The overhaul of the Tiger (K-154 Tigr) nuclear-powered attack submarine (SSN) of project 971 (Akula-class) is to be completed by the end of 2023. The SSN has not made any sorties since 2010s. Three years ago, it was towed to the shipyard in Snezhnogorsk. The overhaul will increase its might due to Kalibr missiles, the Izvestia daily writes.