Recently the captain and crew of one of China’s twelve Kilo class subs (submarine 372) were publically honored for saving themselves and their sub with quick and effective response to a flooding problem that threatened to take the boat deep enough to be crushed. Not many details of the incident were revealed but it was emphasized that the crew acted more effectively than earlier crews had done. Perhaps most importantly the captain did not call for a tug to haul the crippled (for a while until the crew could make repairs) sub back to port. This has happened many times to Chinese subs in the last few decades. But not 372 and that was worthy of praise and a great relief to political and military leaders. The actions of the crew and its captain indicated that the billions of dollars and decades of effort had paid off. A major reason for this was the decision in the late 1990s to have ships, and especially subs, spend more time at sea. This was dangerous because the crews had little experience and were at risk of embarrassing incidents (which did occur) if they were allowed to spend a lot of time at sea. As astute students of history the Chinese leaders were persuaded to allow the increased training as there was no other way to obtain competent crews that could handle emergencies, and combat, successfully.
The Kilo class boats were always more of a known quantity as they had entered service in the early 1980s. Russia only bought 24 of them but exported over 30. It was considered a successful design, especially with export customers. But just before the Cold War ended in 1991, the Soviet Navy began work on the Lada. This project was stalled during most of the 1990s, by a lack of money, but was revived in the last decade. Russia has 17 Kilos in service (and six in reserve) and four improved Kilos on order. More than that is on order from foreign customers.
Meanwhile, the Chinese Navy has been designing and building a rapidly evolving collection of "Song" (Type 39) class diesel-electric submarines that emphasize quietness. The changes have been so great that the four most recently built Songs were recognized as a new type and designated the Yuan class (Type 39A or Type 41). The original design (Type 39) first appeared in 2001, and 13 have been built. Type 39A appeared in 2008. Two of these Type 39As appeared before two of another variant, sometimes called Type 39B, showed up. The evolution continues, and there are now thirteen "Type 41 Yuan Class" subs (of at least three distinct models). These latest models appear to have AIP (air independent propulsion system) along with new electronics and other internal improvements.
This rapid evolution of the Type 39 appears to be another example of China adapting Russian submarine technology to Chinese design ideas and new technology. China has been doing this for as long as it has been building subs (since the 1960s). But this latest version of what appears to be the Type 41 design shows Chinese naval engineers getting more creative. Two or more Yuans are believed to have an AIP that would allow them to cruise underwater longer. Western AIP systems allow subs to stay under water for two weeks or more. The Chinese AIP has less power and reliability and does not appear to be nearly as capable as Russian or Western models. The Chinese will keep improving on their AIP, just as they have done with so much other military technology.
The Songs look a lot like the Russian Kilo class and that was apparently no accident. The 39s and 41s are both similar in appearance but the type 41s appear larger than the 1,800 ton Type 39s. Both have with crews of 60-70 sailors and six torpedo tubes. This is very similar to the Kilos (which are a bit larger). China began ordering Russian Kilo class subs, then one of the latest diesel-electric designs available, in the late 1990s. The first two Type 41s appeared to be a copy of the early model Kilo (the model 877), while the second pair of Type 41s appeared to copy the late Kilos (model 636). The latest Yuans still appear like Kilos but may be part of an evolution into a sub that is similar to the Russian successor to the Kilo, the Lada. The Type 39s were the first Chinese subs to have the teardrop shaped hull. The Type 41 was thought to be just an improved Song but on closer examination, especially by the Russians, it looked like a clone of the Kilos. The Russians now believe that the entire Song/Yuan project is part of a long-range plan to successfully copy the Kilo. If that is the case, it appears to be succeeding.
China currently has 13 Song class, 12 Kilo class, 13 Yuan class, and 18 Ming (improved Russian Romeo) class boats. There are only 3 Han class SSNs, as the Chinese are still having a lot of problems with nuclear power in subs. Despite that, the Hans are going to sea, even though they are noisy and easily detected by Western sensors. Five Hans were built (between 1974 and 1991) but 2 have already been retired. There are 4 newer Shang class SSNs in service, but these are still pretty noisy. The Song/Yuan class subs are meant to replace the elderly Mings. The four Ladas will give Chinese submarine builders some ideas and goals for future subs of this type.