Inside Russia’s Bold (But Noisy) Alfa-Class Attack Submarines

Key Points and Summary: Russia’s Alfa-Class submarines (Project 705 Lira) exemplified the Soviet Union’s push to achieve an undersea technological edge, featuring unprecedented materials like titanium hulls for higher speeds and deeper dives.

-Debuting in the early 1970s, these nuclear-powered attack subs could hit 40 knots and descend to 350 meters, surpassing most NATO counterparts in raw performance. They also pioneered lead-bismuth-cooled reactors for lighter power plants and longer endurance.

-However, their higher noise levels arguably undercut these advantages, especially when compared to quieter U.S. Navy counterparts. Ultimately, while the Alfa-Class highlighted Russian ingenuity in underwater propulsion and hull design, it never outperformed advanced Western submarines.

Alfa-Class: The Soviet Submarine That Redefined Undersea Tech

The Russian Navy is primarily regarded as far less threatening than its land and air military power, as there are few aircraft carriers, destroyers, and sophisticated warships capable of projecting maritime combat power. This is especially true when one compares the Russian Navy with Navy’s from the US and China. 

Russian submarines, however, going back to the days of the Soviet Union, are known for their significant undersea prowess, lethality, and advanced technology. 

This has been the case for many years, a reality that starkly opposes its largely less effective surface warfare fleet.  

Enter the Alfa-Class Submarine 

For decades, the Soviet Union operated on the cutting edge of submarine technologies, integrating quieting technologies such as “air-independent-propulsion” and acoustic signature absorbing coating materials. 

For example, the Soviet Union’s Project 705 Lira submarine emerged in 1971 with a never-before-seen lightweight “titanium hull.”  

The Lira, referred to in NATO nomenclature as an “Alfa-Class,”  was therefore capable of hitting speeds of 40 knots and reaching depths of 350 meters. 

New Attack Submarine Technology

An interesting essay in The National Interest describes the technological advantages associated with using a Titanium hull. 

“Titanium is a chemical element that can be reduced to produce a lustrous transition metal with valuable properties: low density, high strength, and resistance to sea water,” the essay says. 

The lower-density Alfa-Class was the second fastest submarine model, as it was previously known to be slower than a K-222 Soviet prototype. 

Overall, the Alfa-class submarines operated from the early 1970s to the mid-1990s as a leading threat to the US, NATO, and the West. It was even featured in the Hunt for Red October, a classic submarine movie. 

More Details on the Alfa Submarines from Russia 

An interesting research essay from 2002 in the Nonproliferation Review describes key elements of  Alfa-class technologies as operating with a more energy-efficient power plant comprised of a “lead-bismuth cooled, beryllium-moderated reactor.”  

These lead bismuth-cooled reactors enabled longer mission life without a need for refueling and operated as a much lighter and smaller power source when compared with water-cooled reactors. 

Despite these documented technical advances, a certain paradoxical quality is woven into Russian submarines because they do not seem to have outperformed advanced US Navy attack submarines such as the Los Angeles-class and highly revered Sea Wolf submarine.

May experts argue the Alfa-Class was much noisier than American or NATO submarines of that era, taking away from advantages Russia. 

Is Titanium Better for Submarines?

Most scientific assessments say that, while more expensive, titanium is much more effective for submarine performance than the metal alloys used by the US Navy at the time. 

One essay in “Slashgear” in October, 2024, describes the merits of using a Titanium hull as…. 

“Titanium is a pure elemental metal, whereas industrial steel is typically an alloy of iron and carbon. American submarines are primarily made using HY-80, a steel alloy of nickel, molybdenum, and chromium. It’s reliable and durable, but it’s not titanium. During the Cold War, the Soviet Union saw the benefits of building submarines with titanium and designed its Lira-class (NATO designation “Alfa”) using the metal in its hulls. This made Soviet submarines faster, quieter, and able to reach lower depths than their American counterparts,” the SlashGear essay says. 

Russia has arguably not accomplished much with its advanced submarine technologies, and, as a result, it may not be apparent if the boats could truly rival or remain undetected by US Navy Cold War submarines known for many successes. 

Experts also have many questions regarding “air-independent-propulsion,” as its quieting advantages appear to be offset or mitigated by quieting properties and speed built into US Navy submarines.

About the Author: Kris Osborn 

Kris Osborn is the Military Technology Editor of 19FortyFive and President of Warrior Maven – Center for Military Modernization. Osborn previously served at the Pentagon as a highly qualified expert in the Office of the Assistant Secretary of the Army—Acquisition, Logistics & Technology. Osborn has also worked as an anchor and on-air military specialist at national TV networks. He has appeared as a guest military expert on Fox News, MSNBC, The Military Channel, and The History Channel. He also has a Masters Degree in Comparative Literature from Columbia University.