Too Much and Too Little: Overload, Underload and Why Both Sink Watches

It Is A Curve, Not A Line

Performance does not fall only when we are overloaded. It falls at both ends. Too little to do and the mind idles; vigilance on a long quiet watch is a skill that decays. Too much and attention narrows onto one task while others are dropped. The best performance sits in the middle. Both ends are common at sea, often on the same voyage.

Overload

What it looks like: task shedding (dropping the job that seems least urgent, which is often the lookout or the plot), narrowing (all attention on one screen or one paper), missed calls and short, clipped communication.

• IMCA SF 01/24. A workboat master steering by hand between wind turbines also did paperwork at the chart table. Absorbed in it, he lost track of time and nobody kept a lookout. The boat struck a tower and a crew member broke two ribs. The MAIB advised that if paperwork must be done, someone else keeps the lookout, and that the administrative burden itself be reviewed.
• IMCA SF 17/25. A DPO faced alarms from automation, bridge watch, navigation lights, ARPA and AIS, all through one alarm system, and a forward panel known to freeze. He pressed the Take button beside Silence. See the console mistakes guide.
• Exxon Valdez, 1989. A single officer on the bridge, without the helmsman and lookout redundancy normally expected. Our case tags Fatigue, Fitness for Duty and Loss of Redundancy.

Underload

What it looks like: boredom, drowsiness, complacency (‘nothing happens here’), and automation complacency, where a system is trusted more than it deserves. See the guide on AIS-assisted collisions.

• IMCA SF 21/22. A Mate fell asleep on a calm night watch on a monotonous passage after working about 29 hours in 48. Both engines shut down on grounding and could not be restarted.

What Helps

1. Share and protect. If one person has the paperwork, someone else has the lookout. If the watch is a single officer, the ship’s routines should not add tasks that pull the officer away.
2. Reduce the noise. Rationalise alarms so that the critical ones stand out, and keep panels working.
3. Keep a minimum standard when it is quiet. Set the ECDIS alarms. Call out the plot. Stand up. Walk to the bridge wing. Underload is when routine checks matter most.
4. Plan the peaks. Know the busy minutes in advance (pilot boarding, a narrow channel, a crossing) and put the extra people there.
5. Say it. ‘I am saturated, take the radio.’ A bridge team that can say that is a team that shares load.

Test Your Knowledge

Think you've got this covered? Put it to the test in Crew Connect's free Knowledge Checker — try a quick leadership round and see how you score.

Related Reading

• Seven IMCA Safety Flashes about the bridge team
• Fatigue and the watch
• Bridge resource management in six short modules