Figure 5-19.IALA Maritime Buoyage System, Buoyage Regions A and B.
4. Safe water marksused to indicate that there is
water safe for navigation all around the position
(examples: midchannel and fairways).
5. Special markscall attention to an area or
specific feature. Explanation of special marks may be
found on the navigational chart you are using, in Sailing
Directions, or in Coast Pilots.
The meaning of the mark depends upon one or more
of the following features:
1. By daycolor, shape, and topmark
2. By nightlight color and phase characteristics
COLOR. The colors used for lateral marks in
Region A are red, green, green with one red horizontal
band, and red with one green horizontal band.
The colors used for lateral marks in Region B are
green, red, red with one green horizontal band, and
green with one red horizontal band.
SHAPE. There are five basic buoy shapes (fig.
5-20): can, nun, spherical, pillar, and spar. With the
exception of pillar and spar buoys, the shape of the buoy
indicates the correct side on which to pass. Can buoys
may sometimes be referred to as cylindrical, and nun
buoys referred to as conical. The term pillar is used to
describe any buoy that is smaller than a lighthouse buoy
Figure 5-20.Basic buoy shapes.
but 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 wherever practical.
LIGHTS. Where marks are lighted, red and green
lights are reserved for port and starboard or starboard