Dive Computers

One of the most useful pieces of kit for divers in this day and age is a dive computer. When we start to dive, we all learn to use the Recreational Dive Planner or some other form of tables, but most people will soon progress on to a dive computer.

A dive computer allows you to get far more out of your diving, especially if you are doing multiple dives a day, such as on a liveaboard. Dive computers come in all shapes and sizes. Some are wrist-mounted, others fit into your instrument console.

Some are fairly straightforward, others contain all manner of gadgets. However, a common feature is that they all contain algorithms which track your dive profile and alter your no-decompression time accordingly. Thus, with a dive computer, you can drop down a wall, for instance, and then, when the NDL gets to around five minutes, you can come up 5m or so shallower and the NDL will increase.

It is possible to repeat this process until you are so shallow you begin to off-gas and your NDL shoots up as you near your safety stop depth. You get far longer in the deeper sections of the dive than you would using tables, or even the PADI ‘Wheel’.

A dive computer not only allows you to lengthen the time spent underwater by adjusting your NDL to match your profile, it also keeps track of residual nitrogen left in your system, important for when you are doing multiple daily dives.

The vast majority of dive computers can now also handle at least one nitrox mix, if not two or even three, and some even have a digital compass incorporated into their display.

Some dive computers are also air-integrated, which means they show you how much air you have left in your cylinder and calculate your remaining time underwater given your air supply, depth and NDL.

They can either be mounted on a high-pressure hose from your first stage, or be wrist-mounted and communicate with a wireless transmitter attached to the first stage. Some dive computers have user-replaceable batteries, others have to be sent back to the manufacturer.

Dive Computer Reviews

All the dive computers tested here fulfilled their role as a wristwatch dive computer. They all tell the time and have all the usual watch features, as well as being capable of dealing with at least one nitrox mix and full-decompression dives. Any of them would be more than adequate as a dive computer for use abroad or on regular UK dives.

However, there is a vast difference in prices. In terms of the Best Value award, the recent price hike on the Suunto D4 – which used to retail for under £300 – put it out of the running, leaving the Seemann Sub XP-1 to battle it out with the Oceanic Geo. All the testers like the Geo’s large digits and non-restrictive algorithm, but the new XP-1 took the award.

The test team praised its compact size and by-the-second safety stop countdown, and while we found the very conservative algorithm slightly restrictive, the fantastic price meant it had to come in first.

When it came to the Choice award, there were various candidates. If you want the ‘bling, bling’ look and money is absolutely no object, then the titanium-bracelet version of the Suunto D9 has to be considered. It can handle three nitrox mixes, has a transmitter and an integral digital compass, meaning it can cope with pretty much any diving requirement except trimix, but that is an awful lot of money.

The Suunto D6 was also in the running, with its good looks, two nitrox mix capability and integral compass, but the recent price hike had bumped that up into the territory of the Oceanic Atom 2.0, which comes in at less than half the price of the D9 and nearly £100 less than the D6, yet can handle three nitrox mixes and no less than three transmitters. It doesn’t look as aesthetically pleasing as the D6 or D9, but at that price and with that level of ability, it had to take the Choice award. 

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