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Meet the Kilo: The Russian Submarine the US Navy Calls the ‘Black Hole’

Kilo-class Submarine
Kilo-class Submarine. Image Credit: Creative Commons.

Russia Could be Operating Deadly Silent Kilo-class Submarines in the Black Sea: The Russian Navy’s Black Sea Fleet is believed to have four improved Kilo-class submarines, each equipped with Kalibr land-attack missiles operating in the Black Sea. Of those, Rostov-na-Donu (B-237) reportedly transited through the Dardanelles less than two weeks before Russia launched its unprovoked invasion of Ukraine. The submarine, which is part of the Black Sea Fleet’s 4th Independent Submarine Brigade, entered service with the Russian navy in December 2014.

The deployment of the submarine was part of Russia‘s pre-invasion build-up of naval forces in the Black Sea.

Two additional Project 636.3/improved Kilo­-class boats – Stary Oskol (B-262) and Krasnodar (B-265) – are reportedly now in port at Russia’s Tartous Naval Base in Syria. Russia currently operates nine of the improved diesel-electric submarines, while an additional four are under construction.

Maintaining a Non-Nuclear Submarine Force

Unlike the United States Navy, which has gone all-in on nuclear power, the Russian Navy currently maintains a submarine force that consists of diesel and nuclear-powered submarines. Its fleet of diesel submarines has been seen as more than adequate for conflicts in Europe and the Middle East, which could explain why four of the boats are now in the Black Sea.

Nicknamed the “Black Hole” submarine by the U.S. Navy, the improved Kilo-class is noted to be extremely quiet.

A lot of silencing went into making the Kilo-class so quiet. The hull has been described as having the approximate shape of a drop of water, which greatly reduced water resistance over older, World War II-era submarine designs. In addition, the propulsion plant was isolated on a rubber base so it had no contact with the hull, and that prevented vibrations from turning into noise that could be picked up by an enemy.

The ship also was equipped with a rubbery anechoic coating to further deaden noise emanating from the submarine, which occasionally gives the submarines a blocky appearance noticeable in photographs. To help maintain its underwater stealth, an air regeneration system was developed to keep a full crew supplied with oxygen for up to 260 hours, providing the boat with almost two weeks worth of underwater endurance.

Development of the Kilo

The Soviet Navy designed the original Kilo-class tranche, also known as Project 877 submarines, in the early 1980s for anti-submarine warfare (ASW) as well as anti-surface warfare (ASuW) in shallow coastal/littoral waters. To facilitate that role, the Kilo-class is considerably smaller than Russia’s massive ballistic missile submarines, so-called boomers. It was originally meant to serve the navies of the Warsaw Pact countries, replacing older Whiskey– and Foxtrot-class boats.


Kilo-class Submarine. Image Credit: Creative Commons.

Diesel Submarine

A Russian-built, Kilo-class diesel submarine recently purchased by Iran, is towed by a support vessel in this photograph taken in the central Mediterranean Sea during the week of December 23. The submarine and the support ship arrived at Port Said, Egypt, on Tuesday and were expected to begin transiting the Suez Canal today, Jan. 2, 1996. Ships and aircraft from the U.S. NavyÕs Sixth Fleet are tracking the submarine, which has been making the transit on the surface. This is the third Kilo-class submarine the Iranians have purchased from Moscow. DoD photo

Twenty-four Kilo-class submarines were operated by the Soviet Union at the end of the Cold War, of which eleven are still reportedly operated by Russia. One of the aging boats was sold to Poland, which remains operational, while another now-retired sub had been sold to Romania. An additional 10 had been sold to India; nine of which are still operational while the tenth caught fire and sank pierside in August 2013. Iran is believed to operate three Kilo-class boats, and Algeria operates two more. China also has two of the former Soviet submarines in its navy that were purchased after the end of the Cold War.

The Improved Kilo

Since its inception, the Kilo-class has also been steadily improved and is represented by three variants: Project 877, Project 636, and the latest Project 636.3. The latter version was developed to rejuvenate the flagging Russian submarine force after the dissolution of the Soviet Union.

The Project 636.3, which are in service with the Russian Navy’s Black Sea Fleet, are powered by two diesel generators and an electric drive, giving them enough power to make ten knots at the surface and seventeen knots underwater. While stealthy, these are fast submarines in any sense of the word.

Yet, the boats have a range of six thousand to 7,500 nautical miles, meaning that from the Russian Northern Fleet headquarters they can patrol for one thousand nautical miles and then go on to Cuba. Thanks to that air regeneration system they could remain submerged – if necessary – for much of the trip.

Thanks to its stealth and endurance, in addition to its primarily ASW and ASuW roles, the Project 636.3 subs can also be employed in general reconnaissance and patrol missions. The boats are capable of detecting an enemy submarine at a range three to four times greater than it can be detected. The submarines are noted for their ability to work well in shallow water, where a pair of ducted props powered by low-speed motoring motors likely allows it to operate closer to the seafloor.

