A high-resolution synthetic aperture sonar image of DD-224, formerly the USS Stewart, a ship resting on the seafloor of the Cordell Bank National Marine Sanctuary. Photo / Ocean Infinity via The New York Times
A high-resolution synthetic aperture sonar image of DD-224, formerly the USS Stewart, a ship resting on the seafloor of the Cordell Bank National Marine Sanctuary. Photo / Ocean Infinity via The New York Times
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 August 1, a ship dropped its unusual cargo into a patch of ocean some 110km northwest of San Francisco:three orange robots, each more than 6m long and shaped like a torpedo. For a day, the aquatic drones autonomously prowled the waters, scanning nearly 130 square km of ocean floor.
Some 1065m 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 US Navy destroyer captured by Japanese forces during World War II. Formerly known as either the USS 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. Although shrouded in decades of marine growth – and home to sponges and skittering crabs – the 95m-long destroyer is almost perfectly intact and upright on the seafloor.
“This level of preservation is exceptional for a vessel of its age and makes it potentially one of the best-preserved examples of a US Navy ‘four-piper’ destroyer known to exist,” Maria Brown, superintendent of both the Cordell Bank and Greater Farallones national marine sanctuaries, said in a statement.
The find, which came during a technology demonstration, highlights the efficiency of modern robotic ocean exploration. Ocean Infinity, the marine robotics firm that operated the drones that made the discovery, owns the world’s largest fleet of autonomous underwater vehicles. The drones are used to create high-resolution maps of the seafloor – a major gap in our understanding of the oceans. The technology is also crucial for selecting sites for offshore construction projects such as wind farms and oil rigs, or for laying out routes for undersea pipelines and cables.
These robotic fleets are also proving invaluable to marine archaeologists. In 2020, Ocean Infinity helped find the wreck of the USS Nevada. In 2022, the company also contributed to the rediscovery of the Endurance, which sank during a 1915 expedition by Ernest Shackleton.
“We’re in the midst of, I think, a radical change in ocean discovery,” said Jim Delgado, a senior vice-president at SEARCH, Inc., a maritime archaeology firm involved in the DD-224 discovery.
The wreck was found by drones 1065 metres beneath the surface, covered in decades of marine growth. Photo / Ocean Infinity via The New York Times
Delgado joined the hunt for DD-224 a decade ago as the director of maritime heritage for the National Oceanic and Atmospheric Administration, which oversees more than 1.6 million square km of underwater parks in the United States. Marine archaeologists have long been fascinated by the ship’s unusual history.
After being sunk and abandoned in the waters off Java in 1942, DD-224 was raised by Japanese forces, who used it to escort their naval convoys. Allied pilots reported what looked like one of their own ships deep behind enemy lines.
In a symbolic farewell to the ship after its postwar recovery, the US Navy recommissioned DD-224, towed it to California, and then buried the vessel at sea in a hail of target practice gunfire on May 24, 1946. After withstanding two hours of fire, the stubborn ship relented and sank.
“The whole history of that ship was actually exceptionally well documented,” said Russ Matthews, president of the nonprofit Air/Sea Heritage Foundation and a member of the discovery team. “The only piece of that story we didn’t have is, what does it look like today?”
Matthews spent years, off and on, trying to locate the ship’s last known coordinates. An initial lead from a colleague, Lonnie Schorer, turned up a 1946 US Navy communiqué that narrowed the search to what is now the Cordell Bank sanctuary. But no NOAA vessels that sailed through the sanctuary chanced upon the vessel, and Matthews and his colleagues couldn’t secure the funding to go out themselves.
Fortunes turned in April this year, after a meeting between Matthews and Andy Sherrell, the director of maritime operations at Ocean Infinity. The company wanted to test using several of its biggest autonomous drones at the same time. Why not try to find DD-224?
Matthews had made a break in the case, tracking down coordinates from the tugboat that pulled DD-224 out to the area where it sank. With NOAA’s permission, Ocean Infinity went to that spot. Sherrell noted that undersea, mapping a region of 37 square nautical miles – the search area for DD-224 – typically takes weeks. The Ocean Infinity drones spotted the ghost ship within hours.
“We covered it very quickly, and in high resolution,” Sherrell said.
The terabytes of data gathered by Ocean Infinity now constitute the best map of that portion of the Cordell Bank sanctuary. The data set also concludes the eight-decade story of a ship that always meant more than the steel now corroding in the deep.
After DD-224 was recovered, the American crew that brought it home preferred to call the vessel RAMP-224, from the acronym for “Recovered Allied Military Personnel,” a term used at the time for liberated prisoners of war.
“This ship, in its own way, basically was humanised by the Navy,” Delgado said. “People pour so much into ships – and we have since the beginning of time. They represent us.”
