What are Lateral Marks?

As per IALA Buoyage system, Lateral marks, used in conjunction with a “conventional direction of buoyage”, generally employed for well defined channels. These marks indicate the port and starboard sides of the route to be followed. Where a channel divides, a modified lateral mark may be used to indicate the preferred route. Lateral buoys indicate the side on which they may be safely passed.

Definition of ‘conventional direction of buoyage’

The ‘conventional direction of buoyage’, which must be indicated in appropriate nautical charts and documents, may be either:

  • The general direction taken by the mariner when approaching a harbour, river, estuary or other waterway from seaward.
  • The direction determined by the proper authority in consultation, where appropriate, with neighbouring countries. In principle, it should follow a clockwise direction around land
Description of Lateral Marks used in Region A

Lateral Port Hand marks.

  • A port hand buoy marks the port (left) side of a channel or the location of a danger which must be kept on the vessel’s port (left) side when proceeding in the upstream direction.
  • A port hand buoy is coloured Red , displays identification letter(s) and odd number(s) and

Lateral Starboard Hand mark.

  • A starboard hand buoy marks the starboard (right) side of a channel or the location of a danger which must be kept on the vessel’s starboard (right) side when proceeding in the upstream direction.
  • A starboard hand buoy is coloured Green , displays identification letter(s) and even number(s) .

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Modified  lateral marks in  Region A.

At the point where a channel divides, when proceeding in the “conventional direction of buoyage,” a preferred channel may be indicated by a modified Port or Starboard lateral.

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Description of Lateral Marks used in Region B.

Lateral Port Hand marks.

  • A port hand buoy marks the port (left) side of a channel or the location of a danger which must be kept on the vessel’s port (left) side when proceeding in the upstream direction.
  • A port hand buoy is coloured Green , displays identification letter(s) and odd number(s) and

Lateral Starboard Hand mark.

  • A starboard hand buoy marks the starboard (right) side of a channel or the location of a danger which must be kept on the vessel’s starboard (right) side when proceeding in the upstream direction.
  • A starboard hand buoy is coloured Red , displays identification letter(s) and even number(s) .

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Modified  lateral marks in  Region B.

At the point where a channel divides, when proceeding in the “conventional direction of buoyage,” a preferred channel may be indicated by a modified Port or Starboard lateral.

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