# Type 039A submarine

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 533 mm (21 in) 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 Kilo class. 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:
* Type 039A: Original Yuan class, comprising four units (Changcheng 330 to Changcheng 333). The most obvious external visual difference between Type 039A and its predecessor Type 039/039G Song-class submarine is in the conning tower. The conning tower of Type 039A is similar to that of Type 039G, but the tower lacks the fin-shaped extrusion on the rear section of the conning towers of both the Type 039 and the Type 039G.
* Type 039AG: This second member of Type 039A series is frequently but erroneously identified as its development, Type 039B, because externally, the two version looks the same above waterline. The only difference lies below the waterline, which is not readily observed, and it is believed that all Type 039AG have been converted to Type 039B. The most obvious external visual difference between Type 039AG along with its development Type 039B and earlier Type 039A submarine is also in the conning tower: the shape edge at the top of conning tower of Type 039A is replaced with smooth round shape transition. In addition, there is a bulge in the middle of the smooth transition in the forward portion of the conning tower housing some kind of sensor, and this is a new feature earlier Type 039A lacks.
* Type 039B: This third member of Type 039A series looks identical to earlier Type 039AG from which it is developed from. Including those units upgraded as mentioned below, it comprises thirteen units (Changcheng 334 to Changcheng 346). The biggest difference between Type 039B and Type 039AG is that Type 039B has incorporated flank sonar array, which was subsequently retrofitted on Type 039AG and some earlier boats. This difference, however, is not readily observable because the flank array is installed at the lower portion of the hull. It was only in the early 2010s when a Type 039B built by Shanghai Changxing (长兴) Shipyard exposed in the berth, when the flank array of Type 039B became publicized, thus distinguish the type from earlier Type 039AG that lacked the flank sonar.
* Type 039B (upgraded): The fourth variant of the Yuan has been first publicized in December 2013, with a modified hull and redesigned conning tower with extrusion at the root of the conning tower in both the bow and stern direction, similar to that of conning tower of Virginia-class submarine. In addition, the bulge housing unknown sensors on board Type 039B in the forward section of the top edge of the conning tower is absent on the new boat launched in April 2014, but there are three white lines at the top of edge of the conning tower on both sides, presumably for environmental sensors. This new boat is claimed to be an upgraded variant of Type 039B.
* Type 039C: A new variant commissioned from 2022 onwards with redesigned stealth sail. First spotted in May 2021 in Wuhan. It has been noted that the redesigned stealth sail looks similar to the sail of the Swedish A26 Blekinge class submarine. However, there are some noticeable differences, such as the sail of the Type 39C having a less blended lower part and the fairwater planes (hydroplanes) being mounted very differently. Besides a redesigned sail this variant also has a noticeably wider casing and the outer shape of the hatch appears to have been cut in the form of a square. It comprises three units commissioned to date, with another five under development. This class was tentatively called "Olympics-class" before a clear identification with the Yuan-class is made, as a video originally surfaced on Chinese social media around the time of 2022 Winter Olympics in Beijing.
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.

### Export

* S20: At IDEX-2013, China revealed a scaled-down version of Type 039A submarine designated as S20, specially intended for export. The main difference between the S20 and Type 039A is that the AIP system is believed to be optional. Due to its modular design, a variety of sensors and weapons can also be easily adopted up on customers' requests. Specifications of S20:
** Structure: double hulled
** Length: 66 meter
** Beam: 8 meter
** Draft: 8.2 meter
** Surface displacement: 1,850 tons
** Submerged displacement: 2,300 tons
** Maximum speed: 18 knots
** Cruise speed: 16 knots
** Range: 8000 nautical miles at 16 knots
** Endurance: 60 days
** Crew: 38 total
** Maximum depth: 300 meters
* The full-size platform has been modified for export. See section immediately below.

## Export

* Royal Thai Navy: On 2 July 2015, the Royal Thai Navy (RTN) formally selected China's Yuan-class platform to meet a requirement for three submarines. The RTN's procurement committee voted unanimously in favour of purchasing the submarine, which has been designated S26T (Thailand), a modified export version of the Yuan class. On 1 July 2016, the RTN submitted a funding plan for its 36 billion baht submarine procurement project to the cabinet for consideration with the expenditure to be spread over 11 years. If approved, the first submarine would be bought for 13 billion baht between fiscal years 2017–2021. The second and third submarines would be purchased during the remainder of the 11-year period. In May 2017, the Royal Thai Navy and Thai Government signed a contract for one S26T variant of the submarine in a $390 million deal. Orders for an additional two submarines are expected in the coming years. Steel cutting ceremony of the first S26T submarine was held on 4 September 2018 at Wuhan, China.
* Pakistan Navy: (See Hangor-class submarine.) In April 2015, the Government of Pakistan approved purchase of 8 export version of Type 039B (Upgraded) from China for $5 billion for the Pakistan Navy. The deal was finalised on 23 July 2015. In October of the same year, it was revealed that four of the eight of the submarines will be built in Pakistan, with work beginning in both nations simultaneously. Pakistan's Minister for Defense Production confirmed that the agreement included transfer-of-technology to construct the vessels. On 6 July 2015, Tanveer Hussain, minister of defence production, announced two projects for the construction of four submarines in China and four in Pakistan will begin simultaneously. Hussain added that a training centre will also be created at KSEW. In late 2016 it was officially confirmed that China will see about four submarines delivered by 2023 and the remainder delivered by 2028.