A Guide to Dive Computer Algorithms

A Guide to Dive Computer AlgorithmsWhile it may seem complicated at first glance, the definition of dive computer algorithm is actually quite simple. It is a formula that dive computers use to determine level of depth, gas mix, and time at a given depth during a diving session. Depending on the type of algorithm a dive computer possesses, it can also monitor other types of data such as the length of time you’re safe underwater, so as to prevent the risk of decompression sickness (DCS).

As of this writing, there are quite a few type of algorithms being used by leading brands of dive computers. Each of them uses their own proprietary computations and either conservative or liberal leanings. Conservative algorithms reduce the risk or occurrence of DCS by setting a particular time limit for every diving stint. Liberal algorithms, on the other hand, allow you to dive for longer times. But apparently, this exposes you to the risk of getting DCS. For instance, the PADI Recreational Dive Planner utilizes a DSAT algorithm; while Suunto Dive Computers use Reduced Gradient Bubble Model (RGBM) algorithms. More often than not, different algorithms provide different data because they are designed for various circumstances and diver types.

How Algorithms Work

Once installed into your dive computer, algorithms track time and depth within an interval of seconds or so. Using this information, the device computes nitrogen consumption and all other factors covered by the algorithm itself. These measurements also determine the saturation and desaturation of nitrogen while converting them into a digital readout for the diver to view. The great thing about algorithms these days is that they are good at monitoring multi-level diving. At the same time, they help computers in performing other function such as ascent rate monitoring. Keep in mind though, that not all dive computers perform in the same manner. But despite the algorithm being used, most dive computers are able to tell the following data.

During the Dive

  • Order of dive (1st, 2nd, 3rd, etc.)
  • Depth
  • Time elapsed since time of submersion
  • Ascent speed
  • Temperature of water

After the Dive

  • Total depth of dive
  • Time allotment for next dive at various depth levels
  • Time for safe desaturation

Some algorithms are more conservative than others. Some types even allow you to add a particular level of safety measure if you’d like. Majority of models these days can do Nitrogen dives for up to 40%. Others, however, can accommodate other types of gasses by extending their functions. At the moment, some models are also geared with various features, targeting users of different kinds.

Are Dive Computer Algorithms Accurate?

Yes, they produce computations that are pretty accurate. But, do they prevent the bends? The response to this would be “yes” and “no”.

Yes because most divers follow their computers, so most of the time they don’t develop the bends. As compared to dive tables, dive computer algorithms are way more conservative. The average allowed ascent rate at above 60 fsw is 30-35 feet per minute. Once you’re rising too rapidly, the computer’s screen will flash slowly or emit an audible sound.

Generally speaking, an advanced dive computer is accurate when used appropriately. Otherwise, you might find it quite unreliable.

So What Makes a Good Dive Computer Algorithm?

The best algorithm actually depends on your comfort level. Some divers may need to assess more than this, especially if they have sensitive body conditions such as aging, poor physical condition, poor blood circulation, and the likes. If this is you, conservative algorithms is the best way to go. The great thing about new dive computers is that they can be programmed and adjusted to protect your safety by increasing level of conservatism.

How to Avoid Getting DCS

As mentioned above, the chances of you getting DCS during a long diving session is quite high. Here are some guidelines to keep DCS at bay:

  1. Choose a dive computer with relatively conservative algorithm.
  2. Always ascent slowly at every dive.
  3. Include additional conservatism in the computer algorithm by tweaking the device based on your preferred settings. Using higher altitude adjustments than your actual settings can also be a good option.
  4. Include extra shallow stops for safety.
  5. During a deep dive, it pays to add additional deep stops.
  6. Add long intervals of time in between dives.

Plan Your Dive and Dive Your Plan

Especially for entry-level divers, planning a dive is crucial. Using a dive computer, plan out your dive by working out with numbers until you come up with a plan that’s not hard to execute. Do not exceed your limits even though you’re tempted to. This is because it is unsafe, strenuous, and may cause danger to you and your dive buddy. Remember, as soon as you find yourself having trouble underwater, return to the shore or your boat at once.