Harbour Master Hannah Van den Berg Identifies Capsized Hull from Miles Away, Enabling Swift Rescue

The moment

In the early hours of a March morning, Hannah Van den Berg was conducting routine surveillance of Dublin Port’s marine traffic control system. The sky was beginning to lighten, and the port’s busy activity was settling into a predictable rhythm. Her role as harbour master involved constant monitoring of AIS (Automatic Identification System) signals and radar echoes to ensure safety and smooth navigation for commercial vessels, fishing boats, and recreational craft.

Suddenly, she observed irregularities in the AIS data: a vessel near the Dublin Bay entrance was transmitting inconsistent signals. Normally, vessels send regular position updates, course, and speed data. This vessel’s AIS signals were sporadic and showed erratic movement. Simultaneously, her radar scans revealed unusual echoes—an object drifting with a shape inconsistent with a properly upright vessel. The radar cross-section fluctuated unpredictably, and the echo was larger than a typical boat, indicating an overturned hull.

Given the proximity to busy shipping lanes and swimmers in the area, immediate action was essential. Hannah recognised that these anomalies pointed to a vessel in distress, and any delay could allow worsening weather or currents to impede rescue efforts. Her training and experience kicked in as she began correlating the AIS anomalies with the radar echoes, quickly forming a mental picture of a capsized vessel in the water.

Why years of experience made the difference

Hannah’s ability to interpret the signals was rooted in over two decades of hands-on experience managing Dublin Port’s marine traffic. She had developed an acute sense for the subtle variations in AIS patterns and radar signatures that distinguish a vessel in normal operation from one in trouble.

This expertise was not merely learned from manuals; it was built through years of observing vessels in a variety of conditions—calm days, rough weather, congested traffic, and emergencies. Hannah had encountered numerous cases where vessels showed unusual AIS behaviour—such as abrupt course changes, inconsistent speed reports, or signals that abruptly ceased—often indicative of mechanical failure or distress. Her familiarity with the typical radar cross-sections of different vessel types, combined with her understanding of how weather and sea conditions could distort signals, enabled her to interpret anomalies accurately.

For instance, she recognised that an overturned hull would produce a distinctive radar echo pattern—a large, irregular, and often fluctuating return—different from the stable echoes of upright vessels. She knew which AIS inconsistencies were early warning signs, such as sudden stop signals or erratic movement, and how these could be correlated with radar echoes to confirm a vessel’s orientation. This pattern recognition, developed over years, was critical; it allowed her to distinguish between false alarms and genuine emergencies swiftly.

Moreover, her familiarity with local maritime geography and currents allowed her to estimate the vessel’s position even with limited visual cues. She could interpret the drift pattern from the AIS and radar data, predicting where the vessel might be located within a few hundred metres. This spatial awareness was vital in directing rescue teams accurately without delay.

What happened next

Using her expertise, Hannah quickly compiled a comprehensive situational report. She flagged the anomalies in the AIS data—specifically, the irregular transmission pattern and sudden cessation—and cross-referenced these with the radar echoes. The large, fluctuating return strongly suggested an overturned hull, and her understanding of the vessel’s likely orientation enabled her to pinpoint an approximate location near the entrance to Dublin Bay.

She immediately issued alerts to the coastguard rescue coordination centre, providing precise coordinates and a detailed description of the vessel’s state. Recognising the urgency, she coordinated with rescue teams, ensuring they understood the nature of the emergency and the likely location of the capsized vessel. Her detailed briefing included the drift pattern, the vessel’s size, and the potential environmental hazards, such as fuel leakage or debris.

Within 45 minutes, rescue teams arrived on scene. They deployed vessels equipped for swift rescue, locating the capsized vessel amid choppy waters. All five crew members were recovered from the water, some clinging to floating debris, within minutes of arrival. The rescue was executed efficiently, with Hannah’s early pattern recognition and precise communication ensuring no time was wasted. The quick response prevented loss of life and minimized environmental pollution risks, as the vessel’s fuel tanks remained intact and contained.

What this tells us

This case underscores how deep, practical expertise in interpreting marine surveillance data can dramatically influence emergency outcomes. The ability to recognize subtle patterns in AIS signals and radar echoes—skills honed through years of experience—can make the difference between a delayed response and a rapid rescue. It highlights that in marine safety, technical knowledge alone is insufficient without the contextual understanding and pattern recognition developed through sustained field practice. Professional expertise remains a critical component in safeguarding lives and the environment at sea.