The rediscovery of the vessel, which was captured by the Japanese for a time during World War II, highlights the potential of underwater autonomous vehicles to map the ocean floor.
On Aug. 1, a ship dropped its unusual cargo into a patch of ocean some 70 miles northwest of San Francisco: three orange robots, each more than 20 feet long and shaped like a torpedo. For a day, the aquatic drones autonomously prowled the waters, scanning nearly 50 square miles of ocean floor.
Some 3,500 feet beneath the surface, an apparition popped up on the robots’ powerful sonar. Down in the darkness, the drones saw a ghost.
The robots had spotted the wreck of the “Ghost Ship of the Pacific,” the only U.S. Navy destroyer captured by Japanese forces during World War II. Formerly known as either the U.S.S. Stewart, or DD-224, the ship was resting in what is now the Cordell Bank National Marine Sanctuary.
Three days later, another set of underwater robots captured images of the historic wreck. Though shrouded in decades of marine growth — and home to sponges and skittering crabs — the 314-foot-long destroyer is almost perfectly intact and upright on the seafloor.