A sea mark, also seamark and

navigation Navigation is a field of study that focuses on the process of monitoring and controlling the movement of a craft or vehicle from one place to another.Bowditch, 2003:799. The field of navigation includes four general categories: land navigation, ...

mark, is a form of

aid to navigation In international relations, aid (also known as international aid, overseas aid, foreign aid, economic aid or foreign assistance) is – from the perspective of governments – a voluntary transfer of resources from one country to another. Ai ...

and

pilotage Piloting or pilotage is the process of navigating on water or in the air using fixed points of reference on the sea or on land, usually with reference to a nautical chart or aeronautical chart to obtain a fix of the position of the vessel or air ...

that identifies the approximate position of a

maritime Maritime may refer to: Geography * Maritime Alps, a mountain range in the southwestern part of the Alps * Maritime Region, a region in Togo * Maritime Southeast Asia * The Maritimes, the Canadian provinces of Nova Scotia, New Brunswick, and Princ ...

channel, hazard, or administrative area to allow

boat A boat is a watercraft of a large range of types and sizes, but generally smaller than a ship, which is distinguished by its larger size, shape, cargo or passenger capacity, or its ability to carry boats. Small boats are typically found on inl ...

ship A ship is a large watercraft that travels the world's oceans and other sufficiently deep waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research, and fishing. Ships are generally distinguished ...

s, and

seaplane A seaplane is a powered fixed-wing aircraft capable of takeoff, taking off and water landing, landing (alighting) on water.Gunston, "The Cambridge Aerospace Dictionary", 2009. Seaplanes are usually divided into two categories based on their tec ...

s to navigate safely. There are three types of sea mark:

beacon A beacon is an intentionally conspicuous device designed to attract attention to a specific location. A common example is the lighthouse, which draws attention to a fixed point that can be used to navigate around obstacles or into port. More mode ...

s (fixed to the

seabed The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'. The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...

or on shore),

buoy A buoy () is a floating device that can have many purposes. It can be anchored (stationary) or allowed to drift with ocean currents. Types Navigational buoys * Race course marker buoys are used for buoy racing, the most prevalent form of yac ...

s (consisting of a

float Float may refer to: Arts and entertainment Music Albums * ''Float'' (Aesop Rock album), 2000 * ''Float'' (Flogging Molly album), 2008 * ''Float'' (Styles P album), 2013 Songs * "Float" (Tim and the Glory Boys song), 2022 * "Float", by Bush ...

ing object that is usually

anchor An anchor is a device, normally made of metal , used to secure a vessel to the bed of a body of water to prevent the craft from drifting due to wind or current. The word derives from Latin ''ancora'', which itself comes from the Greek ἄγ ...

ed to a specific location on the bottom of the sea or to a submerged object) and a type of

cairn A cairn is a man-made pile (or stack) of stones raised for a purpose, usually as a marker or as a burial mound. The word ''cairn'' comes from the gd, càrn (plural ). Cairns have been and are used for a broad variety of purposes. In prehis ...

built on a submerged rock/object, especially in calmer waters. Sea marks are used to indicate channels, dangerous rocks or

shoal In oceanography, geomorphology, and geoscience, a shoal is a natural submerged ridge, bank, or bar that consists of, or is covered by, sand or other unconsolidated material and rises from the bed of a body of water to near the surface. It ...

s, mooring positions, areas of speed limits, traffic separation schemes, submerged

shipwreck A shipwreck is the wreckage of a ship that is located either beached on land or sunken to the bottom of a body of water. Shipwrecking may be intentional or unintentional. Angela Croome reported in January 1999 that there were approximately ...

s, and for a variety of other navigational purposes. Some are only intended to be visible in daylight ('' daymarks''), others have some combination of lights, reflectors,

fog bell A fog bell is a navigation mark used as an audible aid to navigation in seafaring, especially in fog and poor visibility. Floating navigation signs with bells are called bell buoys. On ships, the ship's bell is used for sound signals. Due to more s ...

foghorns A foghorn or fog signal is a device that uses sound to warn vehicles of navigational hazards such as rocky coastlines, or boats of the presence of other vessels, in foggy conditions. The term is most often used in relation to marine transport. Wh ...

, whistles and

radar reflector A corner reflector is a retroreflector consisting of three mutually perpendicular, intersecting flat surfaces, which reflects waves directly towards the source, but translated. The three intersecting surfaces often have square shapes. Radar c ...

s to make them usable at night and in conditions of reduced visibility. Marks are shown on

nautical chart A nautical chart is a graphic representation of a sea area and adjacent coastal regions. Depending on the scale of the chart, it may show depths of water and heights of land (topographic map), natural features of the seabed, details of the coa ...

s, using symbols that indicate their colour, shape and

light characteristic A light characteristic is all of the properties that make a particular navigational light identifiable. Graphical and textual descriptions of navigational light sequences and colours are displayed on nautical charts and in Light Lists with the cha ...

