Union began to deploy its Typhoon class; at an estimated surface 25,000 tons and a length of 170 metres (560 feet), these were the largest submarines ever built. They have continued in the service of the Russian navy since the dissolution of the Soviet Union in 1991. A Typhoon-class submarine can stay submerged for 120 days in normal conditions, and potentially more if deemed necessary (e.g., in the case of a nuclear war). Their primary weapons system is composed of 20 R-39 (NATO: SS-N-20) ballistic missiles (SLBM) with a maximum of 10 MIRV nuclear warheads each.The worlds largest submarines are the Russian 941 Akula (designated 'Typhoon' by NATO) class. The launch of the first at the secret covered shipyard at Severodvinsk in the White Sea was announced by NATO on 23 Sep 1980.

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