St. Petersburg, Aug 17 (IANS/RIA Novosti): The Admiralty Shipyard here will lay down Friday a new diesel-electric submarine for Russia's Black Sea Fleet, the company said.

Stary Oskol will be the third in a series of six Varshavyanka class submarines that are expected to join the fleet by 2016.

The first sub, the Novorossiisk, was laid down in August 2010, followed by Rostov-on-Don in November 2011.

The Varshavyanka class is an improved version of the Kilo class submarines, featuring advanced "stealth" technology, extended combat range and ability to strike land, surface and underwater targets.

These submarines are mainly intended for anti-shipping and anti-submarine missions in relatively shallow waters.

The vessels, crewed by 52 submariners, have an underwater speed of 20 knots, a cruising range of 400 miles (electric propulsion) with the ability to patrol for 45 days.

They are armed with 18 torpedoes and eight surface-to-air missiles.