How does the equivalent of fourteen million elephants’ worth of junk get into the seas every year? In 2018, a group of South African researchers devised an experiment to find out. They went to the aptly named Inaccessible Island in the South Atlantic between South Africa and Argentina, an island covered with ocean trash. For three months, they examined the items for signs or origins or date stamps. They found that the number of the most common ocean throwaways had increased more than 15 percent every year over the last thirty-five years—and a striking amount from the prior two years. Most items bore Chinese writing. But this was strange, since even the most hydrodynamic bottles would still take about three years to drift from China to a small island on the other side of the world. They scratched their heads and arrived at the only plausible culprit: Chinese merchant ships, whose activity in the South Atlantic had increased since the 1980s at almost the same rate as the build-up of trash on Inaccessible Island. “It’s inescapable that it’s from ships,” Peter Ryan, the lead researcher, told the Agence France-Presse.

  Chinese ships aren’t the only offenders. Until the 1970s, almost any ship in international waters could dump whatever it wanted. Most availed themselves of the convenience under the legal principle of “who’s going to know?” Newer regulations set dumping parameters based on distance from shore, at least in U.S. coastal waters. Once a ship is more than three miles from port, it can dump small wads of paper, cardboard, or food waste. More than twelve miles from shore it can let loose metal and glass and almost any trash, so long as it’s weighted to sink to the bottom. Plastic is verboten everywhere, and sewage—so long as it’s treated—is allowed almost anywhere. One imagines that while Congress deliberated this final provision, a humble aide stood up to make the irrefutable point that if whales, sharks, and dolphins are allowed to poop in the ocean, why can’t we?

  As time went on, the most damaging effects of ships turned out to be not from human waste but from manufactured goods that cross oceans on giant container ships. The burst of twenty-first-century globalization had the predictable effect of making ships bigger. The vessels that brought fruit from Ecuador or flat-screens from China grew to accommodate more capacity, at least to a point. Most container ships on earth have been designed to squeeze through the one-hundred-ten-foot-wide locks of the Panama Canal. But the construction of a wider one-hundred-eighty-foot canal lane in 2016 and plans for an even bigger canal across Nicaragua fueled a shipbuilding boom.

  Bigger ships suggest fewer trips across oceans. But the opposite happened. Bigger ships allowed for more than double the quantity of goods crossing the seas by 2015. The insatiable appetite for manufactured goods—fed largely by e-commerce—fuels projections that ocean freight will triple in the Atlantic and quadruple in the Pacific and Indian Oceans by 2050.

  The unseen effect of ships loaded with millions of pounds of freight is that they can be easily knocked off course or off-balance. The general public rarely sees this, but in early 2021, a cargo ship a quarter mile long called the Ever Given—a ship visible from space—made international news when it lodged its bow into the banks of the Suez Canal. Its momentum from carrying twenty thousand shipping containers swung its stern to the opposite bank and blocked one of the world’s busiest shipping bottlenecks for six days as dozens of tug boats, excavators, and frustrated Egyptians worked to refloat it. Around the same time, the Maersk Essen, a cargo ship carrying thirteen thousand shipping containers, rocked so forcefully on its way from China to Los Angeles that it dropped seven hundred fifty containers into the Pacific Ocean. Several floated, but most sank and will probably never be found, along with thousands more containers lost at sea every year. Ocean trash is bad enough. But it’s a bigger shame that there are millions of pairs of new sneakers, cheap umbrellas, and multicolored beach chairs that no mollusk, starfish, or sea snail will ever want or ever use.

  * * *

  Jack Grimm wasn’t looking for debris, human or otherwise, and he wouldn’t be satisfied if he found it. After the Gyre had towed the “fish” over the last of the fourteen sites and each one had been photographed, studied, and ruled out, Grimm said it was time for the grand finale. He ordered the crew to pull the “fish” out of the water and replace it with waterproof film cameras. If they weren’t going to find the Titanic using the magnetometer, at least they could take a few hours of footage of the seafloor that could be analyzed later for signs of the wreck.

