The Borei represents only half of the Russian Navy’s future sea-based nuclear deterrence force. The other half will come from a unique fleet of four Khaborovsk-class submarines each carrying six nuclear-powered Poseidon drone-torpedoes designed to swim across oceanic distances to blast coastal cities and naval bases with megaton-yield warheads. On May 22, 2018, the Russian submarine Yuri Dolgoruky slipped beneath the waves of the Arctic White Sea. – The National Interest Photo: Russian Defence Ministry