What follows is speculation. As with the chaos immediately following an airplane crash, there is little in the way of evidence that one can hold and examine. To do that takes time, and time is not a luxury available at this moment, about a week after the incident that seems to have destroyed the SSGN Kursk, a proud name harking back to the most decisive land battle of World War II.
What is an SSGN? It’s a submarine designed to launch cruise missiles, as opposed to the ballistic kind that most people think about when they think “missile sub.” Kursk was one of the Oscar II-class subs (so named by NATO) designed to hunt and kill American aircraft carriers; it carried SS-N-19 cruise missiles that NATO calls “Shipwrecks.” Oscar also bore two types of torpedoes, 21-inch–which is the standard diameter–“fish” and 26-inch weapons, designed to snap American aircraft carriers in half. The “little” torpedoes carry warheads of perhaps 800 to 1,000 pounds of high explosive. The bigger ones carry the best part of a ton. How many such weapons Kursk had aboard at the time is unclear at the moment, but 20 or so seems about right, and that translates into 10 or 15 tons of high explosive contained in a sturdy steel hull.
The ship herself is a large one, displacing 19,000 tons when submerged–more than the displacement of a lot of World War II aircraft carriers. It was reported late last week that video from an ROV–a remotely operated vehicle like those that photographed the wreck of RMS Titanic–shows a large and jagged hole starboard-side forward on the hull of the Kursk. That bit of evidence points to a serious explosion within the hull, in the area of the forward torpedo room.
Kursk was a uniquely large and massive ship and, like most Russian designs, had a double hull. This deviates from American practice. Our submarines have single-hull design. That means a single thickness of metal–very high-quality steel–separates the crew from the ocean. In the case of the Oscar class, however, the SS-N-19 missiles are stored outside the pressure hull, and this creates about 3.5 meters of “standoff distance” between the pressure hull and the sea. This gives the Oscar its distinctive squat profile seen in photographs, and also makes the submarine much less vulnerable to severe damage from a ramming incident–the ship that rams must get through 10 or 11 feet of structure before compromising the pressure hull. For that reason, I’ve discounted the likelihood of ramming as the cause of the loss. Besides, ramming does damage to both ships involved. Where is the other damaged ship?
So, what happened? We’re back to speculation. In 1968 the United States Navy lost the USS Scorpion. She was heading back to Norfolk, Va., from a Med cruise when she vanished. The hull was ultimately found on the bottom, under about 12,000 feet of water, but strangely pointed east, when the submarine’s base course had to be westerly. That fact was crucial in determining the cause of her loss. Scorpion carried the Mark 37 torpedo. The Mark 37 had a safety system built into it. Remembering the loss of USS Tang in World War II–Tang had been sunk by her own torpedo, which recurved off its intended course–the Mark 37 was designed to deactivate and go inert if it turned 180 degrees. And so it was surmised after much analysis that the Scorpion’s crewmen had been servicing a “fish,” and that somehow the weapon activated, causing it to “run hot in the rack,” and that the vibration from this had set off the warhead. The Scorpion’s skipper, realizing this, was bringing his submarine about, hoping to cause the fish to deactivate, but didn’t quite make it through the turn as intended. The torpedo exploded, and the weight of water entering the torpedo room took Scorpion her one-way trip to the bottom. It had probably been a simple human error by some torpedoman activating the fish, and causing it to run hot.
Something similar might well have happened to Kursk. The onboard explosion was enough to register on seismic sensors as though it had been a minor earthquake, and it was a double pop, further suggesting that one fish went off, followed immediately thereafter by a second weapon, in what is called “sympathetic detonation.” That would have been sufficient to vent the pressure hull to the sea, and also to rupture the submarine’s internal bulkheads–and probably to scram (abruptly shut down) the reactors just from shock. Within a steel pipe–that’s what a submarine hull is–the shock wave from the explosions had nowhere to go except within the hull, killing many (perhaps all) of the crew in the briefest of instants.
For whatever consolation it might be to the families of the lost, their end would have been rapid. Under such circumstances, the force of the explosion itself would have snuffed their lives out, and depending on the submarine’s depth when the incident took place, the rapid influx of water into the hull can cause such a rapid change in atmospheric pressure that the air itself becomes incandescent, incinerating any human body in seconds. The reason why there has been little, if any, activity inside the submarine is likely due to the fact that there was no living person inside to call for help.
What can be learned from this? There is no substitute for training for the crewmen of a ship of war. There is indeed room on a submarine for anything but a mistake, because even small mistakes at sea can be lethal.
What remains to be done? The Russians will almost certainly salvage the wreck, and then the exact cause of the loss will be more easily diagnosed, and perhaps some changes will be made in training, procedures or the design of the submarine’s weapons. But just as some aircraft crashes are caused by human error in otherwise safe platforms, so it may be that as the fatal errors here were human-caused, so the fixes must be human-effected.
