 Sierra-class submarine

The Sierra class, Soviet designations Project 945 "Barrakuda and Project 945A "Kondor, (NATO reporting names Sierra I and Sierra II respectively), are series of nuclear-powered attack submarines intended for the Soviet Navy and currently in service with the Russian Navy.The class is unique due to its light and strong titanium pressure hull which enables the submarines of the class to dive to greater depths, reduce the level of radiated noise and increase resistance to torpedo attacks.