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Head-on and overtaking situation on the high seas close to shallow water areas

  • Description of scenario: Vessel A: Power-driven vessel
    Vessel B: Power-driven vessel
    Vessel C: Power-driven vessel
    Area: High seas (Depth ~ 15 m close to shallow water areas)
    Visibility: Good (Vessels in sight of one another)
    Vessel A and vessel B are meeting on reciprocal or nearly reciprocal courses so as to involve risk of collision
    Vessel B is overtaking vessel C on her starboard side
  • Rule(s) to be applied: Rule 8 (Action to avoid collision )
    Rule 13 (Overtaking)
    Rule 14 (Head-on situation)
    Rule 16 (Action by give-way vessel)
  • Applying the Rule(s) and comments: Head-on situation (vessel A and vessel B):
    In accordance with Rule 14 (b) (Head-on situation), head-on situation shall be deemed to exist when a vessel sees the other ahead or nearly ahead and by night she could see the masthead lights of the other in line or nearly in a line and/or both sidelights and by day she observes the corresponding aspect of the other vessel.
    In accordance with Rule 14 (a) (Head-on situation), when two power-driven vessels are meeting on reciprocal or nearly reciprocal courses so as to involve risk of collision each shall alter her course to starboard so that each shall pass on the port side of the other.
    In accordance with Rule 16 (Action by give-way vessel), vessels A and B which are both directed to keep out of the way of each other shall, so far as possible, take early and substantial action to keep well clear.

    Overtaking situation (vessel B and vessel C):
    In accordance with Rule 13 (b) (Overtaking situation), a vessel (vessel B) shall be deemed to be overtaking when coming up with another vessel (vessel C) from a direction more than 22.5 degrees abaft her beam.
    In accordance with Rule 13 (a) (Overtaking situation), notwithstanding anything contained in the Rules of Part B, sections I and II, any vessel overtaking (vessel B) any other vessel (vessel C) shall keep out of the way of the vessel being overtaken (vessel C).
    In accordance with Rule 13 (d) (Overtaking situation), any subsequent alteration of the bearing between the two vessels shall not make the overtaking vessel (vessel B) a crossing vessel within the meaning of these Rules or relieve her (vessel B) of the duty of keeping clear of the overtaken vessel (vessel C) until she is finally past and clear.
    In accordance with Rule 16 (Action by give-way vessel), every vessel (vessel B) which is directed to keep out of the way of another vessel (vessel C) shall, so far as possible, take early and substantial action to keep well clear.

    Comments:
    Vessel A is directed to keep out of the way of vessel B in head-on situation (vessel A and vessel B) and shall alter her course to starboard. Sufficient alteration of her course (vessel A) to starboard only to keep out of the way of vessel B would cause close-quarters situation with vessel C.

    Close-quarters situation (vessels A, B and C):
    In accordance with Rule 8 (c) (Action to avoid collision ), if there is sufficient sea-room, alteration of course alone (vessel A) may be the most effective action to avoid a close-quarters situation (vessel A and vessel B) provided that it is made in good time, is substantial and does not result in another close-quarters situation (vessel A and vessel C).

    Comments:
    Vessel A may not alter her course to starboard to avoid collision with vessel B, because this brings she (vessel A) in close-quarters situation with vessel C. Further alteration of her (vessel A) course to starboard to avoid close-quarter situation with vessel C brings her (vessel A) in danger of grounding due to two shallow water locations on her starboard side.
  • Actions: In accordance with Rule 8 (c) (Action to avoid collision ), vessels A may take the following actions to avoid collision and close-quarters situation.

    a) Vessel A shall alter her course to port substantially well in advance (when vessel A undertakes this action there is no more risk of collision with vessel B which means vessel B shall keep her course and speed)

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