Buoy
Videos
A buoy is a floating device that can have many purposes. It can be anchored or allowed to drift with ocean currents.
Smart buoy with solar panels, LED light, and corner reflectors for radar
Green can #11 near the mouth of the Saugatuck River (IALA region B).
Green Can #11 on a nautical chart
The red buoy (1895), by Paul Signac. The usual red color of the buoys has gained some attention even by artists.
Special mark
Videos
A Special Mark, as defined by the International Association of Lighthouse Authorities, is a sea mark used in maritime pilotage. It is recognisable by its yellow colour and "X" top-mark. If a light is
A Special mark indicating an outfall pipe in the Irish Sea off Helen's Bay, Northern Ireland. It has the group flashing sequence "Fl(2) Y" meaning it flashes yellow twice followed by a longer period of darkness.