is used to describe any buoy that is smaller than a
lighthouse buoy and has a tall, central structure on a
broad base. Lighted buoys in the United States are
referred to as pillar buoys.
Topmarks
The IALA Maritime Buoyage System makes use
of can, nun, spherical, and X-shaped topmarks only.
Topmarks on pillar and spar buoys are particularly
important to indicate the side on which they will be
passed and will be used, whenever practical.
Lights
Where marks are lighted, red and green lights are
reserved for port and starboard or starboard and port
lateral marks. Yellow lights are for special marks, and
white lights are used for other types that will be
discussed later in this chapter.
Buoy Color
Under region B of the IALA system, red buoys
mark the starboard side of the channels, or the location
of wrecks or obstructions that must be passed by
keeping the buoy on the starboard (right) hand when
returning from sea. Green buoys mark the port side of
the channels, or the location of wrecks or obstructions
that must be passed by keeping the buoy to port (left)
hand when returning from sea.
Red and green horizontally banded buoys are used
to mark obstructions and channel junctions. They may
be passed on either side, but sometimes the channel on
one side is preferable. If the top band on the buoy is
red, the preferred channel will be followed by keeping
the buoy to starboard. If the top band is green, the
preferred channel will be followed by keeping the
buoy on the port. However, in some instances it may
not be feasible for larger vessels to pass on either side
of such a buoy, and the chart should always be
consulted. The colors indicated above would be
reversed for the region A buoy system.
Red and white vertically striped buoys are
“safe-water marks,” used to indicate the mid-channel,
a fairway, or a landfall. These buoys are also used at
the beginning of some vessel Traffic Separation
Schemes at the entrances to busy ports, or in narrow
passages congested with heavy traffic.
Solid yellow buoys are special-purpose buoys
typically marking anchorage, fishnet areas, and
dredging sites. These buoys have no lateral system
significance; but as most are shown on charts, they can
often serve to assist in determining one's position.
Solid yellow buoys can be any shape.
Buoy Numbering
Most buoys are given numbers, letters, or
combinations of numbers and letters, which are
painted conspicuously on them or applied in white
retroreflective material. These markings facilitate
identification and location of the buoys on the chart.
Solid red or green buoys are given numbers or
combinations of numbers and letters. Other colored
buoys are given letters. Odd numbers are used only on
solid green buoys; even numbers, on solid red.
Numbers increase sequentially from seaward;
numbers are sometimes omitted when there are more
buoys of one type than another.
DAYBEACONS/DAYMARKS
Where daybeacons are substituted for unlighted
buoys, the color of the daymark will be the same and
the shape similar. Red daymarks will be triangular,
approximating the shape of the top of a nun buoy.
Square daymarks, corresponding to can buoys, will be
green.
Daymarks equivalent to spherical buoys are
octagonal. The daymarks on a daybeacon replacing a
yellow special-purpose buoy are diamond-shape.
Daybeacons will be numbered or lettered with
retroreflective material in the same manner as a buoy
and will have a border of that material. Many have
panels of red and green reflective material. Some
channels may be marked with a combination of buoys,
daybeacons, and lights.
LATERAL MARKS
Lateral marks are generally used for well-defined
channels. They indicate the route to be followed and
are used in conjunction with a conventional direction
of buoyage. This direction is defined in two ways, as
follows:
Local direction of buoyage—The direction taken
by a mariner when approaching a harbor, river estuary,
or other waterway from seaward
General direction of buoyage—In other areas, a
direction determined by the buoyage authorities,
following a clockwise direction around continental
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