Key Points and Summary – The Soviet Union’s Project 705 Lira, or Alfa-class, was a technologically brilliant but deeply flawed submarine.
-Thanks to its revolutionary titanium hull and a compact lead-bismuth cooled reactor, the Alfa was the fastest submarine ever built, reaching speeds over 40 knots.
-The Flaw: However, this pursuit of speed created a vessel that was incredibly noisy.
-It was easy to detect due to its lack of stealth, and it had a dangerously unreliable reactor.
-The program was a costly failure, but its legend was so potent that the U.S. and U.K. had to develop new, faster torpedoes just to be able to catch it.
The Soviet Project 705 Lira, the Alfa-Class Submarine: Speed Personified
CIA quoted an old Russian proverb in an intriguing, brilliant piece on the Alfa-class submarine, stating, “Better is the enemy of good enough.”
The Russians had always followed that proverb when building military weapons of war. However, in the case of Project 705 Lira, which evolved into the Alfa-class submarines, they deviated from that philosophy.
The Alfa-class submarines were technically brilliant and unmatched in terms of speed and deep diving capabilities, thanks to their titanium hulls and unique reactors.
But the Alfas were flawed by being very noisy, easily detectable, having significant maintenance issues with their innovative but unreliable reactors, and lacking a balanced combat profile, making them a highly specialized but ultimately not a “good” all-around submarine compared to their balanced NATO counterparts.
Meet The Soviet Submarine Alfa: The Fastest Submarine Ever Built
The Soviets’ Project 705 Lira (NATO: codenamed Alfa) submarines, commissioned in 1971, were groundbreaking due to their use of titanium hulls and lead-bismuth cooled reactors.
Alfas could reach speeds of over 40 knots and dive to depths of more than 800 meters.
The Cold War was at its height in the early 1970s, as the Soviet Union and the United States constantly tried to outdo each other in military technology, as well as in the space race.
The US landed on the moon successfully in 1969, using an onboard computer that had approximately one-hundredth the capacity of a cell phone today. Engineers were innovating technology at a rate never seen before.
Soviet engineers began an extremely ambitious project of using a titanium hull to construct a new submarine, the Alfa, to hunt and target American nuclear subs.
The titanium hull presented a significant challenge, being both expensive and complex to work with, yet it was much more resilient and lightweight than steel.
In addition, this reactor, which was far ahead of its time (although the technology was still rudimentary and straightforward at the time), used liquid lead for cooling and was capable, despite its compact size, of delivering 155 MW. This, combined with the Alfa’s compact size, should provide them with the speed they were looking for.
The “Alfa” class, despite recurring engine woes, was superb in its performance: Its top speed during testing was close to 46 knots, an absolute record in the category, still unmatched. But in service, it rarely exceeded 42 knots. Additionally, their maximum operational depth was 800 meters, whereas it was expected to be more than 1000 meters.
Trouble with the Reactors
The compact lead-bismuth reactors on these boats produced incredible power but proved problematic. Just five years into its service life, K-123 suffered a major reactor failure. Globalsecurity.org described the significant tradeoffs regarding the reactor design and the Alfa class’s capabilities.
For example:
“Project 705 and 705K submarines achieved record-high underwater speeds (exceeding 40 knots) and maneuverability, completing several long autonomous trips. It took them approximately 1 minute to accelerate to full speed, and it took 42 seconds to complete a 180° turn. For speed, the submarine of project 705 was even listed in the Guinness Book of Records.
The US and the UK scrambled to build torpedoes that could catch up with the Alfas. The US built the Mark 48 ADCAP torpedo, while the UK built the “Spearfish” for their boats. The Mark 48 traveled at 64 knots while the Spearfish traveled at 80 knots (92 mph).”
The Soviets built a total of seven Alfa-class vessels.
At least two units received a more standard reactor than their initial system of two Lead-Bismuth reactors, cut with two turboelectric groups.
Three had all-steel, not Titanium, hulls. The first of these submarines, K377, was withdrawn from service with the Northern Fleet (where they were all based) in 1974, the K463 in 1986, and scrapped in 1988; the others were withdrawn from service between 1993 and 1996.
About the Author:
Steve Balestrieri is a National Security Columnist. He served as a US Army Special Forces NCO and Warrant Officer. In addition to writing on defense, he covers the NFL for PatsFans.com and is a member of the Pro Football Writers of America (PFWA). His work was regularly featured in many military publications.
Note: This piece has been updated to fix a numerical mistake.
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