Computer Sub Gear XP10

OLD COMPUTERS NEVER DIE, they just come back carrying another brand name. At least, that's how it seems when you scrutinise the Sub Gear XP10. It's undeniably the Aladin Prime with a new complexion.
At a time when it's quite feasible to spend more than a grand on a diving computer (and it seems that many divers do), this one represents very good value.
The big question is this: considering that the core function of a diving computer is to try to keep you safe from decompression injuries, will it represent a false economy?
After all, nobody would want to save money if it risked their health, would they?
The short answer is that the Sub Gear XP10 is a direct descendant of the Aladin Pro, an instrument that at one time was considered the acme of the diving-computer designer's achievements.
It uses the same Buhlmann ZH-L8 ADT algorithm, tweaked a little here and there, and you can adjust it for different nitrox mixes.
After 20 or more years, this algorithm has been successfully used without incident by a very large number of divers. So one can assume it is just as safe, and some might say that spending more is simply a capricious waste of money.
The other big difference between this and the old Pro is that the user can change the battery when necessary. That's a plus point.

Setting Up
The instructions that came with the Aladin Prime were a nightmare. Nothing's changed there, apart from the fact that they're now on a CD-Rom, so are not available when you're sitting perplexed by it all in a small boat, and about to dive. A CD-Rom might save ink and paper, but not if every owner has to print the manual out.
The maker does supply an abbreviated set
of instructions on a two-sided card, but you would have to know what you were doing to understand it.
It's all about long and short pushes on the two buttons provided. At least this computer has buttons. There are some older divers who suffered permanently damaged personalities from struggling with that wet finger-licking nonsense of the old Aladin Pro.
The XP10 allows you to set nitrox mixes from 21% (air) to 50%. Unlike the Prime, which worked at a fixed maximum PO2 of 1.4bar, you can adjust the XP10 between 1 and 1.4bar in 0.05 steps. Confusingly, you can set the PO2 alarm between 1.2 and 1.6bar. Make sure you know which you are setting!
This instrument also allows you to set clock and alarm-clock functions, and to turn off activation on contact with the water. I would advise anyone, inexperienced computer-user or not, to avoid doing the latter. Why would you risk jumping in with your computer turned off?
You can also reset desaturation logged, but that is mainly for dive centres, which might be frequently renting computers to different divers on a dive-by-dive basis.

In The Water
During the dive, the information was simply and clearly displayed, as I had expected. One assumes, as an entry-level item, that this computer will be purchased by those who tend to stay within diving no-stop times. The little nitrogen-loading bar graphic is obviously a concession to those markets where divers are not very good at reading numbers!
This is a full-function decompression computer, however, and it displays stop depths, stop times and total ascent times when in deco mode. It also displays O2 CNS loading, although the typical user will find that this never amounts to much.
Pressing the left-side button for a couple of seconds activates the backlight. Pressing the right-side button for a moment activates the alternative displays.
The variable ascent rate (according to depth) is displayed as a percentage of the maximum permissible. Stay away from 100% and you won't see the word SLOW appear. The audible alarm gets louder as things get more hazardous.
The XP10 also has a safety-stop timer that can be activated after an ascent, and when at less than 6.5m. It has to be manually activated.
You give a short push to the left-side button and it counts down three minutes, so long as you stay above the stop depth and below 3m, and the displayed remaining no-stop time is at 99 minutes.
Of course, I couldn't remember which button to press when it came to it, but pressing the wrong one caused no problems.

After the Dive
If the XP10 detects a situation of increased risk (due to the potential of micro-bubble accumulation from previous dives, or a CNS O2 level above 40%) the no-dive symbol will appear on the display.
The duration of the no-dive warning is visible in the dive-planner menu. XP10 recommends this as a minimum surface interval to reduce the number of micro-bubbles and/or to reduce the CNS O2 level below 40%. Avoid at all costs getting the SOS display after a dive.
After the dive, information can be downloaded to a PC equipped with a suitable infra-red interface (IrDA) and loaded with the Dive.Log software provided with the XP10.
You can also use Dive.Log to adjust all the pre-dive settings, if you find the buttons on the computer too daunting.

Comparable computers to consider:
Suunto Zoop, £199
Mares Puck, £165

SPECS
PRICE £189
FAST ASCENT WARNING Incremental according to actual depth
NORMAL IN-WATER DISPLAY Current depth, dive duration, max. depth, CNS O2 loading/ ascent rate, nitrogen loading
ALTERNATIVE DISPLAY Temperature, oxygen fraction
DECO INFO Deepest stop-depth, stop time, total ascent time
MAX DEPTH 120m (inc. deco calculations)
DIVE PLANNING Yes
LOGBOOK Yes
PC INTERFACE Infra Red IrDA
MODES Air/Nitrox
BATTERY User-replaceable CR2450
CONTACT www.scubapro.com
DIVER GUIDE