The Kursk was a Russian 'Oscar II' nuclear submarine armed with cruise missiles, operated by a crew of 111. Shortly before leaving base on August 10, 2000, the crew had won an award for best submarine crew of the Northern Fleet. The last message from the sub was received on August 12th at 8:51am. The sub had requested permission for a torpedo launch as part of an exercise involving other ships.

On August 12, 2000, two consecutive explosions destroyed the front of the submarine. The first explosion occurred just before 0730GMT, and registered 1.5 on the Richter scale of seismology sites in Norway.  This corresponds to about 200 pounds of TNT. After the first explosion, the submarine continued for about 1,200 feet through the water. The second, stronger explosion occurred 2 minutes later. This explosion was much more powerful, equivalent to about 2 tons of TNT.  The force of the explosions tore open the front starboard side of the hull. Spaces forward of the reactor room flooded immediately, making it impossible for those on board to escape.  No communications or rescue devices were used, indicating that there was little time for the crew to react.

Some sailors managed to retreat to the rear of the sub. However, these areas ultimately flooded as well, trapping the survivors in increasingly smaller air bubbles under great pressure. There are conflicting reports on whether messages were received from the trapped crew, but it is possible that distress signals were heard as late as August 15th. Any survivors would have exhausted their air reserves by August 20th.

The Russian Northern Fleet quickly began rescue efforts, including DSRV vehicles. These efforts were hindered by high waves caused by bad weather, strong currents, and low visibility. On August 16^th, the Russians requested international assistance. Norwegian divers managed to attach a flexible escape hose between the sub to a British rescue submarine. However, by the time the rescuers opened the rear hatch, the submarine was completely flooded and the crew was already dead.

On October 26^th, a note was found on the body of Dmitri Kolesnikov. Written on August 12th, several hours after the accident, it indicated that 23 had survived but that they were unable to use the escape hatch.

A second note was reportedly written by Kolesnikov on August 15th and directed to Fleet Command. A third note found on the body of an unidentified seaman indicated that the crew had experienced carbon monoxide poisoning and was being subjected to increasing pressure as the rear compartments flooded.

Controversy surrounds the cause of the initial explosions. Most believe a malfunctioning torpedo caused the sinking, but some Russian naval officials have supported a collision theory, possibly with another submarine. Efforts are currently underway to raise the Kursk to recover remaining bodies. However, the front section involved in the actual explosion will not be raised--which may prevent the exact cause of the disaster from ever being known.

Sources:

Leonid A. Kharitonov, Russian Submarine Kursk Catastrophe.

Janes

Associated Press.