divers

Underwater diving is the practice of going underwater, either with breathing apparatus (scuba diving and surface supplied diving) or by breath-holding (freediving). Atmospheric diving suits may be used to isolate the diver from the effects of high ambient pressure, or the saturation diving technique can be used to reduce the risk of decompression sickness after deep dives. Diving activities are restricted to relatively shallow depths, as even armored atmospheric diving suits are unable to withstand the pressures of the deeper waters of the world. Diving is also restricted to conditions which are not excessively hazardous, though the level of risk acceptable to the diver can vary considerably. Occasionally divers may dive in liquids other than water. The term deep sea diving refers to underwater diving, usually with surface supplied equipment, and often refers specifically to the use of standard diving dress with the traditional copper helmet. Hard hat diving is any form of diving with a helmet, including the standard copper helmet, other forms of free-flow helmet and lightweight demand helmets. Recreational diving is a popular activity (also called sports diving or subaquatics). Technical diving is a branch of recreational diving. Professional diving (commercial diving, diving for scientific research purposes or diving for financial gain) takes a range of diving activities to the underwater work site. Public safety diving is the underwater work done by law enforcement, fire rescue, and search & rescue/recovery dive teams, and may be done by professionals or volunteers. Military diving includes combat diving, clearance diving and ship’s husbandry diving. Underwater sports is a group of competitive sports using either free-diving, snorkelling or scuba technique, or a combination of these techniques. Training, types of equipment used and breathing gases used depend on the type of diving.