4 key points: In August 2000, the Russian Oscar-class submarine Kursk tragically sank in the Barents Sea after a catastrophic explosion on board. Designed to target US aircraft carriers with its arsenal of P-700 Granit missiles and numerous torpedoes, Kursk took part in a naval exercise alongside the aircraft carrier Admiral Kuznetsov and the battlecruiser Pyotr Velikiy.

-At 11:28 am Kursk experienced two massive explosions, believed to be caused by an accidental detonation of a Type 65-76A torpedo powered by hydrogen peroxide.

-The submarine sank quickly, resulting in the loss of 118 crew, with only 23 survivors.

-Despite international rescue efforts, the tragedy underlined the inherent dangers of submarine operations and fueled conspiracy theories, although official investigations confirmed it was a result of internal mechanical failure.

Tragedy beneath the waves: the sinking of the Russian Kursk submarine

In 2000, a Russian submarine designed to sink aircraft carriers fell victim to its own arsenal. The cruise missile submarine Kursk suffered a massive explosion and sank after a torpedo on board accidentally detonated. The accident was the worst maritime disaster that post-Cold War Russia had to deal with.

The Soviet Union’s greatest opponents at sea were the aircraft carriers of the US Navy. With their versatile air wings, American carriers could thwart the Warsaw Pact’s wartime plans, doing everything from escorting convoys across the Atlantic to bombing Soviet Northern Fleet bases above the Arctic Circle. They also carried nuclear weapons, making them exceptionally dangerous off the Soviet coast.

The Soviets’ solution was to build Oscar-class submarines. Some of the largest submarines ever built are 160 meters long and have a beam of almost 18 meters – almost twice the size of the Soviet Union’s Alpha-class attack submarines. With a submerged weight of 19,400 tons, they were larger than the US Ohio-class ballistic missile submarines.

They were big for a reason: each Oscar carried two dozen enormous P-700 Granit missiles. The P-700 was a large missile designed to kill large ships. The P-700 was thirty meters long and almost one meter wide. They each weighed 15,400 pounds, most of which was fuel for the jet-powered engine that propelled the rocket at speeds of Mach 1.6 to a range of 388 miles. The missile carried either a conventional, high-explosive, 1,653-pound warhead, enough to damage an aircraft carrier, or a five-hundred-kiloton warhead, enough to vaporize an aircraft carrier. The missiles would receive targeting data from the Legenda space surveillance system, which would hunt fast-moving battle groups from orbit.

The missiles were hidden in two rows of twelve under the fuselage, in silos pointed upwards at an angle of seventy degrees. It was this arsenal that earned them the then unusual SSGN designation in the West, with the G standing for ‘guided missiles’.

If that wasn’t enough, the Oscars had a large number of torpedoes. Each submarine had four torpedo tubes with a standard diameter of 533 millimeters that could launch standard homing torpedoes, SS-N-15 “Starfish” anti-submarine missiles or SS-N-16 “Stallion” anti-ship missiles. It also featured two oversized 650-millimeter torpedo tubes for launching Type 65-76A torpedoes against larger naval targets. Together the six tubes were armed with twenty-four torpedoes.

The Oscars had to be fast to intercept American nuclear-powered aircraft carriers, and that meant they too needed nuclear propulsion. Each was powered by two OK-650 nuclear reactors that produced a combined 97,990 horsepower on board. This accelerated the submarines to fifteen knots on the surface and a fast thirty-three knots underwater.

Twenty Oscar-class submarines were planned, but only thirteen were built before the end of the Cold War and the demise of the Soviet Union. K-141also known as Kurskwas laid down in March 1992 and commissioned into the Russian Northern Fleet in December 1994.

On August 15, 2000, the Kursk was training with key elements of the Russian Northern Fleet, including the aircraft carrier Admiral Kuznetsov and battlecruiser Pyotr Veliki. Kurskwhich was fully loaded with Granit missiles and torpedoes, would conduct a simulated attack on an aircraft carrier. An underwater explosion was detected at 11:28 am, followed two minutes later by a second, larger explosion. One Russian account claims it to be a twenty-eight thousand ton battlecruiser Pyotr Veliki shook from the first explosion, and a Norwegian seismic station recorded both explosions.

Kursk had suffered two enormous explosions and sank in 100 meters of water at a vertical angle of twenty degrees. An explosion had pierced the front of the hull and left a terrible gash along the upper bow. Yet at least twenty-three of the 118 crew members had survived the sinking, as evidenced by a note from one of the ship’s senior officers, Lieutenant Captain Dmitry Kolesnikov. The note was dated exactly two hours after the first explosion. Rescue attempts by Russian – and later British and Norwegian – teams failed to save the survivors.

A Russian investigation into the accident concluded that one of the Kursk‘s Type 65-76A torpedoes had exploded. A defective weld in a torpedo or damage to a torpedo during movement had caused it to leak hydrogen peroxide. Like many torpedoes, the Type 65 used hydrogen peroxide as its underwater fuel. Unfortunately, hydrogen peroxide becomes explosive when it comes into contact with a catalyst, such as organic compounds or fire. It is believed that a similar accident sank HMS Sidona Royal Navy submarine, in 1955.

Conspiracy theories about the sinking of the Kursk are widespread on the Russian Internet. Many claim that nearby American attack submarines sank the boat Kursk with Mark 48 torpedoes. While this is technically possible (in the absence of evidence of an internal torpedo explosion), there is no plausible motive for such an attack during a period of good US-Russian relations. Why attacks on the Kursk? Why was only the Kursk sunk, and not the Kuznetsov And Pyotr Veliki? Why would the Russian government cover up the attack?

Ultimately, the sinking of the Kursk appears to have been caused by a simple, freak chemical accident. The tragedy only reinforces how dangerous life aboard a submarine really is, and how important underwater safety is. Finally, the rush to conspiracy is a warning that if this incident had occurred during a real crisis, such an accident could trigger a dangerous escalation that could lead to war.

About the Author: Kyle Mizokami

Kyle Mizokami is a defense and national security writer based in San Francisco and has appeared in the Diplomat, foreign policy, war is boring and the Daily beast. In 2009, he co-founded the defense and security blog Japan Security Watch. You can follow him on Twitter: @KyleMizokami.

Image credits: Creative Commoms.

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