22.9 Narrow channels

(1) A vessel proceeding along the course of a narrow channel or fairway must keep as near to the outer limit of the channel or fairway which lies on its starboard side as is safe and practicable.

(2) A vessel of less than 20 metres in length or a sailing vessel must not impede the passage of a vessel which can safely navigate only within a narrow channel or fairway.

(3) A vessel engaged in fishing must not impede the passage of any other vessel navigating within a narrow channel or fairway.

(4) A vessel must not cross a narrow channel or fairway if such crossing impedes the passage of a vessel which can safely navigate only within that channel or fairway. If the vessels are in sight of one another, the latter vessel may use the following sound signal as prescribed in rule 22.34(4) if in doubt as to the intention of the crossing vessel—

At least five short and rapid blasts on the whistle. This may be supplemented by a light signal of at least five short and rapid flashes.

(5) If vessels are in sight of each other in a narrow channel or fairway, when overtaking can take place only if the vessel to be overtaken has to take action to permit safe passing, the following provisions apply—

(a) the vessel intending to overtake must signal its intention by sounding one of the following sound signals prescribed in rule 22.34(3)(a) —

(i) two prolonged blasts followed by one short blast, to mean “I intend to overtake you on your starboard side”; or

(ii) two prolonged blasts followed by two short blasts, to mean “I intend to overtake you on your port side.”; and

(b) the vessel to be overtaken must, if in agreement, sound the following signal as prescribed in rule 22.34(3)(b) and take steps to permit safe passing:

four blasts consisting of one prolonged, one short, one prolonged, one short; and

(c) if the vessel to be overtaken has any doubt, it may sound the following sound signal as prescribed in rule 22.34(4):

At least five short and rapid blasts on the whistle. This may be supplemented by a light signal of at least five short and rapid flashes.

This rule does not relieve the overtaking vessel of its obligation under rule 22.13 for overtaking vessels.

(6) A vessel nearing a bend or an area of a narrow channel or fairway where other vessels may be obscured by an intervening obstruction must navigate with particular alertness and caution, and must sound the following sound signal prescribed in rule 22.34(5):

one prolonged blast.

Such a signal must be answered with a prolonged blast by any approaching vessel that may be within hearing around the bend or behind the intervening obstruction.

(7) Any vessel must, if the circumstances of the case allow, avoid anchoring in a narrow channel.