries. It is not clear if any of these LSIL were previously used by ROCN and subsequently captured by the communists at the end of the Chinese Civil War. A total of four LSILs were converted, and although being the first batch of degaussing/deperming ships in the PLAN inventory, these ships served a surprisingly long time, and it was not until 1993 when they were finally retired and scrapped, which was after some of its intended replacement. Specification:
 * Displacement (t): 387
 * Commissioned: 1950s.

Yan Fang class
Sea Fish 16 class is only capable of operating in the coastal waters and to support operation further away from shore in the littoral zone, sea-going degaussing/deperming vessels that are capable of operating in both coastal and littoral waters were needed. Decision was made to convert fishing trawlers for this purpose, based on the fact that these fishing trawlers were successfully deployed in both coastal and littoral waters in fishing. A total of two were converted in the early 1960s, but based on the deployment experience, the result was far from satisfactory because these fishing trawlers are simply too small to carry out the required missions effectively. By 1990, both units were retired from service. Specification:
 * Standard displacement (t): 110
 * Full displacement (t): 125
 * Length (m): 31
 * Width (m): 6.1
 * Draft (m): 1.8
 * Propulsion: 2 Chinese copy of Soviet 3-D-6 diesel engines @ 600 hp
 * Speed (kt): 9
 * Crew: 9

Type 601
Both Sea Fish 16 and Yan Fang class degaussing/deperming vessels have inherit shortcoming because both were constructed of steel, and this would interfere with performing their designated duties. One of the methods attempted to eliminate such shortcoming, was to construct degaussing/deperming vessel out of wood. Type 601 degaussing/deperming vessel is the result of such attempt. Built by Huangpu Shipyard of Guangzhou Shipyard International, the ship entered service in the early 1960s as Sea Magnetic (Hai-Ci or Haici, 海磁) 951. Type 601 retired in early 1990s.

Yerka class
Only a single Type 601 degaussing/deperming ship was built, because China found solution to reduce the magnetism of steel hull, and subsequent classes are constructed from steel. Yerka class degaussing/deperming ship is the fourth degaussing/deperming ship in Chinese service, and it is intended to replace all previous three classes. Built by Hudong-Zhonghua Shipbuilding, these ship entered service from 1966 thru 1968. However, due to the political turmoil in China at the time, namely, Cultural Revolution, production came to a complete stop after only two units were constructed. Furthermore, these two completed units were plagued with problems as disruption caused by the political turmoil. As a result, program was subsequently cancelled. Specification:
 * Length (m): 47
 * Width (m): 7.5
 * Draft (m): 2.2
 * Displacement (t): 395
 * Speed (kt): 18
 * Range: 3000 nm @ 11 kt
 * Crew: 55
 * Propulsion: 2 Chinese copy of Kolomna 9-D-8 diesel engine @ 2000 hp
 * Armament: twin 37 mm gun x 1 and 2 twin 14.5 mm machine guns

Type 912
Experience gained (and/or also lesson learned) from Sea Fish 16, Type 601, Yan Fang and Yerka classes resulted in Type 912, which like its predecessor Yerka class, is also based on experience gained from Type 6610 minesweeper, where reduction of steel hull magnetism is critical in countering magnetic mines. Instead of transferring the knowledge gained to a brand new class that is totally different, as in the case of Yerka class, decision was made to construct a degaussing/deperming ship directly based on Type 6610 minesweeper to reduce risks and cost. The approach proved to be successful and many derivatives followed. A total of two Type 912 ships were built and the one in service with North Sea Fleet and remain active to date (early 2014), and the other went into service with South Sea Fleet but eventually retired and replaced by a newer Type 912IIIA degaussing/deperming ship, using the same Pennant number, which in turned, replaced by newer Type 911. Type 912 is capable of providing degaussing/deperming service to ships up to 5000 tons.Specification:
 * Length (m): 65
 * Width (m): 8.8
 * Draft (m): 2.6
 * Standard displacement (t): 746
 * Full displacement (t): 828
 * Speed (kt): 18
 * Range: 5300 nm @ 8 kt or 800 nm @ 15 kt
 * Crew: 55 – 60
 * Propulsion: 2 Chinese copy of Kolomna 9-D-8 diesel engine @ 2000 hp
 * Armament: twin 37 mm gun x 1 and 2 twin 14.5 mm machine guns

Type 912I
Type 912I is a very simple modification of the original Type 912, mainly as a stop gap measure for more advanced Type 912II design. However, due to Chinese policy of foreign military aid as first priority, Type 912II was cancelled to make room for Type 915, Type 916, and Type 918. When these foreign military aid programs were completed, further improvement Type 912III was already in place because subsequent decision was made to construct it in parallel with foreign military aid programs, and Type 912II never went beyond design stage. Only a single unit was of Type 912I was completed, serving in South Sea Fleet.

Type 915
Type 915 is a variant of Type 912I built for North Vietnam as military aid. The main difference between Type 915 and Type 912I is the improvement of air conditioning system for tropical condition. Built by Huangpu Shipyard of Guangzhou Shipyard International, all units were delivered in 1974.

Type 916
Type 916 is a variant of Type 912I built for North Korea as military aid. The main difference between Type 915 and Type 912I is the improvement of air conditioning system for subarctic condition. These units were delivered in kit form in 1975, and assembled locally in North Korea

Type 918
Type 918 is the improvement of earlier Type 915, based on the experience of countering US magnetic mines laid in North Vietnam, which provided unexploded examples to China for research./reverse engineering. Experience gained in turn, were used in improving the design of later degaussing/deperming ships.

Type 912III
Type 912III is the enlarged version of Type 912I with design improvement from lessons learned from research on US magnetic mines. Type 912III received NATO reporting name Yanbai class. Specification:
 * Length (m): 58
 * Width (m): 8.8
 * Draft (m): 3.5
 * Standard displacement (t): 500
 * Full displacement (t): 570
 * Speed (kt): 16
 * Range: 3500 nm @ 8 kt
 * Crew: 55 – 60
 * Propulsion: 2 Chinese copy of Kolomna 9-D-8 diesel engine @ 2000 hp
 * Armament: twin 37 mm gun x 1 and 2 twin 14.5 mm machine guns

Type 912IIIA
Type 912IIIA is a slight variation of earlier Type 912III, with minor upgrade of Type 912III, mainly with improvement of living condition onboard

Type 912IIIAH
Type 912IIIAH is further improvement of earlier Type 912IIIA, and these are the latest model of Type 912 series (as of early 2014). All Type 912IIIAH ships are built in Shanghai by Shenjia (申佳) Shipyard, also known as 4805th Factory of PLAN.

Ships
Type 912 series are designated by a combination of two Chinese characters followed by three-digit number. The second Chinese character is Qin (勤), meaning service in Chinese, because these ships are classified as service ship. The first Chinese character denotes which fleet the ship is service with, with East (Dong, 东) for East Sea Fleet, North (Bei, 北) for North Sea Fleet, and South (Nan, 南) for South Sea Fleet.