Russian Navy Kilo submarine Alrosa prepares to start post-refit trials

Alrosa pictured before its overhaul and upgrade, which commenced in 2014. (Russian MoD)

The Russian Navy Kilo-class Project 877V diesel-electric submarine (SSK) Alrosa (ex-B 871) is set to start sea trials following the completion of its overhaul and modernisation programme.

In comments to Russian news agency TASS on 16 May, a representative from Sevastopol's military and security authorities confirmed that Alrosa had docked at the Black Sea Fleet's naval base in Sevastopol, Crimea, after departing the service's 13th Ship Repair Plant.

According to the representative, the submarine's complement will soon undertake drills and training, and the boat is to serve with the Black Sea Fleet's 4th Independent Submarine Brigade. In addition, the representative stated that Alrosa is armed with the Kalibr-PL missile system.

According to the Black Sea Fleet press service, the initial period of factory tests will continue until the end of May.

Alrosa was originally commissioned in 1990 and started its overhaul and upgrade at the 13th Ship Repair Plant in 2014. The boat was intended to return to service in 2017, but the programme has been subject to delays. Aside from the improved weapons capability, it is unclear what kind of upgrade Alrosa has benefited from; however, it is likely to have included enhanced sensor, command-and-control, communication, and safety equipment and systems.

Alrosa is the only Project 877 SSK in Russian Navy service that was outfitted with a pumpjet propulsion system instead of a conventional propeller, lowering the boat's acoustic signature and making the submarine difficult to detect. However, it is unknown if the original propulsion system has been retained.