May be lettered - no numbers. Retroreflective material of the same colour as required markings. White bouys will display yellow material. Cautionary Anchorage Mooring A cautionary buoy marks dangers such as firing ranges, underwater pipelines, race courses, seaplane bases and areas where no through channel exists. A hazard buoy marks random hazards such as shoals and rocks.
Information concerning the hazard is illustrated within the orange diamond.
Diving A keep out buoy marks areas in which boats are prohibited. An ocean data acquisition system buoy collects meteorological and other scientific data. A diving buoy marks an area where scuba or other such diving activity is in progress. Not normally charted. Swimming A swimming buoy marks the perimeter of swimming areas.