Kursk submarine disaster

On 12 August 2000, the Russian Oscar II class submarine Kursk sank in the Barents Sea after an explosion. The investigation showed that a leak of hydrogen peroxide in a torpedo led to explosion of its fuel, causing the submarine to hit the bottom which in turn triggered the detonation of further torpedo warheads about two minutes later. This second explosion was equivalent to about 2-3 tonnes of TNT, large enough to register on seismographs across Northern Europe.

Despite a rescue attempt by British and Norwegian teams, which was severely delayed due to the Russians refusing them access, all 118 sailors and officers aboard Kursk died. The next year, a Dutch team recovered the wreckage and all of the bodies, which were buried in Russia.

Wreck of Kursk in a dock

The explosion

Omsk, an Oscar II class submarine similar to Kursk, in 1994

On the morning of 12 August 2000, as part of a naval exercise, Kursk was to fire two dummy torpedoes at Kirov-class battlecruiser Pyotr Velikiy, the flagship of the Northern Fleet. At 11:29 local time (07:29:50 UTC), a 65-76 "Kit" torpedo was loaded into Kursk's number 4 torpedo tube. Due to a leaking weld in the torpedo's fuel system, high test peroxide, a form of highly concentrated hydrogen peroxide used as an oxidiser for the torpedo's rocket engine, escaped into the torpedo casing where it catalytically decomposed on the metals and oxides present there, yielding steam and oxygen. The resulting overpressure ruptured the kerosene fuel tank, causing an explosion that registered as a weak seismic signature on detectors hundreds of kilometers away. A similar incident was responsible for the loss of HMS Sidon in 1955.

Recovered remains of the torpedo later allowed the first explosion to be pinpointed to the middle part of the torpedo. According to maintenance records the dummy torpedoes, manufactured in the 1990s, had never had their welds checked; such checks were considered unnecessary as the torpedoes did not carry warheads.

The explosive reaction of 1.5 tons of concentrated hydrogen peroxide and 500 kg of kerosene blew off the external torpedo tube cover and the internal tube door. (The torpedo tube cover was later found on the seabed and its position relative to the rest of the submarine served as evidence of this version of events.) The tube door, which should have been capable of resisting such an explosion, was not properly closed; the electrical connectors between the torpedoes and the tube doors were unreliable and often required repeated reclosing of the door before a contact was established, so it is likely that at the moment of explosion the door was not fully closed. The blast entered the front compartment, probably killing all seven men there. The bulkhead should have arrested the blast wave, but it was penetrated by a light air conditioning channel which allowed passage of the blast wave, fire and toxic smoke into the second and perhaps third and fourth compartments, injuring or disorienting the 36 men in the command post located in the second compartment and preventing the initiation of an emergency blowout to resurface the submarine. Additionally, an automatic emergency buoy, designed to release itself on detection of conditions such as fire or rapid pressure changes and intended to help rescuers locate the stricken vessel, did not deploy. The previous summer, in a Mediterranean mission, fears that the buoy might accidentally deploy and reveal a submarine's position to the U.S. fleet had led to it being disabled.

Two minutes and fifteen seconds after the initial eruption, a much larger explosion ripped through the submarine. Seismic data from stations across Northern Europe show that the explosion occurred at the same depth as the sea bed, suggesting that the submarine's collision with the sea floor, combined with rising temperatures due to the initial explosion, had caused other torpedoes to explode. The second explosion was equivalent to 2-3 tons of TNT, or about 5-7 torpedo warheads, and measured 4.2 on the Richter scale. Acoustic data from Pyotr Velikiy indicated an explosion of about 7 torpedo warheads in rapid succession.

The second explosion ripped a 2-square-metre (22 sq ft) hole in the hull of the craft, which was designed to withstand depths of 1,000 metres (3,300 ft), and also ripped open the third and fourth compartments. Water poured into these compartments at 90,000 litres (3,200 cu ft) per second killing all those in the compartments, including five officers from 7th SSGN Division Headquarters. The fifth compartment contained the ship's two nuclear reactors, encased in 13 centimetres (5.1 in) of steel and resiliently mounted to absorb shocks in excess of 50g. The bulkheads of the fifth compartment withstood the explosion, allowing the two reactors to shut down automatically and preventing nuclear meltdown or contamination.

