deep-draft vessels in a wide-approach area where the
mark may be used as a center line buoy, a midchannel
buoy, or a landfall buoy.
limits of the channel for normal navigation are marked
by red and green lateral buoys).
Red and white vertical stripes are used to indicate
safe water marks. The vertical stripes distinguish them
Yellow is the color used for special marks. The
from the black-banded danger marks. Spherical, pillar,
shape of a special mark is optional, but it must not
or spar buoys may be used as safe water marks.
conflict with a lateral mark or a safe water mark. For
Whenever practical, a pillar or spar buoy used as a safe
example, an outfall buoy on the port side of a channel
water mark will carry a single red sphere topmark.
could be can-shaped but not conical.
When lighted, a safe water mark exhibits a white
When a topmark is carried, it takes the form of a
light. The phase characteristics of the light may be
single yellow X. When a light is exhibited, it is yellow.
occulting, equal interval (isophase), one long flash
The phase characteristics may be any except those used
every 10 seconds, or Morse "A."
for the white lights of cardinal, isolated danger, and safe
special area or feature. You can find the nature of the
A newly discovered hazard to navigation, not yet
special area or feature by consulting the chart, Sailing
shown on charts or included in Sailing Directions or
Directions, or Notice to Mariners. The uses of a special
sufficiently announced by Notice to Mariners, is called
mark include the following:
a "new danger." The term new danger covers naturally
Ocean Data Acquisition System (ODAS) buoys
occurring obstructions, such as sandbanks or rocks, and
carrying oceanographic or meteorological
man-made dangers, such as wrecks.
A new danger is marked by one or more cardinal or
Traffic separation marks
lateral marks following the IALA Maritime Buoyage
System. When the danger is especially grave, it will be
Spoil ground marks
marked by marks that are identical until the danger has
Military exercise zone marks
been sufficiently announced.
When a lighted mark is used for a new danger, it
Cable or pipeline marks, including outfall pipes
must exhibit a quick flashing or a very quick flashing
Recreation zone marks
light. When it is a cardinal mark, it must exhibit a white
light. When it is a lateral mark, it must exhibit a red or
Another function of a special mark is to define a
channel within a channel (for example, a channel for
Figure 6-26.--IALA Maritime Buoyage System, special marks.