Self-Closing Valve Ruptures Mud Hose



A vessel was discharging Oil Based Mud while alongside in Port. Prior to operations, a tool box talk was held and all necessary precautions were taken as per company Risk Assessment and NLS Discharge Operations Checklist. The Chief Officer was responsible for monitoring discharge operations from the Bridge with the Second Officer assisting and in regular communication with the Cargo Surveyor on the Quayside.

The Second Engineer was monitoring the discharge operation from the Engine Control Room. The first tank was discharged without incident. However, when the Chief Officer switched over to the second tank an instantaneous rise in pressure was noted at the pump output and almost immediately the cargo hose ruptured spraying contents over the main deck and the containerised cargo nearby.

The verbal command “STOP STOP STOP” heard over the UHF Radio by the Watchman and the emergency stop was activated. No injuries or further damage was sustained and the spill was contained on-board with no effect on the surrounding environment.


An investigation was carried out by Ship Staff with the assistance of the Cargo Surveyor, who discovered that the shore side loading valve at the connection to the receiving tank was in a very poor condition. The thrust plate was severely worn and provided no friction to hold the valve in the ‘Open’ position. It was concluded that the valve self-closed during the operation which caused the pressure in the hose to rise and exceed the working limit.


The ship staff are not responsible for checking the reception facilities ashore, therefore, there are no corrective actions noted here at this time.

The incident was reported to the base operators and third parties involved. This should encourage a review of their procedures during a preventative maintenance. Please ensure this issue is raised and discussed during your next toolbox talk with Cargo Surveyors prior to bulk cargo operations in the port.

All crew shall be made aware of this bulletin by displaying it on-board and discussing all learning points and recommendations at the next on-board safety meeting.

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Source: Marine Safety Forum


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