Grunt: The Curious Science of Humans at War

13. UP AND UNDER A Submarine Tries to Sleep

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.”

Like drunks, the chronically sleep-deprived are doubly dangerous in that they’re poor judges of their own impairment. Jeff Dyche, a sometime research psychologist at NSMRL, now with James Madison University, told me about a study that showed that people who’d slept six hours a night for two weeks were as cognitively diminished as people who’d been up for forty-eight hours straight. Unlike the up-all-nighters, routine six-hours-a-nighters see no need for caution. They’ve felt mildly exhausted for so long it’s become their normal, Dyche says. “They’re like, ‘Ah, I’m used to it.’” I’ve been hearing a lot of this over the past two days. “I get four and a half hours and I’m generally okay for a twenty-four-hour period,” said a sailor pushing trash into an institutional-grade compactor that would work with equal efficiency on flesh and phalanges.

Murray and the sub’s commanding officer, Chris Bohner, volunteered to try out a new watch schedule aimed at keeping crew better rested, both for their health—insufficient sleep having lately been linked to obesity, high blood pressure, diabetes, heart disease—and for everyone’s safety. It is not a simple undertaking. “I spend a very significant amount of time,” Murray says, “figuring out people’s rest.” Murray is a popular leader—in both manner and mien, a solid individual. You never see him slouch or lean or jut one hip. He stands steady and square on both feet, like a bag of mortar set down. His hands park on his belt, with an occasional sweep over his head, which he keeps closely shaved. The latitude of Murray’s hairline, like that of the submarine itself, will remain a secret to me.

The problem is that things come up. People fall behind and schedules fall apart. The problem this week is me. Everyone’s work was interrupted because the crew had to spend four or five hours looking for a spot where the seas were calm enough to drop a gangplank between the sub and the vessel we sailed out on.

Part of the Navy’s challenge in dealing with undersleeping has been that somewhere along the line, it became a point of pride. At NSMRL I met a longtime submarine commanding officer named Ray Woolrich. “Marines sitting around in a bar,” said Ray, “will tell you how many push-ups they can do. Aviators will tell you how many g’s they can take. Submariners will tell you how many hours they stayed up.” Better to be exhausted than to gain a reputation as a “rack hound.”[56]

For decades, military sleep research proceeded in lockstep, focusing less on getting sleep than on getting by without it. Study after study tested this or that stimulant on fliers, soldiers, sailors. Only recently has protecting sleep become a Defense Department priority. Current Army policy requires unit leaders to develop and implement a sleep management plan in theater. (Though in one small survey of soldiers returning from Iraq or Afghanistan, 80 percent had never been briefed on such a thing.) A turning point, according to Belenky, was the lengthening of the Army’s field training exercises (FTXs), the massive simulated confrontations that serve as a sort of practical final exam for soldiers. “At some point the doctrine folks had concluded that any war worth going to would probably last a week or two, so they increased the duration of the FTX from three days to two weeks,” Belenky said. Up to that point, there had been a tradition of staying up for all of it, in order to “look motivated and get a good evaluation.” Belenky recalls getting a call from a commander shortly after the change went through. “He said, ‘I need your advice on pharmacology. I need my boys to be able to stay up longer.’” Belenky figured the man was talking about a couple extra days. “I said, ‘How long do you want them to stay up?’ He said, ‘Two weeks.’ People actually tried to gut it out.” It was a vivid and no doubt fairly entertaining demonstration of the importance of sleep to military competence.

History provides equally vivid demonstrations. Medical historian Philip Mackowiak compared eyewitness and officers’ accounts of Stonewall Jackson’s performance during a series of Civil War battles with the general’s opportunities for sleep, if any, in the days leading up to those battles. In 100 percent of the battles for which Jackson had had no chance to sleep in the three days prior, his leadership was rated “poor.” In the Battle of Gaines’ Mill, his chief of staff described him as “thoroughly confused from first to last.” His brigades were not merely “out of order”; “he did not know where they were.” The Battle of Glendale found Jackson “benumbed, incapable… of deep thought or strenuous movement… uninterested and lethargic.” At times during the Battle of Malvern Hill, Jackson “appeared to be almost a bystander.” In the midst of the Battle of McDowell, he was discovered napping.