  This was every bit the Hail Mary it sounded like, and the strangest thing happened: it worked.

  Later that night, as the Gyre and its defeated crew headed back to Boston, the television in the lounge showed the tape from earlier that day. Everyone gathered around to gawk at a starfish as big as a car tire and a shrimp longer than a foot. Fish swam in front of the lens as if posing for a portrait. There was an old bottle, a tin cup, and something that looked like the skull of George Washington.

  And then in the final thirty minutes, the seafloor changed suddenly in texture from sandy nothingness to a distinct object.

  Grimm sprang out of his seat as if shot from a gun.

  “Wait a minute!” he yelled. “Play that back!”

  Chapter 11

  ALL THESE MOTHS DRAWN TO THE SAME FLAME

  The propellers built for the Titanic and its sister ships had been among the largest in the world at the time. At twenty-three feet across, they ran on a triple-screw system, which gave the Titanic, the Britannic, and the Olympic three propellers each—two side by side and a smaller one in the middle. Exactly how big to make each propeller was a complex calculation of fluid dynamics to discern how fast water would flow through the propellers. Then came the matter of pitch, or how angled they should be. Too steep and you’d get no propulsion at all; too sloped and the ship would be pushed up instead of forward.

  The Titanic’s propellers were cast from manganese bronze, and their design had been inspired by an 1836 patent by the British inventor Francis Pettit Smith, who designed a propeller like a screw. The thread extended two full revolutions, like a spiral staircase, which Smith believed offered twice as much propulsion than would a single revolution. At a demonstration on a small boat at the Royal Adelaide Gallery of Practical Science in London, Smith explained that the device transferred rotational motion into linear thrust by creating a pressure differential in the water, thus moving a ship (and later an airplane) forward. The bigger the propeller and the quicker it turned, the greater the propulsion.

  Smith’s audience was easily persuaded. Within three years, the Royal Navy committed to outfitting all future ships with screw propellers, starting in 1838 with the steamship the SS Archimedes, named after the ancient Greek mathematician who invented the screw. There was no question the screw propeller was superior in battle. Compared to a paddle wheel, which could be attacked and destroyed, a propeller was underwater, which also allowed for more guns and cannons on the stern of a ship.

  Yet the question of whether a propeller was more powerful than a paddle wheel could be settled only one way: a tug-of-war. In 1845, navy sailors tied a rope between two comparable ships—the propeller-driven HMS Rattler and the strong paddle steamer HMS Alecto. Then they accelerated both vessels in opposite directions. When the Rattler pulled the Alecto backward at more than two knots, the matter was settled. Paddle wheels were demoted to the slow ships of history, like riverboats and lake ferries.

  The Titanic’s propellers, however, reflected modern breakthroughs in ship speed. No, it turned out, a bigger and faster-turning propeller wasn’t always the most powerful. Large blades provide thrust, but also extra drag. Three blades were more powerful than four, but four provided balance and kept the thrust more even. This combination resulted in the Titanic’s sleek and optimized design of the three propellers—the pitch of each blade nearly equal to its diameter—and made from expensive bronze instead of steel to keep the smooth, sleek blade from rusting. The two outer propellers had three blades and the smaller inner propeller is believed to have had four blades, although this has become an odd point of controversy in the Titanic community. For all the expense, weight, and size of the propulsion system of the world’s most famous ship, not a single pre-sinking photograph has been known to exist of the propellers, fueling endless debates about the number of blades on the sole center propeller.

  At least until Jack Grimm thought he spotted it.

  “Play it again!” Grimm kept saying. “Go back!”

  The cabin was quiet as everyone crowded around the monitor, faces almost touching the glass, as the five seconds of tape were looped over and over. The endless expanse of textured mud was interrupted by a large object that looked like a butterfly wing, large and flat and coming together on one end to attach narrowly to a piston. It was too curved and sleek to be a rock, and it was also enormous, looking every bit the twenty-six tons of a Titanic propeller blade.

