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. A secondary function is to record the dive profile, warn the diver when certain events occur, and provide useful information about the environment.
Hydrospace Explorer Trimix and rebreather dive computer. Suunto Mosquito with aftermarket strap and iDive DAN recreational dive computers
iDive DAN personal dive computer display showing decompression requirement and other data during a dive The central band shows time to surface from current depth, stop depth and stop time.
The dive computer eliminated the previously mandatory interconnected use of three pieces of equipment: diving watch (top right), depth gauge (bottom right) and waterproof decompression table (left).
A dive computer incorporating Nitrox functions (Suunto Vyper Air)
Underwater 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. Humans are not physiologically and anatomically well-adapted to the environmental conditions of diving, and various equipment has been developed to extend the depth and duration of human dives, and allow different types of work to be done.
Surface-supplied divers riding a stage to the underwater workplace
Mild barotrauma to a diver caused by mask squeeze
Views through a flat mask, above and below water
Recreational breath-hold divers in basic equipment with floats and catch bags suitable for collecting lobster or shellfish