Russian submarine B-237

Rostov-na-Donu  (B-237) (Б-237 «Ростов-на-Дону») is an improved Kilo–class attack submarine of the Russian Navy. On 13 September 2023 the vessel was struck during a Ukrainian missile attack on the Sevastopol Shipyard where she was under repair. Based on open-source imagery, the UK Ministry of Defence assessed that the vessel "likely suffered catastrophic damage."

Ship
Rostov-na-Donu is a diesel-electric submarine of the Improved Project 636.3 class of modern Russian ships. B-237 was built in Saint Petersburg shipyard, laid down on 21 November 2011, launched on 26 June 2014 and commissioned on 26 December 2014.

History
The submarine is part of the Russian Black Sea Fleet but had been deployed in the Mediterranean Sea in the early 2020s. The submarine returned to the Black Sea in February 2022, passing the Bosporus on 13 February. With Rostov-na-Donu, the Russian Black Sea Fleet had four Improved Kilo–class submarines equipped with Kalibr land-attack missiles deployed in the Black Sea as of February 2022, with at least three of those four believed to be active.

Missile attack on B-237
On 13 September 2023, the Russian-appointed governor of Sevastopol Mikhail Razvozhaev claimed that Sevastopol Shipyard, belonging to Sevmorzavod, was struck by a Ukrainian "missile attack" at 2 am, causing a large fire. The Russian MoD claimed that ten cruise missiles were fired, with seven shot down. The attack also involved three "maritime drones", which were allegedly all destroyed. The Ministry said, "As a result of being hit by enemy cruise missiles, two ships under repair were damaged". At least 24 people were reported injured. The ships damaged were the landing ship Minsk and the Rostov-na-Donu. Ukraine claimed the two ships were "likely damaged beyond repair", which the Russian government denied and stated they would be repaired and returned to full operational status. Based on open-source imagery, the UK Ministry of Defence has assessed that the vessel has "likely suffered catastrophic damage".

On 18 September, two images were leaked online of the damage dealt to the Rostov-na-Donu and, as assessed, the damage was extensive. Two large breaches in the hull of the submarine are shown, one around the midpoint of the starboard side to the rear of the conning tower and another on the top bow. Due to the nature of the damage, it is assessed that the submarine will be out of action for the duration of the war due to the closure of the Dardanelles Straits to all foreign warships at the beginning of the Russian invasion of Ukraine in accordance with the terms of the Montreux Convention. The submarine would need to be transported to the Admirality Shipyards in Saint Petersburg to be repaired, however it is assessed to be more practical for an entire new boat of the class to be constructed instead due to the extensive repairs that would be required to make the submarine seaworthy again.