July 7, 2022: The submarine component of the Russian Black Sea Fleet has turned out to be less effective than expected, except for the elderly Alrosa. This was one of the original Kilos, entering service in late 1990 and part of the Black Sea Fleet since 2005. As the new 636.3 Kilos arrived in the Black Sea, Alrosa was supposed to return to the Baltic Sea Fleet in 2020 to serve as a training boat for new submarine sailors. That never happened because Russia decided to use Alrosa as a test bed for using pump-jet propulsion in a diesel-electric sub. Work on installing this new tech in Alrosa had been underway, slowly, since 2014. This tech is considered too heavy for use on diesel-electric subs and is a feature of many new nuclear subs. Alrosa has spent several years being modified to carry an advanced pump-jet design. This is not intended as a Kilo upgrade, but to see how well the tech does in a non-nuclear sub. If the tests are successful, the Alrosa pump jet might be installed in the Kilo successor, the long-delayed Lada.

Pump jet propulsion provides several advantages. These include allowing quieter higher speeds. Pump jets have many other advantages, including better handling in shallow water, which the Black Sea has a lot of. Russia revealed that Alroas and its new pump jet began sea trials in mid-June and these would continue for as long as required. That means one of the two or three seaworthy Black Sea Fleet Kilos is using an experimental (for non-nuclear subs) propulsion system that makes Alrosa more difficult to detect when submerged. With Ukraine winning its battle for control of its coastline, the Alrosa may prove to be a major obstacle.

When Russia invaded Ukraine in February, only five of the seven of the Kilo-class subs assigned to the Black Sea Fleet submarine squadron were in actually in the Black Sea. The other two were on patrol in the eastern Mediterranean, a common task for Black Sea Fleet in peacetime. In wartime Turkey, which controls the only deep-water access to the Black Sea, is obliged by international treaty to block warships of nations at war from entering the Black Sea. Russia is trying to get around that for its two Kilos but so far, these Kilos are stuck in the Mediterranean, where Russia has a naval base on the Syrian coast to temporarily host the Kilos.

The five Kilos still in the Black Sea are based at Sevastopol, but at least two of them have been out of action because of required maintenance or, in the case of Alrosa, sea trials for its major experimental upgrade. Ukraine has assistance from NATO to track Russian naval activity, especially west of Sevastopol where Ukraine plans to take control of coastal waters from Russia. This is complicated by the appearance of Alrosa, which has a unique (for Kilo-class boats) acoustic (sound) signature that Western anti-submarines forces have never encountered before and currently have difficulty detecting and tracking. This won’t halt Ukrainian efforts to reclaim control of coastal waters so they can resume shipping wheat by sea. Alrosa will slow down efforts to keep Russian warships out of this area. That also slows down Ukrainian plans for recapturing Sevastopol and Crimea. The Kilos still in the Black Sea are believed responsible for recent cruise missile attacks in which missiles launched from submarines were among some of those employed.

Sevastopol was the original (1783) main base of the Black Sea Fleet and that continued until 1991, when newly independent Ukraine inherited the Sevastopol base and much of the Russian Black Sea fleet. This was the deal made by the collapsing Soviet Union in 1991 to avoid chaos and a ruinous civil war with several factions, including Ukraine, having nuclear weapons. After 1991 Russia had half the population it controlled as the Soviet Union. Ukraine still had those nukes and Russia agreed to another deal to have Ukraine surrender the nukes for decommissioning and turning into metal as well as fuel for nuclear power plants. The U.S. and Russia had a similar agreement which greatly reduced the number of nuclear weapons the two superpowers had and provided a large supply of nuclear power plant fuel. A 1997 treaty also gave Russia a long-term lease on part of Sevastopol so it could continue as the main base for the Russian Black Sea fleet. Russia also got to keep most of the Soviet-era Black Sea Fleet warships. An earlier 1993 treaty with Ukraine included a Russian pledge to never attack Ukraine or its territory if Ukraine surrendered its nuclear weapons.

Russia unilaterally violated that treaty in 2014 when they sized Crimea. That involved capturing or sinking most of the larger warships in the Ukraine fleet and rebuilding the Black Sea Fleet submarine squadron. In 2022 Russia invaded in an effort to control all of Ukraine. Their Black Sea Fleet was still in the midst of rebuilding by replacing Cold-War (pre-1991) era ships with more modern vessels. This included the latest version of the Kilo, the Type 636.3, which entered service in late 2014 with the first ones stationed in Crimea. The 636.3 boats are basically a much-upgraded Kilo. The 636.3 has stealthy features and a top underwater speed of 36 kilometers an hour. The crew of 52 can stay at sea for up to 45 days at a time. Armament consists of 18 torpedoes or missiles plus eight surface-to-air missiles.

The six new 636.3 boats gave Russia 25 Kilos with another seven retired but in reserve (can be restored to active duty). In addition, nearly 40 Kilos have been exported (delivered or under construction) All are the same displacement (about 2,300 tons) and size (70-74 meters/227-240 feet) and all have six 533mm torpedo tubes. All Kilos are very similar to the world-standard diesel submarine, the 1,800-ton German Type 209. The Kilo is a formidable attack submarine and has been continually upgraded with better mechanical and electronic systems since the first one entered service during the Cold War. Of the 73 Kilo’s built, just over half entered service after 1991. The first one entered service at the end of 1980 and production was intense until 1991, when it slowed down but never stopped. Four are currently under construction. Efforts to create a replacement (the Lada class) have been underway since 1997 and failure to surpass the capabilities of Kilo class improvements has stalled introduction of the Lada. The Kilo Type 636 appeared in 1997 followed by the 636.3 in 2014. If the pump jet performs well in Alrosa, the Lada may finally begin replacing Kilo by the end of the decade.