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Application of Rule 18 in narrow channels or fairways where Rule 9 applies

  • Description of scenario: Vessel A: Power-driven vessel constrained by her draught underway (Dynamic draught 11 m)
    Vessel B: Power-driven vessel underway more than 20 m in length (Dynamic draught 6 m)
    Area: Narrow channel (Depth 13~15 m)
    Visibility: Good (Vessels are in sight of one another)
    Vessel A and vessel B are crossing so as to involve risk of collision
    Vessel A has vessel B on her own starboard side (relative bearing STBD 054°)
  • Rule(s) to be applied: Rule 9 (Narrow channel )
    Rule 8 (Action to avoid collision )
    Rule 34 (Manoeuvring and warning signals )
  • Applying the Rule(s) and comments: Crossing situation (vessel A and vessel B):
    In accordance with Rule 9 (d) (Narrow channels ), a vessel (vessel B) shall not cross a narrow channel or fairway if such crossing impedes the passage of a vessel which can safely navigate only within such channel or fairway (vessel A).
    In accordance with Rule 9 (d) (Narrow channels ), a vessel which can safely navigate only within such channel or fairway (vessel A) may use the sound signal prescribed in Rule 34 (d) (Manoeuvring and warning signals ) if in doubt as to the intention of the crossing vessel (vessel B).
    In accordance with Rule 8 (f )(i) (Action to avoid collision ), a vessel (vessel B) which is required not to impede the passage or safe passage of another vessel (vessel A) shall, when required by the circumstances of the case, take early action to allow sufficient sea-room for the safe passage of the other vessel (vessel A).
    In accordance with Rule 8 (f )(ii) (Action to avoid collision ), a vessel (vessel B) required not to impede the passage or safe passage of another vessel (vessel A) is not relieved of this obligation if approaching the other vessel (vessel A) so as to involve risk of collision and shall, when taking action, have full regard to the action which may be required by the Rules of Part B (Steering and Sailing Rules).
    In accordance with Rule 8 (f )(iii) (Action to avoid collision ), a vessel (vessel A) the passage of which is not to be impeded remains fully obliged to comply with the Rules of part B (Steering and Sailing Rules) when the two vessels are approaching one another so as to involve risk of collision.
    In accordance with Rule 34 (d) (Manoeuvring and warning signals ), if a vessel (vessel A) fails to understand the intentions or actions of the other vessel (vessel B), or is in doubt whether sufficient action is being taken by the other vessel (vessel B) to avoid collision, the vessel in doubt (vessel A) shall immediately indicate such doubt by giving at least five short and rapid blasts on the whistle.
    In accordance with Rule 34 (d) (Manoeuvring and warning signals ), sound signal may be supplemented by a light signal of at least five short and rapid flashes.

    Comments:
    In this scenario it is necessary to determine which Rule to apply, Rule 9 (Narrow channels ) or Rule 18 (Responsibilities between vessels)? It is clear that vessel A is vessel constrained by her draught and that vessels are crossing in narrow channel .
    In accordance with Rule 18 (d)(i) any vessel (vessel B) other than a vessel not under command or a vessel restricted in her ability to manoeuvre shall, if the circumstances of the case admit, avoid impeding the safe passage of a vessel constrained by her draught (vessel A), but this Rule cannot be applied if Rule 9 (Narrow channels ) otherwise require.
    Rule 9 (d) (Narrow channels ) requires that a vessel (vessel B) shall not cross a narrow channel or fairway if such crossing impedes the passage of a vessel which can safely navigate only within such channel or fairway (vessel A).
    Actually both Rules (Rule 9 and Rule 18 ) require that vessel B shall not cross a narrow channel or fairway if such crossing impedes the passage of a vessel which can safely navigate only within such channel or fairway (vessel A).

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