The voyage data recorder from El Faro, a U.S.-flagged cargo ship that sank during Hurricane Joaquin in October 2015, was successfully recovered from the ocean floor late Monday.

The recovery of the capsule caps a 10-month-long effort to retrieve the recorder, which was designed to record navigational data and communications between crew members on the ship’s bridge. Investigators hope the recorder will reveal information about the final hours of El Faro’s voyage and the circumstances leading up to the sinking.

“The recovery of the recorder has the potential to give our investigators greater insight into the incredible challenges that the El Faro crew faced,” said Christopher Hart, chairman of the National Transportation Safety Board (NTSB), “but it’s just one component of a very complex investigation. There is still a great deal of work to be done in order to understand how the many factors converged that led to the sinking and the tragic loss of 33 lives.”

Military Sealift Command’s fleet ocean tug USNS Apache departed Virginia Beach, Virginia, Friday with personnel from the NTSB, the U.S. Coast Guard, the U.S. Navy and Phoenix International aboard. After arriving at the accident location on Monday morning, technicians maneuvered CURV-21, a deep ocean remotely operated underwater vehicle, down about 15,000 feet to the sea floor where the wreckage of El Faro rests.

Specialized tools were used to extricate the VDR capsule from the mast structure to which it was attached. The capsule was recovered to the deck of the ocean tug at about 10:30 pm Monday evening.

The voyage data recorder will be examined while at sea by NTSB investigators aboard the USNS Apache, to assess the condition of the device and to ensure proper preservation for readout and further examination ashore. The VDR will be transported to the NTSB’s laboratory here after the Apache returns from sea, expected this Friday August 12. Once at the NTSB’s lab a team of specialists will audition the recording. It is not yet known how long it may take to review the data and audio information that may be captured on El Faro’s VDR. While the minimum design requirement for VDRs of this type is for 12 hours of recording, it may contain additional information.

While investigators examine the VDR, additional photo- and video-documentation of the El Faro wreckage and debris field will be completed concluding NTSB’s activities at the site. No further missions to the accident site are planned unless warranted as the investigation continues.