Seamarks/Beacons

Beacon

The tags defined on this page will render in various nautical charts. This page defines values for the "seamark:type" tag for beacons and their category attribute tags.

Types

A beacon is a prominent, specially constructed object forming a conspicuous mark as a fixed aid to navigation or for use in hydrographic surveys.

Type	S100 Code	seamark:type	Definition
Cardinal Beacon	BCNCAR	beacon_cardinal	A cardinal beacon is used in conjunction with the compass to indicate where the mariner may find the best navigable water. It is placed in one of the four quadrants (North, East, South and West), bounded by inter-cardinal bearings from the point marked.
Isolated Danger Beacon	BCNISD	beacon_isolated_danger	An isolated danger beacon is a beacon erected on an isolated danger of limited extent, which has navigable water all around it.
Lateral Beacon	BCNLAT	beacon_lateral	A lateral beacon is used to indicate the port or starboard hand side of the route to be followed. They are generally used for well defined channels and are used in conjunction with a conventional direction of buoyage.
Safe Water Beacon	BCNINB	beacon_safe_water	A safe water beacon is a prominent specially constructed object forming a conspicuous mark as a fixed aid to navigation or for use in hydrographic surveys.
Special Purpose Beacon	BCNSPP	beacon_special_purpose	A special purpose beacon is primarily used to indicate an area or feature, the nature of which is apparent from reference to a chart, Sailing Directions or Notices to Mariners (UKHO NP 735, 5th Edition). Beacon in general: A beacon whose appearance or purpose is not adequately known.

When top-marks, retro reflectors and/or lights are fitted to these marks, they are encoded as separate objects. Note that such top-marks are encoded as separate "topmark" (TOPMAR) objects). Beacons may also have lights and if such lights are fitted they are encoded as separate "light" (LIGHTS) objects.

Categories

Cardinal Beacons

Cardinal beacons are always painted in yellow and black horizontal bands and their distinctive double cone top-marks are always black.

More on Cardinal Marks: Seamarks/Cardinal_Marks

Category (CATCAM)	beacon_cardinal:category	Definition	seamark:beacon_cardinal:colour (seamark:beacon_cardinal:colour_pattern=horizontal)	seamark:topmark:shape (seamark:topmark:colour=black)
North	north	Quadrant bounded by the true bearing NW-NE taken from the point of interest it should be passed to the north side of the mark.	black;yellow	2 cones up
East	east	Quadrant bounded by the true bearing NE-SE taken from the point of interest it should be passed to the east side of the mark.	black;yellow;black	2 cones base together
South	south	Quadrant bounded by the true bearing SE-SW taken from the point of interest it should be passed to the south side of the mark.	yellow;black	2 cones down
West	west	Quadrant bounded by the true bearing SW-NW taken from the point of interest it should be passed to the west side of the mark.	yellow;black;yellow	2 cones point together

Isolated Danger Beacons

There are no categories of Isolated Danger Beacons. The default colours and topmarks are:

seamark:beacon_isolated_danger:colour	seamark:beacon_isolated_danger:colour_pattern	seamark:topmark:shape	seamark:topmark:colour
black;red;black	horizontal	2 spheres	black

Lateral Beacons

There are two international buoyage regions, A and B, between which lateral marks differ. The buoyage region is encoded using the separate attribute "system" (MARSYS). Lateral beacons and their topmarks are always painted in red, green or red & green horizontal bands.

Category (CATLAM)	beacon_lateral:category	Definition	seamark:beacon_lateral:colour [seamark:beacon_lateral:colour_pattern=horizontal]	seamark:topmark:shape
Port-hand Beacon	port	Indicates the port boundary of a navigational channel or suggested route when proceeding in the 'conventional direction of buoyage'.	IALA-A: red, IALA-B: green	cylinder
Starboard-hand Beacon	starboard	Indicates the starboard boundary of a navigational channel or suggested route when proceeding in the 'conventional direction of buoyage'.	IALA-A: green, IALA-B: red	cone, point up
Preferred Channel to Starboard Beacon	preferred_channel_starboard	At a point where a channel divides, when proceeding in the 'conventional direction of buoyage', the preferred channel (or primary route) is indicated by a modified port-hand lateral mark.	IALA-A: red;green;red, IALA-B: green;red;green	cylinder
Preferred Channel to Port Beacon	preferred_channel_port	At a point where a channel divides, when proceeding in the 'conventional direction of buoyage', the preferred channel (or primary route) is indicated by a modified starboard-hand lateral mark.	IALA-A: green;red;green, IALA-B: red;green;red	cone, point up
Inland Waterway Lateral Beacon	...	Many more categories of lateral marks are used in inland waterways. See: CEVNI Lateral Marks

Safe Water Beacons

There are no categories of Safe Water Beacons. The default colours and topmarks are:

seamark:beacon_safe_water:colour	seamark:beacon_safe_water:colour_pattern	seamark:topmark:shape	seamark:topmark:colour
red;white	vertical	sphere	red

Special Purpose Beacons

Special purpose beacons can be any shape and are generally yellow in colour, with a variety of topmarks.

For "beacon_special_purpose:category" (CATSPM) definitions, see: Special Purpose Marks

Shapes

Shape (BCNSHP)	seamark:<beacon_type>:shape	Definition
Stake, Pole, Perch or Post	stake pole perch post	An elongated wood or metal pole, embedded in the bottom to serve as a navigational aid or a support for a navigational aid.
Withy	withy	A tree without roots stuck or spoiled into the bottom of the sea to serve as a navigational aid.
Beacon tower	tower	A solid structure of the order of 10 metres in height used as a navigational aid.
Pile beacon	pile	A long heavy timber(s) or section(s) of steel, wood, concrete, etc., forced into the seabed to serve as an aid to navigation or as a support for an aid to navigation.
Lattice beacon	lattice	A structure consisting of strips of metal or wood crossed or interlaced to form a structure to serve as an aid to navigation or as a support for an aid to navigation.
Cairn	cairn	A mound of stones, usually conical or pyramidal, raised specifically for maritime navigation.
Buoyant beacon	buoyant	A tall spar-like beacon fitted with a permanently submerged buoyancy chamber, the lower end of the body is secured to seabed sinker either by a flexible joint or by a cable under tension.

Colours

Beacons can be painted in many different colours and colour patterns. See: Colours

Other Objects

Beacons may have other objects as part of their structure

Object	S100	Definition	Wiki page
Topmark	TOPMAR	A characteristic shape secured at the top of a buoy or beacon to aid in its identification.	Topmarks
Light	LIGHTS	A luminous or lighted aid to navigation.	Lights
Fog Signal	FOGSIG	A warning signal transmitted by a vessel, or aid to navigation, during periods of low visibility. Also, the device producing such a signal.	Fog Signals
Radar transponder beacon	RTPBCN	A transponder beacon transmitting a coded signal on radar frequency, permitting an interrogating craft to determine the bearing and range of the transponder.	Radar Beacons
Radio Station	RDOSTA	A place equipped to transmit radio waves.	Radio Stations
Radar Reflector	RADRFL	A device capable of, or intended for, reflecting radar signals.

References

Seamark Tag Values
Seamark Objects
Seamark Attributes
INT-1 Cross Reference