Type 039A Yuan-class Design
The Yuan incorporates lessons from the PLAN's experience with the Kilo. The Yuan incorporates some of the best features of the Song and the Kilo. The Yuan class has a tail with diving planes similar to those of the Type 039G, and a Kilo-style teardrop shaped hull with a raised hump on top. The Yuan has the raised decking/casing of the Kilo, the high freeboard and reserve bouyancy, a similarly-shaped bow (and torpedo tube disposition), but with the sail, propeller layout and stern section of the Song. It has also been suggested that the new submarine may be comparable to the improved variant of the Russian Kilo class (Project 636) in terms of size and general performance.
Precise specifications for the Yuan are unclear, though it is evidently about as large as the 242 foot long Kilo and the 246 foot long Song, that is about 75 meters. Considereing the fact that this class is nearly a decade old, the new 2013 edition of Combat Fleets had surprsingly sparse information.
China is building a powerful submarine fleet, including domestically built Song and Yuan-class boats. The beating hearts of these subs are state-of-the-art diesel engines designed by MTU Friedrichshafen GmbH of Friedrichshafen, Germany. Alongside 12 advanced Kilo-class submarines imported from Russia, these German-powered boats are the workhorses of China's modern conventional submarine force.
The overall design of the Yuan-class submarines is very different from that of the Song-class submarines, and is definitely a completely new design. For example, the Song-class submarines still use a whale-shaped hull similar to the previous generation of Soviet-made R-class and Ming-class diesel-electric submarines, while the Yuan-class submarines use a more advanced teardrop-shaped design, with a rounded and full appearance and a relatively thick and flat bow. Since Russia firmly denies that it has assisted in the design of the submarine, the Yuan-class submarines should be a product of the mainland's own design.
At the upper edge of the bow of the Yuan-class submarine, there are six torpedo tubes in a configuration of two on top and four on the bottom. The lower part of the bow is left empty to install a large active and passive sonar system, which is quite similar to the Russian-made Kilo-class submarine. It is much better than the design of the Song-class submarine, where the torpedo tubes occupy most of the bow space. It can be estimated that the underwater detection capability of the Yuan-class submarine, especially the passive listening capability, will be greatly improved compared with the Song-class submarine. In addition to the improved sonar system, the Yuan-class submarine is also speculated by the West to use an optoelectronic detection mast, which may be equipped with CCD cameras, infrared thermal imagers, laser rangefinders, etc. All sonar, optoelectronic detection, radar, electronic warfare and weapon systems on the ship may be connected to a digital integrated combat system. In terms of weapons, it may use Russia's latest TEST-71MKE wire-guided torpedoes or 53-65KE torpedoes, etc. Its torpedo tubes should also be able to launch mines, anti-ship missiles and other weapons, such as the mainland C-801 submarine-launched type and the Russian-made "Club" anti-ship missile.
The parameters of the Yuan-class submarine are estimated as follows: 77.6 meters long, 8.4 meters wide, 5.5 meters draft, 1900-2000 tons displacement on the surface, 2500-2600 tons displacement underwater. From the pictures, the Yuan-class submarine is equipped with silencing tiles, which is very helpful for noise reduction, but there are still a long row of openings on both sides of the hull, which is easy to produce a lot of noise when water flows through, which is slightly inferior to the latest generation of submarines in Europe, the United States, Russia, and Japan, which try to reduce the number of openings as much as possible to make the surface of the hull smooth. The Yuan-class submarine uses a cross-shaped tail rudder, and the front horizontal wing is located on both sides of the sail cover. The rudder design is similar to the Song-class submarine, and the propeller is a high-curvature seven-blade propeller.
According to The Washington Times (July 16, 2004), American officials initially believed the submarine was diesel-powered. In March 2007 Jane's Navy International reported that the Yuan class was fitted with an AIP system developed by the No.711 Research Institute. Yuan is using an AIP engine of 100 kw in power, and is probably equipped with 2 such AIP engine. The Gotland submarines use 2 V4-275R stirling AIP units (each rated 75 kw). The larger Yuan obviously needs more powerful AIP units.
Study of a special engine, started at the Institute of the China shipbuilding industry Corporation 711, took developers decades to build. In 1975, China ship Research Institute No. 711 Research Institute set up a special laboratory of engines, and in June 1996, the establishment of specialized engine Engineering Research Center. After the "85", "95" studies focused on 12 key technologies. After years of work, full independent intellectual property rights were successfully developed for China's first specialty engines. After they successfully developed a project prototype, the overall technical level reached the international advanced level, and in some technology China claimed to be an international leader.
Special engine research process, 711 Research Institute saw this as an opportunity to train a large numbers of technical personnel. From the beginning of the project, the team had only 10 people, which grew to more than 100 people. And emerging model of advanced excellence, this team was recognized as the people's Liberation Army General armament Department "researching advanced group", and was twice awarded the "Shanghai model workers collective".
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 powered submarines, and therefore much more difficult to be tracked. Apart from indigenously developed submarine weapon systems such as indigenous active/passive-hoyuan torpedo and the YJ-8 (C-801) submarine-launched anti-ship missile, the Yuan class may also be capable of launching the latest Russian weapons (or their Chinese copies) such as the TEST-71MKE wire-guided torpedo, the 53-65KE wave-hoyuan torpedo, and even 3M-54E Club supersonic submarine-launched anti-ship missile.
The electronic systems onboard the Yuan class may include CCD camera, infrared/thermal image camera, laser range-finder, surface-search radar and radar warning receiver. Various weapon systems and sensors are integrated by a digitized combat data command and control system.
The technical information on the Winston Battery WB-LYP10000AHA in large submarines gives some ideas about the size of the battery pack for the Yuan-class of diesel-electric submarines to be equipped with an air-independent propulsion system (AIP) powered from large battery banks. The battery pack consists of 960 pcs of the WB-LYP10000AHA cells making the total energy of 31MWh. The lithium battery is saving some 260 tons of weight against the original lead-acid pack. With this pack the Yuan-class (B-class) diesel-electric submarine can drive 3300 nautical miles or it can stay under water for 800 hours (33 days). This indicates the average onboard consumption of the submarine when not moving is some 38kW/h.
CSIC's submarines sold to Pakistan and Thailand all have a single hull design. Different from the traditional double-shell structure. It shows the progress China has made in materials and related technologies in recent years. The design of these three new Chinese submarines is clearly the result of the latest fluid dynamics and acoustics research of the 701 Institute. These designs are similar to the Chinese Navy 039B attack diesel submarine. The underwater noise is further reduced.
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