  Grimm felt in his bones that he had encountered the underbelly of the ship that had fascinated and eluded him for years. And based on this five-second video clip alone, he was convinced. No one in the control room dared to contradict him or wonder aloud if the object could be something else, or perhaps belong to one of thousands of different ships that had ever wrecked or lost a propeller in the North Atlantic.

  Grimm called for Captain Armand, who was almost as eager to find the ship as Grimm. No one was to say anything to Armand before he saw the footage.

  “It’s a propeller,” Armand said immediately.

  “From the Titanic?” Grimm asked.

  “It’s consistent in size.”

  Grimm made a beeline for the radio room. The Coast Guard was expecting the Gyre back immediately, but surely they’d grant an extension considering the circumstances. Talking to a Coast Guard officer on the other end of the line, Grimm first turned on the charm (Aw shucks, you wouldn’t believe it!). Then he moved to reason (Now listen, if we leave now, we’ll never find it again). And then to name-dropping and political clout (President Reagan is a friend of mine, and I know he’d want us to get this done). When it all failed, he resorted to begging, and when that too failed, he got angry and fell to insults and threats. Finally, he flung the radio receiver across the room.

  Even if Grimm could convince Captain Armand to buck the authorities and swing the helm around, risking both men’s finances, reputations, and potential liability, it would have been extraordinarily difficult to navigate back to the precise spot of the propeller. But it was moot. Armand knew they couldn’t turn back. After the Gyre returned to port in Boston and the thrill faded, the crew disembarked with wistful nostalgia and promises to stay in touch.

  Not Grimm, though. Grimm sat alone stewing. He was angry and tired, feeling he had come so close and still left empty-handed. But his eyes were fixed firmly on the future, obsessed with the image of the possible propeller and what else might be nearby. A man not prone to giving up until he was at the end of his rope, and then a mile or two past that, he announced to reporters on the dock that he had “definitely” discovered the Titanic and, in eleven months, would go back for the third time and bring back detailed photos.

  Grimm’s claim of his discovery made international news. But without irrefutable proof that the propeller was in fact a propeller, and more specifically the Titanic’s propeller, the story stalled. As Grimm’s photos made the rounds, marine archaeologists generally dismissed the object as a propeller-shaped rock outcrop.

  That turned out to be true. But what was also true was that Grimm had come closer than anyone knew, including himself. Years later—and only with the benefit of knowing exactly where and how the ship had fallen—Grimm was made aware that on his fourteenth and final target, the “fish” passed just five hundred feet from the bow.

  * * *

  How might it have felt? What might have happened if Grimm had towed his rig directly over the Titanic and brought up the first color images the world had ever seen? For years, Grimm had fixated on the reveal phase: the clothes he would wear as he was carried off the Gyre like a king, the speech he’d give at the press conference announcing to the world he had done the impossible. But what would it have felt like, deep down, in those early moments when it set in that the quest of many men’s lifetimes had been solved by him? Most people are happy simply to find their lost glasses or misplaced keys. But for men like Grimm, once you made a sport of finding missing items, the only way to scratch the itch was to search for things bigger and bigger.

  I had been warned for months that nobody talks, writes, or even thinks about shipwrecks for long without coming across David Mearns. Shipwreck hunters are an abundant species, but shipwreck finders are a more elite club, one you can’t talk your way into with bravado and deep pockets. Owning salvage rights to a ship or chartering a boat to comb a search area are small maneuvers compared to the triumph of declaring a riddle solved.

  In 1990, Mearns’s first find was his biggest. His discovery also helped solve a crime. The Lucona was a Panama-registered freighter that sank in the Indian Ocean in 1977. Udo Proksch, the Austrian man who owned the cargo, said the ship had been carrying “expensive uranium mining equipment” and filed a hefty insurance claim for $20 million. With little proof, the insurance company paid the claim, but thirteen years later, when Mearns found the Lucona in almost fourteen thousand feet of water, he not only couldn’t find the mining equipment, but he also noticed the remnants of a time-release bomb, suggesting Proksch faked the accident at considerable cost, including the lives of the six men who died in the sinking. A handful of Austrian government officials were discovered to have been in on the plot, signing off on the fake cargo and obstructing an investigation into the incident. Proksch escaped to the Philippines in 1988 but returned to Austria a year later, when he was recognized in a disguise and arrested. Evidence from Mearns’s discovery of the Lucona landed Proksch a prison sentence of twenty years.

