Lessons learned: Falling asleep is a real risk when working at night


It was a summer night and a live fish carrier was on passage, while the bridge was manned by the Officer of the Watch (OOW) and an Able Seaman (AB) lookout.

It was still dark at 0430 when the AB left the bridge to prepare painting materials for the next watch.

Thereafter, the OOW was alone and sitting in the bridge chair. The OOW did not feel tired but must have drifted of to sleep as he was suddenly woken by the ECDIS safety depth alarm indicating that the water depth was less than 10m.

The OOW applied astern power and turned to port in an attempt to avoid shallow water. But it was too late, and the vessel was still underway at 4kts when it grounded.

Following there, the master was called to the bridge, and an initial assessment found no internal damage. The crew refloated the vessel using its own power around 30 minutes after the grounding and headed for harbour.

Once the vessel was within mobile phone range, the coastguard was informed. An inspection by divers found some minor damage and the vessel proceeded to dry dock for repairs.

Lessons learned:

  • An alarm is only of value if it provides sufcient warning for the OOW to make sense of what is wrong and take action accordingly. In this case the depth alarm came too late to be efective as the seabed shelved steeply around the island and the water depth decreased rapidly. Neither the ECDIS of-track alarm, which would have
    alerted the OOW to the missed course alteration, nor the BNWAS, which would have alerted the crew to the inactivity on the bridge, had been set. Had either alarm sounded there might have been sufficient time to avoid the grounding.
  • Alerting the coastguard should be one of the first actions after an incident, not the last. Although the vessel was refloated without assistance, an early call to the coastguard would have been invaluable had the situation escalated. The ship was within VHF coverage and could easily have communicated with the coastguard
    without delay.
  • There have been many incidents caused by lone watchkeepers falling asleep on the bridge. After a previous grounding incident under similar circumstances, the company involved in this case had required that a lookout be posted in the hours of darkness. When the lookout left the bridge to perform other duties while it was still dark the OOW was left alone and vulnerable to falling asleep.

Safety Digest highlights that:

Fatigue can creep up on you. Even if you do not feel tired it is important to recognise that falling asleep is a real risk when working at night, particularly in the pre-dawn hours where circadian rhythms mean the body is most primed for sleep.


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