Later forensic examination of two of the reactor control room casualties showed extensive skeletal injuries which indicated that they had sustained shocks of just over 50g during the explosions. These shocks would have temporarily disoriented the operators and possibly other sailors further aft.

"It's dark here to write, but I'll try by feel. It seems like there are no chances, 10-20%. Let's hope that at least someone will read this. Here's the list of personnel from the other sections, who are now in the ninth and will attempt to get out. Regards to everybody, no need to be desperate. Kolesnikov."

Captain-lieutenant Dmitri Kolesnikov

Twenty-three men working in the sixth through ninth compartments survived the two blasts. They gathered in the ninth compartment, which contained the secondary escape hatch (the primary hatch having been in the destroyed second compartment). Captain-lieutenant Dmitri Kolesnikov (one of three surviving officers of that rank) appears to have taken charge, writing down the names of those who were in the ninth compartment. The air pressure in the compartment following the secondary explosions was still normal surface pressure and so it would be possible, at least from a physiological point of view, to don survival suits and use the hatch to escape one man at a time, swimming up through 100 metres (330 ft) of Arctic water to await help at the surface.

It is not known if the escape hatch was workable from the inside; opinions differ about how badly it was damaged. However, the men would likely have rejected risking the escape hatch even if it were operable. They may have preferred instead to take their chances waiting for a submarine rescue ship to clamp itself onto the hatch. It is not known with certainty how long the remaining men survived in the compartment. As the nuclear reactors had automatically shut down, emergency power would soon have run out, plunging the crew into complete blackness and falling temperatures. Kolesnikov wrote two further messages, much less tidily.

There has been much debate over how long the sailors survived. Russian sources say that they would have died very quickly. The Dutch recovery team report a widely believed two to three hour survival time in the least affected sternmost compartment. In normal operation, water leaks into a stationary Oscar-II craft through the propeller shafts, and at 100 metres (330 ft) depth it would have been impossible to prevent this. Others point out that many superoxide chemical cartridges, used to absorb carbon dioxide and provide oxygen in an emergency, were found to have been used when the craft was recovered, suggesting survival for several days. Ironically, the cartridges seem to have been the final cause of death: a cartridge appears to have come in contact with oily sea water, causing a chemical reaction and flash fire. The official investigation into the disaster showed that some men survived this fire by plunging under water (fire marks on bulkheads indicate the water was at waist level at the time) but the fire would have rapidly used up any remaining oxygen in the air, causing death by asphyxiation.

Rescue attempts

File:Rudnitsky-normand-pioneer.jpg

Russian and Norwegian ships heading towards the Kursk site

Initially the other ships in the exercise, all of which had detected an explosion, did not report it. Each only knew about its own part in the exercise, and ostensibly assumed that the explosion was that of a depth charge, and part of the exercise. It was not until the evening that commanders stated that they became concerned that they had heard nothing from Kursk. Later in the evening, and after repeated attempts to contact Kursk had failed, a search and rescue operation was launched. The rescue ship Rudnitsky carrying two submersible rescue vessels, AS-32 and the Priz (AS-34) reached the disaster area at around 8:40 AM the following morning.

The submarine was found in an upright position, with its nose plowed about 2 meters deep into the clay seabed, at a depth of 108 meters. The periscope was raised, indicating the accident occurred at a low depth. The bow and the sailbridge showed signs of damage, the conning tower windows were smashed and two missile tube lids were torn off. Fragments of both outer and inner hull were found nearby, including a fragment of Kursk's nose weighing 5 metric tons, indicating a massive explosion in the forward torpedo room.

Priz reached Kursk's ninth compartment the day after the accident, but failed to dock with it. Bad weather prevented further attempts on Tuesday and Wednesday. A further attempt on Thursday again made contact but failed to create a vacuum seal required to dock.

The United States offered the use of one of its two Deep Submergence Rescue Vehicles, as did the British government, but all offers were refused by the Russian government. Four days after the accident on 16 August 2000, the Russian government accepted the British and Norwegian governments' assistance and a rescue ship was dispatched from Norway on 17 August and reached the site on 19 August. British and Norwegian deep-sea divers reached the ninth compartment escape hatch on Sunday, 20 August. They were able to determine that the compartment was flooded, and all hope of finding survivors was lost.

Russian government response

"For President Vladimir Putin, the Kursk crisis was not merely a human tragedy, it was a personal PR catastrophe. Twenty-four hours after the submarine's disappearance, as Russian naval officials made bleak calculations about the chances of the 118 men on board, Putin was filmed enjoying himself, shirtsleeves rolled up, hosting a barbecue at his holiday villa on the Black Sea."

