Cressi-sub GX1 Computer

You should be diving simple. It will give you more time to concentrate on the beauty of the sea around you. I always encourage divers to keep that in mind with their gear choices. But you don’t have to give up full features to keep it simple. Case in point is the Cressi-sub GX1 (Galaxy 1) dive computer. I found this computer easy to use, yet has advanced features that the more experienced diver will appreciate. This is a computer for divers of all experience levels.

The GX1 is on all the time in the surface mode and the dive mode comes on automatically on contact with water. There is no need to worry about whether the unit is on. Average battery life is 18 months and the battery is user replaceable. A flashing icon on the screen indicates low battery.

Another automatic feature of this computer is its altitude compensation. Want to dive some of California’s mountain lakes? This computer adjusts automatically for altitude up to 19,680 feet. Altitude sensed and compensated for is indicated clearly on the bottom of the screen.

Also indicated is the current active mode of the computer (Dive, Surface, Log, Profile, Plan, and Transfer). Specifying a mode, then scrolling the data in each mode, is done by the push of “A” or “B” or both buttons at the bottom of the screen. While the buttons are not huge, they are large enough to activate with gloved hands.

A great dive begins with a good plan. The Cressi-sub GX1 dive computer makes your planning easy, yet disciplined and safe. First, are you diving nitrox or air? This computer is nitrox programmable in 1 percent oxygen increments of 22 percent to 50 percent. For you non-nitrox divers, rest easy, you will not accidentally reprogram from air (the default setting) to nitrox. It takes a bit more effort to get into the nitrox programing mode than just accidentally hitting a button. At the same time, once you are there, setting exact nitrox mix is very easy. There are also a number of safeguards built into the computer for the nitrox diver.

If you’ve already made a dive, during your surface interval you are given the useful information of desaturation time (time when your body tissues are clean of excess nitrogen), surface Interval time (time since surfacing from your last dive), and a no-fly icon (24 hours from your last dive).

Moving to the plan mode is accomplished with a simple button push. You can then look at your no-decompression time at a specific depth up to 157 feet. And, yes, the no-decompression time is calculated specifically for whatever breathing mix you have dialed in, be it air or nitrox.

Back in the water the computer will automatically switch back to dive mode, activated by contact with the water. Here are two modes with an alternate display. Most divers will likely be using the no-decompression mode. Displayed will be current depth, dive time, no-decompression limit, maximum depth of the dive, nitrox symbol (if programmed ahead of time), and, my favorites, the bar graphs for oxygen and nitrogen. These graphs give you an at-a-glance look at where you stand with these two critical gasses (oxygen more important for nitrox divers). If your graphs starts to get into the red, pay attention, you may need to take action.

The decompression mode will hopefully appear only if you plan it that way. In addition to maximum depth and dive time, you’ll be given an indicator that you are now in decompression mode, your first stop depth, time at that stop, and total ascent time. (Decompression diving is NOT recommended by this publication.)

During the dive, an alternate screen is available with the push of a button. This will tell you time of day, PO2, and current surrounding water temperature.

There are a number of warnings and alarms built into the unit, indicated with flashing warning on the screen and an audible alarm. They include a fast ascent (I am terrible about this one), PO2 , decompression stop , oxygen bar graph , and out-of-range (exceeding maximum depth of 328 feet, dive time of 599 minutes, or deepest decompression stop of 59 feet).

The log mode holds up to 10 dives, again with data available at the touch of button. Shown will be the dives date, start time, end time, maximum depth, nitrogen bar graph, oxygen bar graph, nitrox indicator, and altitude. Push another button for the same dive and you’ll get water temperature at maximum depth, dive number that day, and more. Also indicated is if you ascended too quickly (rats, goofed that one up again). Want more detailed information? Push a button and go to the profile mode. With this, you will get a minute by minute profile of your dive depth during that dive.

All this data can be downloaded to a personal computer (requires optional hardware and software).

I was able to use this computer right out of the box learning basic air functions quickly. During the surface interval a few more minutes and I was ready for multiple no-decompression dives. Accessing the log told me I’d not corrected my fast ascent problem. The profile feature gave me a look at why my nitrogen bar graph danced into the red. In planning mode I had a third dive for 15 minutes at 60 feet. I then made a dive where I spent nearly the entire dive at 59 feet for 14 minutes. Then I ascended a little too quickly. Don’t worry, I’m O.K. but I should have paid closer attention. My fault, not the computer’s but this wonderful computer has helped me to learn the error of my ways.

I like this computer and look forward to using it when I get into nitrox diving. It gives me a lot of flexibility and data so I can become a better diver.

For more information, see your nearest Cressi-sub dealer. For a dealer near you, call 800-338-9143 or go online at www.cressi-sub.it.