The Borei class (; sometimes transliterated as Borey, also known as the Dolgorukiy class after the name of the lead vessel, the Yuriy Dolgorukiy) is a class of nuclear-powered ballistic missile submarine produced by Russia and operated by the Russian Navy. The class is intended to replace the Delta III, Delta IV and Typhoon classes now in Russian Navy service. The class is named after Boreas, the North wind.