Dive Computers

A dive computer or decompression meter is a device used by a scuba diver to measure the time and depth of a dive so that a safe ascent rate can be calculated and displayed so that the diver can avoid decompression sickness.

Dive computers address the same problem as decompression tables, but are able to perform a continuous calculation of the partial pressure of inert gases in the body based on the actual depth and time profile of the diver. As the dive computer automatically measures depth and time, it reduces the need for the diver to carry a separate watch and depth gauge and is able to warn of excessive ascent rates and missed decompression stops. Many dive computers also provide additional information to the diver, for example, the water temperature, information on the diver's oxygen toxicity or the pressure of the remaining breathing gas in the diving cylinder.

Because of the computer's ability to continually re-calculate based on changing data, the diver can gain the ability to safely remain underwater for longer periods of time using an equal volume of gas. For example, a recreational diver who plans to stay within "no-decompression" limits can simply ascend a few feet at a time (while continuing the dive) in order to remain within safe limits, rather than adhering to a pre-planned bottom time and ascending directly. So-called multi-level dives can be planned with traditional dive tables, but the additional calculations become complex and the plan may be cumbersome to follow. Computers allow for a certain amount of spontaneity during the dive.