Ep 29 Kursk Submarine Disaster

Engineering News – Vertical Axis Wind Turbines (0:18)

This week's episode is about the Kursk Submarine (4:30); a Russian Submarine that sank during a naval training exercise (13:40). The recovery of the ship was less than optimal (16:30) and there were many things to blame, some real and some conspiracy (23:10).


Engineering News

Kursk Submarine

Episode Summary

Hi and welcome to Failurology; a podcast about engineering failures. I’m your host, Nicole, and with me again today is Brian, and we're both from Calgary, Alberta. Welcome Brian!

Thanks for having me again!

This week in engineering news, vertical wind turbines, not traditional propeller wind turbines could change the future of wind farms.

  • Vertical axis wind turbines spin on an axis vertical to the ground – increase performance when arranged in a grid – can be designed much closer together

  • More compact and efficient – when set in pairs, they increase each other’s performance by 15%

  • School of Engineering, Computing and Mathematics at Oxford Brookes University – in depth study with over 11,500 hours of computer simulation

  • The study, which computational methods, allows them to look at array angle, direction of rotation, turbine spacing and numbers of rotors without investing the large costs of experimental test facilities

  • In traditional horizontal axis turbines when wind hits the first row it generates turbulence which impacts the performance of subsequent rows – front row might convert half of the kinetic energy to electricity, but the back row might be 25-30%

  • Global Wind Report 2021 – world needs to implement wind power 3x faster over the next decade to meet NetZero targets

If you want to read more on the xxx, check out the link in the show notes or head to failurology.ca.

Now on to this week’s engineering failure; the Kursk Submarine. A faulty weld on a practice torpedo led to an explosion of high test peroxide and the secondary detonation of 5-7 torpedo warheads.

Submarine Info

  • Nuclear powered Project 949A Antey (Oscar II class) submarine

  • The Kursk was reputedly unsinkable and there were claims that it could withstand a direct hit from a torpedo.

  • It had an 8mm outer steel plate hull covered with 80mm of rubber - this made it hard to detect by other submarines and ships. The inner hull was made of 50mm steel plate and separated from the outer hull by a 1-2m gap. The inner hull was divided into nine watertight compartments. The Kursk was as long as two 747s.


  • Sank on Aug 12, 2000 in the Barents Sea off the northern coasts of Norway and Russia

    • During first major Russian naval exercise in more than 10 years

    • All 118 personnel on board were killed

    • Crews on nearby ships felt the initial explosion and then a second, much larger, explosion

    • Russian Navy didn’t realize an accident occurred and didn't initiate a search for more than 6 hrs

    • Rescue buoy had been intentionally disabled during an earlier mission - took more than 16 hrs to locate the Kursk

    • Over 4 days, the Russian Navy made 4 failed attempts to attached diving bells and submersibles to the escape hatch - diving bells are a chamber used to transport divers from the submarine to the surface

    • Seven days after sinking, after Russian reluctance to accept help, British and Nrowegian divers opened the escape hatch in the flooded 9th compartment but found no survivors on the submarine

Naval Exercise

  • Aug 12, 2000

  • “Summer-X” exercise, the first large-scale Russian Navy exercise in more than a decade and since the fall of the Soviet Union. The exercise included 30 ships and 3 submarines. The USSR was dissolved over a 4 year process, ending in 1991.

  • Being one of the few submarines authorized to carry a combat load at all times, the Kursk had a full complement of conventional combat weapons on board.

  • At 8:51 am the Kursk requested permission to conduct a torpedo training launch and received the go ahead

  • After a delay, they set to fire two dummy torpedoes and at 11:29 am the first torpedo was loaded without a warhead into the number 4 tube on the starboard side. The torpedo was 10.7m long and weighed 5.5 tonnes.

  • At 11:29:34 am, seismic detectors at NORSAR (Norweigan Seismic Array) recorded a 1.5 magnitude seismic event in the area where the training exercise was taking place.

