Scuba divingScuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface air supply, and therefore has a limited but variable endurance. The name "scuba", an acronym for "Self-Contained Underwater Breathing Apparatus", was coined by Christian J. Lambertsen in a patent submitted in 1952. Scuba divers carry their own source of breathing gas, usually compressed air, affording them greater independence and movement than surface-supplied divers, and more time underwater than free divers.
Underwater divingUnderwater diving, as a human activity, is the practice of descending below the water's surface to interact with the environment. It is also often referred to as diving, an ambiguous term with several possible meanings, depending on context. Immersion in water and exposure to high ambient pressure have physiological effects that limit the depths and duration possible in ambient pressure diving.
Recreational divingRecreational 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.
Diver rescueDiver rescue, following an accident, is the process of avoiding or limiting further exposure to diving hazards and bringing a diver to a place of safety. A safe place is often a place where the diver cannot drown, such as a boat or dry land, where first aid can be administered and from which professional medical treatment can be sought. In the context of surface supplied diving, the place of safety for a diver with a decompression obligation is often the diving bell.
Diving helmetA diving helmet is a rigid head enclosure with a breathing gas supply used in underwater diving. They are worn mainly by professional divers engaged in surface-supplied diving, though some models can be used with scuba equipment. The upper part of the helmet, known colloquially as the hat or bonnet, may be sealed directly to the diver using a neck dam, connected to a diving suit by a lower part, known as a breastplate, or corselet, depending on regional language preferences.
Diver trainingDiver training is the set of processes through which a person learns the necessary and desirable skills to safely dive underwater within the scope of the diver training standard relevant to the specific training programme.
ShipwreckA 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. There were approximately three million shipwrecks worldwide as of January 1999, according to Angela Croome, a science writer and author who specialized in the history of underwater archaeology (an estimate rapidly endorsed by UNESCO and other organizations). When a ship's crew has died or abandoned the ship, and the ship has remained adrift but unsunk, they are instead referred to as ghost ships.
SwimfinSwimfins, swim fins, diving fins, or flippers are finlike accessories worn on the feet, legs or hands and made from rubber, plastic, carbon fiber or combinations of these materials, to aid movement through the water in water sports activities such as swimming, bodyboarding, bodysurfing, float-tube fishing, kneeboarding, riverboarding, scuba diving, snorkeling, spearfishing, underwater hockey, underwater rugby and various other types of underwater diving.
List of diving hazards and precautionsDivers 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.
Underwater archaeologyUnderwater archaeology is archaeology practiced underwater. As with all other branches of archaeology, it evolved from its roots in pre-history and in the classical era to include sites from the historical and industrial eras. Its acceptance has been a relatively late development due to the difficulties of accessing and working underwater sites, and because the application of archaeology to underwater sites initially emerged from the skills and tools developed by shipwreck salvagers.