Fundamentals of

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• Fundamentals of
• Naval Science

Visual Navigation Aids
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Objectives
1. Describe the major types of aids to
navigation. 2. Describe buoy types, colors,
numbers, and purpose. 3. Discuss and
compare the IALA A and B buoyage
systems, including lateral and cardinal
marks.
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Objectives
4. Describe the attributes of a lighted aid to
navigation. 5. Describe the chart symbols
for aids to navigation. 6. Discuss use of
lights and buoys in piloting.
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Types of Aids to Navigation
Buoys - The most plentiful NAVAID. Serve a
variety of purposes depending on their color,
type, and number. Lights - Fixed NAVAIDS that
have powerful lanterns with distinctive
characteristics that make them identifiable at
night.
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Types of Aids to Navigation
Lights - Two types Major - Light used to
mark landfall or to mark a harbor or
river entrance. Minor - Light used to mark
a specific channel or location. Care
should be taken NOT to confuse minor
lights with lighted buoys.
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Types of Aids to Navigation
Ranges - Pairs of NAVAIDS, either lighted or
unlighted, when aligned, normally mark a
channel. Daymarks - Fixed structures that mark
hazards or channels, but do not have lights.
May have a fog signal to provide a signal
during periods of low visibility.
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Range Lights
On the Range
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Visual Range
Out of Range
On the Range
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Beacons

• Fixed NAVAIDS used in U.S. waters
• Each has daymark ( or ) to denote
  right or left-side channel boundary
• Safe water and preferred channel daymarks are
  open triangles with appropriate color schemes
• Beacons may be unlighted (daybeacons) or lighted

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Typical Beacons
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Types of Aids to Navigation
Radio Beacon - NAVAIDS which emit a
distinctive signal on a specific freq. and, when
used with a direction finding receiver, will
yield an LOP. Racons - Signals, usually on
lights or buoys, that are triggered by a
ships radar and appear as a symbol on the
radar screen.
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General Buoyage Classification
Lateral - Used to indicate which side the buoy
should be passed and are used to mark
channels. Cardinal - Indicate which direction
the buoy should be passed and usually mark
hazards to navigation. The U.S. does NOT use
Cardinal Buoys, but you can expect to see them
in foreign ports of call.
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Systems of Buoyage

• Lateral
• Cardinal

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Buoy Description and Purpose
Can Buoy - In the shape of a tin can and is
flat across the top. A can buoy marking a
channel will always be on the port side of the
channel when returning from sea. Nun Buoy -
Resembles a cone. A nun buoy marking a
channel will always be on the STBD. side of
the channel when returning from sea.
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Can Buoy
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Nun Buoy
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Sound Buoys

• Bell
• Gong
• Whistle
• Horn

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Lighted Buoys

• Metal float on which short skeleton tower is
  mounted

Tower supports lantern powered by electric
batteries in body of the buoy
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Combination Buoys

• Any buoy in which a light and a sound signal are
  combined
• Examples include
• Lighted bell
• Lighted gong
• Lighted whistle
• Lighted horn

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Buoy Description and Purpose
Buoys are painted different colors according to
their purpose. Lateral Aids - Either red or
green or the combination of the
two. Cardinal Aids - Painted black and yellow.
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Lateral Buoys
Lateral Buoys are painted either red or green,
or a combination of the two. Numbered from
seaward, meaning the numbers rise as you approach
land.
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Channel Buoys
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6
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Cardinal Buoys

• Topmarks

N
E
S
W
Color Scheme
BY
BYB
YB
YBY
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Buoy Description and Purpose
Safe Water Marks - Usually indicate the center
of a channel, are usually painted with red and
white vertical stripes. Special Marks - Painted
yellow. Isolated Danger Marks - Painted black
and red.
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Special Buoys

• Used to mark
• Prohibited areas
• Limits of fish traps
• Cable crossings
• Anchorages
• Color is yellow
• Usually unlighted

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Buoyage Systems
There are two buoyage systems in the world today
IALA A and IALA B. International Association
of Lighthouse Authorities (IALA)
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Buoyage Systems
IALA B memory aids Red
Right Returning Even Red Nuns have Odd
Green Cans
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Lights and Lighted Buoys

• Used to provide the mariner with aids to
  navigation at night.

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Light Attributes

• Color
• Phase Characteristics
• Period

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Color

• Color of light during time it is
• shining
• Common colors

White
Red
Green
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Phase Characteristic

• Light sequence or pattern of light shown within
  one complete cycle of the light.

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Phase Characteristics
F. Fixed
F.Fl. Fixed and flashing
F.Gp.Fl. Fixed and group flashing
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Phase Characteristics
Fl. Flashing
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Phase Characteristics
I.Qk.Fl. Interrupted quick flashing
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Period

• Length of time required for light to progress
  through one complete cycle

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Lights and Lighted Buoys
Lateral and Channel Buoys - Are always red or
green with flashing phase characteristics. U.S.
Safe Water Marks - Show a white light with
Morse Alpha ( ) with a period of
about eight seconds.
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Lights and Lighted Buoys
Fixed Lights and Lighthouses - Show a wide
variety of phase characteristics, lights, and
colored sectors, primarily to distinguish then
from the background lights of the shore.
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Chart Symbols
Buoys - Marked by a small diamond, the color
of which is the color of the buoy (the color is
also indicated by an abbreviation). - If the
buoy is unlit, it will also indicate the shape
with an N for nun, and a C for can. -
Lighted buoys will be distinguished by a small
magenta circle at the base of the diamond.
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Chart Symbols
Lighted Buoys - Are distinguished by a small
magenta circle at the base of the diamond. -
Attributes of the light are displayed on the
chart with an R for red, and G for green.
If no light is indicated, the light is white. -
The phase characteristic is indicated with
abbreviations
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Chart Symbols
Lights - Period is shown in seconds. - Height
of the light and is nominal range in nautical
miles is also shown.
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10
Mast
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Aids To Navigation
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Using Buoys and Lights in Piloting
Buoys should never be used to fix your
position! - Are anchored in place using chain
that is usually three times the depth of water,
and thus they actually move in small circles
around their mooring. - Storms and collisions
with vessels may move buoys from their assigned
positions.
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Using Buoys and Lights in Piloting
Lights and Lighthouses - Are fixed and provide
for good visual fixing both during the day and
at night.
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Review Questions
NONE