COLREGs Part D: Sound and Light Signals — The Language of Warning at Sea
Understanding Rules 32–37 for Safe Communication Between Vessels When visibility becomes poor, ships cannot depend entirely on visual observation. Fog, heavy rain, darkness and other conditions can make it difficult to identify another vessel or determine its intentions. In these situations, sound and light signals become an essential part of communication at sea . Part D of COLREGs covers Rules 32–37 , dealing with sound and light signals. The six rules cover the definitions of whistle signals, sound-signalling equipment, manoeuvring and warning signals, restricted-visibility signals, attention signals and distress signals. For a seafarer, learning Part D is not simply about memorising patterns of short and prolonged blasts. The real objective is to understand what a signal means, when it should be used, how it should be interpreted and how it fits into the overall navigational situation . Rule 32 — Definitions Before understanding the individual signals, COLREGs first est...