The Intracoastal Waterway (ICW) is a largely sheltered waterway,
suitable for year-round use, extending some 2,400 miles along the
Atlantic and Gulf Coasts of the United States. In general, it follows
ATONs along the ICW have some portion of them marked with yellow.
Otherwise, the coloring and numbering of the ATONs follow the same
system as that in other U.S. waterways.
So vessels may readily follow the ICW, special markings consisting of
yellow triangles and squares are employed. When you are following the
ICW from the north along the Atlantic Coast and west along the Gulf
Coast, aids displaying yellow triangles should be kept to starboard; those
aids displaying yellow squares should be kept to port, regardless of the
color of the aid on which they appear. Nonlateral aids in the ICW, such
as ranges, safe-water, and other nonlateral daymarks, will be identified
by the addition of a yellow stripe instead of a triangle or square.
The conventional direction of buoyage in the ICW is generally southerly
along the Atlantic Coast and generally westerly along the Gulf Coast.
Aids to navigation on the western rivers of the United States--the
Mississippi River and its tributaries above Baton Rouge, Louisiana, and
on other certain rivers that flow towards the Gulf of Mexico--are
generally similar to those on other U.S. waters, but there are a few
differences that should be noted (see fig. 4-17).
ATONs are not numbered. Numbers on ATONs do not have lateral
significance, but instead, indicate mileage from a fixed point.
Diamond-shaped crossing daymarks, red or green as appropriate, are
used to indicate where the river channel crosses from one bank to
Lights on green aids show a single flash, which may be green or white.
Lights on red aids show a double flash, which may be red or white.
Isolated danger marks are not used.
This concludes or discussion on ATONs and the buoyage system. We
now have information on the road signs of the nautical road. We can
now take a look at the traffic laws, or as they are known, the Rules of