A Special Mark is the name given to a sea mark that is designed to show the boundary of an area (such as for speed limits, waterskiing or where no mooring is permitted), may be used to show a feature such as the end of an underwater pipe, or could be used as a monitoring point for meteorological or tidal data.

There is usually no way of telling the nature of the mark by the buoy itself, and so a chart of the area is necessary to clarify its significance (if any).

Light Characteristics