Maneuvering and Warning
Signals, Inland and International
Rules
• One short (1 second) blast–I intend to
alter my course to starboard (I intend to
leave you to my port side).
• International Rules—I am altering course
to starboard. No agreement required.
• Two short blasts–I intend to alter my
course to port (I intend to leave you to
my starboard).
• International Rules —I am altering course
to port. No agreement required.
• Three short blasts — I am operating
astern propulsion.
• If the other vessel returns the same signal
to indicate agreement, proceed to maneuver.
If the other vessel sounds the danger
signal, do not proceed with the maneuver.
Inland rules require a response. International
rules do not require a response.
Overtaking
• One short blast — I intend to overtake
you on your starboard side.
• Two short blasts — I intend to overtake
you on your port side.
• If the other vessel echoes the signal to
indicate agreement, proceed. If the other
vessel sounds the danger signal, do not
proceed with the maneuver. International
rules do not require a response.
Doubt of Suffi cient Action
Sounding of at least fi ve short blasts indicates
there is doubt that suffi cient action
is being taken to avoid collision, or your
intentions are not clearly understood.
Alert
Upon departure from a dock or slip or
when rounding a bend in a channel or river
where visibility may be limited, sound one
prolonged blast.
Sound Signals in
Restricted Visibility
Sound signals are especially important
when visibility is restricted. Table 6-4
shows a summary of the signals.
Power-Driven Vessel
• Making way–sound one prolonged blast
at intervals of not more than 2 minutes.
82 Chapter Two
Table 6-3. Sound Signals for Vessels in Sight
Meaning Signal
I intend to pass you on my port side 1 short
I intend to pass you on my starboard side 2 short
I am operating astern propulsion 3 short
I am departing from a dock, pier, or mooring 1 prolonged
I am approaching an intervening obstruction 1 prolonged
or channel bend
I am in doubt of suffi cient action to avoid 5 or more
short
collision
I am in doubt as to your intentions 5 or more
short
I do not agree with your maneuver 5 or more
short.
Table 6-4. Sound Signals Underway in Restricted Visibility
Vessel Type Signal
Powerboats making way 1 prolonged blast at
intervals of not more
than 2 minutes
Powerboats underway, but stopped 2 prolonged blasts at
intervals of not morethan
2 minutes
Sailing, fi shing, trawling or 1 prolonged blast,
towing vessels followed by 2 short
blasts at intervals of
not more than 2
minutes
78
79
80
81
82
83
84
85
86
87
88
89
Vessells restricted in ability to
maneuver
Vessels not under command