2015 New York Safe Boating - 59

NAVIGATION

12
Compass Rose

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,	
or commercial courses specifically aimed at the subject.

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.

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.

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

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.

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.

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.
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
navigation equipment.

Aids to Navigation

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/.

Waterways, just as roads, are marked to provide direction,
advise caution and to point out specific hazards.
Understanding the waterway marking systems is important
as these markers will assist in navigation, mark safe waters,
and convey important information to the skipper. Aids to
Navigation systems use red and green markers to indicate the
right and left sides of the channel.
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http://www.cgaux.org/ http://www.usps.org/index.html/ http://www.uscgboating.org/ATON/index.html http://nauticalcharts.noaa.gov/ http://www.uscgboating.org/ATON/index.html
2015 New York Safe Boating

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