An image of debris of the Titan submersible recovered from the ocean floor and the crew’s final message — “all good here” — were among the details shared Monday during the U.S. Coast Guard’s investigatory hearing into what caused the deep-water vessel to implode last year, killing all five on board.

The Titan had suffered more than 100 equipment issues in the two years before the calamity, investigators also revealed, as concerns over safety standards came to light during the first day of…