Russia:
Project 949A Antey (NATO Oscar II) class cruise missile submarine K-141
Kursk being raised, 2001
Kursk joined the "Summer-X" exercise, the first large-scale naval exercise planned by the Russian Navy in more than a decade, on 10 August 2000. It included 30 ships including the fleet's flagship
Pyotr Velikiy ("Peter the Great"), four attack submarines, and a flotilla of smaller ships. The crew had recently won a citation for its excellent performance and been recognized as the best submarine crew in the
Northern Fleet. While it was on an exercise,
Kursk loaded a full complement of combat weapons. It was one of the few ships authorized to carry a combat load at all times.
On the first day of the exercise,
Kursk successfully launched a Granit missile armed with a dummy warhead. Two days later, on the morning of 12 August,
Kursk prepared to fire
dummy torpedoes at the
Kirov-class battlecruiser Pyotr Velikiy. These practice torpedoes had no explosive warheads and were manufactured and tested at a much lower quality standard. On 12 August 2000, at 11:28 local time (07:28
UTC), there was an explosion while preparing to fire. The Russian Navy's final report on the disaster concluded the explosion was due to the failure of one of
Kursk's hydrogen peroxide-fueled
Type 65 torpedoes. A subsequent investigation concluded that
high-test peroxide (HTP), a form of highly concentrated
hydrogen peroxide used as propellant for the torpedo, seeped through a faulty weld in the torpedo casing. When HTP comes into contact with a catalyst, it rapidly expands by a factor of 5000, generating vast quantities of steam and oxygen. The pressure produced by the expanding HTP ruptured the kerosene fuel tank in the torpedo and set off an explosion equal to 100–250 kilograms (220–550 lb) of
TNT. The submarine sank in relatively shallow water, bottoming at 108 metres (354 ft) about 135 km (84 mi) off
Severomorsk, at
69°40′N 37°35′E. A second explosion 135 seconds after the initial event was equivalent to 3-7 tons of TNT. The explosions blew a large hole in the hull and caused the first three compartments of the submarine to collapse, killing or incapacitating all but 23 of the 118 personnel on board.
The
British and
Norwegian navies offered assistance, but Russia initially refused all help. All 118 sailors and officers aboard
Kursk died. The Russian Admiralty initially told the public that the majority of the crew died within minutes of the explosion, but on 21 August, Norwegian and Russian divers found 24 bodies in the ninth compartment, the turbine room at the stern of the boat. Captain-lieutenant Dmitri Kolesnikov wrote a note listing the names of 23 sailors who were alive in the compartment after the ship sank.
Kursk carried a
potassium superoxide cartridge of a
chemical oxygen generator; these are used to absorb
carbon dioxide and chemically release oxygen during an emergency. However, the cartridge became contaminated with sea water and the resulting chemical reaction caused a flash fire which consumed the available oxygen. The investigation showed that some men temporarily survived the fire by plunging under water, as fire marks on the bulkheads indicated the water was at waist level at the time. Ultimately, the remaining crew burned to death or suffocated.
Vice-Admiral Valery Ryazantsev differed with the government's official conclusion. He cited inadequate training, poor maintenance, and incomplete inspections that caused the crew to mishandle the weapon. During the examination of the wrecked sub, investigators recovered a partially burned copy of the safety instructions for loading HTP torpedoes, but the instructions were for a significantly different type of torpedo and failed to include essential steps for testing an air valve. The 7th Division, 1st Submarine Flotilla never inspected
Kursk's crew's qualifications and readiness to fire HTP torpedoes.
Kursk's crew had no experience with HTP-powered torpedoes and had not been trained in handling or firing HTP-powered torpedoes. Due to their inexperience and lack of training, compounded by incomplete inspections and oversight, and because the
Kursk's crew followed faulty instructions when loading the practice torpedo, Ryazantsev believes they set off a chain of events that led to the explosion.