For every twenty-four hours awake, Belenky told me, people lose 25 percent of their capacity for useful mental work. Jackson was leading the charge (or not) on 25 percent of his waking best. I’m trying not to think about a man named Patterson in one of the Tennessee’s machinery rooms. He’d been up for 22 hours trying to fix the electrolytic oxygen generator, a large, pulsing metal-hulled molecule splitter. “Basically it’s a hydrogen bomb,” he’d said cheerfully.

The longest Belenky has kept subjects awake is 85 hours—three-plus days—which is about the limit, he says. “They’re not,” he adds, “very useful to anybody.” There are people who claim to have stayed awake for 100 and even 200 hours, but because their brain waves weren’t continuously monitored, as Belenky’s subjects’ are, it’s impossible to be sure they weren’t microsleeping. The very tired can slip into Stage 1 sleep for a few moments, eyes open, carrying out some quasi-coherent version of whatever it is they’re up to. As anyone who has slept on an airplane knows, it’s possible to maintain muscle tone while sleeping—that is, until you slip into REM sleep, during which muscles relax. (When people fall sleep at odd times in their circadian cycle, they may enter REM early. Blame “early-onset REM” for the slack-jawed head-lolling that happens when you nap sitting up.)

Soldiers, including Stonewall Jackson’s, have on occasion reported sleeping during night marches. If you’re tired enough, Belenky says, your brain appears to briefly dissociate—one part sleeping, another awake. There are birds and marine mammals that manage this regularly. Dolphins and seals are able to sleep unihemispherically—with one half of their brain. This is because the other half needs to attend to breathing, which in their case requires swimming to the surface for air. When geese and ducks sleep in groups on the ground, the birds on the outer edge will keep one eye open and the corresponding brain hemisphere awake, scanning for predators.

From a military perspective, a soldier who could march or swim or look out for enemies while simultaneously catching up on sleep would be a desirable item. It fits right in with one of the goals of the military’s futuristically minded Defense Advanced Research Projects Agency (DARPA): “to enable soldiers to stay awake, alert, and effective for up to seven consecutive days without suffering any deleterious mental or physical effects and without using any of the current generation of stimulants.” This is why you’ll find the Defense Department on the sponsor lists of some of the basic research on unihemispheric sleep. If science could just figure out how the ducks do it, perhaps troops could be enabled—chemically or surgically, God only knows—to do it, too. Belenky scoffed. “We’re not even sure what triggers whole brain sleep.”

That hasn’t stopped military organizations from fantasizing about it. I came across a NATO symposium on Human Performance Optimization that included a roundup of medical technologies that might be repurposed to optimize warfighters. In among the prosthetic limbs “to provide superhuman strength” and the infrared and ultraviolet vision–bestowing eye implants was this: corpus callosotomy to “allow unihemispheric sleep and continuous alertness.” Surgeons have on occasion severed this connector between the brain’s halves as a way of reducing the number of seizures in patients with severe epilepsy. Does this in fact change how these patients sleep? No, says Selim Benbadis, director of the University of South Florida Comprehensive Epilepsy Program and the author of a paper on the procedure. He added that there are infants with incompletely developed corpora callosa and they sleep normally and with both hemispheres at the same time.

“They think a lot of harebrained things are good ideas,” Belenky said of DARPA. Yes, they do. The wish list also included “surgically provided gills.”

“RELEASE OF nuclear weapons has been authorized.” It’s the intercom man again. Even in a simulation, it’s a sickening thing to hear. I look around at the sailors standing near. One untangles an extension cord. His face betrays nothing. A sailor seated at a control console blows his nose. “Is this what it would be like?” I ask Murray. “If it were the real deal? Would people just be calmly carrying out their tasks, blowing their nose…” The whole business is straight off my fathometer.

Murray’s not playing this game. “If your nose is running, you blow it.”

Two sailors hustle past, each holding a corner of what looks at a glance like some kind of Lotto ticket. It’s the code for the key box, the box with the keys to launch the missiles. Two people must have a hand on it at all times once it’s out of safekeeping, for the same reason some airlines, in the wake of the 2015 Germanwings suicide flight, require a second person in the cockpit.

