AWO Near Miss 24-04 - Terminal Air Actuated Valve Malfunction

While preparing to relieve the Chief Mate for the midnight cargo watch, the Second Mate heard over the radio that there was a “banging noise” coming from the offshore side of the barge.  The Second Mate came out early to assist as needed and saw the Chief Mate with a flashlight looking around the cargo tanks actively being discharged.  When the crew inquired with the dock to ascertain the source of the noise, the dock operator noted that an air actuated valve on the dock was “acting up.”  The crew returned to the barge, with the Second Mate manning the Emergency Stop and Tankerman standing by the manifold.  Shortly after, the dock air actuated valve lost pressure and started to close automatically, with two barge cargo pumps online and discharging at full rate.  The Second Mate pressed the Emergency Stop button to relieve manifold pressure and drained residual cargo back into the tanks before blocking in the manifold.