Kayaking is the use of a kayak for moving over water. It is distinguished from canoeing by the sitting position of the paddler and the number of blades on the paddle. A kayak is a low-to-the-water, canoe-like boat in which the paddler sits facing forward, legs in front, using a double-bladed paddle to pull front-to-back on one side and then the other in rotation. Most kayaks have closed decks, although sit-on-top and inflatable kayaks are growing in popularity as well.
Drift diving is a type of scuba diving where the diver is transported by the water movement caused by the tide, an ocean current or in a river. The choice whether to drift dive depends on the purpose of the dive, and whether there is an option. At some sites there is almost always a current running, and at others the strength and direction of water movement may vary with the tide, or other driving forces, like wind or recent rainfall. At some sites there may be considerable variation in visibility and underwater life activity based on the speed and direction of flow.
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.
A diving weighting system is ballast weight added to a diver or diving equipment to counteract excess buoyancy. They may be used by divers or on equipment such as diving bells, submersibles or camera housings.
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 buddy check is a procedure carried out by scuba divers using the buddy system where each dive buddy checks that the other's diving equipment is configured and functioning correctly just before the start of the dive. A study of pre-dive equipment checks done by individual divers showed that divers often fail to recognize common equipment faults. By checking each other's equipment as well as their own, it is thought to be more likely that these faults will be identified prior to the start of the dive. The correct use of a well designed written checklist is known to be more reliable, and is more likely to be used by professional divers, where it may be required by occupational health and safety legislation, and by technical divers, where the equipment checks are more complex.
Scuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface breathing gas supply, and therefore has a limited but variable endurance. The name scuba is an anacronym for "Self-Contained Underwater Breathing Apparatus" and 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. Although the use of compressed air is common, a gas blend with a higher oxygen content, known as enriched air or nitrox, has become popular due to the reduced nitrogen intake during long or repetitive dives. Also, breathing gas diluted with helium may be used to reduce the effects of nitrogen narcosis during deeper dives.
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.
Diver rescue, usually 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 generally means 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.
Sidemount is a scuba diving equipment configuration which has scuba sets mounted alongside the diver, below the shoulders and along the hips, instead of on the back of the diver. It originated as a configuration for advanced cave diving, as it facilitates penetration of tight sections of cave, allows easy access to cylinder valves, provides easy and reliable gas redundancy, and tanks can be easily removed when necessary. These benefits for operating in confined spaces were also recognized by divers who conducted technical wreck diving penetrations.
Buddy breathing is a rescue technique used in scuba diving "out-of-gas" emergencies, when two divers share one demand valve, alternately breathing from it. Techniques have been developed for buddy breathing from both twin-hose and single hose regulators, but to a large extent it has been superseded by safer and more reliable techniques using additional equipment, such as the use of a bailout cylinder or breathing through a secondary demand valve on the rescuer's regulator.
Advanced Open Water Diver (AOWD) is a recreational scuba diving certification level provided by several diver training agencies. Agencies offering this level of training under this title include Professional Association of Diving Instructors (PADI), and Scuba Schools International (SSI). Other agencies offer similar training under different titles. Advanced Open Water Diver is one step up from entry level certification as a beginner autonomous scuba diver. A major difference between Autonomous diver equivalent Open Water Diver (OWD) certification and AOWD is that the depth limit is increased from 18 to 30 metres.
CMAS one-star scuba diver is the entry-level diving certification for recreational scuba diving issued by the Confédération Mondiale des Activités Subaquatiques (CMAS).
Underwater search and recovery is the process of locating and recovering underwater objects, often by divers, but also by the use of submersibles, remotely operated vehicles and electronic equipment on surface vessels.
Diving equipment, or underwater 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.
Scuba skills are skills required to dive safely using self-contained underwater breathing apparatus, known as a scuba set. Most of these skills are relevant to both open-circuit scuba and rebreather scuba, and many also apply to surface-supplied diving. Some scuba skills, which are critical to divers' safety, may require more practice than standard recreational training provides to achieve reliable competence.
The following outline is provided as an overview of and topical guide to underwater diving:
Diving support equipment is the equipment used to facilitate a diving operation. It is either not taken into the water during the dive, such as the gas panel and compressor, or is not integral to the actual diving, being there to make the dive easier or safer, such as a surface decompression chamber. Some equipment, like a diving stage, is not easily categorised as diving or support equipment, and may be considered as either.
Human factors in diving equipment design are the influences of the interactions between the user and equipment in the design of diving equipment and diving support equipment. The underwater diver relies on various items of diving and support equipment to stay alive, healthy and reasonably comfortable and to perform planned tasks during a dive.
