CREW WAS IN THE PROCESS OF CHANGING HAMMERS. HELPER HAD HOLDING WRENCH BOLTED UP AGAINST THE MAST. WHILE CONNECTING, DRILL STEEL CROSS THREADED ONTO HAMMER. DRILLER REVERSED ROTATION TO UNTHRE AD. WHEN HE DID THIS IT CAUSED THE HOLDING WRENCH TO MOVE. HELPER RE-GUIDED DRILL STEEL ONTO HAMMER, THE DRILLER HIT THE ROTATION TO SCREW ONTO THE HAMMER, CAUSING THE WRENCH TO HIT HIS ANKLE