Designing bridge systems for the worst moment, not the demo

Systems can look good in controlled conditions and still fall apart in the middle of a difficult berthing. A decision-ready bridge environment is one that holds up when crews are fatigued, under time pressure, and managing several competing demands at once.

This article sets out what a decision-ready bridge environment should look like under real-world conditions: fatigue, time pressure and competing demands.

More information on the bridge does not always lead to better judgement. Performance is often shaped by workload and attention, especially during busy voyages, high-pressure moments, and difficult manoeuvres. Crew members do not necessarily care how much a system can do, but whether it can help them in their daily routines.

A common key finding in human factors research is that more information does not always lead to better outcomes. Increased cognitive load, through workload and stress, can directly affect decision-making performance.

Cognitive load refers to the total demand placed on attention and decision-making capacity at any given moment. In a bridge environment, this demand is contributed to by a combination of navigation, communication, system monitoring, compliance tasks, and environmental conditions.

This challenges the commonly held view that human performance is inconsistent. A decision-ready system is not about providing people with more to look at. It should be about making things simpler and presenting the right information in the right way, so people can make decisions quickly and confidently.

The importance of cognitive load is often highlighted when considering real-world operations. Fatigue has been recognised as a safety risk to crew members for a long time. IMO guidance under the STCW Convention, furthered through the 2010 Manila Amendments, sets minimum rest requirements, including 10 hours in any 24-hour period and 77 hours over seven days.

It also hinted that workload does not tend to occur evenly, but rather in clusters. That pattern is familiar to many operators. As Pradeep Chawla explained, “if they have touched more than two or three ports in the past one week, everybody is shattered.”

This is important as it shows how fatigue is often driven by repeated cycles of intense operational demand. For example, traffic, adverse weather conditions, busy port operations, unexpected administrative tasks, and bridge system issues can all occur simultaneously. Newer risks, like GNSS interference, can further increase pressure by causing sudden system disruptions.

A decision-ready bridge environment needs to reflect these changeable and volatile conditions, not perfect ones. It needs to assume that operators manage multiple competing demands while fatigued or under time pressure.

This involves recognising that bridge workload rarely builds in a neat, linear way, but rather in layers. A bridge team approaching port may be handling traffic, pilot communications, company reporting, checklist completion, changing environmental conditions, and multiple active systems simultaneously.

When another complication is added, whether GNSS interference, a last-minute course change, or a number of alarms in tandem, the task moves beyond navigation and becomes about managing attention under pressure.

This is where the quality of system design matters most. Systems might work well in normal conditions but become distracting in busy conditions. The test is whether they help crews stay focused during busy operational periods.

As James Shaw explained, “they are an issue at the times when you want maximum focus”, highlighting how poorly timed alerts can undermine crew attention in important moments.

That includes recognising how fatigue and interruption are built into life on board. As Amitvikram Chitnis noted, “people normally sail for anywhere between 4 weeks to 3 months, by the time you adapt to the systems, it’s time for you to move on.” This makes continuity and handover harder than shore-based system designers envision.