How Do Dive Computers Work?



To be an exceptional diver, commercial divers must be prepared and have a plan when they submerge, in order to get their tasks completed responsibly, without jeopardizing their safety.  Divers can work in many job fields, such as welding, repairing ships, construction, and various kinds of inspection.  Other divers even specialize in photography and exploratory studies of underwater life.  Divers have a responsibility to be prepared, and this means that they always need to have the proper equipment with them to ensure a safe job.  One of the most important pieces of technology that a diver possesses is a dive computer.

oceanic dive computer

What Is A Dive Computer?

A dive computer is most often found in the form of a watch, and serves to monitors a diver’s depth, temperature, their safe time to be underwater, and many additional options depending on the type of computer that you purchase. The main purpose of the computer is to track the nitrogen and oxygen levels, and give the diver a time period that is safe for them to be under water.

Here is an overview of the Cressi Leonardo dive computer, giving an overview of how this popular model works.

Dive computers are able to record a diver’s nitrogen levels, and compare how much nitrogen is in the body, to how much is being expelled as the diver breathes.  Many possess the ability to automatically update statistics and give you adjusted decompression times and depths when it comes to altitude diving.  An air integrated computer can actually count down the remaining minutes of a dive at a certain depth.  Dive computers may be used in the form of:

  • Wristwatch
  • Wrist Mount- are usually larger, but more natural while exploring
  • Console Models- available in one, two, or three configurations that offer the ability to have a pressure gauge, and the third adding a compass

It is important to understand how to read measurements without risking getting decompression sickness.  Decompression sickness is when a diver has nitrogen build up in the tissues of the body which causes muscle pain, joint pain, and at times even paralysis.  To help you avoid this potentially fatal sickness, a dive computer can calculate depth, and give you an accurate reading for how deep you are, and how much time you have before you should go up again.

Watch this informative video on decompression sickness to get more details on the condition.

Mechanical dive computers commonly use a Bourdon tube pressure gauge, which includes a spiral tube filled with oil with a closed in gauge and a diaphragm on the end. As the diver descends into the water, pressure pushes the diaphragm and straightens the tube.  This degree is put into the measurements as water depth.       

 bourdon tube 2

The right algorithm is important for a dive computer, and for a diver’s safety.  An algorithm is a dive table that is built into the dive computer watch.  Two common types of algorithms are conservative and liberal algorithms.  Conservative algorithms limit dive time, and as a result lessen the risk of decompression sickness.  Liberal algorithms are the opposite, by allowing a longer dive time, but increasing the possibility of decompression sickness.

dualalgor chart

Different companies may use variations of algorithms for its dive computer. Other diving algorithms include:

DSAT Algorithm (Oceanic Dual Algorithm)

Oceanic Dive Computers not only possess a detailed algorithm for maximum diving possibilities, but two.  This gives divers the opportunity to achieve longer dives.  The two options for algorithms are the Pelagic DSAT and Pelagic Z+.  The Pelagic DSAT is based upon the original PADI Recreational Dive Planner that is used by many different companies.  It is used to determine time by calculating No Decompression Time, Surface Interval time, which is the time you spend out of the water, and Adjusted No Decompression Time.  The Pelagic Z+ algorithm uses the Buhlmann ZHL-16 findings and helps achieve maximum dive times at lower depths. It also adjusts to colder climates.

Oceanic Geo 2.0 Air/Nitrox Computer Watch

RGBM (Reduced Gradient Bubble Model)

Suunto diving computers use the RGBM algorithm for its devices, and have even worked with professionals to maximize the usefulness in its products by producing other available algorithms such as Suunto Technical and Suunto Fused.  Suunto Technical allows divers to achieve depths as low as 120m, and is the first to include helium in breathing mixes.  Suunto Fused brings the best features together included in RGBM and Technical combined.  It supports dives as low as 150m, and automatically chooses between the accepted dual algorithm models to decrease the risk of decompression sickness in each dive.  Technological advances in dive computers are making an impressive change in divers’ experiences.  Whether you are a new or experienced diver, dive computers will always have a major impact on your diving explorations.

  • Decompression – updated nanotechnology may bring a cure to the problem of decompression sickness.  It is reported that scientists are in the process of creating a pill that could prevent nitrogen build up in the body.
  • Color screens provide a personal touch to individual wrist watches.
  • Dual algorithms provide multiple uses and adapt to each dive.  Some dive computers are able to adapt and switch between algorithms, depending on depth, nitrogen level, and surface time.
  • Integrated Wireless gas gauge
  • Larger screens can include temperature measurements, gas mix ratios, and time to surface readings.  It allows easier screen reading in darker or murky water.
  • Increased safety stops, ensuring safety at varying depths, protect the diver. Stops may even be based on previous times, depths, and recorded nitrogen levels in past dives.


About the author: Garth loves camping under the stars with his Arb III, scuba diving, snorkeling, and also tanning. His favourite snorkel spots include Alanya (Turkey), Koh Rong (Cambodia), and Maui (Hawaii, USA). He also loves to visit the cenotes in Mexico and he recommends everyone reads the book, “The Soul of an Octopus”, because, he says “they are sensitive, just like me”.