1. CHAPTER 1
NAUTICAL RULES OF THE ROAD

2. Nautical traffic laws
are known as the
Nautical Rules of
of the Road.

3. International Inland
Nautical Rules of the Road were first
established in 1897 by all maritime
nations of the world. The latest major
revision was in 1972.

4. International Rules of the Road
The official name is The International
Regulations for Preventing Collisions
at Sea, 1972, or ―the 72 COLREGS.‖

5. Convention on the International
Regulations for Preventing Collisions
at Sea, 1972 (COLREGs)
The COLREGs include 38 rules divided
into five sections:
• Part A - General
• Part B - Steering and Sailing
• Part C - Lights and Shapes
• Part D - Sound and Light Signals
• Part E - Exemptions

6. Inland Waters – Unified Rules
The inland rules for the U.S. were
established by Congress under The
Inland Navigational Rules Act of 1980.

7. Purpose of
the Rules
Prevent
Collisions

8. The rules govern all
waterborne traffic.

9. Power Vessel
Propelled by
machinery, even
if under sail
Sailing Vessel
Under sail alone,
even if machinery
is aboard

11. A vessel is underway
when not:
• Anchored
• Moored to a dock
or buoy
• Aground

12. Underway
A vessel that is not anchored,
moored, or aground
It is not required that you are
moving or making way.

13. Both international and inland rules of
the road cover:
• Lights and shapes
• Sound signals
• Steering and sailing rules
• Distress signals

14. Maritime courts
of law use both
international and
inland rules after
a collision to
decide who will
pay for damages.

15. Display lights from sunset to sunrise
and in periods of restricted visibility.
Do not display lights that could be
mistaken for required lights.

16. Running Lights
(Port, Starboard, and Stern)

17. Running Lights
(Masthead and Range)

18. Running Lights
Any of various lights required to
be displayed by vessels operating
between sunset and sunrise

19. Running lights are white, red, and
green lights carried by all seagoing
power-driven vessels underway.

20. Masthead Light
225°
The white light in the fore part of the ship
is required for all ocean-going ships.

21. Masthead Light
(Vessels less
than 12 meters,
39 feet)
360°
All-around white light.

22. Range Light
(Vessels over 50 meters or 150 feet)
Range Light
(15 feet higher than
Masthead Light)
Masthead Light

23. Stern Light
12 Pts.
135°
A ship underway must display a white
stern light.

24. Port
112.5°
112.5°
Starboard
Running Lights

25. What side of a vessel is called the port
side, and what color is its sidelight?
What side of a vessel is called the
starboard side, and what color is its
sidelight?

26. What side of a vessel is called the port
side, and what color is its sidelight?
Left and red
What side of a vessel is called the
starboard side, and what color is its
sidelight?
Right and green
An easy way to remember is
―Port wine is red.‖

27. Arc of Visibility
The angular dimension (horizontal
arc in degrees) within which a light
can be seen from a location off the
vessel

28. What is the required arc of visibility, in
degrees, of the following ship’s lights?
Masthead light:
Sidelights:
All-around light:
Stern light:

29. What is the required arc of visibility, in
degrees, of the following ship’s lights?
Masthead light: 225°
Sidelights: 112.5°
All-around light: 360°
Stern light: 135°

30. The white masthead and range lights, together with
sidelights, indicate the course of the sighted ship.

31. The white stern light warns overtaking
ships that another ship is ahead.

32. ―Reading‖ Navigation Lights
(Vessels Underway)

33. ―Reading‖ Navigation Lights
(Vessels Underway)
S
B T
O E
W R
N
STAR-
PORT BOARD

34. The upper white lights must be visible
from a distance of at least 5 miles.

35. The port and
starboard sidelights
and the stern light
must be visible at
least 2 miles away.

36. International Maritime Organization (IMO)
The international and inland rules agree
in the arcs of visibility required by the
lights shown.

