Dive computers are by far the most common dive instruments and have become a compulsory piece of equipment as they combine your depth gauge, timer and sometimes your SPG into one single device. There are myriad of dive computers on the market nowadays, with all sorts of additional features and fancy extras, but here we explain what a dive computer must do at a bare minimum, how they work and why you use one.
What is a Dive Computer?
Worn like an ordinary wrist watch, your dive computer is a device used to measure the time and depth of a dive, so that a safe ascent profile can be calculated and displayed. Nitrogen is absorbed into your body during a dive, but even though your body can tolerate a certain amount of excess nitrogen, after a dive, too much and this can cause decompression sickness. The question is how much is too much?
Physiologists and scientists created mathematical decompression models that track the theoretical nitrogen you have in your body before, during and after diving. For practical field use, these models are expressed by dive tables and in dive computers which divers use to determine their maximum allowable time at any given depth. Therefore you can advertently avoid decompression sickness by adhering to this system, which will be displayed by your dive computer.
How do Dive Computers work?
As the dive computer measures depth and time accordingly, it is able to provide warning of excessive ascent rates and missed decompression stops. Almost all divers purchase a dive computer at some point, but it recommended that new divers have full understanding of the tables and how they work before purchasing a dive computer. This will enable the diver to understand the underlying principals of decompression sickness.
Dive computers estimate how much dissolved nitrogen you theoretically have in your body based on a decompression model (mentioned earlier).Dive computers are no more or less valid than a dive table, but take advantage of electronics to apply the model to your exact dive depths and times, constantly updating you on your allowable dive time remaining based on your individual depth. Dive computers have many advantages, not to mention they reduce the factor of human error, here's a summary of the benefits of even the most basic dive computer;
• They're more convenient to use than tables because they track your depth and time automatically, giving you time to enjoy your surroundings rather than working out your remaining dive time. This also helps to reduce human error.
• They give you more no stop time on multilevel profiles. So as you ascend, you can take up nitrogen more slowly and your dive computer credits you for this by increasing your available no decompression time. Tables must assume you spend the whole dive at the deepest depth you reach, giving you much shorted no stop times. The increased dive time offered by a computer is substantial and one of the primary reasons you'll want one.
• They track your theoretical nitrogen throughout the course of an entire dive and often longer. With tables, you have to calculate different no stop times for each successive dive, which depends upon the depth and time of prior dives and how long you've been out of the water. Using an RDF, this isn't difficult but a computer is far more convenient and you'll use a computer the majority, if not all the time.