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A sea lion on navigational buoy #14 in San Diego Harbor. Buoy seal.jpg
A sea lion on navigational buoy #14 in San Diego Harbor.
Green can #11 near the mouth of the Saugatuck River.
Can 11 in Saugatuck river.jpg
Green Can #11 on a nautical chart
NOAA Weather buoy NOAA-NDBC-discus-buoy.jpg
NOAA Weather buoy

A buoy ( /ˈb.i,bɔɪ/ ) [1] [2] is a floating device that can have many purposes. It can be anchored (stationary) or allowed to drift with ocean currents.



Marker buoys

Buoys are often used to temporarily or permanently mark the positions of underwater objects:


Several types of marker buoys may be used by divers:





Specific forms


buoy with letter box in Tore Arrival Polar.jpg
buoy with letter box in Töre

Other uses

See also

Related Research Articles

In underwater diving, open water is unrestricted water such as a sea, lake or flooded quarries. It is the opposite of confined water where diver training takes place. Open water also means the diver has direct vertical access to the surface of the water in contact with the Earth's atmosphere.Open water diving implies that if a problem arises, the diver can directly ascend vertically to the atmosphere to breathe air. Penetration diving—involving entering caves or wrecks, or diving under ice—is therefore not "open water diving". In some contexts the lack of a decompression obligation is considered a necessary condition for classification of a dive as an open water dive, but this does not affect the classification of the venue as open water.

<span class="mw-page-title-main">Night diving</span> Underwater diving during the hours of darkness

Night diving is underwater diving done during the hours of darkness. It frequently refers specifically to recreational diving which takes place in darkness. The diver can experience a different underwater environment at night, because many marine animals are nocturnal.

<span class="mw-page-title-main">Surface marker buoy</span> Buoy towed by a scuba diver to indicate the divers position

A surface marker buoy, SMB, dive float or simply a blob is a buoy used by scuba divers, at the end of a line from the diver, intended to indicate the diver's position to people at the surface while the diver is underwater. Two kinds are used; one (SMB) is towed for the whole dive, and indicates the position of the dive group throughout the dive, and the other, a delayed surface marker buoy, DSMB or decompression buoy, is deployed towards the end of the dive as a signal to the surface that the divers have started to ascend, and where they are going to surface. Both types can also function as a depth reference for controlling speed of ascent and accurately maintaining depth at decompression stops. Surface marker buoys are also used by freedivers in open water, to indicate the approximate position of the diver when submerged. They may also be used to support a catch bag or fish stringer by underwater hunters and collectors. A DSMB is considered by recreational scuba divers and service providers to be a highly important item of safety equipment, yet its use is not part of the entry level recreational diver training for all training agencies, and there are significant hazards associated with incompetent use.

<span class="mw-page-title-main">Diver communications</span> Methods used by underwater divers to communicate

Diver communications are the methods used by divers to communicate with each other or with surface members of the dive team. In professional diving, diver communication is usually between a single working diver and the diving supervisor at the surface control point. This is considered important both for managing the diving work, and as a safety measure for monitoring the condition of the diver. The traditional method of communication was by line signals, but this has been superseded by voice communication, and line signals are now used in emergencies when voice communications have failed. Surface supplied divers often carry a closed circuit video camera on the helmet which allows the surface team to see what the diver is doing and to be involved in inspection tasks. This can also be used to transmit hand signals to the surface if voice communications fails. Underwater slates may be used to write text messages which can be shown to other divers, and there are some dive computers which allow a limited number of pre-programmed text messages to be sent through-water to other divers or surface personnel with compatible equipment.

<span class="mw-page-title-main">Distance line</span> Line deployed by scuba divers for navigation

A distance line, penetration line, cave line or guide line is an item of diving equipment used by scuba divers as a means of returning to a safe starting point in conditions of low visibility, water currents or where pilotage is difficult. They are often used in cave diving and wreck diving where the diver must return to open water after a penetration when it may be difficult to discern the return route. Guide lines are also useful in the event of silt out.

<span class="mw-page-title-main">Diving shot</span> Substantial weighted near-vertical line with buoy

A diving shot line, shot line, or diving shot, a type of downline or descending line, is an item of diving equipment consisting of a ballast weight, a line and a buoy. The weight is dropped on the dive site. The line connects the weight and the buoy and is used by divers to as a visual and tactile reference to move between the surface and the dive site more safely and more easily, and as a controlled position for in-water staged decompression stops. It may also be used to physically control rate of descent and ascent, particularly by surface-supplied divers.

