Spoil ground marks
Military exercise zone marks
Cable or pipeline marks, including outfall pipes
Recreation zone marks
Another function of a special mark is to define a
channel within a channel (for example, a channel for
deep-draft vessels in a wide approach area where the
limits of the channel for normal navigation are marked
by red and green lateral buoys).
Yellow is the color used for special marks. The
shape of a special mark is optional but must not
conflict with a lateral or a safe-water mark.
When a topmark is carried, it takes the form of a
single yellow X. When a light is exhibited, it is yellow.
The phase light characteristics may be any other than
those used for white lights of cardinal, isolated danger,
and safe-water marks.
A newly discovered hazard to navigation, not yet
shown on charts or included in Sailing Directions or
sufficiently announced by Notices to Mariners, is
called a new danger. New danger covers naturally
occurring obstructions, such as sandbanks and rocks,
or man-made dangers, such as wrecks.
A new danger is marked by one or more cardinal
or lateral marks, following the IALA Maritime
Buoyage System guidelines. If the danger is especially
grave, it will be marked by two marks that are identical
until the danger has been announced.
If a lighted mark is used for a new danger, it must
be a quick flashing or very quick flashing light. If it is
a cardinal mark, it must exhibit a white light; if a
lateral mark is used, it must exhibit a red or green light.
AIDS IN THE INTRA
The Intracoastal Waterway, called the inland
waterway, is a channel in which a lightdraft vessel can
navigate coastwise from the Chesapeake Bay almost
to the Mexican border, remaining inside natural or
artificial breakwaters for almost the entire length of
the trip. The following paragraphs describe special
markings for the Intracoastal Waterway proper and for
those portions of connecting or intersecting
waterways that must be crossed or followed in
Every buoy, daymark, or light structure along the
Intracoastal Waterway has part of its surface painted
yellow, the distinctive coloring adopted for this
waterway. Lighted buoys have a band or border of
Red buoys and daymarks are to the right, and
green to the left, as you proceed from the Chesapeake
Bay toward Mexico. As in other channels, red buoys
have even numbers; green buoys, odd numbers.
Because the numbers would increase excessively in
such a long line of buoys, they are numbered in groups
that usually contain no more than 200 buoys. At
certain natural dividing points, numbering begins
again at 1.
Lights on buoys in the Intracoastal Waterway
follow the standard system of red or white lights on
red buoys, and green lights on green buoys. Lights on
lighted aids besides buoys also agree with the standard
rules for lights on aids to navigation.
Two daybeacons located some distance apart on a
specific true bearing constitute a daybeacon range.
Two lights similarly located comprise a lighted range.
When a ship reaches a position where the two lights
or beacons are seen exactly in line, it is on the range.
Ranges are especially valuable for guiding ships along
the approaches to or through narrow channels.
Lights on ranges may show any of the four
standard colors, and they may be fixed, flashing, or
occulting, the principal requirement being that they
stand out distinctly from their surrounding. Range
light structures are usually fitted with colored
daymarks for daytime use. Range lights appear to lose
brilliance rapidly as a ship veers from the range line
Ranges should only be used after a careful
examination of the charts; it is particularly important
to determine how far the range line can be followed
safely. This information is available on the chart.
Most lighthouses, light towers, and large
navigational buoys are equipped with fog-signaling
apparatus, generally sounded automatically by
mechanical means. For purposes of identification,
each station has its own assigned number of blasts,
recurring at specified intervals. A definite time is
required for each station to sound its entire series of
blasts, providing additional identification.