THE SHIPWRECK DETECTIVE

Nigel Pickford has spent a lifetime searching for sunken treasure-without leaving dry land.

- SAM KNIGHT

The wreck was like a bug on the wall, a jumbly shape splayed on the abyssal plain. It was noticed by a team of autonomous-underwater vehicle operators on board a subsea exploration vessel, working at an undisclosed location in the Atlantic Ocean, about a thousand miles from the nearest shore. The analysts belonged to a small private company that specializes in deep-sea search operations; I have been asked not to name it. They were looking for something else. In the past decade, the company has helped to transform the exploration of the seabed by deploying fleets of A.U.V.s-underwater drones which cruise in formation, mapping large areas of the ocean floor with high-definition imagery.

"We find wrecks everywhere, just blunder into them," Mensun Bound, a maritime archeologist who works frequently with the company, told me. The pressures of time and money mean that it is usually not possible to stop. (Top-of-the-line search vessels can cost about a hundred and fifty thousand dollars a day to charter.) "Sometimes it's heartbreaking," Bound said. A few years ago, he was with a team that stumbled across a wreck in the Indian Ocean. They had a few hours to spare, so they brought a sodden box up to the surface. It was full of books. "That was the most exciting thing I've ever found in my life," Bound said. "But then the question becomes: What do we do with it?"The seabed is a complicated, as well as an expensive, place to operate in. So they put it back.

This Atlantic wreck was beguiling.