February 17, 2022: China has apparently started retiring the Russian Kilo class subs it purchased since the 1990s. The first of these arrived in 1994 and by 2006 China had 12 Kilos, all but two of them the latest models. China planned to obtain up to ten more Kilos but Russian prices kept going up while quality and reliability visibly declined. China had been buying Russian Whiskey-class diesel-electric subs since the 1950s but most of those it put in service were assembled in China from Russian parts. In the 1960s China began assembling the new Romeo-class but only two were made from Russian parts before a major diplomatic crisis (over disputed borders) halted all Russian military assistance in 1969. China continued building Romeos as Type 033 subs but had to manufacture all the components. This China found it was able to do, and was soon building Type 033s that surpassed current Russian Romeos in quality and performance.

By the 1980s Chinese Type 033s were being exported to nations that rejected Romeos. China built 84 Type 033s, most for its own use. Russia built 133 Romeos between 1957 and 1961. Then came 74 Russian Foxtrots. These were built between 1957 and 1983 and the last was retired in the late 1990s. Foxtrot was followed by 18 Tangos, built between 1972 and 1982 with the last of them gone by 2016. Tango was followed by 73 Kilos, with the first one entering service in 1982. Russia has been unable, after several attempts, to develop a Kilo replacement while China has succeeded. This is why China is retiring its Kilos. Russia tried to downplay this development but that became increasingly difficult.

For example, in early 2021, when Russia announced its planned warship deliveries for 2021, one delivery was considered doubtful. This involved actually putting a second Lada class diesel-electric boat into service by the end of the year. The first one was finally accepted by the navy in 2010, but only as a test vessel for experiments with new equipment. Russia has been sending mixed signals about the Lada Class boats for two decades and the second Lada was to be the first “production model” fit for active service.

In early 2019 Russia announced that the second Lada class submarine would be completed and ready for sea trials by the end of 2019. That turned out to be just another overly-optimistic plan. While the first Lada was “accepted” by the navy in 2010, the second two were canceled in 2011. That was because the Navy had conducted years of sea trials after the first Lada was completed in 2005 and those extensive trials demonstrated that the performance of this design did not meet Navy requirements. The problems were so severe that the navy demanded that work be halted on the second and third ones.

All this was surprising because the second Lada was nearly ready for launch. Because of that the unfinished Lada was not scrapped and the sub was preserved in case some solution to all the problems could be found work resumes quickly. That eventually happened and the second Lada was launched in September 2018. Construction of the third Lada began in 2015 but was also halted before it was ready for launch.

There were many problems with the Lada, but the main one appears to be the failure of the long promised Russian AIP (air independent propulsion) system. This was supposed to be a key feature of Lada. That AIP and several other upgrades planned for new Kilo class models were supposed to justify calling the Ladas a new class of sub, not just another improved Kilo.

Desperate for a solution to all the design and construction problems, Russia turned to an Italian ship builder to jointly develop and build Lada export models, called the Amur class, which would use Western AIP tech. Russia was never able to obtain any export sales for Amur and the project was canceled in 2013. Amur would have been dead soon anyway because of the sanctions imposed on Russia because of the 2014 invasion of Ukraine.

Lada began development in the 1990s as the successor to the Kilo, but the promised improvements that made Lada unique, especially the AIP, were never ready so there was not enough difference between the Lada and the improved Kilos being built to justify continuing work on a Kilo successor.

The 2,700-ton Lada is 72 meters (236 feet) long, and carries a crew of 35. Each crew member has their own cabin. Although individual quarters were very small for the junior crew, this feature was a big morale boost. When submerged Lada moved at up to 39 kilometers an hour but only half that on the surface. Maximum depth is about 300 meters (984 feet). The Lada can stay at sea for as long as 45 days and travel submerged indefinitely using its diesel engine while at periscope depth, via the snorkel device that brings in fresh air and vents the diesel exhaust. Submerged at any depth, using battery power alone, Lada can travel about 450 kilometers. There is also an electronic periscope, which goes to the surface via a cable, that includes night vision capability and a laser range finder. From the beginning Lada was designed to accept an AIP system that never arrived.

Lada was designed for anti-surface and anti-submarine operations as well as reconnaissance. It has six 533mm (21 inch) torpedo tubes, with 18 torpedoes and/or missiles carried. As many as 44 mines can be carried instead of torpedoes and missiles and deployed via the torpedo tubes. Ladas were described as eight times quieter than the Kilos. This was accomplished by using anechoic (sound absorbing) tile coatings on the exterior as well as very quiet (skewed) propeller. All interior machinery was designed with silence in mind. The sensors include active and passive sonars, including towed passive sonar.

