Tanker overfill alarm failure

A recent MARS (Marine Accident Reporting Scheme) article published by the Nautical Institute highlighted a potentially very serious problem experienced by one tanker operator which we wish to bring to the attention of all tanker operating Members and their sea staff.

The tanker in question was loading a clean product with a light density of only 0.665. During the loading operation tanks were filled in excess of 95% during which it was found that the automatic high overfill alarms did not activate.

Pre-arrival tests had been successfully conducted on this equipment. A thorough investigation ensued in cooperation with the equipment manufacturers. This resulted in the revelation that the float devices manufactured from stainless steel did not provide sufficient buoyancy to operate effectively in cargoes with density less than 0.750.

In this particular instance the manufacturers accepted the responsibility for replacement of all the flotation devices on this ship. For those operators likely to carry lighter density products and/or chemicals we strongly recommend that their technical departments and sea staff review the nature of the equipment fitted on board their particular ships, if necessary in conjunction with the manufacturers, in order to assure themselves that a similar problem could not happen on board their ships.

For those operators likely to carry lighter density products and/or chemicals we strongly recommend that their technical departments and sea staff review the nature of the equipment fitted on board their particular ships.