Choosing a Dive computer

Do I need a Dive Computer, and how to choose one?

You will hear many opinions on this matter, but you can dive without a dive computer. As a diver, you can track your dives using dive tables, a timing device and depth gauge. For many years, before dive computers existed, divers dove and enjoyed their experiences just as they do today. Ask yourself this question: does this tool, a dive computer help with navigation, log book information, decompression stops, mixed gas calculations and ascent rates? And is this tool beneficial? The answer to that is DEFINITELY! So, what do I look for when choosing a computer?

Why Do I Need One:

A dive computer provides real time information to the diver underwater. The diver can adjust his or her dive profile according to the information received during the actual dive. The dive computer takes depth and dive time information, it applies these to a decompression model to track the Nitrogen that has dissolved in your body during the dive. Dive computers vary, standard features are; No stop Limits, Time, Ascent Rate, Depth, Emergency Decompression, No Stop time remaining and previous dive information. A dive computer is a safe and reliable diving tool, with live information directly available.

Depth Gauge:

Dive computers are fitted with a depth gauge. They accurately record your dive depth profile as you descend and ascend from the dive. The computer will take into account depths that may negatively affect your decompression stop calculations. The real time information given to the diver has been carefully determined, so any adjustments in the dive profile will be given immediately to the diver. Safety stops and any decompression stops must be adhered to at all times. Dive computers can supplement your depth gauge, or even replace it. But remember, a backup device is always good to have.


This is an important feature for any scuba diver. The compass is a key element of a scuba divers kit, enabling you to find your way to and from shore or boat. Some dive computers offer digital compass versions, as well as the manual version. The digital version does not have to be held completely level when in use. The dive computer with a digital compass is an easy and reliable tool to use.

PC Compatible:

Some dive computers allow you to download your dive details to your personal computer. Sometimes dive computers have a storage capacity of only 10 dives. With the download method, the diver can create a permanent record on the PC of all diving activities. A software with interface is required to download your data. This purchase you will have to make, although some models now include the software with the purchase of the dive computer. The software will convert your dive into a graph. It will show various depths and ascents, the time spent at each depth and the ascent speed. More sophisticated computers show violations of ascent rates, missed decompression stops and mixed gas functions. An Air integrated dive computer monitors the air consumption of a diver during the dive.


Dive computers calculate on a real time basis, adjusting for any errors on the divers behalf. It takes out the mathematical problem of a dive and can make some life saving calculations. The basic function of a modern dive computer, is to calculate how many decompression stops (if any) need to be made, according to the depth, time and profile of your dive. If a diver inadvertently misses a deco-stop, the dive computer will perform a revised decompression stop. 

Many divers rely on air travel to get to their destination. Some computers show no-fly times, these times are calculated on your dive profile over the last days. The dive computer calculates the amount of time your body will require to eliminate the rest Nitrogen in your body. This is crucial, flying to early can cause rest Nitrogen to expand in your body, causing Decompression sickness. The dive computer will tell you how many hours you have before you can fly.

Log Book Memory:

Dive computers offer a log book memory function. Here you can review your previous dives and log them in the log book. When purchasing a computer, check how many dives the computer will log, before it starts to delete the older ones. This is important if you are travelling without a PC or log book. There is a new version App, from Aqualung for the i300c computer that brings you directly to your personal log-book.

Back Lit and Activation:

Back lighting is offered almost on all computers. This is a very useful function, especially at night, or in dark areas. Most divers would not purchase a computer that does not have this function. Dive computers usually are activated in one of two ways: either by water or by a manual button. The water contact method is preferable by many divers, usually they forget to turn it on before descending. If this happens you cannot turn it on during the dive. Most dive computers with basic functions are equally priced, when looking for more high end equipment, the price rises accordingly.

Wrist or Mounted Version:

Wrist versions are easy to wear, often fixed to a lanyard in case of loss. Wrist straps are made to fit almost anyone, and can be adjusted as required. The mounted version is attached with a hose to your regulators first stage.There is no right or wrong way here, it is solely down to preference and configuration of your dive gear.

Take Care of Your Computer:

Be familiar with your computer before going into the water. Check all buttons are functional and how to use them. Read the Instruction Manual if you have purchased a new computer. Rinse your computer thoroughly after each dive in fresh-water. Check batteries before going on the next dive.

Purchasing a Computer:

What type of diving do I do? Is the computer adequate for what i require? Think also further ahead. As your diving skills improve, so will your diving capabilities, so plan also for the future. Can your read the display, is it big enough? Do you understand the information it is giving you and does the data display make sense to you? When purchasing your computer, make sure the instruction booklet is included in the box.

We, at DiveSMART Gozo have a wide range to offer, please contact us at

Safe diving to you all.

The DiveSMART Team

Janet Bulmer @ diveSMART Gozo