|
Night Diving
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. There are additional hazards when diving in darkness, such as dive light 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 computers and diving cylinder 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 dive light, and adequate protection from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 recreational diving which requires more training and experience to develop the competence to reliably manage more complex equipment in the more hazardous conditions associated with the disciplines. Breath-hold diving for recreation also fits into the broader scope of the term, but this article covers the commonly used meaning of ''scuba diving for recreational purposes, where the diver is not constrained from making a direct near-vertical ascent to the surface at any point during the dive'', and risk is considered low. The equipment used for recreational diving is mostly open circuit scuba, though semi closed and fully automated electronic closed circuit rebreathers may be included in the scope of recreational diving. Risk is managed by tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. Marine organisms, mostly microorganisms, produce oxygen and sequester carbon. Marine life in part shape and protect shorelines, and some marine organisms even help create new land (e.g. coral building reefs). Most life forms evolved initially in marine habitats. By volume, oceans provide about 90% of the living space on the planet. The earliest vertebrates appeared in the form of fish, which live exclusively in water. Some of these evolved into amphibians, which spend portions of their lives in water and portions on land. One group of amphibians evolved into reptiles and mammals and a few subsets of each returned to the ocean as sea snakes, sea turtles, seals, manatees, and whales. Plant forms such as kelp and other algae grow in the wat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nocturnal
Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed senses of hearing, smell, and specially adapted eyesight. Some animals, such as cats and ferrets, have eyes that can adapt to both low-level and bright day levels of illumination (see metaturnal). Others, such as bushbabies and (some) bats, can function only at night. Many nocturnal creatures including tarsiers and some owls have large eyes in comparison with their body size to compensate for the lower light levels at night. More specifically, they have been found to have a larger cornea relative to their eye size than diurnal creatures to increase their : in the low-light conditions. Nocturnality helps wasps, such as ''Apoica flavissima'', avoid hunting in intense sunlight. Diurnal animals, including squirrels and songbirds, are active du ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Diving Hazards And Precautions
Divers face specific physical and health risks when they go underwater with scuba or other diving equipment, or use high pressure breathing gas. Some of these factors also affect people who work in raised pressure environments out of water, for example in caissons. This article lists hazards that a diver may be exposed to during a dive, and possible consequences of these hazards, with some details of the proximate causes of the listed consequences. A listing is also given of precautions that may be taken to reduce vulnerability, either by reducing the risk or mitigating the consequences. A hazard that is understood and acknowledged may present a lower risk if appropriate precautions are taken, and the consequences may be less severe if mitigation procedures are planned and in place. A hazard is any agent or situation that poses a level of threat to life, health, property, or environment. Most hazards remain dormant or potential, with only a theoretical risk of harm, and when a h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 routinely used during night dives and cave dives, when there is little or no natural light, but also has a useful function during the day, as water absorbs the longer (red) wavelengths first then the yellow and green with increasing depth. By using artificial light, it is possible to view an object in full color at greater depths. Need Water attenuates light by absorption, so use of a dive light will improve a diver's underwater vision at depth. As the depth increases, more light is absorbed by the water. Color absorption depends on the purity of the water - pure water is most transparent to blue frequencies, but impurities may reduce this significantly. Color vision is also affected by turbidity and larger particulate matter. History ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 the programmed decompression algorithm, will give a low risk of decompression sickness. Most dive computers use real-time ambient pressure input to a decompression algorithm to indicate the remaining time to the no-stop limit, and after that has passed, the minimum decompression required to surface with an acceptable risk of decompression sickness. Several algorithms have been used, and various personal conservatism factors may be available. Some dive computers allow for gas switching during the dive. Audible alarms may be available to warn the diver when exceeding the no-stop limit, the maximum operating depth for the gas mixture, the recommended ascent rate or other limit beyond which risk increases significantly. The display provides d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 scuba cylinder, scuba tank or diving tank. When used for an emergency gas supply for surface supplied diving or scuba, it may be referred to as a bailout cylinder or bailout bottle. It may also be used for surface-supplied diving or as decompression gas . A diving cylinder may also be used to supply inflation gas for a dry suit or buoyancy compensator. Cylinders provide gas to the diver through the demand valve of a diving regulator or the breathing loop of a diving rebreather. Diving cylinders are usually manufactured from aluminium or steel alloys, and when used on a scuba set are normally fitted with one of two common types of cylinder valve for filling and connection to the regulator. Other accessories such as manifolds, cylinder band ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diving Signals
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 wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diving Shot
A diving shot line, shot line, or diving shot, a type of downline or descending line (US Navy), is an item of diving equipment consisting of a ballast weight (the shot), 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. A "lazy shot" is a shot which is suspended above the bottom. It may be tethered to the main shot line at a convenient depth. It is used for decompression and frees the main shot line for other divers. The lazy shot's line does not need to be longer than the decompression depth and is often only deep enough for the longer stops. It only needs a weight heavy enough to provide diver buoyancy co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Marker Buoy
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 se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
