SEVASTOPOL, June 27. /TASS/. The Black Sea Fleet’s oldest submarine Alrosa will make the first voyage over the past eight years for sea trials after repairs and upgrade, the Black Sea Fleet’s 13th ship repair plant told TASS.

Earlier, a military source in Sevastopol said that the submarine had been upgraded to carry Kalibr cruise missiles.

"The submarine is completely ready for sea trials due soon," the source said.

Alrosa was built in the city of Gorky (currently Nizhny Novgorod) at the Krasnoye Sormovo shipyards shortly before the collapse of the Soviet Union. It was an experimental project 877. Instead of a customary propulsion system with a propeller at the rear the submarine was equipped with a water jet, which made it very quiet and hard to notice. For this reason, submarines with water jet propulsion systems are called a "black hole". Shortly after the collapse of the Soviet Union Alrosa remained Russia’s only combat-ready submarine in the Black Sea.

In early May, it was reported that the submarine’s repairs had been completed. Alrosa acquired new combat and technical capabilities, which "put it on a par with the six submarines joined the Black Sea Fleet in recent years".