Night diving is underwater diving done during the hours of darkness. It frequently refers specifically to

recreational diving Recreational diving or sport diving is diving for the purpose of leisure and enjoyment, usually when using scuba equipment. The term "recreational diving" may also be used in contradistinction to "technical diving", a more demanding aspect of ...

which takes place in darkness. The diver can experience a different underwater environment at night, because many

marine animal Marine life, sea life, or ocean life is the plants, animals and other organisms that live in the salt water of seas or oceans, or the brackish water of coastal estuaries. At a fundamental level, marine life affects the nature of the planet. M ...

s are nocturnal. There are additional

hazards A hazard is a potential source of harm. Substances, events, or circumstances can constitute hazards when their nature would allow them, even just theoretically, to cause damage to health, life, property, or any other interest of value. The probabi ...

when diving in darkness, such as

dive light A dive light is a light source carried by an underwater diver to illuminate the underwater environment. Scuba divers generally carry self-contained lights, but surface supplied divers may carry lights powered by cable supply . A dive light is ...

failure. This can result in losing vertical visual references and being unable to control depth or buoyancy, being unable to read instruments such as

dive computer A dive computer, personal decompression computer or decompression meter is a device used by an underwater diver to measure the elapsed time and depth during a dive and use this data to calculate and display an ascent profile which according to th ...

s and

diving cylinder A diving cylinder or diving gas cylinder is a gas cylinder used to store and transport high pressure gas used in diving operations. This may be breathing gas used with a scuba set, in which case the cylinder may also be referred to as a sc ...

contents gauges, and potential separation from the rest of the diving group, boat, or shore cover. Even with a functioning light, these hazards are still present in night diving. Backup lights are recommended.''NOAA Diving Manual, 4th Edition'' CD-ROM prepared and distributed by the National Technical Information Service (NTIS)in partnership with NOAA and Best Publishing Company Normal requirements for night diving are a

, and adequate protection from exposure. Some precautions and skills for night diving include: avoiding shining the light in other divers' eyes, to be aware of and use surface light

signals In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The ''IEEE Transactions on Signal Processing'' ...

for bearings, and if appropriate to use an illuminated shotline buoy. A surface marker buoy with an attached

strobe light A strobe light or stroboscopic lamp, commonly called a strobe, is a device used to produce regular flashes of light. It is one of a number of devices that can be used as a stroboscope. The word originated from the Ancient Greek ('), meaning ...

or cyalume stick can be used to indicate the position of the divers to the surface team. The use of a strobe light by a diver under water can damage the night vision of other divers.

Training and certification

Several diver certification agencies offer specialty training in night diving, but professional diver training will usually include it in entry level training as it is considered a normal part of occupational diving.Staff, South African Department of Labour, (2007), ''Class IV Training Standard Revision 5.03 October 2007''

Recovering divers

If the team surfaces away from the boat, dive lights can be used to signal the dive boat. A surface marker buoy can be illuminated with a dive light at night to increase the visibility of the dive team to the boat. Mirrors or other reflective surfaces can also be used to increase visibility of the team on the surface.

References

External links

Night Diving Guide
*https://web.archive.org/web/20160303183616/http://www.divinglore.com/RecreationalNightDiving.htm {{authority control Underwater diving procedures