Buying guide for best dive computers
Like the ocean itself, the world of diving is vast. Divers come in all shapes, sizes, and experience levels, ranging from casual swimmers to hardcore aquanauts who explore depths of hundreds of feet or more. This same variance applies to the type of equipment these explorers carry. Regulators, masks, flippers, and wetsuits each have their place in a diver’s tool kit, but today, we’re focusing on he tool known as “the diver’s best friend,” the dive computer.
Some dive computers are simple devices that display depth, diving time, and temperature, but others are significantly more complex. Computers are available that feature gas mixture tracking, programmable alarms, several diving modes, and are rated for extreme depths. No matter where on the spectrum you lie, though, a dive computer is at the very least something to consider.
Dive computers come in two flavors — wrist and console. A wrist computer is relatively self-explanatory, and often looks like an oversized watch. A console computer, however, sits on a designated unit with other tools like tank pressure gauges, recording instruments, or a compass. The advantage to this is it allows you to check all of your data in one place at a glance, but modern wrist computers — particularly if they connect to your tank wirelessly — offer many of the same features in a compact size.
To learn more about the best dive computers, read on. When you’re ready to buy one, consider our recommended models.
Key considerations
Interface design
A large, high-contrast dive computer screen is a plus, as the information displayed is vital and visibility at depth can be a huge concern. Large buttons are similarly advantageous, as they allow you to switch between the different menus and functions even if you’re wearing thick gloves. Some have several buttons, making the process even more intuitive.
Overly bulky computers are not ideal, though, because they raise the risk of entanglement on fishing lines, nets, or even kelp. Anything that sticks or hangs out could potentially cause issues, so in general, look for sleek designs that still clearly display the information you need.
Battery Life
Thought battery life on your mobile phone was important? Wait until you’re 400 feet underwater. A healthy battery not only means you have to charge less often, it means you can undertake longer dives without worry. Check manufacturer ratings for this, and it never hurts to have a battery indicator on your display.
Replacing your battery every other year is a wise guideline. Also, make sure to check your charge as part of your post-dive routine.
Desktop compatibility
Desktop compatibility is essential if you want to record, format, and interpret your dive data. The possibilities are nearly endless for this, but here are a few things you can log:
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Location databases including coordinates, recommended depths, frequency of visits, decompression tables, and wrecks.
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Equipment information such as purchase dates and maintenance cycles.
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Dive partner information.
Certain dive computers plug into your computer via USB port, but others require additional cords and software. In addition, some aren’t compatible with Apple/Mac computers, narrowing their applications significantly.
Find one that jives with your computer first, and consider models that offer automatic formatting, sorting, analysis, and printing programs. There’s no easier way to create your own digital logbook.
Depth rating
When it comes to depth ratings, the higher (or lower, depending on your perspective), the better. These ratings are dependent on the type of materials, bezels, and seals used. According to the International Standards Organization, dive watches must be “designed to withstand diving in water at depths of at least 100 meters” (300 feet). One hundred meters is likely sufficient for the majority of divers, however there are dive computers capable of going much lower.
Consider your application before buying, though. Do you need something that can dive beyond 500 feet? If not, save yourself some money. Remember that recreational divers aren’t permitted to go deeper than 40 meters; that depth requires technical diving permits and training.
Features
Dive modes
Dive modes allow single devices to accommodate a variety of diving styles, kits, and variables. Offerings can vary by manufacturer, as some use proprietary terms to package different measurements. Let’s touch on the most common.
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Watch mode displays the date, time, a countdown timer, and battery levels.
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Scuba mode typically measures depth, dive duration, temperature, and ascension, while allowing multiple gas types. It also calculates no-decompression limits (NDLs) in real-time, suggesting how long you can stay at a given depth and when you should take a safety stop during surfacing.
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Gauge mode reads depth and time only and does not calculate NDLs. This mode relies on the diver to determine appropriate safety stops.
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CCR mode is made for closed circuit rebreathers, which are devices that absorb the carbon dioxide the diver exhales. The unused oxygen is mixed with supplemental oxygen, resulting in efficient gas use and lower depth ratings.
Algorithms
“Dive computer algorithm” may sound slightly redundant, but they determine how long a diver can safety stay at a certain depth without risking decompression sickness. They measure depth, gas type, diving time, and temperature among other things, and while most manufacturers have their own, some can be tuned to be more conservative or liberal. We recommend staying on the safe side and leaving this to the professionals.
Keeping you safe is the primary function of a dive computer algorithm, but they’re also useful when diving with a group. If you choose similar algorithms as your partner, you can dive with similar NDLs and bottom time restrictions, allow you to follow the same path.
Alarms and reminders
There’s little room for error hundreds of feet underwater, which is why high-end dive computers bundle smart alerts for extra assurance. These can use audio cues, visual cues, or both and remind the diver of gas levels, time, stop times, and if they’re approaching maximum depths or NDLs.
Dive computer prices
A quality dive computer will cost you somewhere between $150 and $500. Some units cost significantly more than that, but those include professional features such as AI and wireless tank pressure transmitters.
Computers in the $150-200 range offer intuitive displays, support more than one gas mixture, and include mid-range batteries with impressive charges. These are fantastic for new divers or those looking for a backup.
Double that price and you’ll see units with programmable gas mixtures, larger batteries, and larger feature sets.
Above that, look for options with built-in planners, sophisticated alarms, and unique algorithms.
Tips
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Dive computer algorithms offer excellent decompression sickness safeguards, but their calculations do not consider factors like weight, age, hydration levels, or stress. Use them to your advantage, but do not let them take the place of safe diving knowledge and practices.
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Diving environments can be incredibly distracting. Sea life, coral, caves, photography, and even diver banter can throw you off-schedule, which makes it all the more important to program alarms and reminders on your dive computer.
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Entanglement is one of the main concerns of scuba diving. To avoid this, streamline your equipment and keep an eye out for ship wreckage, anchors, coral, or anything else that could have rogue lines in tow.
FAQ
Q. What equipment do I need to complete my diving setup?
A. A diving kit should match your skill level, but nearly every diver will need a mask, fins, tank, regulator, buoyancy regulator, exposure suit, and, of course, a dive computer. There are countless accessories and add-ons, too, such as cameras, defoggers, torches, gloves, dive knives, and surface buoys.
Q. How do divers become scuba certified?
A. The journey to become scuba certified may sound like a lot, but it can be broken down into three steps: knowledge development, confined water dives, and open water dives. Course length and price may vary, so search for a reputable PADI-approved dive shop (Professional Association of Diving Instructors) to begin the process.
Q. What causes decompression sickness and how can I prevent it?
A. Decompression sickness, or the bends, is caused by surfacing too quickly after a deep dive. This is because the body’s tissues absorb nitrogen in proportion to the surrounding pressure. If the pressure is reduced too quickly, i.e. when you swim toward the surface, the amount of nitrogen you breathed at depth will not have time to off-gas. This creates bubbles in the tissues and blood, resulting in symptoms like headache, dizziness, fatigue, joint pain, and numbness. To prevent this, divers abide by no-decompression limits (NDLs), surfacing slowly and timing stop points to allow their bodies to acclimate.
