Ballasting while Loading or Discharging from Barges

On two occasions the vessels concerned were discharging into barges and ballasting simultaneously. During the ballasting operation the double bottom tanks were flooded and water overflowed on to the main deck. The water then drained away via the overboard scuppers and into the open holds of barges moored alongside.

In another case, topside wing tank drop valves were opened without the operator recognising that the overboard discharge was situated above an uncovered barge. Although shouting from the barge personnel resulted in the valves being closed again shortly afterwards, the damage had already been done.

If possible, and particularly if the vessel is loading or discharging a water sensitive cargo, ballast operations should be postponed until cargo work has ceased and the barges have been covered or removed. If ballasting cannot be avoided with barges alongside, double bottom tanks should be filled by gravity inflow alone to ensure that water does not overflow on to the main deck. Pumps may then be used to top up the tanks after the barges have departed. It is also good practice to fill ballast tanks only when the adjacent cargo spaces are free of cargo. Scuppers located in the vicinity of open barges should be plugged for the duration of cargo operations, allowing any water that may accumulate to run off well away from where the barges are moored.

Similarly, consideration may be given to locking or chaining shut any topside wing tank drop valves which, if opened, may result in barges being flooded with ballast water. Warning notices may also be attached to such valves.