An error with fire flaps led to engine space flooding, causing costly damage

A member has reported an incident in which there was sea-water flooding of one of the engine spaces on a crew transfer vessel, leading to significant and expensive equipment damage. The immediate cause of the flood was a small error -fire flaps not being secured properly.

Some days before the incident, the engine space fire flaps had been operated. But the retaining pin to hold the fire flap open had not been returned to the correct position. This led to the fire flap bouncing shut on the next occasion when the vessel was out in moderate seas. With the fire flap now shut the engine air intake began to loosen fixings within the engine space due to its immense suction. One of the fixings loosened was the toilet overboard pipe. With no-one aware of it until the bilge alarm sounded, the engine room had been filling quickly with sea water as the suction, combined with gravity, drew it in.

On the way back to port and long before the cause of the flooding had been realised, the engine room continued to flood. The engine room bilge pump became blocked and the manual bilge pump (whale gusher) quickly perished after a lot of operation. The mobile suction bilge pump was used to contain the water level.

The vessel returned to port on one engine, with the other engine bay flooding up to its engine mounts and the engine in reduced power mode. The flooding caused the engine on that side to require substantial servicing and repair to remove damaged parts and water residue/ emulsified oil from its machinery and drive gear, resulting in significant off-hire time. There were no injuries or risk to life, but it was an extremely expensive lesson to learn.

Members may wish to refer to the following incidents (search words: flooding, crew):

• Water ingress to bow thruster space
• Near-miss: Engine room flooding