37. Power-driven motorboats
• Range light optional
• Masthead light visible for at least 3 miles
• Stern and sidelights visible for 1 mile

39. Pilot Boat

40. Pilot Boat
A boat carrying pilots to or from
large ships

41. Pilot Boat
―White over red, pilot ahead‖
is a memory aid used when
looking for a pilot boat.

42. Pilot Boat
A vessel engaged in pilotage duties may
sound an optional identity signal of four
short blasts on its horn.

44. Vessel at Anchor
Ships less than 50 meters in length at anchor
show an all-around white light forward.
Ships more than 50 meters in length show an
all-around white light forward and aft.

45. Vessel at Anchor
Dayshape
In daytime, vessels
at anchor must display
a black ball, known as a dayshape.

46. Dayshape
Vessel at Anchor

48. Vessel Towing

49. Vessels towing must:
• Display two masthead lights in
a vertical line.
• If the tow extends beyond 200
meters, a third light must be
added below the second light.

51. Vessel Not under Command
A ship or craft that is disabled and
cannot operate in accordance with
the Rules of the Road

52. Vessel Not under Command
Day
Shape
Not Making Way

53. Vessel Not under Command
Day
Shape
Making Way

54. A ship not under command at night must show
two red lights, one over the other. They must be
visible all around the horizon at a distance of 2
miles.

55. Vessels Not under
Command during
Daylight
Merchant ships will hoist two
black balls.
Naval vessels will hoist the
―5‖ flag and two black balls.

57. Other lights and day shapes are
prescribed for various operations
such as:
• Commercial fishing
• Cable laying
• Underwater or diving operations
• Dredging
Some examples of day shapes follow.

58. Special Rules for Naval Vessels
The horizontal separation of white lights
on destroyers and smaller ships is often
less than that required by the rules.

59. The white lights on aircraft carriers are
usually on the superstructure and off the
centerline.
Special lights such as speed lights,
carrier-landing lights, and colored
recognition lights may be shown on
naval vessels during certain operations.

60. During ship exercises, naval vessels
may show no lights at all.
In peacetime, however, if a merchant ship
approaches, lights are usually turned on.

61. When lights are required, the three black
balls are replaced with three green lights.
MINESWEEPER

62. Amber-colored intermittent flashing
beacon – 3 seconds on – 3 seconds
off when submarine running surfaced,
in addition to other required lights

63. Whistle Signals
Whistle signals are required by both sets
of rules for vessels maneuvering within
sight of one another.

64. INLAND
RULES
Signifies intention only. A response
IS required.

65. INTERNATIONAL
RULES
Signifies execution of maneuver.
A response is NOT required.

66. Duration Times for
Whistle Signals
Short Blast: TOOT
I 1 second I
Prolonged: T - O - O - T
I 4 - 6 seconds I
Long Blast: T – O – O – T
I 8 - 10 seconds I

67. INTERNATIONAL
1 Short Blast:
―I am altering
my course to
starboard.‖

68. INTERNATIONAL
2 Short Blasts:
―I am altering
my course to
port.‖

69. INTERNATIONAL
3 Short Blasts:
―My engines are
going astern.‖

71. INTERNATIONAL - INLAND
5 Short Blasts:
―DANGER!’

72. Confusion over whistle signals probably
causes more collisions than any other
part of the rules of the road.

73. Both international and inland rules
consider the situation in which two
ships are approaching each other
with the risk of collision. They are:
• Meeting
• Overtaking
• Crossing

74. Give-Way Vessel — Must keep clear
Stand-On Vessel — Has the right of way

75. The risk of a collision exists when
the bearing of an approaching vessel
remains constant.

76. A collision at sea can ruin your whole
day.

78. General Rules to Avoid Collision
1. Take action in ample time.
2. Make the passing agreement
signals.
3. Make obvious changes.
4. Check and recheck your actions
until clear of other vessels.
5. If necessary, stop or reverse your
engines.