<span class="mw-page-title-main">Runnel Stone</span>

The Runnel Stone, or Rundle Stone, is a hazardous rock pinnacle about 1-mile (1.6 km) south of Gwennap Head, Cornwall, United Kingdom. It used to show above the surface at low water until a steamship struck it in 1923.

<span class="mw-page-title-main">Dive boat</span> Boat used for the support of scuba diving operations

A dive boat is a boat that recreational divers or professional scuba divers use to reach a dive site which they could not conveniently reach by swimming from the shore. Dive boats may be propelled by wind or muscle power, but are usually powered by internal combustion engines. Some features, like convenient access from the water, are common to all dive boats, while others depend on the specific application or region where they are used. The vessel may be extensively modified to make it fit for purpose, or may be used without much adaptation if it is already usable.

<span class="mw-page-title-main">Diver navigation</span> Underwater navigation by scuba divers

Diver navigation, termed "underwater navigation" by scuba divers, is a set of techniques—including observing natural features, the use of a compass, and surface observations—that divers use to navigate underwater. Free-divers do not spend enough time underwater for navigation to be important, and surface supplied divers are limited in the distance they can travel by the length of their umbilicals and are usually directed from the surface control point. On those occasions when they need to navigate they can use the same methods used by scuba divers.

<span class="mw-page-title-main">Canoe and kayak diving</span> Recreational diving from a canoe or kayak

Canoe diving and Kayak diving are recreational diving where the divers paddle to a diving site in a canoe or kayak carrying all their gear in or on the boat to the place they want to dive. Canoe or kayak diving gives the diver independence from dive boat operators, while allowing dives at sites which are too far to comfortably swim, but are sufficiently sheltered.

An underwater acoustic positioning system is a system for the tracking and navigation of underwater vehicles or divers by means of acoustic distance and/or direction measurements, and subsequent position triangulation. Underwater acoustic positioning systems are commonly used in a wide variety of underwater work, including oil and gas exploration, ocean sciences, salvage operations, marine archaeology, law enforcement and military activities.

<span class="mw-page-title-main">Diving equipment</span> Equipment used to facilitate underwater diving

Diving equipment is equipment used by underwater divers to make diving activities possible, easier, safer and/or more comfortable. This may be equipment primarily intended for this purpose, or equipment intended for other purposes which is found to be suitable for diving use.

<span class="mw-page-title-main">Alligator Reef</span>

Alligator Reef is a coral reef located within the Florida Keys National Marine Sanctuary. It lies to the southeast of Upper Matecumbe Key. This reef lies within a Sanctuary Preservation Area (SPA).

Underwater searches are procedures to find a known or suspected target object or objects in a specified search area under water. They may be carried out underwater by divers, manned submersibles, remotely operated underwater vehicles, or autonomous underwater vehicles, or from the surface by other agents, including surface vessels, aircraft and cadaver dogs.

Save Ontario Shipwrecks (SOS) is a Provincial Heritage Organization in Ontario, Canada. SOS is a public charitable organization which operates through Local Chapter Committees supported by a Provincial Board of Directors and Provincial Executive.

<span class="mw-page-title-main">Decompression equipment</span> Equipment used by divers to facilitate decompression

There are several categories of decompression equipment used to help divers decompress, which is the process required to allow divers to return to the surface safely after spending time underwater at higher ambient pressures.

<span class="mw-page-title-main">Outline of underwater diving</span> Hierarchical outline list of articles related to underwater diving

The following outline is provided as an overview of and topical guide to underwater diving:

<span class="mw-page-title-main">Index of underwater diving</span> Alphabetical listing of underwater diving related articles

The following index is provided as an overview of and topical guide to underwater diving:

In underwater diving, a downline is a piece of substantial cordage running from a point at the surface to the underwater workplace, and kept under some tension. It can be used as a guideline for divers descending or ascending, for depth control in blue-water diving, and as a guide for transfer of tools and equipment between surface and diver by sliding them along the downline at the end of a messenger line. A shotline is a special case of downline which uses a heavy weight at the bottom and a float at the top. A jackstay is a more lateral equivalent, that commonly follows a surface, and will not usually allow materials transfer without a messenger line from the destination end.


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