Amelia Gentleman

The first fax sent from the Russian Navy to the various Press offices said the submarine had "minor technical difficulties". The government downplayed the incident and then claimed bad weather was making it impossible to rescue the people on board.

On 18 August 2000 Nadezhda Tylik, mother of Kursk submariner Lt. Sergei Tylik, produced an intense emotional outburst in the middle of an in-progress news briefing about Kursk's fate. After attempts to quiet her failed, a nurse injected her with a sedative by force from the back, and she was removed from the room, incapacitated. The event, caught on film, caused further criticism of the government's response to both the disaster, and how the government handled public criticism of said response.

According to Raising Kursk broadcast by the Science Channel:

In June of 2002... the Russian government investigation into the accident officially concluded that a faulty torpedo sank Kursk in the Summer of 2000.

Salvage

Most of the submarine's hull, except the bow, was raised from the ocean floor by the Dutch marine salvage companies Smit International and Mammoet in late 2001 and towed back to the Russian Navy's Roslyakovo Shipyard. The front section was cut off because of concerns it could break off and destabilize the lifting, and was recovered in 2002. It was cut off using a chain of drums covered with an abrasive, pulled back and forth between two hydraulic anchors dug into the seabed; the cutting took 10 days.

The bodies of the dead crew were removed from the wreck and buried in Russia–three of them were unidentifiable because they were so badly burned. Russian President Vladimir Putin signed a decree awarding the Order of Courage to all the crew and the title Hero of the Russian Federation to the submarine's captain, Gennady Lyachin.

The first five fragments to be raised were a piece of a torpedo tube weighing about a ton (to ascertain if the explosion occurred inside or outside), a high-pressure compressed air cylinder weighing about half a ton (also to ascertain the nature of the explosion), part of the cylindrical section of the hard frame and part of the left forward spherical partition to determine the intensity and temperature of the fire in the forward compartment, and a fragment of the sonar system dome.

The presence of explosives in the unexploded torpedoes (about 225 kg TNT equivalent each) and especially in the 23 SS-N-19 cruise missiles aboard (about 760 kg each, plus about 7 kg TNT equivalent of the silo ejection charge), together with the risk of radiation release from the reactors, presented a unique set of challenges to the salvage teams.

See also

• August curse
• List of sunken nuclear submarines
• List of the Kursk submarine dead
• Major submarine incidents since 2000
• Nadezhda Tylik
• National Geographic Seconds From Disaster episodes
• Soviet submarine K-129 (1960), sunk in 1968 according to some claims after collision with a US submarine
• Soviet submarine K-278 Komsomolets, sunk in 1989 in Barents Sea after fire and refusal of Western help
• AS-28, Russian mini-submarine trapped underwater in 2005 and saved by the British after initial refusal of help

Further reading

• Robert Moore (2002). A Time To Die: The Kursk Disaster. Bantam Books. ISBN 0-553-81385-4.
• Barany, Zoltan (2004). The Tragedy of the Kursk: Crisis Management in Putin's Russia. Government and Opposition 39.3, 476-503.
• Truscott, Peter (2004): The Kursk Goes Down – pp. 154–182 of Putin's Progress, Pocket Books, London, ISBN 0-7434-9607-8

External links

• Капитан Колесников, A song about the Kursk explosion by Russian band ДДТ
• The Recovery of the Russian Federation Nuclear Powered Submarine Kursk, Peter Davidson, Huw Jones, John H. Large, Society of Naval Architects and Marine Engineers - World Maritime Technology Conference, October 2003
• Risks and Hazards in Recovering the Nuclear Powered Submarine Kursk, John H. Large, Royal Institution of Naval Architects, 23–24 June 2005
• Site in Russian
• In depth coverage by the BBC
• Flash Animation of the explosion and the rescue attempts (Turkish)
• Pictures of Kursk in dry dock after explosion
• The Kursk Odyssey, a symphony to the 118 submariners of the Kursk, composed by Didier Euzet
• Sequoya's "Barren the Sea", a folk song about the tragedy — link is sampling of song on CDBaby.com
• English Russia - The Remains of the Kursk Submarine, photographs of the recovered wreck
• BBC World Service, BBC Witness talks to people who experienced the disaster