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.
Sea mark
Videos
A sea mark, also seamark and navigation mark, is a form of aid to navigation and pilotage that identifies the approximate position of a maritime channel, hazard, or administrative area to allow boats,
The Ketch Popoff, approaching Concarneau harbour and passing between the sea mark buoys of the entrance, while an approaching trawler in the background sails around the red buoy
Inland sea mark on Ashey Down, Isle of Wight, built in 1735 and now a historical monument
Red buoy in San Diego Harbor, with a light, number, and radar corner reflectors.