Were this an actual missile launch, I’d wager that adrenaline would keep the crew alert regardless of how long they’d been up. But the normal day-to-day routines of a ballistic missile sub are a good deal less invigorating. Most watches are just that: hour upon hour of watching. Watching displays, readouts, dials, sonar feed. It’s a worrisome mix: sleep deprivation, tedium, and large, potentially destructive items. “The Navy doesn’t want us to publish anything saying that these guys monitoring these nuclear reactors are falling asleep on watch,” Dyche told me. “But we know that’s happening.” Even awake, the tired are poorly suited for standing watch. When psychologists give sleep-deprived people a standard battery of cognitive tasks, their score on measures of “psychomotor vigilance”—paying attention and noticing shit—drops dramatically.

I never visited the Tennessee’s reactor and its tenders, because I didn’t have security clearance for that part of the sub, but I did visit the torpedo room. There are four of them, massive as medieval battering rams. Sweetly (I guess), they are named for the torpedomen’s wives. I asked the torpedoman on watch when last a US submarine had had cause to fire a torpedo at another vessel. He thought for a moment. “World War II.” He’s the Maytag Repairman, ready for action in the extremely unlikely event it’s called for. The torpedoman’s watch is a checklist of inspections, walk-arounds, paperwork. Always with the paperwork.[57] Outside of the sonar shack and the Missile Control Center, much of the Tennessee remains charmingly analog. I looked around the missile compartment at one point and thought, tuba parts. The torpedo launch console has big square plastic buttons—Flood Tube, Open Shuttle, Ready to Fire—that flash red or green, like something Q would have built into James Bond’s Aston Martin. The missile compartment has similarly retro-looking panels of buttons. They provided the setup for one of the more quotable things Murray said to me—a line that, were fewer precautions in place, could have joined “Houston, we’ve had a problem” or “Watch this” in the pantheon of understated taglines for calamity: “I wouldn’t lean on that.”

On an intuitive level, the prospect of marginally vigilant humans babysitting reactors, torpedoes, and weapons of mass destruction is unsettling. That the scene takes place in a vessel under hundreds of feet of water, all the more so. Statistically, however, the highest risk doesn’t lie in the nuclear reactor compartment or even, for that matter, in deep water. The biggest risk lies with the seemingly straightforward but in fact reliably harrowing task of surfacing a sub.

A BALLISTIC MISSILE submarine will take you to the remotest places you’ll ever travel and show you none of it. The sub has no windows or headlights, nothing to make it visible in the surrounding black. Below the depth that sunlight penetrates, a periscope is useless. The crew see by sonar, picking up propeller sounds from ships and plotting their distance and course. To remain undetected, ballistic missile subs use passive sonar only: no pinging. Echolocation—sending out sound and timing its bounce-back—would give away the sub’s own location. The Tennessee is blinder than a bat.

At 450 feet down, our current depth, there are no other vessels to smack into. (Each sub has an assigned territory, or “box,” extinguishing the infinitesimal likelihood that two of them might collide.) The biggest danger outside at the moment is shrimp. When galley crew empty the grind bucket, vast schools of snapping shrimp rush the hull to feed. Their collective tumult can mask engine noise from other vessels.

In the sonar shack this morning, four men sit at monitors, watching snowy green crawls of sonar feed and listening through headsets. A sonarman can identify a ship by propeller noise the way a birder might distinguish one woodpecker species from another by the speed or timbre of the hammering. Someone passes me a headset to hear the click-jabber of some porpoises. After a few days in a submarine, any contact with nature can be a bit heady. “Flipper!” I hate to apply the verb squeal to myself, but that’s what it is.

“Uh huh,” says the sonarman. “Flipper all night long.”

Although ballistic missile subs are able to stay deep for months, they typically do not. The Tennessee surfaces regularly, like a whale, to exhale emails. We’re about to come up in a merchant transit lane, which has everyone a little on edge. In the hour-long lead-up to the moment when the sub breaches the water’s surface, someone’s been at the periscope, face pressed to the eyepiece, scanning for anything sonar might have missed. Because the view is less than 360 degrees, he circles slowly, around and again, crossing one leg behind the other, a slow dance with a canister vacuum. You want to be very, very sure there’s nothing up there.

In 2001, the USS Greeneville surfaced directly beneath a 191-foot Japanese fishery training ship. The sub’s rudder sliced the hull, causing the trawler to sink and resulting in the death of nine people aboard. (Sleep deprivation wasn’t cited as a contributing factor. A group of visitors was: fourteen CEOs and, um, a writer. All but one of the group were up in the control room, crowding the periscope platform, blocking access to critical displays, distracting the sonarmen.)

