Chinese diesel-electric submarine class
The Type 039A submarine (NATO reporting name: Yuan class) is a class of diesel-electric submarine in China's People's Liberation Army Navy. It is China's first AIP powered submarine. The "Yuan" class is the successor of the "Song" class submarine. The class is designed to replace the aging Type 033 (Romeo class) and the older Type 035 submarines that previously formed the backbone of the conventional submarine force. The "Yuan" class is armed with wired-guided and wake-homing torpedoes, long-range land-attack and anti-ship cruise missiles, and naval mines.
According to an early assessment by the US Naval Institute, the Yuan class was primarily designed as "an anti-ship cruise missile (ASCM) platform capable of hiding submerged for long periods of time in difficult to access shallow littorals." However, another assessment by USNI includes an open-ocean capability which can be used beyond coastal waters. Also updated was its role within China's naval fleet, and as of August 2015 it is considered to be a more traditional attack submarine, with a secondary ASCM role.
Design.
The design of the "Yuan" class is thought to be modeled on, or heavily influenced by, the Russian "Kilo" class. In addition, the design also appears to show some similarities to the Chinese "Song" class. When it comes to general performance it is believed that the "Yuan" class could be comparable to the improved Project 636 variant of the "Kilo" class. Submarines of the "Yuan" class have been built at Wuhan Shipyard and Jiangnan Shipyard.
Hull.
The "Yuan class" submarines have a teardrop-shaped hull and are believed to be double-hulled. They also have a angled casing, which appears like a distinctive hump. While earlier variants of the "Yuan" class have a large upright sail, newer variants have instead a more angled sail.
The Type 039A inherits the tail design of the Type 039 (NATO codename: Song class) with upper and lower rudders and sternplanes with a single propeller shaft. A pair of fairwater dive planes are positioned on the sail. The submarine is equipped with indigenously developed machinery rafts (shock absorbers) system that helped to reduce noise level by over 35 dB. Additionally, the submarine is covered with rubber anti-sonar anechoic tiles to reduce the risk of acoustic detection.
Armament.
The "Yuan" class has six torpedo tubes, which are located at the bow. These can be used to launch indigenous torpedoes such as the Yu-3, Yu-4 and the Yu-6. Furthermore, the submarines of the Yuan class are also capable of launching the YJ-82 or YJ-18 anti-ship missiles. In addition, they can be armed with naval mines. The general designer of the torpedo and missile launching system is Sun Zhuguo (孙柱国).
Combat control systems.
China was known to have imported the Thales TSM 2233 ELEDONE / DSUV-22 and Thales TSM 2255 / DUUX-5 from France during the 1980s and early 1990s. It also has access to a wide range of modern Russian sonar systems (MG-519 MOUSE ROAR, MGK-500 SHARK GILL) through its purchase of the . Comparable systems are expected to be copied for the Type 039A. It is likely to be fitted with a comparable surface/air search radar similar to the MRK-50 SNOOP TRAY, a commercial navigation radar like a Furuno unit observed on a number of SONG class and ESM system is comparable to the Type 921A.
Propulsion.
The "Yuan" class is equipped with an air-independent propulsion (AIP) system. The AIP system is believed to be using closed-cycle Sterling engine technology. According to the Chinese newspaper "Science and Technology Daily" (科技日报), this 039A class is equipped with an air-independent propulsion system developed by the 711th Research Institute of the China Shipbuilding Heavy Industry Group Corp. In 1998, the first experimental sample was built and a decade later and after a dozen technological breakthroughs, a wide range of matured versions became commercially available and the newest diesel-electric submarine in Chinese navy became the first customer. Although the official Chinese source had not mentioned the exact class of the submarine, it is generally accepted that the class is no other than Type 039A Yuan class, since it is the newest conventional powered submarine in the Chinese navy. The engine is built by Shanghai Qiyao Propulsion Technology Ltd. (上海齐耀动力技术有限公司), a wholly owned subsidiary of the 711th Institute.
Noise.
The Yuan-class SSK is integrated with advanced noise reduction techniques including anechoic tiles, passive/active noise reduction, asymmetrical seven-blade skewed propeller, the 039A is expected to be as quiet as other modern diesel-electric submarines, which are difficult to track.
Variants.
China.
A total of four variants of Type 039A have been developed by the first half of 2014, and they are listed here in chronological order based on their public debut:
A satellite image of the Wuchang Shipyard, dating to 26 April 2024, was acquired by Tom Shugart, an adjunct senior fellow at the Center for a New American Security (CNAS) think tank and retired U.S. Navy submarine warfare officer, whom was first to notice the new boat, at the Wuchang Shipyard, in Wuhan. The new design features X shaped stern control planes. Further images began circulating in December showing a submarine with "X" planes and a lockout chamber on top of the deck. Chinese users on Facebook pointed out that the submarine was allegedly a modified Type 039C. H.I Sutton, an author at USNI News, stated on Twitter that "Some things look right to me, except... no way they are already testing DDS on this submarine, much too quick development is my gut feel" 
Of the first seventeen units (Types 039A and 039B), ten vessels (numbers 330 to 339) are active with the East Sea Fleet, two vessels (numbers 340 and 341) with the North Sea Fleet, and five vessels (numbers 342 to 346) with the South Sea Fleet.
Notes.
Citations.
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