79. INLAND
Meeting One Short Blast
Situation Port to Port
Give-way
Vessel
Give-way
Vessel

80. INTERNATIONAL
Meeting Two Short Blasts
Situation Starboard to Starboard
Only done if it is clearly the most convenient,
safe maneuver for both vessels.
Give-way
Vessel
Give-way
Vessel

81. INTERNATIONAL
Meeting Two Short Blasts
Situation Starboard to Starboard
It is implied that a starboard-to-starboard
passing is only proper when there is no risk
of collision.
There is an old nautical saying that
warns: ―Two short blasts are the first
two notes of the collision waltz.‖

82. In U.S. Inland Waters
Starboard-to-starboard passing is
authorized only if the ships are not
meeting end-on and safe passage is
assured without any maneuvering.

83. INTERNATIONAL
Crossing Situation
Stand-on
Vessel
The give-way vessel is
Give-way required to maneuver to
Vessel avoid crossing ahead of
the stand-on vessel.

84. INTERNATIONAL
Crossing Situation
Stand-on
Vessel
This means reducing
Give-way speed, stopping, altering
Vessel course to starboard, or
backing down.

85. INTERNATIONAL
One Short Blast
Crossing Two Short Blasts
Situation Three Short Blasts
Stand-on
Vessel
Give-way
Vessel

86. Overtaking Situation
In inland waters, the overtaking vessel
must signal on which side it intends to
pass; one blast to starboard and two
blasts to port.
It cannot pass until it hears the same
signal from the overtaken vessel.

88. INTERNATIONAL
Overtaking Situation
In international waters, a ship that can pass
another without a change of course may do
so without a signal.

89. INTERNATIONAL
Overtaking Situation
If overtaking vessel must change course to
pass, she sounds one short blast if turning
to the right, or two short blasts if turning to
the left, and does not have to wait for an
answer.
Vessel being overtaken may respond with 5
or more short blasts if she considers
proposed maneuver dangerous.

90. Overtaking Situation
I An overtaking vessel must give a signal
N whether or not she must change course
L to pass, and she may not pass until she
A hears the agreeing signal from the vessel
N ahead.
D
The signals are one short blast if
proposing to pass the other vessel on her
R starboard side, and two if proposing to
U pass on her port side.
L
E
S

91. Overtaking Situation
I
N DANGER
L
A
N
D Vessel being overtaken
responses with 5 short
blasts indicating danger
R to port.
U
L Overtaking vessel
indicates overtaking This is followed by a signal for
E on the port side by what is considered the safer
procedure and the overtaking
S 2 short blasts.
vessel answers signal and
passes on the correct side.

92. Avoid Collision – ―In Extremis‖
A vessel may depart from the requirements
of the rules of the road when there is
imminent danger of collision. Such a
danger of collision is called ―in extremis.‖

93. A ship’s captain is
required to use good
judgment to avoid
collision even if the
action might violate
the rules.

94. Fog Signals Underway
Inland Rules
Prolonged blast 4 to 6
seconds on the whistle
at 1-minute intervals
International Rules
Prolonged blast 4 to 6
seconds on the whistle
every 2 minutes

95. Inland Rules
Fog Signal at Anchor
Ring the bell for about
5 seconds at 1-minute
intervals.

96. In restricted visibility, you must:
Go at a safe speed.
Maintain a proper look-out.
Display navigation lights.

98. If you hear a fog signal forward of your
beam:
Reduce speed to bare steerageway.

99. Steerageway
The minimum speed at which the
rudder is effective
or
The minimum speed at which your
vessel can be kept on course

101. Distress Signals
for
Inland & International Rules
FOGHORN GUN FIRED AT FLAMES ON
CONTINUOUS INTERVALS A VESSEL
SOUNDING OF 1 MINUTE (NIGHT ONLY)

