Mary Roach - Grunt

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. Good-bye, 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.

THE BEDS IN THE missile compartment are a recent addition. When the USS Tennessee got a technology upgrade, some years after the sub was built, extra crew were needed to serve the servers. This posed a problem, until it occurred to someone that there’s room for a bunk pan in the space between two nuclear missiles. The Trident II launch tubes—of which there are twenty-four on board—stand 45 feet tall, spanning all four decks of the submarine. The multifloor missile compartment is the least hectic place on board. It’s like the stacks in an old college library—a still, private place to put your head down and catch some sleep.

Though not just now. “All hands awake!” The voice on the intercom is accompanied by an alarm, loud and insistent. Bong, bong, bong, bong. An annoying child with a stick and pot.

“Simulate sending all missiles.” This is a lot of missile. Each Trident carries multiple warheads, each programmable to its own destination, with sufficient precision to, as I’ve twice heard it put, “hit a pitcher’s mound.” The ballistic missile submarines of the US fleet, fourteen in all, are a roving underwater nuclear arsenal. Along with missiles in underground silos and others on bomber aircraft, they make up the “nuclear triad” of US strategic deterrence. You would be crazy to nuke us, is the message here; we have more bombs than you have, and you can’t take ours out first because you’ll never find the ones on the subs. Ballistic missile submarines have whole oceans to hide in, and a nuclear reactor aboard to generate power and water, so they never need to surface for fueling. They can stay deep until the food runs out.

The Tennessee ’s second-in-command, Executive Officer Nathan Murray, invited me to join him in the missile compartment for the drill. (I sailed out to the sub with a group of prospective commanding officers going aboard for a practical evaluation.) We pass a row of sleeping spaces along one wall, some closed off with black vinyl curtains, giving them the look of bathroom stalls at certain punk clubs in the 1980s. Murray points out the bed of a young man who shares his space with the wall coupling for the fire hose. He was woken up last night for a fire drill, and now this.

The Submarine Force has formally acknowledged that it has a sleep problem. Quoting Force Operational Notes Newsletter (Special Crew Rest Edition) , “An individual’s sleep at sea is not protected, allowing administrative training, maintenance, and ‘urgent’ matters to routinely shorten or interrupt a person’s sleep….” The crew of the Tennessee endure fire drills, flooding drills, hydraulic rupture drills, air rupture drills, man overboard drills, security violation drills, torpedo launch drills. They practice launching the missiles more regularly than some people floss. On one hand, you want the crew to be well trained. You don’t want to hit the wrong pitcher. On the other, you don’t want training and drills going on so often that the people tending the bombs and reactors are chronically sleep-deprived.

In 1949, submarine schedules allowed ten hours a day for sleep. On top of their “long sleep,” half the crew took at least one nap. Starting in 1954, subs went from diesel to nuclear-powered engines. The result being that there’s a lot more to watch than a temperature gauge and an oil level. On the USS Tennessee , four hours’ sleep has been about the average.

Before coming aboard, I spoke by phone with sleep researcher Colonel Greg Belenky (Ret.), the founder of the Sleep and Performance Research Center at Washington State University, Spokane. Belenky knows what happens when people go from sleeping eight hours a night to sleeping four or five. Their cognitive mojo declines over the course of a few days, whereupon it plateaus, settling in to a new, compromised state. The less sleep they’re getting, the longer their mental abilities deteriorate before they plateau. Which mental abilities? Most. Sleep deprivation shrinks memory and dims the network that sustains thought, decision making, and the integration of reason and emotion, Belenky said. “You know when you have a problem you’re working on and you give up? Then you get a good night’s sleep, wake up, and suddenly there’s your solution? That’s what sleep does. It returns the brain to its normal specs.”

On submarines, the junior crew have it worst. On top of work and watch duties, they are preparing for “qualification,” a sort of submarine version of passing the bar: sixty-plus verbal quizzes on submarine components and systems plus practical tests on various elements of your particular sub—anything from taking the helm to using a fathometer to blowing a sanitary tank. “I’ll get three hours of sleep one night, and the next night none,” said a long-faced seaman studying dive hydraulics in the vaporizer haze of the Tennessee ’s enlisted crew lounge. (Between the vaping, the zombie-apocalypse video-gaming, and some aggressive tabletop football flicking, a terrible place to study. Or maybe just to be middle-aged.)

The seaman will tell you he’s fine, but Belenky knows he’s not. When people drop below four hours a night, they don’t plateau. Their abilities continue to erode until they end up at the point where sleep researchers have had to come up with special terms, like “catastrophic decompensation.” “Put simply”—and here Force Operational Notes shifts into typographic overdrive, simultaneously boldfacing, underlining, and italicizing—“failure to get adequate continuous sleep every day results in overly fatigued personnel who, in a matter of days, function at a deficit similar to being intoxicated.”