Modern electronics can bring rescuers remarkably close to a casualty, but the last stage of finding the actual person or vessel can still be difficult. That is where visual location remains important.
A distress alert tells someone that help is needed. Systems such as VHF DSC and EPIRBs can also provide useful position information. That can guide a lifeboat, aircraft or nearby vessel towards the casualty.
Once the rescue asset reaches the area, a different problem begins. The crew still needs to see the correct vessel, liferaft or person among waves, spray, darkness and background lights.
GPS accuracy is excellent, but a small object can still be difficult to see. Sea state moves both the casualty and the rescuer. A yacht may be visually lost against a dark coastline, while a person in the water presents an even smaller target. At night, harbour lights and navigation marks can add visual clutter.
A distinctive, high-output light can provide a clear visual reference once search crews are close enough to see it. This is why the RYA discusses EVDS as useful locating devices, particularly in the final mile of a rescue.
The current RYA guidance is available on its Electronic Visual Distress Signals page.
Peak intensity is important, especially in daylight, but beam angle, flash pattern, colour and the background all influence whether a signal catches the eye. A moving vessel also means the beam cannot be assumed to stay perfectly aligned with the observer.
The strongest approach is to use equipment with complementary roles. Alerting technology can call for help and transmit position. Visual equipment can help identify the casualty as rescuers approach. Crew procedures, communications and redundancy tie those layers together.
UltraFlare Daylight is designed for this visual location role, using controlled beam geometry, SOS and triple-flash modes and independently measured high luminous intensity. See the technical details or read how EVDS fits into a UK marine safety plan.