The completion of the new submarine type, known as the Yasen project, could take some time. The Yasen-class submarine will replace Soviet-era nuclear submarines by 2020. The new submarine is expected to be 118 meters (390 feet) long, 13.5 meters (44 feets) wide and weight almost 14 tons. The Yasen will have a maximum speed of 31 knots when submerged and 16 knots surfaced.
All future Yasen-class submarines will have a state-of-the-art design featuring a modified hull profile and modernized equipment. The hull is made of low-magnetic steel. The Yasen-class is the first Russian submarine to be equipped with a spherical sonar system, which consists of a spherical bow array, flank arrays and a towed array. Due to the large size of this spherical array, the torpedo tubes are slanted and placed behind the main control compartment.
It is expected that the Yasen will be among the stealthiest submarines in the world. According to Russian designers, the Yasen will be quieter than the latest US Seawolf nuclear submarine.
Full article: Russia to Receive Fifth-Generation Nuclear Submarine by 2020 (Spacewar)