Search crews have found the voyage date recorder from the cargo ship El Faro, which sank off the Bahamas last year with 33 crew members on board.
The U.S. National Transportation Safety Board said Tuesday the recorder is 4,500 meters beneath the surface.
Officials said the next step would be to determine how to recover the device, which may contain navigational data and communications from the ship's bridge.
"Finding an object about the size of a basketball almost three miles under the surface of the sea is a remarkable achievement," NTSB Chairman Christopher Hart said.
The 240-meter freighter sank last October after losing propulsion while traveling between Florida and San Juan, Puerto Rico. The ship got caught in Hurricane Joaquin's 250 kph winds and strong seas. All 33 crew died.