Despite the age of the initial design, the improved Kilo-class has remained a workhorse in the modern Russian Navy.

Now a Senior Editor for 1945, Peter Suciu is a Michigan-based writer who has contributed to more than four dozen magazines, newspapers and websites. He regularly writes about military hardware, and is the author of several books on military headgear including A Gallery of Military Headdress, which is available on Peter is also a Contributing Writer for Forbes.

Written By

Expert Biography: A Senior Editor for 1945, Peter Suciu is a Michigan-based writer who has contributed to more than four dozen magazines, newspapers, and websites with over 3,000 published pieces over a twenty-year career in journalism. He regularly writes about military hardware, firearms history, cybersecurity, and international affairs. Peter is also a Contributing Writer for Forbes. You can follow him on Twitter: @PeterSuciu.



  1. Mike Mosley

    March 25, 2022 at 4:01 pm

    Surprised your story didn’t mention the Walker’s spying providing the sound isolation technology you mentioned.

  2. Alex Michaels

    March 25, 2022 at 9:06 pm

    I’m surprised you guys are believing any estimates after what we’ve seen in Ukraine. Russia is an old, toothless, bear because Putin let his oligarch buddies loot the military like everything else in Russia. Let’s hear again how super duper scary the ISKANDER missile system is, or how the tank cages render anti-tank missiles near useless, or how the SA-400 will kill anything.

    For the past three weeks we’ve seen why Russia sticks to shooting people who have no realistic chance of shooting back. Don’t get me wrong, the USSR stole and built a sub fleet that was actually within 10%-15% of US capability, and they put in the money to train / retain crews. Today? The vaunted USSR fleet is a rusting hulk with many Typhoons and Kilos unable to put to sea, because of maintenance failures, and those that can put to sea are loud enough to hear across the ocean with poorly trained crews.

    Tell me again that we should be afraid of Russia…

  3. Sharpie Dan

    March 25, 2022 at 9:54 pm

    Hmmmm…think I will rewatch my favorite Alec Baldwin film ‘The Hunt for Red October’

  4. Nanyang bidness

    March 26, 2022 at 12:17 am

    Why is this news? The design is 40 years old. It’s MAYBE equal to a first flight 688.

  5. Dave

    March 26, 2022 at 1:19 am

    American Navy does not call that boat the black hole….we detect those boats LOOONNNGGG before they could ever get close enough to us to detect.

  6. Joseph P Hurley

    March 26, 2022 at 1:25 am

    Surprised you didn’t mention the U.S superior ASW ability and Kilos are always where we track them.

  7. Michael Park

    March 26, 2022 at 7:35 am

    Russia is a black hole.

  8. Alex

    March 26, 2022 at 3:00 pm

    How many mother’s warriors in the comments who want to make war with Russia 🙂
    This is reminiscent of the Hitler Youth, who fled to fight against “weak” Russia and remained forever in Russian soil.

  9. Hardy K

    March 26, 2022 at 6:58 pm

    We need stories like this so the military industrial complex can sell more on imaginary dears!

  10. Justin

    March 26, 2022 at 7:32 pm

    After witnessing the bumbling idiot centralized Russian army failing in Ukraine, it solidifies a U S win against them in any form of combat.

  11. Longtrail

    March 26, 2022 at 8:37 pm

    Alex, good comment.

  12. Longtrail

    March 26, 2022 at 8:40 pm

    “Russia’s improved invasion of Ukraine”

    You make me laugh. I bet you’re also paid to lie about the 2020 Election being the best run ever!

  13. SB SFO

    March 26, 2022 at 11:43 pm

    ‘Black hole’ is probably an apt name for this sub, and could be applied to many other aspects of the Soviet (sorry, Russian 😉 military, economy, governance, culture, etc.

    Black holes are all that’s left after the gravitational collapse and implosion of end-of-life stars. And that’s not much (size-wise, at least)… just a lot of nothing.

    If the shambolic performance of Russia’s vaunted military in Ukraine is any indication (and that includes everything from strategic planning to support & logistics to troop training & preparedness to morale to equipment maintenance, etc.), I’d like to think that it’s only a matter of time until the hulls of these boats collapse and implode due to shoddy maintenance and ensuing structural fatigue.

    Such an ignominious end would be entirely in character with the name. Let’s hope that’s how Vladimir Putain [sic] goes down, too.

  14. Alex

    March 27, 2022 at 11:53 am

    I see only two things:
    1. Russia is moving forward and freeing more and more cities from the Bandera Nazis,
    2. Bandera Nazis and those who support them for some reason make hysterics in the comments.

    Or you can just go to the Ukrainian legion and fight there. But, no – these are cowardly jackals, they can only fight here 🙂

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