8 Best Dive Computers | March 2017
- digital and bar graph indicators
- measures in imperial or metric units
- gives deep stop reminders
- counts down safety stops
- dual-color strap
- intuitive interface
- auto altitude adjustment
- shows max and current depth
- 110-dive memory bank
- large digits are easy to see
- battery life gauge
- audible alerts of critical info
- great for multi-gas switch dives
- auto brightness feature
- comes with adjustable elastic straps
Exploring under the water can be a fascinating adventure and experience to behold. Descending into the depths of the unknown gives you a thrill, as you never know what you're going to see or find. Perhaps you have aspirations to find buried treasure or you're simply enamored with the opportunity to study underwater life. Whatever the reasons, you're going to need some type of monitor to ensure that your trip is as safe as possible so that you avoid getting lost or experiencing decompression sickness when you decide to surface. While it's possible to dive without a dive computer, this little device will provide you added assurance for your safety and you'll be glad for having made the investment.
A dive computer is a small, watertight, battery-operated device housed in a pressure-resistant case and sometimes worn around the wrist (like a watch). The computer is designed to measure the time, depth, and ambient pressure of a deep dive under the water. In so doing, the computer ensures that a safe ascent profile can be calculated and conveniently displayed back to the diver in order to avoid complications when surfacing. In other words, once a diver has spent a certain amount of time at a particular depth, after which a direct ascent (without stopping) would be unsafe or inadvisable, it is the dive computer's job to calculate an algorithm (a self-contained and step-by-step set of operations to be performed) that is based on the surrounding water pressure and time input to estimate when a no-stop ascent is no longer possible.
Part of the calculation for this algorithm involves the measurement of inert gases that have dissolved inside a diver's tissues at a given point. An inert gas is defined as one that does not go through a chemical reaction under particular conditions. For a diver, an inert gas is part of the breathing mixture that is not metabolically active. Once the dive computer has calculated this algorithm, it then estimates which decompression stops will need to be made by the diver during his ascent, at particular altitudes, and for how long. This process minimizes the chances for decompression sickness.
So what types of information can a dive computer display? Most dive computers feature liquid crystal displays for easy viewing in the water. Firstly and most important is the no stop time, which is displayed as the amount of time that a diver can remain at his current depth without the need to make decompression stops on the way up to the surface. The computer will also display the current depth and the total elapsed time for the dive. Some dive computers can also display total ascent times, the temperature of the surrounding water, and they have audible alerts when a diver is ascending too quickly or when a decompression stop has been missed.
A Brief History Of The Dive Computer
Up until the early 1980s, recreational diving was learned by leveraging United States Navy diving tables. Because these tables were not based on multi-level diving profiles, algorithms were produced to account for changes in nitrogen uptake when a diver's depth was constantly changing. These algorithms were not computer-accessible until the invention of the microchip.
In 1983, Austrian biologist Hans Haas innovated the first decompression diving computer called the DecoBrain, which was capable of displaying the same information that most modern dive computers display today. Around the same time, Orca Industries released the Orca Edge, which became the first commercially available dive computer. Rather than showing a decompression plan, the Orca Edge would display a safe-ascent depth instead.
The problem with this design was that the diver didn't always know how long he would have to decompress at a particular depth. Orca Industries continued refining its design with the Skinny-dipper in 1987, which was capable of running calculations for repetitive diving, followed by the Delphi in 1989 for calculating altitude.
In 2001, the US Navy approved the use of Cochran NAVY decompression computer, which made use of the Thalmann algorithm for Special Warfare operations. Developed by Captain Edward D. Thalmann, the Thalmann algorithm produces a decompression schedule for divers based on the use of the Mk15 rebreather.
By 2008, the release of the Underwater Digital Interface (UDI) combined the functionality of two-way digital messaging, SOS and homing capabilities, and a 3D digital compass into a single dive computer.
Do Your Research And Keep Your Options Open
The best dive computer for you is the one that makes you feel the most confident in your ability to stay informed about your underwater circumstances and to keep yourself safe before, during, and long after you've surfaced from a dive. One should take time and research the features they would most like to have on the device.
It goes without saying that a dive computer should be durable and easy to read. As a diver will need to be able to find his or her way back to their boat, finding one with an integrated compass will definitely come in handy, as it can supplement the need for a separate compass and it will also function accurately without having to be held level.
One must also ensure that their dive computer has a reliable depth gauge that will accurately record various depths as well as how much time has been spent at those depths. This will minimize the difficulty with decompression. If you plan to dive often, adequate memory storage is also important so that you can maintain an accurate history of your dives. The most cutting-edge dive computers can maintain a memory for up to ten dives.