Russian submarine Kursk (K-141)
K-141 "Kursk" (, transl. , meaning "Atomic-powered submarine "Kursk"") was an Oscar II-class nuclear-powered cruise missile submarine of the Russian Navy. On 12 August 2000, K-141 "Kursk" was lost when it sank in the Barents Sea, killing all 118 personnel on board. Construction. K-141 "Kursk" was a Project 949A class "Antey" () submarine of the Oscar class, known as the Oscar II by its NATO reporting name, and was the penultimate submarine of the Oscar II class designed and approved in the Soviet Union. Construction began in 1990 at the Soviet Navy military shipyards in Severodvinsk , near Arkhangelsk, in the northern Russian SFSR. During the construction of K-141, the Soviet Union collapsed; work continued, and she became one of the first naval vessels completed after the collapse. In 1993 K-141 was named "Kursk" after the Battle of Kursk in the 50-year anniversary of this battle. K-141 was inherited by Russia and launched in 1994, before being commissioned by the Russian Navy on December 30, as part of the Russian Northern Fleet. "Kursk" was assigned to the home port of Vidyayevo, Murmansk Oblast. Capabilities. The Antey design represented the highest achievement of Soviet nuclear submarine technology . They are the second-largest cruise missile submarines ever built, after some ballistic missile submarines were converted to carry cruise missiles in 2007. It was built to defeat an entire United States aircraft carrier group. A single Type 65 torpedo carried a warhead powerful enough to sink an aircraft carrier. Both missiles and torpedoes could be equipped with nuclear warheads. She was longer than the preceding Oscar I-class of submarines. The senior officers had individual staterooms and the entire crew had access to a gymnasium. The outer hull, made of high-nickel, high-chromium stainless steel thick, had exceptionally  good resistance to corrosion and a weak magnetic signature which helped prevent detection by U.S. magnetic anomaly detector (MAD) systems. There was a gap to the -thick steel pressure hull. She was designed to remain submerged for up to 120 days. The sail superstructure was reinforced to allow it to break through the Arctic ice. The submarine was armed with 24 SS-N-19/P-700 Granit cruise missiles, and eight torpedo tubes in the bow: four and four . The Granit missiles with a range of , were capable of supersonic flight at altitudes over . They were designed to swarm enemy vessels and  intelligently choose individual targets which terminated with a dive onto the target. The torpedo tubes could be used to launch either torpedoes or anti-ship missiles with a range of . Her weapons included 18 SS-N-16 "Stallion" anti-submarine missiles. "Kursk" was part of Russia's Northern Fleet, which had suffered funding cutbacks throughout the 1990s. Many of its submarines were anchored and rusting in Zapadnaya Litsa Naval Base, from Murmansk. Little work to maintain all but the most essential front-line equipment, including search and rescue equipment, had occurred. Northern Fleet sailors had gone unpaid in the mid-1990s. Deployments . During her five years of service, "Kursk" completed only one mission, a six-month deployment to the Mediterranean Sea during the summer of 1999 to monitor the United States Sixth Fleet responding to the Kosovo crisis. This was due to a lack of funds for fuel. As a result, many of her crew had spent little time at sea and were inexperienced. Naval exercise and disaster. "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 vessels authorized to carry a combat load at all times. Explosion. 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 "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 of TNT. The submarine sank in relatively shallow water, bottoming at about off Severomorsk, at . 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. Rescue attempts. 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 boat 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. Russian President Vladimir Putin, though immediately informed of the tragedy, was told by the navy 	Russian submarine Kursk (K-141)
23204840	that they had the situation under control and that rescue was imminent. He waited for five days before ending his holiday at a presidential resort in Sochi on the Black Sea. Putin was only four months into his tenure as president, and the public and media were extremely critical of his decision to remain at a seaside resort. His highly favourable ratings dropped dramatically. The president's response appeared callous and the government's actions looked incompetent. A year later he said, I probably should have returned to Moscow, but nothing would have changed. I had the same level of  communication both in Sochi and in Moscow, but from a PR point of view I could have demonstrated some special eagerness to return." Submarine recovery. A consortium formed by the Dutch companies Mammoet and Smit International was awarded a contract by Russia to raise the vessel, excluding the bow. They modified the barge "Giant 4" which raised "Kursk" and recovered the remains of the sailors. During salvage operations in 2001, the team first cut the bow off the hull using a tungsten carbide-studded cable. As this tool had the potential to cause sparks which could ignite remaining pockets of  reactive gases, such as hydrogen, the operation was executed with care. Most of the bow was abandoned and the rest of the vessel was towed to Severomorsk and placed in a floating dry dock for analysis. The remains of "Kursk"s reactor compartment were towed to Sayda Bay on Russia's northern Kola Peninsula, where more than 50 reactor compartments were afloat at pier points, after a shipyard had removed all the fuel from the boat in early 2003. Some torpedo and torpedo tube fragments from the bow were recovered and the rest was destroyed by explosives in 2002. Official inquiry  results. Notwithstanding the navy's oft-stated position that a collision with a foreign vessel had triggered the event, a report issued by the government attributed the disaster to a torpedo explosion caused when high-test peroxide (HTP), a form of highly concentrated hydrogen peroxide, leaked from a faulty weld in the torpedo's casing. The report found that the initial explosion destroyed the torpedo room compartment and killed everyone in the first compartment. The blast entered the second and perhaps the third and fourth compartments through an air conditioning vent. All of the 36 men in the command post  located in the second compartment were immediately incapacitated by the blast wave and possibly killed. The first explosion caused a fire that raised the temperature of the compartment to more than . The heat caused the warheads of between five and seven additional torpedoes to detonate, creating an explosion equivalent to 2–3 tons of TNT that measured 4.2 on the Richter magnitude scale on seismographs across Europe and was detected as far away as Alaska. Alternative explanation. 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.