Scuba Diving Computers FAQ

1. What is a dive computer used for?

Dive computers are used to increase diver safety.  They are used by scuba divers to measure the depth and time of a dive.  This will allow the easy calculation of a safe ascent rate which will help to avoid problems such as decompression sickness.

2. Can dive computers replace compression tables?

Dive computers can replace decompression tables and have the benefit of being much easier to use.  Once you have input the main dive data the computer will automatically calculate the pressure of inert gases in the body during a dive.  The dive computer will monitor the depth and time of the dive and warn divers of missed decompression stops or excessive ascension rates.

3. Are dive computers suitable for beginners?

Dive computers are ideal for beginners as this means you will not have to work out decompression tables and carry a separate dive watch and depth gauge on your dive.  Dive computers make it much easier for you to dive safely and will alert you if any problems with decompression are sensed.

4. What data can dive computers display?

As well as measuring depth and time dive computers can also display additional information such as water temperature, oxygen toxicity and diving cylinder pressure. 

5. Why are dive computers safer than compression tables?

Because dive computers are constantly working to monitor and provide new data the diver has access to real time information about their dive.  This can create a much safer diving environment and can allow the diver to stay underwater for longer periods of time.  Compression tables need to be worked out manually and there is some element of guess work involved.  This is because the calculations are based on certain mathematical premises.  Dive computers can quickly and accurately assimilate dive data and tell the diver what they need to know about tank pressure, temperature, depth and dive time.

6. Can dive computers be used for multi-level dives?

Dive computers are essential for safely calculating multi-level dives.  These types of dive can be planned with dive tables but these can be complex and difficult to follow when you are underwater.  Computers will provide automatic alerts telling you when it is safe to ascend which leaves you free to concentrate on your diving experience.

7. Are there any wide display dive computers available?

There is a trend in modern electronics to miniaturisation devices.  This is true of diving computers but smaller displays are not actually that helpful when you are in underwater conditions.  It can be difficult to read small digits when you have a face mask on and are diving in conditions that are cloudy or have poor light.   Also more mature divers and those that need prescription goggles may struggle to read small display dive computers.  However there are a few wide display dive computers on the market such as the Nemo Wide Dive Computer from Mares.  This has a larger display screen which is much easier to read under water.  This design features a special high contrast display with large digits and a superior back light function which improves visibility in most conditions. There are four easy to use buttons which allow you to set the computer up for each dive.   These wider dive computers are still compact enough to wear comfortably on your wrist but are much easier to read when you are underwater.

8.  How are dive computers powered?

Dive computers are battery operated.  Some models offer rechargeable battery options others you will need to replace with a new battery now and again.  The watertight case keeps the internal electronics components dry and free from salt and other corrosive influences.  When you are changing the battery you do need to be very careful not to damage the casing or seals which could compromise the integrity of the dive computer unit.  Before each dive you need to check the dive computer and make sure the battery is powered up and the device in full working order. You should also check the computer after a dive as well to make sure no damage has occurred and the battery is fully operational.  This will give you a chance to make any repairs or replacements before your next dive.

9.  How do dive computers assist with ascension rates?

Divers need to ascend slowly as they return from depths to the surface.  This is because there are different pressure levels to pass through that can significantly affect the gases in the body.  By ascending slowly the body can adjust to new pressure levels gradually and this prevents problems such as decompression sickness.  Ascension rates can vary depending on the depth and time of the dive. Dive computers will automatically calculate the correct ascension rates for each dive and will alert divers if they are ascending too fast.  This is a great safety feature and is much more consistent then decompression tables which rely on the accuracy of the manual calculations and do not automatically adapt to changing conditions.

10. What are air integrated dive computers?

Air integrated dive computers add another layer of protection for divers.  As well as calculating accurate information on depth, time and decompression these computers also measure cylinder pressure and remaining air time.  This is a useful tool as air time can vary depending on the diver's individual consumption rate, depth and diving conditions.  This makes it difficult to accurately estimate air tank time manually.  Air integrated dive computers are connected to the air tank and can provide real time information on pressure and remaining air time.  This increases diver safety and can help to prevent any ‘out of air’ emergencies from occurring on dives.