A day beacon is an unlighted nautical sea mark

Sea mark

A sea mark, also seamark and navigation mark, is a form of aid to navigation and pilotage aid which identifies the approximate position of a maritime channel, hazard and administrative area to allow boats, ships and seaplanes to navigate safely....

. Typically, day beacons mark channels

Channel (geography)

In physical geography, a channel is the physical confine of a river, slough or ocean strait consisting of a bed and banks.A channel is also the natural or human-made deeper course through a reef, sand bar, bay, or any shallow body of water...

 whose key points are marked by lighted buoy

Buoy

A buoy is a floating device that can have many different purposes. It can be anchored or allowed to drift. The word, of Old French or Middle Dutch origin, is now most commonly in UK English, although some orthoepists have traditionally prescribed the pronunciation...

s. Day beacons may also mark smaller navigable routes in their entirety. They are the most common aid to nautical navigation in shallow water as they are relatively inexpensive to install and maintain. Navigation

Navigation

Navigation is the process of monitoring and controlling the movement of a craft or vehicle from one place to another. It is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks...

 around day beacons is the same as with all other navigational aids.

Lateral marking

For historical reasons, there are two systems for lateral daybeacons. When proceeding from open water towards harbor, marks with cylindrical topmarks or square dayboards are kept to port in both regions, but colors and numbers are reversed.

Differences between the two IALA

International Association of Lighthouse Authorities

The International Association of Marine Aids to Navigation and Lighthouse Authorities is a non-profit organization founded in 1957 to collect and provide nautical expertise and advice.-Background:...

 regions

IALA Region	Area covered, very roughly	Colors when approaching harbors from seaward	Numbers	Shape
Region A	Europe, Africa, most of Asia, Australia	Lefthand side marks are red Right: green	Left: even numbers Right: odd numbers	Left: cylindrical topmarks, square dayboards, can buoys Right: conical topmarks, triangular dayboards, nun buoys
Region B	N&S America, Japan, Philippines, Eastern Pacific	Left: green Right: red	Left: odd Right: even	The same

When lateral beacons are paired, vessels should pass between the pairing. However, beacons are also frequently placed individually. Generally, single lateral beacons are at the inside corner of a turn. Interior or exterior placement can be determined based upon the passing side (port or starboard) dictated by beacon designation. However, a current chart should always be consulted for all but the shallowest-draft

Draft (hull)

The draft of a ship's hull is the vertical distance between the waterline and the bottom of the hull , with the thickness of the hull included; in the case of not being included the draft outline would be obtained...

 vessels, as channel conditions are rarely ideal.

Cardinal marking

Cardinal day beacons are used to indicate the position of a hazard and the direction of safe water as a cardinal direction (north

North

North is a noun, adjective, or adverb indicating direction or geography.North is one of the four cardinal directions or compass points. It is the opposite of south and is perpendicular to east and west.By convention, the top side of a map is north....

, east

East

East is a noun, adjective, or adverb indicating direction or geography.East is one of the four cardinal directions or compass points. It is the opposite of west and is perpendicular to north and south.By convention, the right side of a map is east....

, south

South

South is a noun, adjective, or adverb indicating direction or geography.South is one of the four cardinal directions or compass points. It is the opposite of north and is perpendicular to east and west.By convention, the bottom side of a map is south....

 or west

West

West is a noun, adjective, or adverb indicating direction or geography.West is one of the four cardinal directions or compass points. It is the opposite of east and is perpendicular to north and south.By convention, the left side of a map is west....

) relative to the mark. This makes them meaningful regardless of the direction or position of the approaching vessel, in contrast to the lateral mark system.

A cardinal daybeacon indicates one of the four compass directions by:

• the direction of its two conical top-marks, which can both point up, indicating north; down, indicating south; towards each other, indicating west; or away from each other, indicating east
• its distinctive pattern of black and yellow stripes, which follows the orientation of the cones - the black stripe is in the position pointed to by the cones (eg at the top for a north cardinal, in the middle for a west cardinal)

See also

• Bowditch's American Practical Navigator
  Bowditch's American Practical Navigator
  The American Practical Navigator , originally written by Nathaniel Bowditch, is an encyclopedia of navigation. It serves as a valuable handbook on oceanography and meteorology, and contains useful tables and a maritime glossary...
  
  
• Cardinal mark
  Cardinal mark
  A cardinal mark is a sea mark used in maritime pilotage to indicate the position of a hazard and the direction of safe water....
  
  
• Daymark
  Daymark
  A daymark or a day marker is a structure such as a tower constructed on land as an aid to navigation by sailors. While similar in concept to a lighthouse, a daymark does not have a light and so is usually only visible during daylight hours...
  
  
• Safe water mark
  Safe water mark
  thumb|right|Examples of Safe Water MarksA Safe Water Mark, as defined by the International Association of Lighthouse Authorities, is a sea mark used in maritime pilotage to indicate the end of a channel...
  
  
• Isolated danger mark
  Isolated danger mark
  An Isolated Danger Mark, as defined by the International Association of Lighthouse Authorities, is a sea mark used in maritime pilotage to indicate a hazard to shipping such as a partially submerged rock....
  
  
• Special mark
  Special mark
  A Special Mark, as defined by the International Association of Lighthouse Authorities, is a sea mark used in maritime pilotage to indicate the boundary of an obstruction, administrative area such as a speed limit, water skiing or mooring area, or to highlight other features such as outfall sewerage...
  
  
• Lighthouse
  Lighthouse
  A lighthouse is a tower, building, or other type of structure designed to emit light from a system of lamps and lenses or, in older times, from a fire, and used as an aid to navigation for maritime pilots at sea or on inland waterways....
  
  
• Foghorn
  Foghorn
  A foghorn or fog signal or fog bell is a device that uses sound to warn vehicles of hazards or boats of the presence of other vehicles in foggy conditions. The term is most often used in relation to marine transport...
  
  
• Lightvessel
  Lightvessel
  A lightvessel, or lightship, is a ship which acts as a lighthouse. They are used in waters that are too deep or otherwise unsuitable for lighthouse construction...