When diving was new, three instruments were key to safety: a manometer, to show your available air; a depth gauge, to show your current and maximum depth; and a timer, to show how long you’d been underwater. These crucial components were analog, and each was a separate item — a manometer on a hose connected to the tank, a depth gauge on one arm and a dive watch on the other.
The first major innovation was the dive console, a single unit that featured all three instruments and often also a compass, first in analog versions and later in digital. However, these fairly quickly fell out of fashion with most divers, as they tend to be quite large and bulky. The next innovation was the wrist-worn dive computer that measured time, depth, logged the dive and real-time calculated the remaining dive time at a given depth.
These dive computers have had largely the same look for years, but a generation of new dive computers is hitting the market. With most major manufacturers joining the trend, dive computers have gone from increasingly compact, wristwatch-sized units to larger units with color screens and more advanced features. I call this the “iPhone-ification” of the dive computer — examples include the Suunto Eon Steel and the Shearwater Petrel.
New Dive Computers
So, is it time to retire your current dive computer for one of the new models? Maybe, but not necessarily. Let’s have a look at some of the new functions of these larger computers, and of course, these computers do much more than the three things mentioned here — closed or open-circuit setup, built-in compasses, integrated-wireless gas gauge, and much more. But since those features are common on many other computers, we won’t include them here.
The new computers are all quite recognizable based on their much larger, often square screens. The design is similar to technical dive computers from a few years ago, but these new models feature color screens and many functions visible at a single glance. Whereas the smaller computer screens often show only current depth, maximum depth, dive time and no-deco time, with other info available in a sub-menu, the larger screens allow for more function. Items on display can include temperature, current gas mix, available gas mixes, time-to-surface (an indication of how long you’d need to reach the surface at any given time, including any safety or decompression stops) and other functions. The color makes for easier reading, and many of the screens are more powerfully lit, which also makes them easier to read in dark or murky conditions. Larger screens also often allow software designers to make more intuitive interfaces.
A New Approach to Stops
Safety stops for recreational diving have always been fairly uncomplicated. Any dive beyond 30 feet should end with a safety stop at 15 feet for three minutes before surfacing. It is not a requirement (as with a decompression stop while tec diving), but simply a good idea to lower the risk of decompression illness. Most dive computers have had this built in for years, and will automatically give you a warning when it is time to do your safety stop. Some computers add in a deep stop, typically for dives beyond 60 feet.
A number of the new computers take a different approach, essentially treating each dive as if it is a technical dive, just a very shallow one. And, technically speaking, they’re right, insofar as every dive is a decompression dive. Whenever we ascend from deep waters to the surface, we are decompressing and releasing stored nitrogen from our tissue. While diving recreationally, we limit the time and depth so that a normal ascent rate and a safety stop is plenty to ensure we don’t overtax our body’s ability to dispel the nitrogen. So when using one of these computers, you’ll probably find yourself being told do many more stops, at varying depths. You may never do three minutes at 15 feet, but may instead do one minute at 65 feet, two minutes at 20, and one minute at 10 feet, based on your depth profile, time and any calculated nitrogen load from previous dives. For a longtime recreational diver this can seem a bit disruptive, but essentially, it is the manufacturer’s attempt to make dives safer by utilizing the fact that with a computer, you don’t have to limit yourself to a one-size-fits-all safety stop.
While designers have generally done a good job with these new interfaces right out of the box, users are also typically able to customize what is displayed on their screen, and where. This allows you to set up your computer so it makes the most sense to you, rather than relying on a standard setup.
So, based on the differences between one of the more standard dive computers and this new bunch, is it time to upgrade? As stated earlier, maybe. If you’re a tec or rebreather diver, many of these computers have features that you’re likely to appreciate, even for recreational diving. If you’re a typical scuba diver, the price tag might be a bit prohibitive (most fall in the $1,000-plus category), especially if you already have a dive computer that works well. Many of the innovations have mostly to do with ease of use, while also adding a bit to the safety margin. But since all dive computers are well within the margins of safety, there’s probably little need to retire a fully functional dive computer and shell out the cash for an upgrade, unless you need a new computer anyway.