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 Prin ...

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 taking off and landing (alighting) on water.Gunston, "The Cambridge Aerospace Dictionary", 2009. Seaplanes are usually divided into two categories based on their technological characteri ...

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), buoys (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 ἄ� ...

ed to a specific location on the bottom of the sea or to a submerged object) and a type of cairn built on a submerged rock/object, especially in calmer waters. Sea marks are used to indicate channels, dangerous rocks or shoals, mooring positions, areas of speed limits, traffic separation schemes, submerged shipwrecks, 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 bells,

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 reflectors 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 co ...

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 graphical representation of an object or its external boundary, outline, or external surface, as opposed to other properties such as color, texture, or material type. A plane shape or plane figure is constrained to lie ...

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 assoc ...

s and characteristic lights 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 t ...

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 Korean Peninsula and sharing a land border with North Korea. Its western border is formed by the Yellow Sea, while its eas ...

and Japan * 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 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 H ...

. 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 buoy 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, w ...

. 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 Medit ...

File:Enslinje - Ystad-2021.jpg, Triangular daymark in the marina of

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, a ...

2021.

References

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

Definitions

Image gallery

See also

Mark types

Other

References