The captain of the Greeneville exhibited what is known in these parts as poor periscope discipline. He scanned for about half as long as procedure called for. Another potential danger for a surfacing sub is “bow null.” If the front of a ship points straight into a submarine’s sonar array, the sound waves emanating from that ship’s propulsion are blocked by its own body and cargo. The Tennessee’s safety officer compares it to “yelling through the trunk of a car to your kids in front of the car.” A helpful, if disquieting, metaphor.

It’s the weekend, which can be a more dangerous time to come up. Container ships that are nearing a port outside standard work-week hours will sometimes loiter, timing their arrival for Monday, when pay scales drop back to normal. A container ship is the size of a strip mall, but if its engines are silent, it’s all but invisible to the crew of a ballistic missile sub. Aboard the Tennessee, a sailboat is more worrisome than a warship. Now you understand how it came to pass that the USS San Francisco, in January 2005, ran into an undersea mountain. They’re very quiet, mountains.

Adding to stress levels: Last-ditch evasive maneuvers are out of the question. A surfacing ballistic missile sub is traveling between 6 and 12 miles per hour. “It’s like a baby crawling out of the way of a truck,” says the safety officer, as though yelling through the trunk of a car that there may be something just a little bit off with him.

Extreme caution is ever the mind-set. If a new sonar contact should appear on the screen during surfacing, an “emergency deep” may be ordered. Because without echolocation, you don’t immediately know how far off the other vessel is. “Be safe now and figure it out after,” the commanding officer said yesterday, as we dove to avoid a ship that would turn out to be several miles off. A ballistic missile sub is a boat without a destination, its course a series of evasions and nervous retreats. Any time a contact is calculated to be within two miles, the commanding officer is called. And, often, the navigator and the executive officer.

And there goes another night’s sleep. “I expect to be woken three or four times per sleep,” the navigator told me. Murray wakes up, too, because he has a speaker mounted on the wall of his stateroom, above his pillow, that picks up the conversation in the control room. He’s like a new mother with a baby monitor on the nightstand. “All of a sudden, out of a lot of background noise and chatter, you’ll catch a certain word or a change in the tone or volume of somebody’s voice. It just snaps you out of a sleep.”

Unsurprisingly, submariners have a robust tradition of caffeination.[58] The Tennessee left port with a thousand pounds of coffee. The world’s first nuclear-powered submarine, built in 1954, is now a floating museum in Groton, Connecticut, and if you tour it, you will see metal rings bolted to consoles and bulkheads at the different watch stations: cup holders! Caffeine is safe and effective but not without a downside. Depending on one’s sensitivity, it has a half-life of six to eight hours. Even if you have no trouble falling asleep after drinking coffee late in the day, you may wake more easily during the night because your nervous system is still aroused, your brain attuned to sounds and other stimuli that would otherwise go unheeded. The more poorly you sleep, the more caffeine you tend to consume the next day, and the more lightly you sleep the following night. And so on. As Murray said upon seeing me refill my mug, “That’s not a long-term solution, shipmate.”

We’re approaching periscope depth. The lights in the control room have been shut off. This is done for the benefit of the man at the periscope, who will shortly be taking a look around in the 5:00 a.m. darkness at the surface. To everyone else up here, many of whom are going on four or fewer hours of sleep, darkness is the opposite of helpful. Not only is it warm and dark in here, but because we’re nearing the surface, the submarine is now rocking gently with the swells. “Torture,” says the helmsman.

Torture was the word used by sleep researcher William Dement, who, as a student in the 1950s, helped Nathaniel Kleitman document Rapid Eye Movement (REM) sleep. Before there were eyelid electrodes and electrooculargraphs, there were grad students pulling all-nighters. “Staring at the closed eyes of human adults by the dim light of a 30-watt bulb in the middle of the night was sheer torture,” Dement wrote in a tribute to Kleitman, who is known in his field as “the Father of Sleep Research.” (Tougher yet was the job of the chaperone Kleitman insisted be present when the subject was female: watching someone else watching the eyes of a sleeping human all night.)

