Flooding of Engine Room During Ballast Operation

During a ballast operation at night, while at a shipyard in order to trim the vessel for drydocking, it was discovered that the engine room was flooded. Damage to submerged electrical equipment occurred Furthermore, the engine room had to be cleaned after the flooding. The ballasting could, however, have caused serious consequences for the safety of the vessel and sinking if not discovered in time.

The most probable cause of the flooding was lack of communication between the deck side and the engine room and lack of adherence to sounding of alarms. The vessel was alongside a shipyard for renewal survey, hull. Some pipes and a main ballast pump had been dismantled for maintenance. The vessel needed to be ballasted, after midnight, in order to be trimmed for entering into the drydock.

Investigations afterwards revealed that during the ballasting, bilge alarms in the engine room sounded three times as follows:

the engine room aft bilge alarm, then after some time
the engine room forward bilge alarm, and sometimes later
the sludge tank level alarm (this tank had been opened for cleaning and survey)

The watch keeper cancelled the alarms every time without physically going down into the engine room bottom floor to check. After some three hours the deck officer discovered that water level in the ballast tanks did not increase. It was finally discovered that the engine room was flooded by 2.5 m forward and 3 m aft.

This incident stresses the importance on the following:

Stay at repair yard means change in risk, and requires special precautions/planning.
Systems which need to be operated and where maintenance is going on, are to be confirmed suitable for use before operation.
Valves are to be confirmed in a closed position involving equipment under maintenance.
Watch keepers to be proactive and investigate the cause of every alarm.
Good communication is required to ensure no misunderstanding of each other (superintendent – deck officer – engineers.)