Mars Report 2013

The Nautical Institute has issued Mars Report No.25 regarding Cargo overflow.

The vessel arrived at the discharge port with a cargo of Methyl Tertiary Butyl Ether (MTBE) with most of the cargo tanks loaded to 98% capacity. The cargo was split in two parcels and was to be discharged separately at same berth, using same manifold connection. On arrival cargo sampling was carried out. During cargo sampling the manual drop valves were opened and pump was started from the cargo control room at slow speed. After completion of sampling, deck crew shut the valves. On board this ship, all manual valves are tied with rope to indicate they are shut. The duty officer was instructed to carry out independent checks of all valves and lines on deck in order to confirm they were correctly set- up for discharge. Discharging commenced from No 7 port and starboard centre tanks with the chief officer and duty officer present in the cargo control room.

The cargo monitoring system indicated No 7 port centre tank low pressure alarm and the chief officer confirmed with deck crew that the vacuum side of the pressure vacuum (PV) valve for that tank was activated. Following this, another audible alarm sounded and the chief officer assumed it to be the low pressure alarm of No 7 starboard centre tank. However, he failed to check the source of the second audible alarm.

For more information, pleace click atMars Report No. 25-2013

Source: The Nautical Institute