THE PHOTOGRAPH dates from 1938. Nathaniel Kleitman sits at a dinner table, knife and fork crossed in a slab of hickory-smoked ham. What’s unusual about this ham supper is that it took place in a cave 119 feet underground. Kleitman, with a graduate student assisting, spent thirty-two days in Kentucky’s Mammoth Cave investigating the cycles of human sleep and wakefulness. He wished to find out: to what extent are these rhythms tied to external cues and routines? If you took away the cues—sunlight, established mealtimes, regular business hours—could people slip easily into an altered routine? Going underground seemed like the easiest[59] path to an answer.

Submarines interested Kleitman, because, like caves, they present a sort of real-world laboratory for chronobiology. Kleitman, in turn, interested the Submarine Force. They were, as they are today, having some alertness issues. Kleitman came up with a watch schedule that took advantage of a submarine’s isolation from sunlight—the fact that it’s always, as Murray put it, “70 degrees and fluorescent.” It should thus be possible, Kleitman reasoned, to put each of three separate watch crews on a different schedule by staggering their waking hour, each crew beginning the day at a different time.

Beginning in 1949, three submarines, the Corsair, the Toro, and the Tusk, gave the Kleitman watchbill a two-week trial. At the end of it, Kleitman distributed questionnaires. “Should new schedule replace old?” read the last question. “Yes,” said 19 sailors. “No,” said 143. What happened? Catastrophic decompensation in the galley. Rather than cooking and cleaning up one breakfast, one lunch, and one dinner every twenty-four hours, galley crew had to do three of each, accommodating the different start times of each watch group’s “day.” The cooks were exhausted and peeved. The galley was a mess—“never clear and clean for more than an hour and a half,” causing every meal to be “flavored with the odor of the last, and the whole permeated with the aura of aged refuse.” And because a submarine’s galley doubles as its rec room, movies could no longer be screened. “Recreational activities had to be curtailed to such an extent that they degenerated to periods of loafing around trying to keep out of the way.” Friends who weren’t assigned to the same “time zone” were now isolated from each other. “It is considered neither desirable nor feasible to continue this experimental watch schedule any further,” concluded the final memo in the submarine folders of the Nathaniel Kleitman Papers.

There were some in the Submarine Force who believed Kleitman’s watchbill deserved a fuller chance, that the galley and recreation routines could have been adjusted. One executive officer blamed “just plain orneriness. Sailors,” he wrote, “hate to try anything new.” It is perhaps no coincidence that the colloquialisms “don’t rock the boat” and “don’t make waves” share a nautical element.

The officer was probably right. The Kleitman watchbill was grounded in sound science. Sunlight is our most powerful internal clock-setter. Along with rods and cones, we have a third kind of photoreceptor, one that is keyed to the blue wavelengths of sunlight. Information about this light, or the lack of it, is passed along to the pineal gland, producer of melatonin, the body’s natural soporific. Sunlight triggers a cutoff of melatonin, bringing on wakefulness. (Indoor light—particularly the light from tablets and smartphones—can also suppress melatonin, but nowhere near as dramatically as sunlight.) This is why night shift workers who drive home in the morning through sunlight and then struggle to fall asleep may find relief by buying amber-lensed Bono-style glasses that block the sun’s blue light wavelengths.

NSMRL has been developing goggles rimmed with battery-powered lights that emit the blue melatonin-suppressing wavelengths, thereby fooling the brain into thinking it’s daytime. Depending on which direction you’re flying, one or another of these distinctive eyewear options can help you preadjust to a new time zone. Or, in the case of Special Operations types heading to the Middle East to undertake secret 3:00 a.m. missions, not adjust. Lieutenant Kate Couturier, a circadian rhythm researcher at NSMRL, outfitted a planeload of Navy SEALs with blue light–emitting goggles on a series of flights from Guam to the East Coast of the United States, to see if it were possible to make them unattractive to females, oops, I mean, to keep them on Guam time. It worked.

It is probably fair to say that circadian dysrhythmia affects alertness and performance as much as or more than the amount of sleep a person has been getting. In the late 1990s, a team of sleep researchers and statisticians from Stanford University analyzed twenty-five seasons of Monday Night Football scores. Because the games were played at 9:00 p.m. eastern standard time, West Coast players were essentially competing at 6:00 p.m.—a time chronobiologically closer to the body’s late afternoon peak for physical performance.[60] As the researchers predicted, West Coast teams were shown to have won more often and by more points per game. The effect was striking enough that teams sometimes travel a few days in advance of a game to give the players’ body rhythms a chance to adjust.

