New York Safe Boating - 2020 - 59

NAVIGATION

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Learning all aspects of navigation is beyond the scope
of this course. However, all boaters need some basic
knowledge about finding their way on the water. This
section will introduce you to the basic features of a nautical
chart and navigation aids and discusses how weather
pertains to navigation. Boaters can learn more about charts
and enhance their navigation abilities by attending courses
through the US Coast Guard Auxiliary, US Power Squadron,
US Sailing or commercial courses specifically aimed at the
subject.

navigation equipment.
Navigational charts feature coastline characteristics, points
of interest, rocks, wrecks and obstructions, and describe the
type of bottom. Not all waterways have been charted, but
if a chart exists, you can find it at the Office of Coast Survey
of the National Oceanic and Atmospheric Administration, or
NOAA. The web address is:http://nauticalcharts.noaa.gov/.

Compass Rose
Charts are oriented with True North at the top. Nautical
charts usually have one or more compass roses printed on
them. These are similar in appearance to the face of the
compass. Directions on the chart are measured by using the
compass rose.

Introduction to Charts
The art and science of navigation is an ancient skill. For
thousands of years, sailors navigated by using the stars as
their guide. The art of navigation has expanded from using
the stars and planets (celestial navigation) to sophisticated
satellite navigation systems. You won't enjoy boating, and
you won't be a safe boater, if you don't have at least basic
navigation knowledge.

Soundings
Nautical charts describe the characteristics of the bottom of
a body of water, information that is vital to a boat operator.
The chart uses combinations of numbers, color codes, and
underwater contour lines to mark channels, hazards and
other bottom characteristics. The numbers on the chart
represent "soundings," or measurements of the depth of
the water at average low tide. Since the greatest danger to
navigation is during low tide, a number of the depths of low
tide are averaged to produce the average low tide.

The nautical chart is one of the mariner's most useful and
most widely used navigational aids. Navigational charts
contain a wealth of information to you as a boat operator.
They show channels, depth of water, buoys, lights,
lighthouses, prominent landmarks, rocks, reefs, sandbars,
and much more useful information for the safe piloting
of your boat. The chart is the most essential part of all

Contour lines (also called fathom curves) connect points of
roughly equal depth and provide a profile of the bottom.
These lines are either numbered or coded according to
depth using particular combinations of dots and dashes.
Generally, the shallow water is tinted darker blue on a chart,
while deeper water is tinted light blue or white. Depth of
water may either be in feet, meters or fathoms (a fathom
equals six feet). The chart legend will indicate which unit
(feet, meters or fathoms) is used.

Navigational Chart

Symbols for Buoys
The basic symbol for a buoy, which is an aid to navigation
and is discussed in depth in the next section, is a diamond
and small circle. The small circle denotes the approximate
position of the buoy mooring. The diamond is used to draw
attention to the position of the circle and to the description
of the aid. The initials "N" or "C" will indicate the shape of
the buoy: (N) Nun Buoys, and (C) Can Buoys. If the buoy is
painted red, the diamond will usually be indicated in red on
the chart; if the buoy is painted green, the diamond will be
green and so on. Other markings by the buoy symbol may
indicate a buoy identifier, a sound signal, or note that it is a
lighted buoy.

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