is the practice of going underwater, either with breathing apparatus (scuba diving
and surface supplied diving
) or by breath-holding.
Recreational diving is a popular activity (also called sports diving or subaquatics), and includes technical diving, recreational scuba diving, freediving, snuba, snorkeling and a range of competitive sports performed underwater.
Professional diving includes diving as part of one's occupation, and takes a range of diving activities to the underwater work site. Commercial diving, military diving, public safety diving and scientific diving are aspects of professional diving.
Freediving is a form of underwater diving that does not involve the use external breathing devices, but relies on a diver's ability to hold his or her breath until resurfacing. Activities include breath-hold spear fishing, freedive photography, apnea competitions, and to some degree, snorkeling.
The scope of this portal includes the technology supporting diving activities, the physiological and medical aspects of diving, the procedures of diving, underwater activities which are to some degree dependent on diving, economical and commercial aspects of diving, biographical information on notable divers, inventors and manufacturers of diving related equipment and researchers into aspects of diving,
Standard circular search pattern
Underwater searches are procedures carried out by divers in order to find a known or suspected target object or objects in a specified search area under water. There are a number of techniques in general use by Commercial, Scientific, Public service, Military, and Recreational divers. Some of these are suitable for Scuba, and some for surface supplied diving. The choice of search technique will depend on logistical factors, terrain, protocol and diver skills.
As a general principle, a search method attempts to provide 100% coverage of the search area. this is greatly influenced by the width of the sweep. In conditions of zero visibility this is as far as the diver can feel with his hands while proceeding along the pattern. When visibility is better, it depends on the distance at which the target can be seen from the pattern. In all cases then, the pattern should be accurate and completely cover the search area without excessive redundancy or missed areas. Overlap is needed to compensate for inaccuracy.