Sierra-class submarine
 The Sierra I class (NATO reporting name) or (Soviet design serial number) Project 945 (Барракуда/Barrakuda) nuclear submarine was the Soviet Union's successor class to the partly successful Project 705 Lira (Alfa) class submarine. The Sierra class has a light and strong titanium pressure hull which enables the class to dive to greater depths reduce the level of radiated noise and increase resistance to torpedo attacks. It is powered by a single OK-650 pressurized water reactor.