Chapter 1 What About the Hunley Being a scientist is like being an explorer. You have this immense curiosity, this stubbornness, this resolute will that you will go forward no matter what other people say. -Sara Seager, planetary scientist I stood on the deck of the slightly rolling ship and looked down at the sea below. A faint breeze across the Gulf of Mexico was not enough to make the day comfortable. I had rolled out of bed at 0330, or less specifically oh-dark-thirty, as the smaller numbers of the morning are sometimes called by the men and women of the United States Navy. That had left me just enough time to rouse myself to a state of consciousness sufficient for driving, get to base, and get safely on board the specialized military diving vessel before she got under way. We had been waiting for good weather to undertake this mission, and the calm waters off the starboard gunwale looked bleary through my tired eyes. I had been working toward the next moments for the last year and a half.

My job as a civilian engineer in Panama City, Florida, had been to get us to this point: to find a new underwater breathing system, prove it was safe, and get the navy to let us test dive it in the open ocean. It was a seemingly straightforward task, but one that had required plenty of sweat, creativity, and math. By the time the divers emerged from the ocean, I knew that the new system worked. We cast celebratory fishing lines off the stern and trolled for dinner on the way home. The success of this project meant that the navy would want me to lead projects myself, to submit proposals for new technologies. They had even offered me the chance to go back to school and get a PhD in biomedical engineering so I could do it. A few months later, I was assigned a seat at a curved desk with pale faux-wood veneer in the far corner of a narrow office on the Duke University campus. Wedged to the left of my desk was a battered black filing cabinet containing hundreds of meticulously labeled manila folders, shoved full of papers by a compulsive graduate student who had long ago studied cardiac function from my chair.

The filing cabinet blocked my view of the lone, slitlike window on the wall opposite the doorway, and I had recycled the papers in the bottom drawer to make room for a small stockpile of individual-serving bags of potato chips-stolen booty from the catering tables at lectures on campus. Unlike undergraduate students, who pay the costs of their own tuition, engineering PhD students are paid a stipend to perform their work and are often given the job title of "research assistants." However, these students are still different from normal employees because from the first day they arrive at their new labs they are already hoping to leave as quickly as possible. Graduation with a PhD is not guaranteed by completing certain classes; rather, the degree is granted only when, and if, a student''s adviser declares the student to be finished. It''s tacitly forbidden to ask the senior students when they will graduate because they are likely asking themselves the same question every day. As students finish and move on, they often leave behind objects like relics of their time there, and new students moving into these borrowed spaces shift around the layers of abandoned artifacts to clear themselves an area. I had claimed my secret snack drawer but moved almost nothing else since I had first been placed into that office when I arrived at Duke in August 2011. My research adviser was Cameron R.

Bass, known as Dale to everyone who had ever spoken with him. He was an associate research professor of biomedical engineering and the director of Duke''s Injury Biomechanics Laboratory. Dale believed in efficiency above all else. His white hair and facial stubble were all trimmed to the same short-cropped length, a process his wife could do for him at home without wasting time at a barber. Every day he wore the same type of black polo shirt, with black or gray cargo hiking pants that zipped off at the knee, and the same heavy black lace-up combat boots. This daily uniform saved time shopping or picking out clothes. The students in Dale''s lab researched injury biomechanics: the various mechanisms by which human beings got injured and killed. About half the students worked on car crashes, and the other half, including me, focused on explosions.

For several months I had been working through medical case reports from underwater explosions. Scientists have long had a fairly clear idea of how well human beings can tolerate blasts in air, but not as much is known about human tolerance to blasts that occur underwater. Injured people and shrapnel chunks tend to stay where they fall when explosions occur on dry land, leaving a scene that can be safely examined later, whereas the waves and currents of the ocean quickly destroy all clues. The underwater science, therefore, had received much less attention. But cases with eyewitness testimony, with survivors to describe the details of what had happened and where, were still useful. My first goal had been to compile as many cases of human exposures to underwater explosions as I could find. Then, I would use a complex piece of navy modeling software, called Dynamic System Advanced Simulation (DYSMAS), to calculate how strong of a blast each person experienced. The DYSMAS software could accept crucial information like the size of the charge and the depth at which it detonated, then model the resulting explosion.

The output from the software about the strength of the shock wave could then be combined with the medical report describing how badly each person was hurt. These cases, examined together as a group, would allow me to find the blast levels at which humans in the water get injured or killed. The hope, at least at that time, was to turn the project into my PhD dissertation. Most of my cases were from World War II. I had been spending long days sorting through testimonies of human wreckage, seventy years after the fact, hoping to convert them into something useful. I combed through dozens of reports a day, looking for those where a sailor''s physicians reported enough information to let me model his case. The stories were usually the same: feeling of a sharp kick to the groin, with a stabbing pain in the gut. Sometimes they would immediately vomit blood, sometimes they would have sudden and uncontrollable bloody diarrhea.

Both are signs of severe trauma to the intestinal tract. Sometimes they would start coughing blood, a sign of damage to the lungs. Sometimes they watched a nearby friend sink silently beneath the waves. The doctors in World War II were weirdly obsessed with food. They seemed to think there was some relationship between injury severity and the victim''s most recent meal. The case reports are riddled with statements like "Case 47 had a sandwich three hours before the blast, but Case 48 had only coffee." I would find a case that reported distance from the charge, plug it into the navy''s software, and then stare vapidly at the blank beige wall above my desk, munching on stolen potato chips while the code ran, wondering what was in Case 47''s last sandwich. Were there pickles? I wondered what it was like to be moments from death, screaming in agony, with a large intestine split open along its length by a bomb, and then to have your doctor ask you about your sandwiches.

It was during one of these depressing reveries that I was glad for a distraction. In graduate school, you learn to sense when your adviser is coming for you. Dale in particular had a distinct way of walking down a hallway. Point A and Point B were never close enough together, and the time spent between them is time he could have used more beneficially for research. His office was at the west end of the hallway and the lab''s grad students, myself included, worked in the shared offices scattered down the line between him and most useful destinations. We all knew the rapid staccato thunk of his ever-present combat boots coming down the hall. Each of us would listen for the boots to pass our door. If they kept going, we kept working uninterrupted.

But sometimes the boots stopped a few steps past a door, paused, and then reversed. This interruption in their rhythm meant Dale had an idea. This day, a few years after my arrival at Duke, the boots stopped for me. Dale pulled a tattered blue office chair out of the corner, sat down, and looked at me expectantly. "What about the Hunley." The words were delivered as a statement. There seemed to be no question mark in his tone. I had no idea what he was talking about, and the expression on my face probably told him so.

"What about the Hunley," he repeated. Dale often spoke in the clipped, truncated pattern I was familiar with from working on the navy base and talking to military operators. Minimal adjectives. Pleasantries are an inefficient use of time. Make your point and move on. My need for the repetition must have irked him, but still I had no idea what he was talking about. "Can your fancy software model it?" he asked. "Sure," I responded, still without any idea what he was asking.

"I don''t see why not." In grad school, unless you already have a damn good reason locked and loaded, the correct answer is always yes. Besides, DYSMAS was designed to assess ship damage. Whatever he was talking about, assuming it was a boat of some kind, the navy''s software could probably model it. The boots proceeded back on their mission d.