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We Have Things to Say About Russia’s Titanium Submarines (The U.S. Navy Has None)

Russia Submarine
Modern Russian Navy Submarine. Image Credit: Creative Commons.

The U.S. Navy clearly builds the most powerful, silent, and sophisticated submarines on the planet today. However, during the days of the Cold War, Russia had submarines that were made of titanium that could dive quite deep and made Washington quite nervous: 

Innovations in military technology are often the byproducts of strategic interactions between world powers and their economies. The Project 705 “Lira” nuclear submarine (NATO reporting name “Alfa”) is a great illustration of that dynamic. Indeed, the Lira is both the product and the cause of such an interaction.

In the decades after World War II, the United States leapt out in front of the Soviet Union in submarine technology. The USSR had acquired many of the most advanced German submarine types by the end of the war, but the U.S. had gained invaluable submarine and anti-submarine experience during the Pacific War and the Battle of the Atlantic. This experience, alongside existing technological advantages, gave the United States a strategic advantage in submarine warfare.

More specifically, the Soviet Union’s early nuclear submarines were known to be less stealthy and reliable than Western submarines. Aware of their strategic disadvantage in submarine warfare, and unable to compete in the areas of stealth and reliability, the Soviets sought to innovate.

Lira-Class with a Titanium Will

What Moscow needed was a submarine that could move faster and dive deeper than Western submarines. In order to do this, the Soviets would design the Lira-class. By building a submarine with a titanium hull and unique reactor – both innovations at the time – the Lira would become the fastest, deepest-diving submarine in the ocean, so fast that it could evade Western torpedoes.

Titanium creates surfaces as strong as steel with half the weight, meaning a titanium hull can withstand greater pressure and allow for deeper dives. However, titanium is also three to five times more expensive than steel, and it is an extremely difficult material to work with. Manipulating large titanium panels for hull sections is especially hard. Failures in the welding process, for example, can lead to the titanium becoming embrittled, lowering its strength. Moreover, as was demonstrated in the building of the Lira-class submarines, titanium requires welders to work in hermetically sealed warehouses full of argon gas, adding further expense. Despite these costs and risks, the titanium hull was a necessary component of the Soviet Union’s innovation strategy.

A Cozy Space for a Reactor

Reactors take up space in a submarine. The Lira’s designers sought to minimize this space, thereby reducing the size of the submarine and allowing for higher speeds. The solution in the Lira’s case was to utilize a liquified lead-bismuth mixture to cool the reactors, reducing submarine reactor size, and therefore increasing the submarine’s speed. Such a reactor – as the Soviets later found out – has its difficulties. It requires much automation to work properly, and the engine must be constantly heated so the liquified metal coolant won’t solidify.

But again, as in the case of the titanium hull, the reactor was absolutely necessary to fulfilling Soviet needs. Both were necessary components in the Soviet Union’s attempt to gain either strategic parity or strategic advantage, through innovation, in submarine warfare.

Lira-Class – She Can Dive, Run, and Loiter

The Lira indeed turned out to be rather fast and able to dive quite deep. It was, in fact, the fastest and deepest-diving submarine ever produced, able to cruise at 41 knots when submerged and dive as deep as 1,148 feet. Its speed allowed it to outrun NATO torpedoes, and its depth kept it out of range of other anti-submarine weapons. Theoretically, the Lira could even loiter beneath a NATO submarine and shoot torpedoes overhead.

Needless to say, the prospect of the Lira prowling the seas upset the existing strategic balance between NATO forces and the USSR, to the latter’s benefit. Upon learning of the Lira’s capabilities, the U.S. and British navies rushed to build weapons that could target the submarine. The American Mark 48 ADCAP torpedo was said to travel at 63 knots. The British developed a similar torpedo named “Spearfish.” The U.S. also pursued the “Sea Lance” supersonic missile program, which would deliver a torpedo or nuclear depth charge at ranges of up to 100 miles.

