The Alfa class, Soviet designation Project 705 Lira (Russian: Лира, meaning "Lyre", NATO reporting name Alfa), was a class of nuclear-powered attack submarines in service with the Soviet Navy from 1971 into the early 1990s, with one serving in the Russian Navy until 1996. They were among the fastest military submarines ever built, with only the prototype submarine K-222 (NATO reporting name Papa-class) exceeding them in submerged speed.
The Project 705 submarines had a unique design among other submarines. In addition to the revolutionary use of titanium for its hull, it used a powerful lead-bismuth liquid metal cooled reactor as a power source, which greatly reduced the size of the reactor compared to conventional designs, thus reducing the overall size of the submarine, and allowing for very high speeds. However, it also meant that the reactor had a short lifetime and had to be kept warm when it was not being used. As a result, the submarines were used as interceptors, mostly kept in port ready for a high-speed dash into the North Atlantic.
Foto: Wikimedia Commons — Department of Defense. American Forces Information Service. , Anastasiya Lvova, Luis Miguel Bugallo Sánchez (Lmbuga) (proste licence / javna domena)
