What is a dive computer?
A dive computer or decompression meter is an electronic device used by a scuba diver to measure the dive profile (depth, bottom time etc) and to display information needed for a safe dive, avoiding decompression sickness. Dive computers essentially address the same problem as decompression tables - telling scuba divers safe limits for how deep they can go and how long they can stay down there - but dive computers provide this information dynamically instead of as table readings before/after a dive:
How does a dive computer work?
The dive computer performs a continuous calculation of gases in the body based on the actual dive profile (the time spent at different depths dyring the dive). 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.
A main differentiator between different brands of dive computers (beyond look and feel, price and obvious features (backlight, audible alarms etc)) is which algorith they use: there's the Haldanian algorithm, Suunto's Reduced Gradient Bubble Algorithm and a number of others with various merits, used by different manufacturers.
Debate is neverending about which algorithms provides the best results, quite frankly, nitrogen gas bubble formation in human tissue ("the bends") seems to be a field in biology that isn't particularly well-understood.
A key thing is that different algorithms and different dive computers ' implementation of those algorithms can be more or less conservative or aggressive: An "aggressive" computer gives more bottom time than a "conservative" one does, and it's wise to understand the properties of one's own dive computer to ensure it fits the skill and comfort level expected.
Anders Jacobsen |