Komsomolets: the prototype Soviet nuclear sub still resting at the bottom of the ocean

Dig into the archives of the Cold War-era United States or USSR and you’ll find some fascinating stories of technology races, prototype vehicles, and occasionally deranged ideas. Sometimes, the crazy ideas paid off — and even when they didn’t, the US and USSR often gained useful knowledge in the process of trying. The Soviet-era submarine K-278, aka Komsomolets, was a one-of-a-kind vessel designed to reach depths no other submarine could navigate — and while the design worked, its deep-water capabilities weren’t enough to save the ship or its crew.

K-278 was a prototype 4th-generation nuclear submarine designed to implement a number of features. She was designed to be loaded with either conventional torpedoes and cruise missiles or nuclear equivalents and to be capable of launching both. The class design began in 1966, but the keel wasn’t laid until 1978, with a launch following in 1983. Unlike American designs (at least the ones we know about), all of which rely on high-strength alloyed steel, the Russians opted to build some of their designs with titanium pressure hulls, despite the difficulty of welding and working with that metal. (Reports vary on whether both the inner and outer hull were made of titanium, or just the inner hull.)

There are numerous advantages to titanium, provided you can adapt to the difficulty of welding and working it. Specifically, it allows for a pressure hull design that dramatically exceeds the maximum depth of alloyed steel hulls. The Los Angeles class submarines have a maximum operating depth of between 650 and 950 feet with a maximum dive depth of 1,475 feet. Komsomolets, in contrast, was designed to operate below 3,000 feet, with a crush depth of nearly 5,000 feet. The submarine was apparently praised as unsinkable, though it’s not clear that if the Russian media portrayed it in this fashion at the time. It had an escape capsule for emergency crew evacuations, and its pressure hull was divided into seven sections, several of which were reinforced to create a safe zone in the event of a catastrophic breach. The sub also contained numerous automated systems designed to draw down its crew requirements.

In order to function properly at depth, a submarine has to be capable of blowing its ballast tanks and rapidly rising to the surface. This, in turn, requires the presence of extremely high-pressure air tanks — remember, the water pressure at depth can exceed 1,500 PSI, which means the air firing into the tanks must under even higher pressure. After four years of testing and shakedowns, the USSR awarded K-278 a name: Komsomolets, which means “a member of the Young Communist League.”

In April 1989, while on its first operational patrol and cruising at a depth of 1,100 feet, disaster struck. A compressed-air line is said to have ruptured. Somehow, oil strikes a hot surface, igniting a flash fire. (This is less implausible than it might seem, as a broken air line under that much pressure will bend, whip, and contort wildly, and could easily have slashed through other equipment).

Andrey Makhota, a crewman aboard K-278, told RT in 2009 he immediately verified that the reactor had been scrammed before attempting to fight the fire. “I was right near the reactor, and heard its emergency shutdown system activate. I can confirm that it had fully shut down to prevent any possible leak of radioactivity.” Unfortunately, locking down the reactor had no impact on the fire. The raging fire in the engine room laughed at the Freon fire retardant from the emergency fire suppression system, and the watertight doors within the submarine weren’t sufficient to keep fire from propagating through its cableways. Within minutes, the fire has spread into Compartment 6, the reactor and oil pumps have shut down, and the stricken submarine can no longer maneuver. Repeated ballast blows brings the ship to the surface, but Komsomolets‘ problems have only just begun.

Komsomolets internal design

Komsomolets’ internal design

Everything we’ve covered to this point occurred within a matter of minutes. At 11:00 AM, Seaman Nodari Bukhnikashvili reported that all was well within Compartment 7, where the fire ignited. By 11:21 AM, Komsomolets is on the surface, but in critical condition. The fire was burning out of control; surviving crew indicate that the rubber coating secured to the outside of the sub to dampen its acoustic profile slid off in strips due to the tremendous heat. Over the next few hours, Captain Yevgeniy Vanin and a skeleton crew fight to save crewmen still trapped within the sub, to contain the fire, and to control the crippled boat. While Vanin radios for rescue in the clear, the USSR does not formally request aid from Norway, and the Norwegians, uncertain whether the event is real or a practice, do not dispatch their own ships. The Soviet Union dispatches multiple vessels, but none will arrive before 6 PM.

What happened next is not entirely clear. It appears that Vanin blew the port-side ballast tanks in an attempt to correct a starboard list that had developed. This does not work, and apparently accelerated the submarine’s flooding. Komsomolets quickly develops a severe list aft. At 4:30 PM, Vanin blew the port-side ballast, and by 4:42 he orders the crew to abandon ship and sends his final radio message. The crew still aboard Komsomolets seals the conning tower hatch at 5 PM to prevent water from pouring in and drowning the handful of crew still aboard. Komsomolets has a feature that its American counterparts lack — an emergency escape capsule, built directly into the conning tower, and designed for just this eventuality.


K-238, at some time prior to her disaster.

Vanin and five of the six crew members make it to the capsule, which is flooding and filled with the same smoke that had permeated the rest of the sub. The emergency system isn’t designed to trigger from a near-vertical dive, and reports indicate that the emergency capsule fails to eject at all until the submarine hits the ocean bottom, more than five thousand feet below. The shock of impact triggers the capsule release, and the air pressure difference sends it rocketing to the surface. Once it breaches, the pressure differential blows the top off, and blows two of the five crewman into the ocean. Only Warrant Officer Slyusarenko survives — Vanin and the other men were overcome by smoke and sank with the escape vessel as it flooded in high seas.

Of the 69 sailors aboard Komsomolets, 42 of them die, most from hypothermia while waiting for rescue vessels to arrive.

Our mutual nuclear graveyard

Since Komsomolets was lost, the site has been extensively monitored for signs of radiation leaking from its two nuclear warheads or its reactor. While it’s far from the only nuclear submarine on the ocean floor, it’s located within a major commercial fishery. The site is believed secure until at least 2024 or 2025.

Russia is far from the only country to have lost nuclear submarines. The USS Thresher and USS Scorpion were lost in 1963 and 1968, respectively, though what caused the Scorpion’s loss remains unknown to this day. The USSR lost K-27, K-8, K-219, K-278, and K-429. Since the fall of the Soviet Union, there have been two additional losses. The Kursk was destroyed when a torpedo exploded inside the torpedo room, and the derelict K-159 sank in 2003 while being towed for demolition.

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