  Mearns could hang his hat on the Lucona alone, dining out and giving speeches about how he dug through historical records and plotted points on maps. But he felt drawn toward bigger mysteries and deeper wrecks. In 1994, Mearns found the MV Derbyshire, the biggest British ship ever lost at sea. It was nearly three times the displacement weight and sat at almost the exact same depth as the Titanic. Several years later, he found the British two-mile-deep battle cruiser the HMS Hood, which had been sunk by a German battleship in 1941. Like the Titanic, the Hood had also been a symbol of invincibility that fueled decades of enthusiasm and fascination. Every expedition for Mearns seems to bring a new announcement of a new discovery: in 2008, the Australian battlecruiser the HMAS Sydney; in 2015, the Japanese battleship Musashi; and of course the Guinness World Record for the deepest shipwreck ever found, the German runner Rio Grande, waterlogged under three and a half miles of water.

  I finally got ahold of Mearns one morning. Slim, with gray hair and a goatee, he looked more like a mid-level accountant than a grizzled ocean veteran. What was his secret, I wondered, that allowed him to turn up dozens of wrecks that other people—many of them extremely smart, experienced, and well funded—had tried to find and to make it look almost effortless? It was clear from the stories of Woolley and Grimm that obsession wasn’t nearly enough.

  “You’d be surprised how much you can learn in books and old newspapers,” he said. “But the most important part are eyewitness accounts.”

  “Like accounts from survivors?” I asked.

  “Yeah, and people on other ships in the area.”

  He explained that, like Jack Grimm, he had found details about the weather and the water current. Was there wind that night? More than once he tracked down descendants of survivors—people who weren’t even alive when the ship sank—and they said something like, “My dad used to say it was a full moon that night,” which led Mearns to a new breakthrough. Often, even harder than finding the ship’s location was raising the money for each expedition. Investors weren’t interested in old battleship radios or navigation computers. They wanted flashy finds like gold or diamonds. He often partnered with TV companies or foreign governments with a media or historical interest. Occasionally philanthropists got involved, but only if a big anniversary of a battle was coming up, thereby guaranteeing free media and public credit that, naturally, could be monetized.

  Mearns was good at what he did, but even for the best hunters, there were still ships out of reach. For a long time, the one that haunted him was the Endurance, the ship Ernest Shackleton took in 1914 to Antarctica, where it was sandwiched by converging ice floes and spawned one of the greatest survival stories in the history of exploration. In 2003, Mearns met Shackleton’s daughter, who gave her family’s blessing for him to go find the Endurance and recover its artifacts. The only problem was that the Endurance was almost two miles deep at the bottom of the ice-covered Weddell Sea, an area almost as dangerous to ships today as it was in Shackleton’s era. I understood the challenge facing Mearns or anyone who looked for the Endurance. But then, as this book was heading to the printer, the darndest thing happened: someone found it. A team led by the polar geographer John Shears and the maritime archaeologist Mensun Bound—a man sometimes called the “Indiana Jones of the deep”—used battery-powered drones to comb 150 square miles of Antarctic seabed 10,000 feet deep. The drones worked for two weeks until they returned with high-definition photos of the Endurance’s bow and its helm. In the wreckhead community, this was enormous news, a discovery almost as seismic as finding King Tut’s tomb or landing on the moon. But for the biggest fans—and competing hunters like Mearns—the news also seemed to have an undercurrent of disappointment. During its century-long absence, the mystery of the Endurance had become more interesting than the Endurance itself. Now that it was revealed to be exactly where everyone thought it might be, looking exactly like everyone hoped it would, there wasn’t much left for anyone following at home to do but pack up and move on.