It is recommended to buy your own dive computer as one of the first pieces of equipment, but why it is so important to have your own dive computer?
- to know your profile (not the one of your dive guide or buddy or the person who used the rental computer before)
- you know the settings (rental could have some stuff set differently)
- you know the display (especially at depth when your thinking is slower it might be difficult to understand what the computer tries to tell you)
The dive computer is your buddy during the dives and will keep you safe.
A wide variety of features are available. Most recreational divers will not need half of what many of the computers can do.
It might get confusing to find the right one as there are many different brands and models. Every diver and dive shop will probably recommend different models. Don’t worry too much about choosing the wrong computer. Most available models will meet all basic needs of a recreational diver.
And then there is an incredible amount of more sophisticated devices offering all kinds of features which you might not need.
Important criteria to consider when purchasing the right computer are
- diving level
- big buttons
- wrist or console
- air integration
- user replaceable battery
- connectivity to pc
- integrated compass
- easy to read
- altitude diving
- deep stop
- freedive mode
- any other fancy extras
The most economic computers cost under USD 200 and the most expensive way over USD 1000. Try to find your must-have features and then compare prices.
All the well-known brands are fine and will do the job. If you just want one without spending a lot of money get the cheapest you can find like Mares Puck for USD 150, Suunto Zoop for USD 180, Cressi Leonardo for USD 200. These are all a bit larger wrist models. Nothing to wear all the time but they do all you need.
A diver who just finished their open water course and one doing 300 dives per year including technical diving have completely different needs.
For beginners a simpler model is more advisable as the extra features might make it more complicated and can cause a lot of fiddling around underwater. The chances are also higher to confuse the settings. If you are looking into a starting model I can recommend simpler versions like (Suunto Zoop, Mares Puck, Cressi Leonardo, Cressi Giotto, Scubapro Aladin)
If you need further features later on your first buy can be used as a back-up. It’s nice anyway to have one in case the main computer breaks or gets lost.
Most divers I know wear computers in watch size, me included. Like this the computer remains where it is all the time – I don’t even take it off at night! The computer becomes my watch when I am on a dive trip.
Other divers may need bigger buttons as they dive in cold water with thick gloves. A small wrist watch style computer might then be hard to use.
Good choices are then the computers with big screens like listed above or the entry-level computers which are often a big bigger and only have a few large buttons.
Wrist or console
While some people prefer to have the computer on the wrist others like to have it together with everything else (pressure gauge and compass) on the console. This is a personal preference, there is not one better thing. Many models are available in both variations.
Be careful if you decide to have a large console as it is best then to attach it with a clipper to the BCD. If these are just stuck under the belt they might protrude too much and drag along the ocean floor.
To have all information readily available on the computer go for an air integrated version. For wrist computers this works via transmitter. Console type computers can directly replace the gauge. Most high end computers will allow for air integration. The transmitters do cost around USD 300 to 500.
Don’t ditch your pressure gauge. It can be attached to the BCD with a clipper. It is a nice back up in case something goes wrong with the computer or the transmitter. It’s enough to have low battery in either to cause a failure in transmission. Without an extra gauge you would have to end the dive in such a scenario.
Most current models will even calculate how much longer you will be able to stay at a certain depth with the air left in the tank.
User replaceable battery
Some computers have to be sent to a shop in order to change the battery while others allow the user to change it.
I am traveling a lot and thus prefer a computer that allows me to change the battery myself. It is important to do so in a dry and clean place. The o-ring has to be replaced as well from time to time and it is vital to follow the instructions.
Connectivity to PC
When planning to have a digital log book instead of a paper one a nice option is to directly load your profiles to a PC. Many come with software to integrate the data from the dives into a log.
This also allows you to check the dive profiles on the PC. The options are a cable connection (Oceanic OCI, Suunto D6i) or wireless via bluetooth/infrared (Shearwater Research Petrel 2 and infrared for Scubapro computers).
Some of the new models even allow the computer to synchronize with a mobile phone or tablet (Oceanic VTX).
The exact algorithm a computer works with might be difficult to understand in detail. What does make a difference is how conservative a computer is. During deep dives some divers get a couple of minutes more than others and in shallow waters the difference might even get bigger. This depends on how conservative or liberal the algorithm is.
For newer divers a more conservative computer definitely makes more sense. Alternatively most computers can be set to a “conservative” mode. All are supposed to be safe yet it doesn’t harm to add some extra safety.
In general Suunto computers are amongst the most conservative and Oceanic the most liberal. Oceanic computers do have two different algorithms to choose from.
With new models like Scubapro Mantis 2 it is now possible to adjust the algorithm according to age, fitness and age.
In order not to carry around an extra compass many divers prefer to have one integrated and if you decide to have this then make sure it is easily readable.
If this is an important feature for you make sure you research how the compass looks. Some might be too basic and cannot really replace the external compass. Yet there are amazing versions, some even correct for tilt if the computer is not completely horizontal (Oceanic VTX, Scubapro Galileo Luna, Suunto D6i).
Large and easy to read display
Some people don’t want to spend a lot of time checking the computer. Then a model with a large display and big numbers displaying the most important information like depth, time and NDL (no decompression limit) on the first screen is the best choice.
All of the computers above are high-end models with many many other features as well. Alternatively the larger entry-level computers do normally have larger and easier to read displays.
Others might not mind having a closer look or even to press a button to find the information. My computer for example shows the dive time on the “second screen”. Instead there is remaining air and time left with regards to air consumption shown on the main screen.
When diving at a site more than 300 m above sea level the algorithm has to be adapted. Some computers have integrated algorithms allowing the divers to set the altitude themselves. The computer then makes the necessary correction. Many higher level modern computers do this automatically.
All current dive computers will count down the safety stop for you. Some even allow to change the time and depth range.
In addition it is possible with many computers to add a deep stop for more safety. This is either set at a fixed depth (like 18 m) or at a depth related to the deepest point during the dive (half of the deepest depth).
Many computers allow you to change the mode. For divers who like to sometimes jump in without all the gear these models allow to change between diving and freediving mode.
Any other fancy extras
Today the computers can do so much more than just calculating the no decompression limit.
There are ultrasound based transmitters that allow several divers within a certain range to share information about air supply and location. It is even possible to send messages between buddies (Aqwary). I had a chance to look at this computer at a dive exhibition and think it actually is an awesome option for buddies who do really want to be safe.
Such computers allow dive masters or instructors to monitor air consumption and location of a whole class. Another example is Liquidvision Lynx.
And some even factor heart rate, skin temperature and work load into the decompression calculations (Scubapro Mantis 2) or allow customization of the display to choose what is shown on the main screen (Suunto Eon Steel).
For technical divers or people who might wanna develop to that direction later on it might be important to choose a model that allows for trimix and multi-gas (Hollix TX1). There is even a wrist style computer compatible with rebreathers (Suunto DX).
If you get bored during safety stops (I hope not) there are models that allow you to play simple games.