AS MAINTENANCE, A TEMPORARY HOISTING MECHANISM WAS BEING USED TO LIFT AN I-BEAM, APPROX 20'L ANDWEIGHING 860 LBS. INJURED EE WAS STANDING ON THE LAUNCH, HOLDING A TAGLINE WHEN THE I-BEAM AND T HE HOISTING EQUIP FELL TO THE BOAT AND INTO THE WATER. WHILE THE INJURED CANNOT REMEMBER THE ACCIDENT, THE INJURY APPEARS TO HAVE RESULTED FROM THE FALL, THE EE STRUCK HIS BACK ON THE LAUNCH.