The legendary Russian Lira class submarine of Project 705 (NATO code name Alfa) is one of the most prominent combat vehicles of the Soviet Union during the Cold War

The legendary Russian Lira class submarine of Project 705 (NATO code name Alfa) is one of the most prominent combat vehicles of the Soviet Union during the Cold War as well as the Russian Navy in the later period. In the late 1960s, the Soviet Union began to produce a new generation of Project 705 Lira nuclear submarines, which possessed a number of unique features, such as a titanium hull and a reactor with liquid metal coolant.

These special nuclear submarines gradually built a reputation, becoming a legend in the eyes of the public and Western observers. Lira-class submarines were even featured in the movies. They appear in the famous American writer Tom Clancy’s military fantasy film – The Hunt for Red October. Books about the super-secret Soviet nuclear submarine also sold well in the West. There was a reason for this, mainly because these boats carried the very innovative technologies of the time.

Soviet nuclear-powered attack submarines tended to be faster and deeper-diving than their Western counterparts—though they were also noisier and more prone to horrifying accidents. The Project 705, originated as a 1958-design concept to push the speed advantage to the maximum, allowing the submarine not only keep pace with but overtake NATO carrier task forces typically cruising at 33 knots – while keeping one-step ahead of enemy torpedoes and out-maneuvering enemy submarines. A single reactor and turbine plant driven the boat at the phenomenal 42 knots under water. Reactor’s power could be rapidly increased, as well as the submarine’s speed.

This extraordinary performance would be achieved by ruthlessly maximizing speed and subtracting from weight. Thus the Alfa featured a relatively small hull made of titanium alloy. Titanium is a rare metal which can create surfaces as strong as steel for roughly half the weight. It is also paramagnetic, making the submarine’s hull more difficult to detect for maritime patrol planes using Magnetic Anomaly Detectors.

The resulting Project 705 submarine measured 81-meters long but weighed only 3,200-tons submerged. For comparison, the 84-meter-long American Permit class submarine displaced 4,800 tons submerged. The Project 705 Lira, looked the part with svelte tear-drop shaped hull, rakishly trimmed-down sail designed to minimize aquadynamic drag, and even its convertible-style pop-up windshield.

The Alfa featured a typical Soviet double-hull configuration, but only one of its six internal compartments was intended for habitation by the crew. Extraordinary degrees of automation allowed a complement of 15 officers cooped together in the heavily protected third compartment of the vessel, instead of the roughly 100 personnel typical on contemporary SSNs.

Each Project 705 carried eighteen to twenty 533-millimeter torpedoes which could be automatically loaded into six tubes which could pneumatically ‘pop’ the weapons upwards to engage ships overhead. Optionally, RPK-2 “Starfish” nuclear anti-submarine missiles and ultra-fasted Shkval super-cavitating torpedoes could also be carried. Alfa variants armed with ballistic missiles or gigantic 650-millimeter torpedo tubes were conceived but never built.

After spending nine years in development, four Alfas were laid down in Severodvinsk and Lenningrad between 1967 and 1969. However, only one—K-64 Leningrad, had been launched and commissioned by the beginning of 1972. That same year, K-64 experienced both cracking in its titanium hull and a leaking liquified metal ‘froze’ on the exterior of the reactor causing irreparable damage. The super-submarine was decommissioned and scrapped just a few years after going on duty. After several years of tweaking, six more Alfas were finally commissioned between 1977-1981, with later 705K boats using a moderately more reliable BM-40A reactors.

When British and American submariners first encountered the Alfa they were astounded. The result that NATO navies allocated massive funding to the development of new deep-running torpedoes. During the Cold War Soviet titanium technology was far in advance of the West, requiring fewer passes to achieve a successful weld. Successors of the Alfa class became the Sierra I class and further improved Sierra II class. These were also extremely expensive titanium-hulled boats. However the cost of the hulls limited the numbers built, despite advantages in depth, underwater speed and resistance to damage.


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