Dive computers are ubiquitous in the scuba community. As responsible divers, we should still understand the theory behind the calculations they make.

Dive computers have become ubiquitous in the dive community. In fact, many training organizations now teach decompression theory solely via dive computers, even to the point of omitting teaching dive tables. Strapping on a dive computer makes diving even more convenient, fun and accessible — no more time spent with a table trying to figure out how deep you can go, how long you can stay down and how long you need to stay on the surface before your next dive. With our reliance on dive computers increasing, we must ensure that we are using them correctly to avoid post-dive complications.

Account for your risk

Although recent statistics show a decrease in incidents that lead to decompression illness, they might not necessarily take into consideration that some dives carry a higher risk than others, including deep and multi-day diving. More-complex dives affect how your dive computer calculates decompression models, especially if you enter decompression on a dive. This could lead you to exceed the limits that your dive computer manufacturer placed on the unit.

Don’t misread your computer

You could also misunderstand the readings that your computer is giving you, or worse, ignore them. This is especially tempting if your dive buddy’s computer displays less-conservative decompression times, longer time in the water, or shorter surface intervals.

While misreading your computer can lead to post-dive complications, so too can using it incorrectly. Diving with a computer programmed to the wrong settings (this includes altitude settings and blended-gas settings) can increase your risk of post-dive complications. And diving on your buddy’s computer — while you go without — can have the same effect. Finally, misunderstanding (or even ignoring) your dive computer’s error messages can have some serious negative consequences.

How to dive safely while using a dive computer

  • Become familiar with your computer’s decompression model and error messages.
  • Never try to “cheat” your dive computer’s decompression model by hanging it on a shot line to ‘de-gas’ while on your surface interval.
  • Follow the most conservative computer in the group.
  • Use the same computer for all your dives on one trip. Do not change your computer to one that has a clear profile (no residual nitrogen reading) in between dives.
  • Monitor your air throughout your dive. Just because you might be far from your decompression limit in minutes doesn’t mean that you have enough breathing gas.
  • Consider diving with two dive computers and following the most conservative one.

Staying safe

While it is impractical to return to dive tables, it is beneficial to have a thorough grasp of how they work and the decompression theory behind them. This knowledge will give you a better understanding of how your dive computer works.

While diving is becoming safer, becoming complacent or overly reliant on your equipment without fully understanding how it works can place you at a higher risk of suffering post-dive complications. It is therefore important that you know how your computer works, what the error messages mean, and to always dive the more-conservative profile.

 

 

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