What is now well known is that the Soviet Union ended up producing only seven Project 705 Lira submarines; that some of them did, in fact, experience cracking in the hull; and that making repairs proved difficult, as the aforementioned coolant in the reactors had to stay heated at all times to remain liquified.

The submarine also turned out to be especially noisy, so the vessel was easy to detect. Most of the Lira were decommissioned and scrapped in the early 1990s at the tail end of the Cold War. They were too expensive to maintain.

Yet what the Lira proves is that innovation in military technology is often part of an ongoing competitive process to maintain strategic advantage in discrete areas. The Lira was both the outcome (as a response to U.S. naval dominance) and cause (Western developments in anti-submarine weaponry) of such a process, regardless of its ultimate use or lifespan.

Alex Betley is a recent graduate of the Tufts University Fletcher School of Law and Diplomacy where he was an International Security Studies Civil Resistance Fellow and Senior Editor with the Fletcher Security Review.

Written By

Alex Betley is a recent graduate of the Tufts University Fletcher School of Law and Diplomacy where he was an International Security Studies Civil Resistance Fellow and Senior Editor with the Fletcher Security Review.



  1. Michael Kenny

    September 12, 2022 at 5:40 am

    Your article is about a advanced SOVIET era submarine with amazing technology and the rest of the world should lose sleep over it. Then comes the part where it couldn’t be made and operated properly and no longer exists, why did you bother to write the article,sounds like clickbait, Did Tufts ever return money it received stolen from the Philippines during the Marcos regime, another Tufts dwarf.

  2. Jonny tran

    September 12, 2022 at 5:58 am

    It’s not the us navy building anything. It’s the shipyard workers


    September 12, 2022 at 7:46 am

    Alex hi,

    Excellent well-written article. I had no idea about the Lira class submarines so this is an eye-opener. Titanium hull – whatever next. I hear the russians are or have created a submarine that can fire long torpedos which can create gigantic (nuclear) tidal waves – scary stuff.

    Alan Grant

  4. Anthony Watts

    September 12, 2022 at 2:52 pm

    The United States had submarines that were construct from HIGH YEILD 80 titanium. That were quiter faster and could dive deeper that the Soviet Union Submarines.
    I gradurated from US Naval Submarine located in Groton Connecticut in 1975.

  5. Robert J Kovach

    September 12, 2022 at 3:34 pm

    Great article!! I learned about these subs a year ago and was impressed. I think it was that bismuth reacter that did them in.A couple of relatively new subs accidentally let the bismuth cool off and it solidified in the reactors causing them to have to scrap the subs! By the way. do you know who pays to have Russian nuclear subs decommissioned? We do!! So does Japan the French and the UK!

  6. Marcus

    September 12, 2022 at 8:11 pm

    The picture posted is not an Apha class Soviet submarine. It looks like an Oscar class. Speaking of Oscar class, the Kurse which blew up in August 2000 was titanium hull as well. I was on one of the two US submarines deployed very near when the incident occured. That day I learned that Russia and United State submariners may be adversaries, we share the same enemy: the unforgiven sea especially in that area. Nothing will erase in my memories the banging of the hull of the few survivors which slowly got quieter and eventually stopped. And there was nothing my submarine can do about it.

  7. Donald Mackay

    September 12, 2022 at 9:23 pm

    As a fmr. U.S. Submariner, I can tell you, titanium hulls are not exclusive to soviet subs, although, ironically, it is exclusive to the Ural mountains of Russia, we have obtained it and developed a more manageable version, and better super structure for our sub hulls then anything the soviets had, or have.

  8. Aloha

    September 13, 2022 at 3:15 am

    Russian boats are rubbish. Their sailors enlist for a few more rubles a month. Most don’t want to be there. US submariners and the boats they command are superior. Russian sewer pipes are doomed. They cannot hide. American nuke armed torpedoes don’t make contact with their targets. They detonate at a distance. The target implodes. до свидания

  9. Jamesrudolph

    September 13, 2022 at 8:10 am

    I believe the type 80 titanium someone referred to was actually a type of high straight steel which was expensive and difficult to work with. It was only used on the seawolf subs. I don’t believe the us ever had an actual titanium hulled sub.

