In or near an area of restricted visibility, whether by
day or night, the signals prescribed in this Rule shall be used as
follows:
(a) A power-driven vessel making way through the
water shall sound at intervals of not more than 2 minutes one prolonged
blast.
(b) A power-driven vessel underway but stopped
and making no way through the water shall sound at intervals of not
more than 2 minutes two prolonged blasts in succession with an interval
of about 2 seconds between them.
(c) A vessel not under command, a vessel restricted
in her ability to manoeuvre, a vessel constrained by her draught,
a sailing vessel, a vessel engaged in fishing and a vessel engaged
in towing or pushing another vessel shall, instead of the signals
prescribed in paragraphs (a) or (b) of this Rule, sound at intervals
of not more than 2 minutes three blasts in succession, namely one
prolonged followed by two short blasts.
(d) A vessel engaged in fishing, when at anchor,
and a vessel restricted in her ability to manoeuvre when carrying
out her work at anchor, shall instead of the signals prescribed in
paragraph (g) of this Rule sound the signal prescribed in paragraph
(c) of this Rule.
(e) A vessel towed or if more than one vessel
is towed the last vessel of the tow, if manned, shall at intervals
of not more than 2 minutes sound four blasts in succession, namely
one prolonged followed by three short blasts. When practicable, this
signal shall be made immediately after the signal made by the towing
vessel.
(f) When a pushing vessel and a vessel being pushed
ahead are rigidly connected in a composite unit they shall be regarded
as a power-driven vessel and shall give the signals prescribed in
paragraphs (a) or (b) of this Rule.
(g) A vessel at anchor shall at intervals of not
more than one minute ring the bell rapidly for about 5 seconds. In
a vessel of 100 metres or more in length the bell shall be sounded
in the forepart of the vessel and immediately after the ringing of
the bell the gong shall be sounded rapidly for about 5 seconds in
the after part of the vessel. A vessel at anchor may in addition sound
three blasts in succession, namely one short, one prolonged and one
short blast, to give warning of her position and of the possibility
of collision to an approaching vessel.
(h) A vessel aground shall give the bell signal
and if required the gong signal prescribed in paragraph (g) of this
Rule and shall, in addition, give three separate and distinct strokes
on the bell immediately before and after the rapid ringing of the
bell. A vessel aground may in addition sound an appropriate whistle
signal.
(i) A vessel of 12 metres or more but less than
20 metres in length shall not be obliged to give the bell signals
prescribed in paragraphs (g) and (h) of this Rule. However, if she
does not, she shall make some other efficient sound signal at intervals
of not more than 2 minutes.
(j) A vessel of less than 12 metres in length
shall not be obliged to give the above-mentioned signals but, if she
does not, shall make some other efficient sound signal at intervals
of not more than 2 minutes.
(k) A pilot vessel when engaged on pilotage duty
may in addition to the signals prescribed in paragraphs (a), (b) or
(g) of this Rule sound an identity signal consisting of four short
blasts.