Another complicating factor with military sleep is that the people making the schedules are often middle-aged and the people following them are teenagers. Not only do adolescents typically need more sleep, but their circadian rhythm is “phase-delayed” compared to adults’; melatonin production begins later in the evening, with the result that a teenager or even a twenty-two-year-old may not feel sleepy until well past midnight. Horrifically, the traditional boot camp lights-out is at 10:00 p.m., with a 4:00 a.m. wake-up.

Jeff Dyche told me about an admiral who approached him wanting to address sleep deprivation in the Navy boot camps. She wanted to move lights-out to an hour earlier—9:00 p.m.—to give the lads more time to sleep. Dyche quietly took her for a walk around camp after lights-out. “Almost every sailor was sitting up wide awake, twiddling his thumbs. They’re all going to sleep at midnight no matter how early they have to get up.” Dyche managed to move some 4:00 a.m. wake-ups to 6:00 a.m. Test scores improved so dramatically that one of the command master chiefs assumed there’d been a cheating scandal.

For the past four decades, submarines have run on a watchbill known as “sixes,” which divides sailors’ time into six-hour chunks: six hours on watch, six for other duties and studies, six for personal time and sleep, then back on watch. The creation of an 18-hour day saw each sailor putting in six extra hours of watch time every 24-hour period. The problem is that his activities ceased to align with his biological rhythms. He’s now working when his body badly wants to be sleeping. “It’s like flying to Paris every day,” Kate Couturier said. Without Paris. “It’s a quadruple whammy,” said Couturier’s colleague Jerry Lamb, when I met with him and other Navy sleep experts before boarding the Tennessee. “We flip around their sleeping and working times, we work them like dogs, we give them very short periods of sleep, and we wake them up for drills.” He turned to his colleagues. “Did I miss anything?”

Lamb was involved in the push for the new “circadian-friendly” watchbill. There has been, as there always is, some resistance. Sixes is how it’s been done for fifty years. “As flawed as it is, we’d perfected it,” commanding officer Bohner said one morning as we sat in his stateroom. “Now we’re going to shake the ball and throw the pieces back down again.” I tried to picture what game that might be.

The problem resides mainly with the midnight to 8:00 a.m. shift—the dreaded “mids.” You come off watch and instead of sitting down to dinner, you’re having breakfast. You’re sleeping from 4:00 p.m. to 10:00 p.m., when there’s often, despite Nathan Murray’s best efforts, something that you have to get out of bed for. To more fairly distribute the suck, the crew swap watch schedules every other week. Instead of flying to Paris every day, it’s every two weeks. The switchover happens on a Sunday, its being normally—that is, when riders are not coming aboard creating extra work for everyone—the quietest day of the week.

Today is that Sunday. Lieutenant Kedrowski, the man on the periscope platform, the officer of the deck, is switching to mids. It’s his birthday. Happy birthday, Kedrowski. You get to scramble your circadian rhythms and get three hours sleep—in a rack that smells like someone else, because you had to give yours up to some writer from California.

“I’m really sorry, by the way.” I would have been happy to sleep among the warheads.

“It’s no problem,” says Kedrowski, with unforced bonhomie. Almost everyone I’ve met down here has been easygoing and upbeat, especially given how tired they must be. I am, to quote the Dole banana carton in the galley pantry, “hanging with a cool bunch.” If everyone in the world did a stint in the Navy, we wouldn’t need a Navy.

Up above Kedrowski’s head, a red light is flashing. Kedrowski explained this alarm box earlier. It’s the one that goes off if the President of the United States orders a nuclear missile launch.

“So this is another drill then?”

“No.” Kedrowski finishes writing something in a three-ring binder and looks over at the box. “It’s kind of broken.” He puts down his pen and listens. “They’re supposed to say, ‘Disregard alarm.’” They don’t, and soon it stops. “They need to fix that,” he says.

The missile alarm is mildly unnerving (good god, what if?) but not particularly frightening. In the queer logic of war in general and nuclear conflagration in specific, five hundred feet underwater on an undetectable Trident submarine is the safest place you could possibly be. The crew of the modern ballistic missile submarine endures long hours and grueling tedium, homesickness, horniness, and canned lima beans, but they are spared the thing that keeps most of us out of the military: the nagging awareness that you could be shot or blown up at almost any moment. Better dead-tired than dead.