  • At 11:31:48 am - 2 minutes and 14 seconds after the first, NORSAR detected a 4.2 magnitude seismic event about 400m from the initial event, suggesting the submarine sank 108m and sat on the seafloor between the two events. This second event was 250 times larger and registered across northern Europe and as far away as Russia.

  • A Russian sub and battlecruiser felt the explosion. The sub thought it was part of the exercise and the ship reported a hydro-acoustic signal characteristic of an underwater explosion and felt their hull shudder. Fleet HQ ignored their report.

Rescue Attempts

  • 4 different rescue attempts failed for various reasons. British, Norweigan, American, French, German, Israel, and Italian governments offered assistance almost immediately but were turned down. Norweigan divers finally managed to open the flooded 9th compartment but found no survivors.

  • Russia had operated two India class submarines that carried Deep Submergence Rescue Vehicles (DSRV’s) but these submarines had been held at a shipyard for the last six years due to lack of funds, the submarines had been held at a shipyard and were unavailable.

  • First Russian submersible from the rescue ship launched was damaged when it ran into the Kursk.

  • 2nd submersible was launched but couldn’t locate the Kursk as incorrect heading was provided by rescue ship

  • First submersible was relaunched but was unable to place a diving trunk on the Kursk. The batteries were depleted, the submersible returned to the surface, no spare batteries were available and when the batteries were recharged, the winds were too high to launch the submersible.

  • At 2000 hours on Tuesday, the first submersible was relaunched but was damaged being lowered into the water. It was repaired and launched again.

  • A crane ship with a more maneuverable submersible was brought to site but weather prevented the launch of this submersible.

  • On Wednesday at 00:20, the first submersible made two attempts to attach a rescue trunk to the sub. Both failed, and the propulsion system was severely damaged when it was being lifted on board. The second submersible was cannibalized for parts, however, this took a significant amount of time.

The British are Coming! The British are Coming!

  • 5 days after the incident occurs, the Russian government finally accepts foreign help to rescue the submariners trapped aboard the Kursk.

  • 6 teams of British and Norweigan divers arrived on Friday August 16th (6 days after the incident occured). Norweigan divers were finally able to gain entry into the Kursk but found the escape truck flooded with water.

  • There were delays in opening the rescue trunk due to the Russian Navy stating the incorrect direction to open a valve.

  • On 21-August, Norweigan divers confirmed there were no survivors.

Official Inquiry

  • July 26, 2002 Russia announced that hydrogen peroxide fuel in the dummy torpedo inside the fourth launcher set off the first explosion.

  • They released a 133 volume top secret report in August 2002 and a 4 page summary to the public stating quote “stunning breaches of discipline, shoddy, obsolete and poorly maintained equipment” end quote, as well as quote “negligence, incompetence and mismanagement” end quote.

  • Initial blast damage

    • There was a 470mm air conditioning duct that passed between the first and second compartment bulkhead.

    • The pressurised valve in said ventilation system, as per standard Russian submarine practice, was left open at the time to minimize pressure changes during a weapons launch.

    • The open valve is believed to have allowed the first blast, which is believed to have started a fire that burned at 2,700 C, to spread fire and smoke as far back as the fourth compartment.

    • No one in the command post, which was located in the second compartment, was able to send a distress signal or send the submarine to the surface

  • Secondary explosion

    • 2 minutes and 14 second later - the fire had set off an explosion of 7 combat ready torpedo warheads

    • Under normal circumstances, there were 78 crew in the first four compartments, and 49 crew in the rear five compartments.