, and are usually identified by name or number. In a wider sense the phrase "sea mark" is often understood to include all types of landmarks, structures and devices that can be used to provide warning and guiding signs to mariners. Thus a sea mark can be and often is located on dry land. Examples of land-based sea marks are various signal lights and leading marks. The latter are mainly used to indicate the centerline of a fairway in narrow passages. Sea marks may also on occasion be used to help mark the boundaries of defensive sea minefields, or the safe lanes through same, especially during wartime.

Definitions

The

International Association of Lighthouse Authorities The International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA), previously known as International Association of Lighthouse Authorities, is an intergovernmental organization founded in 1957 to collect and provide naut ...

defines one system of marks specifying the

shape A shape or figure is a graphics, graphical representation of an object or its external boundary, outline, or external Surface (mathematics), surface, as opposed to other properties such as color, Surface texture, texture, or material type. A pl ...

colour Color (American English) or colour (British English) is the visual perceptual property deriving from the spectrum of light interacting with the photoreceptor cells of the eyes. Color categories and physical specifications of color are associ ...

s and

characteristic light A light characteristic is all of the properties that make a particular navigational light identifiable. Graphical and textual descriptions of navigational light sequences and colours are displayed on nautical charts and in Light Lists with the cha ...

s of buoys depending on their purpose, the IALA Maritime Buoyage System. For historical reasons, there are two regions of

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

s in use: * IALA ''Region B'' in the

Americas The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World. Along with th ...

, the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

South Korea South Korea, officially the Republic of Korea (ROK), is a country in East Asia, constituting the southern part of the Korea, Korean Peninsula and sharing a Korean Demilitarized Zone, land border with North Korea. Its western border is formed ...

and

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

* IALA ''Region A'' everywhere else. The two regions differ principally in the colours used to denote the two sides of a channel. When approaching a harbour from seaward, ''Region A'' places conical green marks to

starboard Port and starboard are nautical terms for watercraft and aircraft, referring respectively to the left and right sides of the vessel, when aboard and facing the bow (front). Vessels with bilateral symmetry have left and right halves which are ...

and cylindrical red ones to

port A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as Ham ...

. In ''Region B'' these are replaced with conical red marks to starboard and cylindrical green ones to port. This can be remembered (for ''Region B'') with the

mnemonic A mnemonic ( ) device, or memory device, is any learning technique that aids information retention or retrieval (remembering) in the human memory for better understanding. Mnemonics make use of elaborative encoding, retrieval cues, and imag ...

''"Red, right, return"''. Another ''Region B'' mnemonic, which also helps with buoy numbering is "Even Red Left Port" (as in Eric the Red) - Even Numbered buoys are red, on your left (port) side leaving port. In any case, since in many harbours it is not always apparent which direction is seaward, buoys should be used in connection with the appropriate

. Additionally, since marks may be off station due to collision with ships, storms or other factors, they should be used with caution and not relied on solely for

. The two regions are often referred to as two systems, which was the original intent. In 1980 it was decided however to combine these systems and distinguish between regions.

Image gallery

File:Buoy seal.jpg, Red

in San Diego Harbor, with a light, number, and radar corner reflectors. File:Canbuoy11.jpg, Green can #11 near the mouth of the

Saugatuck River The Saugatuck River is a river in southwestern Connecticut in the United States. It drains part of suburban and rural Fairfield County west of Bridgeport, emptying into Long Island Sound. , a U.S. Navy oiler that saw service in World War II, wa ...

. File:Can 11 in Saugatuck river.jpg, Same Green can #11, on a NOAA

. File:Sea mark near Hurghada.JPG, Sea mark near

Hurghada Hurghada (; ar, الغردقة ', ) is a city in the Red Sea Governorate of Egypt. It is one of the country's main tourist centres located on the Red Sea coast. Overview Hurghada was founded in the early 20th century. For many decades it wa ...

Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Mediter ...

File:Enslinje - Ystad-2021.jpg, Triangular

daymark A daymark is a navigational aid for sailors and pilots, distinctively marked to maximize its visibility in daylight. The word is also used in a more specific, technical sense to refer to a signboard or daytime identifier that is attached to a ...

in the

marina A marina (from Spanish , Portuguese and Italian : ''marina'', "coast" or "shore") is a dock or basin with moorings and supplies for yachts and small boats. A marina differs from a port in that a marina does not handle large passenger ships o ...

Ystad Ystad (; older da, Ysted) is a town and the seat of Ystad Municipality, in Scania County, Sweden. Ystad had 18,350 inhabitants in 2010. The settlement dates from the 11th century and has become a busy ferryport, local administrative centre, and ...

2021.

References

{{DEFAULTSORT:Sea Mark Navigational buoys Coastal construction Coastal fortifications Maritime signalling Nautical terminology

Definitions

Image gallery

See also

Mark types

Other

References