Thread by @ChrisO_wiki

1/ Last night's highly successful Ukrainian attack against a drydock in Sevastopol appears to have caused significant damage to a Kilo-class submarine, the Rostov-on-Don (B-237), as well as to a Ropucha-class landing ship.

https://twitter.com/Tatarigami_UA/status/1701960181402239266

2/ Ian Matveev has written a useful thread explaining why this is so significant and why the submarine may have been the principal intended target. Translation follows below. ⬇️

By @ian_matveev:

Which submarine was attacked in Sevastopol?

3/ It is reported to be the Rostov-on-Don, Project 636.3 "Varshavyanka", a multipurpose diesel submarine with Kalibr missiles. Let me tell you more about it in a short thread.

4/ Project 636 "Varshavyanka", known as 'Improved Kilo' according to NATO classification, is the export version of Project 877 "Paltus" [the original Soviet designation for the Kilo-class vessels – Project 636.3 is a further improvement from the mid-2010s]. (Pic by @CovertShores)

5/ Together they make up the Russian Navy's fleet of 20 diesel multipurpose submarines. There are 7 such boats in the Black Sea Fleet.

6/ One of them was spotted in a dry dock next to a Project 775 landing ship – which was attacked this night and badly damaged. Perhaps the real target was the submarine – I will explain why below. (Photo published by @DefMon3)

7/ As the name suggests, the Varshavyankas [named after a Polish revolutionary song, 'Warszawianka'] were built for the Warsaw Pact countries, but then something happened. Some of them went to China, the rest stayed at home and are still being built.

8/ Despite their age (the project began in the late 1970s), the boats look very competitive and strong in their class.

9/ They provide the same 20 knots (40 km/h) underwater speed as the German 214 and Chinese 041, but have a much larger underwater displacement of almost 4,000 tons. However, the endurance of the German submarine is half as much - 45 days against more than 80.

10/ But for local theatres like the Black Sea, endurance does not play a significant role. On the other hand, Varshavyankas are considered to be extremely undetectable, due to special engine operating modes. Among the major operators are China, India and Vietnam.

11/ The armanent is the standard torpedo tubes of 533 mm calibre and 18 torpedoes. But in addition to that, which is much more important now, they carry Kalibr missiles, which are launched from the same torpedo tubes.

12/ These photos show the process of loading Kalibr-PL missiles onto a submarine through torpedo tubes. An important point is the possibility of launching from an underwater position. The missiles can be both anti-ship and anti-submarine, and 3M14(E) - for attacking land targets.

13/ Project 636.3 submarines have already launched Kalibrs at Ukrainian territory. The country's authorities suspect that the 14 July strike on Vinnitsa was launched from a submarine. This video shows one of the submarine launches in the Black Sea.

14/ Here is another video – also apparently with an underwater launch.

15/ Therefore, the most likely target of today's strike was the cruise missile carrier. The submarine was conveniently docked, where it was easier to cause damage, although it was impossible to sink.

16/ However, I think even a serious fire and damage to the hull will lead to a long repair or even total disablement.

17/ We can assume that the Ukrainian military has begun a full-fledged hunt for the Kalibr naval carriers; they also wrote about an attempt to use naval kamikaze drones to attack surface missile-carrying ships.

18/ One more fact about the Varshavyanka class submarine. It is the one depicted in the film "72 Metres" - the B-471 "Magnitogorsk" of the Northern Fleet and the B-871 "Alrosa" of the Black Sea Fleet were used for filming. By the way, the Alrosa could also be docked today. /end

(Original thread is below.)

https://twitter.com/ian_matveev/status/1701886721258885375