A buoyage system consists of fixed, floating, lighted, and unlighted
ATONs. These aids are used to mark waterways. There are two
buoyage systems that are in use throughout the world-the lateral
system and the cardinal system.
In the lateral system, aids are placed to mark the sides of a navigable
channel. They also mark junctions and bifurcations, indicate the safe
side on which to pass hazards, and mark the general safe centerline of
wide bodies of water.
In U.S. waters, a vessel returning from seaward and proceeding toward
the head of navigation is generally considered as moving southerly along
the Atlantic Coast, westerly along the Gulf Coast, and northerly along
the Pacific Coast. This is what is known as the "conventional direction"
of buoyage. Virtually all U.S. lateral marks are located in what is
known as IALA region B and follow the traditional "red right returning"
Cardinal System In the cardinal system, aids generally mark the geographic relationship
to the aid of a hazard in terms of 90-degree quadrants centered on the
cardinal directions of north, east, south, and west. The cardinal system
is not widely used in the United States and will not be discussed in this
text. For more information on the cardinal system, consult Dutton's
Navigation and Piloting or Bowditch.