TAMPA, Florida — A voyage data recorder thought to contain key evidence on last year’s deadly sinking of the cargo ship El Faro in a hurricane cannot be immediately recovered, authorities said on Wednesday, a day after announcing it had been found.

The research vessel used to find the recorder in 15,000 feet of water off the Bahamas lacks the specialized equipment needed to extract it, the National Transportation Safety Board said in a news release.

All 33 crew members died when the 790-foot El Faro went down on Oct. 1 during a cargo run between Florida and Puerto Rico. It was the worst cargo shipping disaster involving a U.S.-flagged vessel in more than three decades.

The crew included 28 Americans and five Poles. Among crew members lost were 53-year-old Capt. Michael Davidson of Windham, a 1988 graduate of Maine Maritime Academy; Michael Holland, 25, of Wilton, a 2012 graduate of Maine Maritime; Danielle Randolph, 34, of Rockland, a 2004 graduate of Maine Maritime; and Dylan Meklin, 23, a 2010 graduate of Rockland District High School and a 2015 graduate of Maine Maritime. Another crew member, Mitchell Kuflik of Brooklyn, New York, graduated from Maine Maritime in 2011.

The data recorder, which may contain information related to communications from the cargo ship’s bridge before the sinking, still appears to be attached to a steel beam connected to the ship’s mast, the NTSB said.

“Extracting a recorder capsule attached to a four-ton mast under 15,000 feet of water presents formidable challenges, but we’re going to do everything that is technically feasible to get that recorder into our lab,” Brian Curtis, acting director of the NTSB Office of Marine Safety, said in a statement.

Authorities did not immediately set a time line to launch a retrieval effort, but said they hoped to carry out the mission in the next several months.