102. NAUTICAL RULES OF THE ROAD
THE END

103. Distress Signals
for
International Rules
Gun Fired at 1-Minute Intervals

104. Distress Signals
for
International Rules
Continuous Sounding of Foghorn

105. Distress Signals
for
International Rules
Rockets or Shells

106. Distress Signals
for
International Rules
SOS

107. Distress Signals
for
International Rules
Signal ―MAYDAY‖ by Radio

108. Distress Signals
for
International Rules
Flaghoist with November Charlie

109. Distress Signals
for
International Rules
Square Flag and Ball

110. Distress Signals
for
International Rules
Flames from Tar or Oil Barrel

111. Distress Signals
for
International Rules
Parachute Flare

112. Distress Signals
for
International Rules
Smoke Signal

113. Distress Signals
for
International Rules
Wave Arms

114. Q.1. Name the two sets of rules of
the road used by ships in the
United States.

115. Q.1. Name the two sets of rules of
the road used by ships in the
United States.
A.1. The International Regulations
for Preventing Collisions at
Sea, 1972, and The Inland
Navigational Rules Act of
1980

116. Q.2. What is the purpose of the rules
of the road?

117. Q.2. What is the purpose of the rules
of the road?
A.2. To prevent ship collisions

118. Q.3. How can you determine if risk
of collision exists?

119. Q.3. How can you determine if risk
of collision exists?
A.3. If the compass bearing of an
approaching vessel does not
appreciably change as the
range decreases (―constant
bearing decreasing range‖)

120. Q.4. What do the rules of the road
cover?

121. Q.4. What do the rules of the road
cover?
A.4. Lights and shapes, sound
signals, steering and sailing
rules, and distress signals

122. Q.5. Explain the difference between
power-driven and sailing
vessels.

123. Q.5. Explain the difference between
power-driven and sailing
vessels.
A.5. A power-driven vessel is one
that is being propelled by
machinery even if she is
equipped with sails. A sailing
vessel is any vessel which is
being propelled by sail alone.

124. Q.6. What is the definition of
―underway?‖

125. Q.6. What is the definition of
―underway?‖
A.6. Any vessel not at anchor;
moored to a buoy or dock or
not aground

126. Q.7. What additional white light
must be shown for vessels 50
meters or more in length?

127. Q.7. What additional white light
must be shown for vessels 50
meters or more in length?
A.7. A range light

128. Q.8. Name the colors of the lights
used aboard ships.

129. Q.8. Name the colors of the lights
used aboard ships.
A.8. White, red, and green (and
amber for special
circumstances)

130. Q.9. What color is the masthead
light?

131. Q.9. What color is the masthead
light?
A.9. White

132. Q.10. State the colors of the port
and starboard sidelights.

133. Q.10. State the colors of the port
and starboard sidelights.
A.10. Red on the port, green on the
starboard

134. Q.11. Why are special rules made
for lights on naval vessels?

135. Q.11. Why are special rules made
for lights on naval vessels?
A.11. Construction and mission
requirements

136. Q.12. What is the meaning of one
short blast of a ship's whistle
in international waters?

137. Q.12. What is the meaning of one
short blast of a ship's whistle
in international waters?
A.12. I am changing course to
starboard.

138. Q.13. What is the whistle signal for
danger?

139. Q.13. What is the whistle signal for
danger?
A.13. Five or more short blasts

140. Q.14. What is the meaning of one
short blast of a ship’s whistle
in inland waters?

141. Q.14. What is the meaning of one
short blast of a ship’s whistle
in inland waters?
A.14. It is a signal of intention to
pass port to port and only
executed if acknowledged by
the other vessel.

