THE STUDENTS troop single file to the stairwell, ducklings in a row. They are going down to the bottom of the Escape Trainer for the big ascent, the 37-footer. This time they’ll wear a SEIE (Submarine Escape and Immersion Equipment) suit, a partially inflatable head-and-face-encompassing zip-up that attracts unwanted comparisons to a body bag. Like its more minimal predecessors the Momsen lung and the Steinke hood, the SEIE suit incorporates an air supply and openings to vent excess air as it expands on the ascent. This allows the escapee to breathe normally and not have to worry about bursting lung parts. Students practiced the “exhaling ascent” earlier so they’d know what to do if there was a problem with the escape suits. Something like this, for example: “The rubber was cracked and tacky and most of them were stuck together.” This is Andrew Karam in an email to me, describing the Steinke hoods he was asked to inventory for an underway in the late 1990s.
“On the bright side,” Karam went on, “we spent almost all our time in water more than a thousand feet deep, so opportunities to use them were few and far between.” The maximum depth at which a Steinke hood has been successfully tested is 450 feet. The greatest depth at which a SEIE suit can be counted on to save you is 600 feet. That is really all you need ask for, because if you’re escaping into water deeper than 600 feet, you’re likely to be killed by decompression sickness no matter what outfit you have on.
To understand decompression sickness (the bends), it’s useful to think about one of those countertop carbonation units. Bubbly water is tap water with the bends. When you force pressurized gas into a container with liquid in it—be that container a SodaStream bottle or a scuba diver—some of that gas may go into the liquid. (To get all jargony, the gas goes “into solution” for the greater cause of equilibrium.) Now say the pressure in the container lets up suddenly—because the bottle has been opened or the diver has swum up toward the surface. Those gas molecules that had been forced by the air pressure into the liquid will now come back out of solution. (Here again: seeking equilibrium.) As they do this, the gas molecules link together in the form of bubbles. Never mind why. They just do. Now you have a glass of refreshing fizzy water, or a looming case of the bends. The bends is bubbles migrating through the body and causing problems: acting like a clot and disrupting the flow of blood to vital organs, or pushing apart tissue and causing pain, or both, and more.
Divers can avoid the bends by ascending slowly. This gives the body a chance to simply exhale the gas as it comes out of the blood and into the lungs. (Nitrogen is the main culprit; air contains a lot of it, and it likes to dissolve and hide in fat.) The more time a diver has spent breathing pressurized air, and/or the more highly pressurized the air, the more nitrogen she’ll need to dump and the slower, therefore, she’d need to ascend.
Decompression may or may not pose a danger to escaping submariners. If they’re lucky, the air inside the stricken sub has remained as it was when they left port: pressurized to sea level. In that case, submariners can usually escape with little danger of the bends. But if the vessel floods, the water that’s come on board will compress the air like a trash compactor. Now the sailors are like scuba divers: They’re breathing pressurized air, and some of the gases in that air will be pushed into their blood and tissues. Depending on how long they breathe this air and how compressed it is, they may, like a diver, need to decompress in order to ascend to the surface safely. Breathing the pressurized air in the escape trunk for the minute or so that one is inside it isn’t enough time to create a problem unless one is down very deep. At, say, 800 feet, the air in the escape trunk would have to be so highly pressurized (to equalize with the outside pressure and allow the hatch to open) that breathing it for even a minute would force enough nitrogen into the body to put one at risk for the bends.
At the far, nightmare extreme of the bends is something called explosive decompression. On November 5, 1983, four divers were relaxing in a decompression chamber on the deck of an oil rig in the North Sea. For reasons that remain unclear, one of the dive tenders opened the hatch, reducing the pressure in the chamber from what it would be at 305 feet underwater to what it is at sea level—in a fraction of a second. Nitrogen bubbled out of solution instantly, in the men’s brains, their blood, their fat and muscles. The pathologists wrote in the case report that the men’s fat looked like “sizzling butter on a frying pan.” They surmised that the blood had begun to bubble instantly, “leading to an instantaneous and complete stop of the circulation.”
Diver four had been at the hatch when it blew. Goodbye, Wilkie. He was the champagne at the top of the bottle. The pathologists speculated that in addition to the breakage caused by being shot through the partially open hatch, he “also must have exploded.” He arrived at the autopsy suite in four plastic bags. Some of his organs were missing, having been “blown straight into the sea.” Like the gases in the abdominal cavity, air in the brain pan had also expanded in an explosive manner. “The scalp, with long blond hair, was present but the top of the skull and the brain were missing.”
I’ve been looking through a porthole at the bottom of the Escape Trainer. Watching this scene, the rag doll movements of the divers and the silvery jellyfish air bubble that floats from the hatch in a languid blurp, it is easy to forget the murderousness of deep water. Submariners can’t afford to forget. Mistakes can so swiftly give rise to disaster, and then where are you? Too deep for help or escape.
The risks are amplified when someone on your crew has been up for sixty hours. It has been an enduring unease of the military that the last people you’d want operating subs or fighter jets or automatic weapons are often the ones doing it: the persistently, catastrophically sleep-deprived.
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* As someone for whom the phrase “top secret” has applied mainly to decoder rings and campy spy movies, I had to remind myself that these are actual security classifications. I found it hard to take seriously the sign on the chain stretched across the navigation room door saying, TOP SECRET—KEEP OUT. They may as well have added NO GIRLS ALLOWED. I saw a printer in the crew lounge labeled SECRET PRINTER. Secret printer!
? Almost as good as this one, by Andrew Karam, in the cold war–era submarine memoir Rig Ship for Ultra Quiet: “Bug juice didn’t come in flavors, just colors.”
Up and Under
A submarine tries to sleep