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.”
58
To reduce troops’ load, the Army adds caffeine to gum or mints or foods that soldiers are already carrying, like jerky. Natick public affairs officer David Accetta feeds a Caffeinated Meat Stick to reporters who visit the food lab. To me, it tasted just like you’d expect caffeinated meat to taste. Accetta was taken aback. “Brian Williams loved them.”