    • The Kursk’s hull could withstand external pressure of depths up to 1,000m, which is about 9,800 Kpa. But the second blast opened a 2 metre square hole in the hull and the first four compartments flooded with water; at a rate of 90,000 L/s

  • Practice torpedo blamed

    • High test peroxide - 85-98% solution, remainder is water - when the high test peroxide comes in contact with a catalyst, it expands 5,000 times in volume and turns into steam and oxygen - used as a propellant - often mixed with kerosene fuel in the torpedo engine to propel the missile higher and further

    • The leaking high test peroxide reacted with the copper in the torpedo tubes and the pressure this generated burst the kerosene fuel tank and cause the first explosion

    • High test peroxide is a known risk - HMS Sidon a Royal Navy submarine sank in 1955 due to an exploding high test peroxide torpedo

  • Faulty weld

    • Apparently the officers who issued the order to use high test peroxide torpedoes did not have authority to do so

    • Sources say that one of the practice torpedoes was dropped during transport - possibly how it got a crack

    • The rubber seals were leaking fuel - no action was taken due to the importance of the training exercise

    • The torpedoes came from a batch that was manufactured in 1990 that were rejected due to faulty welding - since they were never intended to carry warheads the welds were not carefully inspected

    • The torpedo and launch tube showed signs of distortion near an essential weld, which led them to believe the faulty weld led to the explosion

  • Escape capsule - was located in the third compartment which was inaccessible even if it was usable and there was also one in the first compartment that was destroyed with the explosion

  • Nuclear reactors - these were located in compartment 5, with 130mm thick steel - it withstood both explosions and the two reactors shut down automatically, preventing a nuclear meltdown and contamination

  • Rescue buoy - on top of compartment 7 - meant to automatically deploy if it detected any emergency conditions like a fire for rapid pressure change - it was problematic and ultimately disabled when the accident occurred.

  • Russia investigated and didn’t file any charges, even absolving the torpedo manufacturer

  • Other explanations

    • Inadequate training, poor maintenance, incomplete inspections

    • The internal door to the torpedo tube was 3 times as strong as the external door, intended to direct any explosion in the tube out to sea - investigators believe the internal door was not full closed when the explosion occurred

    • Electrical connectors between the torpedoes and internal tube door were unreliable - the crew had to open and close the door multiple times for the contact would register

    • The crew had not prior experience with or been training in handling high test peroxide torpedoes - even going so far as to fake documentation that said they were

    • Lieutenant Captain Dmitri Koselnikov left a note dated two hours after the second explosion recording 23 survivor

  • Conspiracy theory

    • Explosion in the high pressure air tanks used to blow the ballast tanks - located near the torpedo tubes

    • Struck by a missile - either from friend or foe

    • Chechen espionage

    • Human error

    • Sabotage

    • Testing a new top-secret torpedo

  • Recovery

    • Cut off the bow - risk of warheads and it could fall off and destabilize the lift

    • Towed it under a semi-submersible deck barge to a dry dock

    • The investigation found that the crew who had survived both explosions had gathered in compartment nine, but with no way to safely escape. Based on the scale of the explosion and the fact that they were in the middle of a training exercise with many other ships, they thought they would get rescued. But unfortunately, that was not the case.

So there you have it, the sinking of the Kursk submarine. Whatever the actual cause, and as with all of the failures covered on this show, many things went wrong. It was a series of unfortunate events. The faulty weld, the location of the escape capsule, failure to launch the rescue buoy and of course poor rescue efforts. Just like with the Titanic that we covered in episode 11, unsinkable ships do in fact sink and one should always be prepared. The only real silver lining I can see here is that the nuclear reactors shut down safely and didn’t meltdown. Chernobyl was already bad enough, this could have been just as bad or worse.

For photos, sources and an episode summary from this week’s episode head to Failurology.ca. If you’re enjoying what you’re hearing, please rate, review and subscribe to failurology, so more people can find it. If you want to chat with me, my twitter handle is @failurology, you can email me at thefailurologypodcast@gmail.com, or you can connect with me on Linked In. Check out the show notes for links to all of these.

Thanks everyone for listening. And tune in to the next episode for another special engineering marvel. If you’ve been following the show, every 10th episode, we cover an engineering marvel rather than a failure. Next episode’s marvel is the Panama Canal. But more on that next time. Bye everyone, talk soon!