Russian submarine designers apparently believed they could install most of these quieting features into improved Kilos, along with many other Lada features. But the main distinction between Lada and late-model Kilos was the AIP and the first two Ladas did not have it. The 2019 announcement confirmed this. The current plan is to see if the other accumulated Kilo upgrades applied to the Lada work, and then install the AIP in the third Lada.

What Russia has not discussed is the fact that most Kilos, and Ladas as well, are meant for export and China has been getting more and more export sales that otherwise would have been for Russian Kilos. China has been building its own Kilo clones and in mid-2018 the Chinese navy proclaimed that its new AIP equipped “Kilo” submarine performed very well. Actually, as described, the Chinese AIP performed about as well as early Western AIP systems. For the Chinese that was good enough because they have had problems getting their AIP, apparently based on the Swedish Stirling AIP system, to perform adequately and reliably. China worked on getting a reliable AIP system in one of their Yuan class Type 39B subs for over fifteen years but until 2018 no Chinese AIP equipped boats were seen in action. That changed in early 2018 when a new Yuan class sub went to sea and operated like an AIP boat by staying underwater for more than a week. According to the Chinese press releases, their AIP sub stayed under for over two weeks at a time, which is typical of what a Stirling AIP system can do.

China currently has as many as seventeen AIP equipped Type 39 (Yuan) boats. Type 39s are no longer built with AIP as a standard feature. Instead, AIP is offered, to export customers, as an expensive option. China is building a lot more Type 39s, having recently completed a new shipyard in Wuhan for mass production of the Type 39 and the S20 export version. China originally planned to build twenty Type 39s but the new Wuhan shipyard indicates there will be a lot more than twenty.

Type 39s are based on the late model Russian Kilos. Construction of the Yuans appeared to have halted in 2013 for reasons unknown. Then at the end of 2016 three more of these Yuan class (Type 39B) subs were seen being built. The last new Type 39B appeared in late 2013 but even before that, there were indications that this was another pause to absorb user experience with the current model and plan modifications for the next batch.

In late 2016 it was believed the three latest 39Bs would have many modifications and upgrades, some of them visible because of minor changes in the conning tower or hull features. China upgraded its sensor and fire control electronics as well. The Chinese AIP appears to have encountered no major problems but Chinese naval commanders have concluded that AIP is not always worth the additional cost.

One thing was certain about the latest Type 39Bs; the Chinese are continuing their relentless effort to create world-class subs one tweak and improvement at a time. Since the late 1980s, China has been designing and building a rapidly evolving collection of "Song" (Type 39) class diesel-electric submarines that emphasize quietness and incremental improvements. The changes were eventually so extensive that the four Songs completed in 2013 were recognized as a new type and designated the Yuan class (Type 39A). The original design (Type 39) was a 2,200-ton Kilo type sub that first appeared in the late 1990s and 13 were built. The larger (2,800 ton) Type 39A first appeared in 2006 and quickly evolved into the larger and more lavishly equipped Type 39B. The evolution continues, and there are now thirteen "Type 39 Yuan Class" subs (of at least four distinct models). These latest models were designed to have AIP along as well as 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, which they began doing since the 1960s. The recent versions of the Type 39B design show Chinese naval engineers are getting more creative. The Yuans were meant to have an AIP that would allow them to cruise underwater longer. Western AIP systems allow subs to stay underwater for two weeks or more. China has been working on AIP since 1975 and the first working prototype was available by 1998 but required over a decade to become reliable. The Chinese kept improving on their AIP via numerous tweaks and was finally installed in some of the latest Type 39B subs.

The Songs look a lot like the Russian Kilo class and that was no accident or coincidence. The 39s and 39A/Bs are both similar in appearance but the type 39A/Bs appear larger than the original Song Type 39s. Both have 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 39Bs appeared to be a copy of the early model Kilo (the model 877), while the second pair of Type 39Bs 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 unsuccessful Lada. The Type 39s were the first Chinese subs to have the teardrop shaped hull. The Type 39B 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. It was and it succeeded. Realizing this Russia suddenly rushing to resume work on an AIP Lada. Russia could not get their AIP to work, and that became obvious when AIP equipped Chinese subs were being offered to export customers. China has been offering its “improved Kilo” designs to export customers like Pakistan and Thailand for $400 million to $600 million each.

So far, 73 Kilos have been built of which 60 are still in service, and more may be built. It may be an old design, but it is mature and has been updated with modern electronics and quieting technology. Kilo may never have AIP and Russia still gets exports sales for Kilo because not every customer is looking for AIP.