WHILE LOADING BARGE #OR6155, THE HEAD CABLE 3/4""CAME OFF FROM BEHIND TIMBERHEADS OF DOCK BARGE PINCHING EMPLOYEE BETWEEN CABLE AND 4'HIGH COMBING.CO-WORKER AT WINCHES DID NOT SEE EMPLOYEE CAUG HT IMMEDIATELY AND WAITED TO SEE HIM. WHEN SEEING HIM CAUGHT, CO-WORKER PULLED ON CABLE SLIGHTLY TO RELEASE LOCK MECHANISM, THEN RELEASED EMPLOYEE, HE FELL TO BARGE AND CO-WORKER LOCKED WINCH