Factors Influencing the Performance of Visual Distress Signals

The present paper summarizes efforts undertaken to review the performance characteristics of visual distress signals using light emitting diodes that might replace pyrotechnic-based flare distress signals in the future. Field photometric measurements were made on board a rescue vessel and near the shore at a coastal station to ascertain typical visual environments under which visual distress signals might be viewed, and to understand the visual tasks associated with searching for and detecting these signals. With this information in mind, the literature was systematically reviewed to identify the factors that are likely to influence the performance of visual distress signals, and to provide preliminary guidance regarding the design of visual distress signals constructed with lighting emitting diodes.