All buoys are fitted with retroreflective materials that show well when
illuminated with a spotlight, and most buoys are fitted with radar
Retroreflective material is applied to lighted as well as unlighted buoys
to increase their visibility. This application greatly assists you in
locating aids at night using a searchlight. Retroreflective material may
be red, green, white, or yellow; the coloring has the same significance as
the colors of lights.
Many buoys are equipped with radar reflectors, which are vertical metal
plates set at right angles to each other in such a manner as to greatly
increase the echo returned to a radar receiver aboard ship. The plates
are shaped and mounted in order to preserve the overall characteristic
shape of an unlighted buoy or the general appearance of a lighted buoy.
Some buoys have a radar reflector mounted inside the actual body of the
Although buoys are valuable ATONs, you must never depend
exclusively on themthey may fail. Some of the reasons for their
failure are as follows:
Passing vessels may hit a buoy and shift it, overturn it, or set it adrift.
Buoys can drag their moorings in heavy weather.
The light on a lighted buoy may fail or be extinguished.
Sound signals may not function because of ice, storm damage, collisions,
or other accidents.
Whistles, bells, and gongs actuated by the seas motion may fail to
function in smooth water. For these reasons, a prudent mariner must not
rely completely upon the position or operation of buoys, but must also
navigate using bearings from fixed structures and ATONs on shore.