Lateral mark


Lateral mark

A lateral buoy, lateral post or lateral mark, as defined by the International Association of Lighthouse Authorities, is a sea mark used in maritime pilotage to indicate the edge of a channel.

Each mark indicates the edge of the safe water channel in terms of port (left-hand) or starboard (right-hand). These directions are relative to the "direction of buoyage"; this is usually a nominally upstream direction. In a river, the direction of buoyage is towards the river's source; in a harbour, the direction of buoyage is into the harbour from the sea. Where there may be doubt, it will be labelled on the appropriate chart.

A vessel heading in the direction of buoyage (eg into a harbour) and wishing to keep in the main channel should:
* keep port marks to its port (left), and
* keep starboard marks to its right.

IALA Systems

Marks are distinguished by their colour, being red or green, and shape.

For historical reasons, two different schemes are in use worldwide, differing in their use of colour.
Previously there had been 30 different buoyage systems, prior to IALA introducing the rationalised system.

The IALA defines them as System A and System B:

* System A is used by nations in Europe, Australia, New Zealand, parts of Africa and most of Asia other than the Philippines, Japan and Korea.

* System B is used by nations in North America, Central America and South America, the Philippines, Japan and Korea.

System A

* port marks are red and may have a red flashing light.
* starboard marks are green and may have a green flashing light.

(Port) (left) (Red) _____________________________________ (Starboard) (right) (Green)

System B

* port marks are green, and may have a green flashing light.
* starboard marks are red and may have a red flashing light.

(Port) (left) (Green) _____________________________________ (Starboard) (right) (Red)

Both systems

* port marks are square or have a flat top
* starboard marks are conical (or present a triangular shape) or have a pointed top.

The shape is an important feature, as colours cannot be distinguished in some light conditions, or by persons with red-green colour blindness. Marks may also carry unique markings of letters and numbers; these may be used to identify the mark as one indicated on a nautical chart. Likewise, a mark's light may flash in a distinctive sequence for the same purpose.

Also defined in the lateral mark systems is a "bifurcation" mark, which has both red and green horizontal bands, one over the other. This mark indicates that a "preferred" channel (often, a deep channel suitable for heavy commercial traffic) lies to one side, and a secondary channel on the other. Vessels wishing to use the preferred channel observe the top colour of the mark, and vessels wishing to use the secondary channel observe the bottom colour.

In System A only, the phrase "Is there any red port left?" (referring to the red colour of the fortified wine "port") may be used as a mnemonic, indicating that a red mark must be kept on the left when "returning" to (i.e, entering) a harbour or river.

In System B only, the phrase "red right returning" may be used as a mnemonic, indicating that a red mark must be kept on the right when "returning" to ("i.e.", entering) a harbour or river.

The alternative system of cardinal marks is used where there is no clear upstream reference direction.

External links

* A [http://www.tc.gc.ca/marinesafety/Tp/tp14070/b3-buoys.htm web site of Transport Canada] , showing lateral marks in System B.

See also

*Navigation
*Cardinal mark
*Safe water mark
*Isolated danger mark
*Special mark


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Lateral — may refer to:*Lateral, an anatomical direction see Human anatomical terms *Lateral pass, type of pass in American and Canadian football *Lateral thinking, thinking concerned with changing concepts and perception *Lateral consonants, L like… …   Wikipedia

  • Mark I tank — A British Mark I male tank near Thiepval on 26 September 1916, fitted with wire mesh to deflect grenades and the initial steering tail, shown raised …   Wikipedia

  • Mark Adams — Retrato del artista[1] Nacimiento 1925 (hace 86 año …   Wikipedia Español

  • Mark González — Nombre Mark Dennis González Hoffman Apodo San Mark, Speedy, Chico Mark, Mark el Trotamundos …   Wikipedia Español

  • Mark Miodownik — Do you have a picture of Mark Miodownik? Please, post here. Nationality …   Wikipedia

  • Mark Mattson — 2009 Mark P. Mattson is Chief of the Laboratory of Neurosciences at the National Institute on Aging Intramural Research Program National Institute on Aging. He is also professor of Neuroscience at Johns Hopkins University. Mark P. Mattson was… …   Wikipedia

  • Mark Williams (futbolista) — Mark Williams Nacimiento 28 de septiembre de 1973 (38 años) Stalybridge(Irlanda del Norte), Nacionalidad …   Wikipedia Español

  • Mark Simpson (soccer) — Mark Simpson Personal information Date of birth March 18, 1966 (1966 03 18) (age 45) Place of birth …   Wikipedia

  • Lateral Link — Infobox Company company name = Lateral Link company company type = Private| foundation = New York City, New York, 2005 headquarters = New York City, New York key people = Michael Allen, Principal and T.J. Duane, Principal industry = Legal… …   Wikipedia

  • Mark Little — Pour les articles homonymes, voir Little. Mark Little …   Wikipédia en Français