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Why didthe Kursksink?

Twenty years ago, planned sea exercises in the Barents Sea ended in a horrifying tragedy. There were two explosions aboard the Kursk submarine. The vessel sank. All 118 members of the crew were killed.

Kursk – Pride of the Fleet

On August 10, 2000, The Kursk, a nuclear submarine, put out to see to take part in military Northern Fleet exercises. There were 118 seamen on board.

118 crew members

The Kursk was a 949A Antaeus design. That name was no accident – in Greek mythology, the giant Antaeus, the son of Poseidon, was undefeatable.

The vessel was specially developed to fight American aircraft carriers. It had 24 cruise missiles and 24 torpedoes. Each could destroy an entire ship. The submarine’s armoring was capable of withstanding underwater explosions. This was a beautiful and highly-developed piece of weaponry.

The Kursk’s mission is to track down its nominal enemy being played by the Peter the Great Cruiser and carry out training shooting. The seamen successfully launch a winged rocket, now it’s time for volley firing (launch of several torpedoes from several launching devices simultaneously). This was planned for August 12.

The sub’s crew is regarded as the best in the Northern Fleet. However, due to poor financing of the fleet in the 1990s, the seamen hadn’t even fired training torpedoes in three years.

A DIRTY BOMB

August 11^th — the day before the firing – the seamen check the missile. This is a 65-76 “Kit” training torpedo. There are no explosives in it, though there is an aggressive fuel oxidant – high-test peroxide, which allows the torpedo to go faster and further.

The high-test peroxide provides the 65-76 with its advantage, but also its main danger. If the peroxide for some reason mixes with the hydrocarbon gases – evaporating off the engine oil, kerosene, the wire casings – there will be an explosion. Due to accidents, similar torpedoes in the USA and Great Britain were no longer being used.

The sensors indicate that one torpedo has to be filled with compressed air. This is a standard procedure, similar to pumping the tires on a car. The submariners hook the torpedo up to the sub’s air supply system with a flexible pipe.

The air supply system hadn’t been used on the Kursk for a long time. The pipe hadn’t been cleaned or degreased for years. Dust and old lubrication micro-particles had built up in it over those years.

The compressed air mixes with this dirt and fills the torpedo’s air reservoir. The training torpedo is transformed into a bomb.

INADVERTENT MISTAKE

On August 12^th, the next day, between 9 and 10 in the morning, the seamen load the torpedo into the launching device. Before doing so they remove the torpedo’s safety-mechanism: they switch the cocking valve from “off” to the “ready to operate” position.

A characteristic of the 65-76 torpedo is that when the valve is switched it doesn’t necessarily fix itself in the correct position precisely. That allows the compressed air to react with the peroxide. This appears to be what happened with the torpedo on the Kursk.

According to the instructions, before loading the torpedo into the launching mechanism, the safety switch has to be checked.

Why didn’t the seamen check the dangerous valve? The answer is simple: They didn’t know what they were working with.

The crew had not used the peroxide torpedoes on the Kursk since its construction in 1995, which is to say never. Later the investigation would establish that the necessary instructions for the torpedoes weren’t even on board the sub.

Up to this point the dirty air had been kept apart from the fuel by the cocking valve. Now, due to the gap in the valve, the hydrogen peroxide began a violent chemical reaction with the particles of dirt. The pressure in the torpedo’s air reservoir began to rise.

EXPLOSION

At 11:28 the trigger cylinder inside the torpedo exploded. This immediately detonates 1,500 tons of hydrogen peroxide mixed with kerosene. The powerful explosion was recorded by a seismic station in Norway.

Seven submariners in the 1^st compartment die immediately from the blast. Through the hole in the roof of the torpedo mechanism the compartment is filled with water.

7 DEAD

111 ALIVE

Theoretically, there could have only been 7 victims of this tragedy. The sub could have gone into an emergency mode and surfaced. But that didn’t happen.

Antaeus class submarines have a specific feature in their design. When firing volleys from several weapons at once, the pressure in the torpedo section rises to such an extent that the seamen risk suffering contusions. To avoid this, before firing the torpedo crew unsealed their compartment, opening the ventilation between the compartments, in full accordance with their instructions.

The shock waves of the explosion pass through the ventilation ducts into the second compartment where the command station is located. The shock wave is weakened, but has sufficient force to inflict severe contusions and possibly deaths among the 36 submariners there.

3643 DEAD

75 ALIVE

The explosion causes the reactors and turbines to automatically shut down. The Kursk stops progress, only moving as a result of its momentum. Water fills the first compartment, and the sub begins to heel dangerous towards the bow.

SECOND EXPLOSION

A minute after the explosion, the angle of the heeling reaches 20°, in two minutes it is already 35°. After another 15 seconds, this multi-ton juggernaut hits the bottom. The full force of the blow is taken by the torpedo compartment.

At the moment of the collision, 10 live torpedoes explode with a force equivalent to 2 tons of TNT. This horrific explosion is recorded by seismographs all across Northern Europe.

The Kursk ploughs on for about 30 meters and stops, having dug 2.5 meters into the seabed. The 1^st compartment no longer exists. Neither do the 2^nd, 3^rd, 4^th or 5^th.

5-b – the reactor section – has been fitted with the toughest bulkhead, which stops the blast wave and suppresses its destructive force. It is only thanks to this bulkhead that the submariners in the 6th to 9th compartments are still alive. Of the 118 crewmembers, 23 remain.

5295 DEAD

23 ALIVE

SAFETY COMPARTMENT

The seamen make their way into the 9^th compartment – the safety compartment – and hermetically seal it. There is already water in the compartment, however, which has got in through the technical piping. There is also fuel and technical oil in the water, which has spread through the sub following the explosion.

While the seamen block the leaks, a thin film of oil settles on the parts of the compartment.

The seamen don’t take any steps to abandon the submarine – they are confident that they will be saved. But no help comes. The air temperature falls to +4–7 degrees Celsius. There is not enough oxygen, and they breathe with difficulty. The emergency batteries run down, and the lights in the compartment die out.

At 15:00 the crew takes a decision to leave the submarine through the emergency hatch. In order to do that, a series of complex processes has to be carried out in total darkness. Firstly, oxygen is needed – at this point it can only be received from regenerative plates containing oxygen which have to be put into a special device.

The submariners find the plates in the darkness. This is their last, very slim chance. The plates can’t be used in premises where there is fuel or oil – if one drop gets on the plates by chance that will be enough for a fire that will burn at a temperature of up to 1000 degrees Celsius.

In total darkness, in a space covered in a film of oil, the submariners didn’t stand a chance. The fire flared up in an instant. There was no way to put it out, and the submariners didn’t have the strength anymore anyway.

23118 DEAD

not one alive

The submarine is found 17 hours after the explosion, when, according to Vice-Admiral Valery Ryazantsev, there were already no submariners left to save.

But what if the situation had developed in a different way and the submariners had waited for several days? Could a life perhaps have been saved?

A chronicle of the rescue operation gives an unambiguous answer to this question.