  10. Hon Robert F Frazier Esq

    September 13, 2022 at 10:13 am

    Dear Mr. (Alex) Betley …

    … Please explain your motive &/or interest in studying “civil resistance” as part of your “International Security Studies” curriculum at the Tufts University Fletcher School Of Law.

    The words themselves suggest either (1) That “civil resistors” pose a “security [risk]” to state order on an “International” level, or (2) That “International Civil Resistors” ought be versed in state “Security [risks]” they pose to states wherein they are engaged in “civil resist[ance]”.

    Are your motive & interests in undertaking such a course of study either of the above alternatives, or are you seeking knowledge & training in your particular course of study for some reason(s) other than the alternatives I’ve cited herein??

    How did you come to study of Soviet-era Russian submarines, & as a recent graduate in your field of study, have you become employed in your field (& in what Country)??

    Seeking To Know More About You, Mr. Betley, & About Your Purpose(s), I Trust I Am Yours …
    … Robert (F. Frazier, Esq.);
    Cap’t., USA (Ret’d.).

  11. Kenneth Shull

    September 14, 2022 at 1:44 am

    Your diving depth comparison between Russian and USA submarines is incorrect. I participated in several test-depth dives on submarines during my 23 years in the USNavy Submarine Service. The actual test depths are classified information.

  12. Mike Homchick

    September 19, 2022 at 4:23 am

    I liked the article, but I was wondering about the AKULA CLASS..TYPHOON.
    I know she is not RED October but she still is newer sub. So I’m wondering. Anyone email me pls if you have any info.

  13. T. Dougherty, Ph.D.

    January 31, 2023 at 7:35 pm

    Several comments: HY-80 was a high strength steel, not titanium. US test depths are currently stated officially as “In excel of 800 feet”. The reactor used liquid lead-bismuth, not bismuth. These operate at higher temperature and lower pressures (due to lead-Bismuth much higher boiling point) and can generate superheated dry steam, much more thermally efficient. The Lira was noisy at high speed and due to the propeller design suffered from low frequency blade rate acoustics. Several other titanium hull submarines were built: Project 661 (Papa), K-278 Komsomolets, and the four Project 945 Sierra class submarines. Kursk was not titanium hulled. I have written an article on the Russian Titanium hull submarines which will be in an issue of American Submariner this year. I used several Russian language primary sources from the Malakhit Bureau and other sources. Contact me if you want a copy.

  14. T. Dougherty, Ph.D.

    January 31, 2023 at 7:55 pm

    Several points about the comments here. US submarines were constructed of HY-80 which is a high yield steel alloy, not titanium. The Seawolf class used HY-100. US diving depths are currently officially given as “In excess of 800 feet”. It is lead-bismuth, not bismuth. The lead-bismuth liquid metal combination is a fast neutron design which operates at much higher temperatures and much lower pressures than pressurized water reactors. It can generate superheated “dry” steam which is much more thermally efficient. There are drawbacks (excessive corrosion, must be kept above 123.5 C to remain liquid, generates polonium). The Alfas were indeed noisy at high speed, but at slower tactical speeds quieter. They did suffer from blade rate low frequency acoustic emissions, due to the propeller design. These low frequency emissions travel in the deep sound channel and were the basis for large sonar arrays on submarines as well as SOSUS.

    The Soviet Union also produced other titanium hull submarines: The Project 661 Anchar (Papa), the Project 685 Plavnik K-278 Komsomolets (Mike) and the four Project 945 Kondor (Sierra) submarines. The last four are still in service. The Typhoon (Akula) SSBNs are all out of service. The Delat IV and new Borei class are the current Russian SSBN classes.

    I have just completed a very extensive article on the Russian Alfa and Papa class pioneers of titanium hull submarines, employing mostly Russian and other intelligence primary sources information, as well as information from the Malakhit Bureau. It will be published in American Submariner this year. Anyone who would like a copy once it is published, email me. I’ll send you a PDF.

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