142. Q.15. When is a vessel required to
fly the national ensign upside
down as a signal?

143. Q.15. When is a vessel required to
fly the national ensign upside
down as a signal?
A.15. Never

144. Q.16. According to the rules, what is
the vessel called that must
take action in any given
situation?

145. Q.16. According to the rules, what is
the vessel called that must
take action in any given
situation?
A.16. Give-way

146. Q.17. Briefly explain what the Rule
of Good Seamanship states.

147. Q.17. Briefly explain what the Rule
of Good Seamanship states.
A.17. A ship's master must
exercise professional
judgment and may deviate
from the rules if a possible
dangerous situation arises

148. Q.18. In a crossing situation, which
vessel is the stand-on vessel?

149. Q.18. In a crossing situation, which
vessel is the stand-on vessel?
A.18. The vessel to the starboard
of the other

150. Q.19. In a meeting situation, which
vessel is the stand-on vessel?

151. Q.19. In a meeting situation, which
vessel is the stand-on vessel?
A.19. Neither, they are both
designated give-way vessels

152. Q.20. In an overtaking situation,
which vessel is the stand-on
vessel?

153. Q.20. In an overtaking situation,
which vessel is the stand-on
vessel?
A.20. The vessel being overtaken
(passed)

154. Q.21. What signal must a vessel
sound if, when rounding a
bend, it is unable to see for at
least ½ mile?

155. Q.21. What signal must a vessel
sound if, when rounding a
bend, it is unable to see for at
least ½ mile?
A.21. A prolonged blast of its
whistle (4 to 6 seconds)

156. Q.22. What do two short blasts of a
ship's whistle signal in
international waters?

157. Q.22. What do two short blasts of a
ship's whistle signal in
international waters?
A.22. Changing course to port

158. Q.23. What do three short blasts of
a ship's whistle signal?

159. Q.23. What do three short blasts of
a ship's whistle signal?
A.23. Engine backing (going
astern)

160. Q.24. In conditions of reduced
visibility, what signal does a
power-driven vessel underway
and making way sound?

161. Q.24. In conditions of reduced
visibility, what signal does a
power-driven vessel underway
and making way sound?
A.24. One prolonged blast at least
every 2 minutes

162. Range Light
The white light on the aftermast
of vessels 50 meters or more

163. Sidelights
Either of two lights carried by a
vessel underway at night, a red
one on the port side and a green
one on the starboard

164. Day Shape
(Black Ball)
A metal ribbing
roughly oval in
shape, over which
canvas is stretched

165. Obstructed View
1 Prolong Blast

166. Change of Status
I (leaving a dock or berth)
N 1 prolong blast
L
A
N
D
R
U
L
E
S

167. Leaving a Dock or Berth in Reverse
I
N 1 prolonged blast, (change of status)
then 3 short blasts, (making sternway)
L
A
N
D
R
U
L
E
S

168. VESSEL AT ANCHOR

169. At night, ―Red over red, the captain is
dead‖ may help you remember the
vessel is not under command.
VESSEL NOT UNDER COMMAND

171. VESSEL AGROUND

172. VESSEL TOWING ASTERN, TOW LENGTH
MORE THAN 200 METERS ASTERN

173. SAILING VESSEL UNDER POWER

174. VESSEL ENGAGED IN FISHING

175. VESSEL ENGAGED IN FISHING, GEAR
EXTENDING MORE THAN 150 METERS

176. VESSEL CONSTRAINED BY DRAFT

177. VESSEL ENGAGED IN
MINESWEEPING

178. VESSEL RESTRICTED IN ABILITY TO
MANEUVER

179. VESSEL RESTRICTED IN ABILITY TO
MANEUVER, OBSTRUCTION EXISTS ON SIDE
WITH TWO BALLS

181. Meeting Two Short Blasts
Situation Starboard to Starboard
I
N
Give-way
L Vessel
A
N Give-way
Vessel
D
Meeting One Short Blast
Situation Port to Port
R
U Give-way
L Vessel
E
Give-way
S Vessel

182. Crossing Situation
I One Short Blast
N Port to Port
L
A In inland waters,
N starboard-to-
starboard passing
D
is authorized only
if ships are not
R meeting end-on
U and safe passage
L is assured
E without any
S maneuvering.