John 



Unashamedly going after the big American leisure-diving market, where this style has dominated, Mares has made a computer for the diver who enjoys a long interval between one diving holiday and the next. It has to be intuitive enough for those who might have forgotten everything by the time their next outing comes around.
I took it diving to see how it fared with a grumpy old European diver.
The Puck is set up with a single button, the user needing to differentiate between a short push and a long one. The changes go only one way, so miss your stop and, like someone on a one-way loop line, you have to stay with it until you get back to where you came in. This is a bit frustrating.

Algorithm
The Puck uses the Mares version of Bruce Wienkes RGBM algorithm. As such, it becomes progressively cautious during a sequence of dives, decreasing no-stop times and increasing the mandatory deco-stop times as the tiny micro-bubbles of nitrogen are thought to build up in the divers tissues. This gives them time to be off-gassed via exhaled gases before they can aggregate into bigger symptomatic bubbles.
The Puck displays one or more recommended deep-stops, too, where you can wait to off-gas a little by watching the timer count down for a minute before proceeding shallower.
You need to press the button during the dive to find out which deep-stops might be suggested during the ascent.

Display Legibility
As you can see from the picture, the display shows the minimum of information, but it is all you need to conduct a typical leisure dive safely, and its clearly readable.

Settings
Once you have got the hang of the frantic button-pushing, its relatively straightforward to set the nitrox percentage (21 to 50%) and the maximum ppO2 (1.2 to 1.6) you want to use. You can also set one of four personal caution levels to reflect your overall fitness, and you can set the Puck to account for diving at altitude, too.
You can turn off the fast-ascent warning if you want to, but goodness knows why you would, unless you were intentionally demonstrating such a fast ascent.
At least it wont lock you out from further diving if you do.
The Puck can be set for fresh or sea water and, of course, it can be changed from metric
to imperial measurements. There is the option to set it for stops at half the pressure of the maximum depth obtained, as well as using it as a full deco-stop computer.
The shallow-water safety stop is timed down over three minutes. The Puck can also be set to work simply as a dive-timer and depth gauge.

Display
The regular display shows the actual depth and the remaining no-stop time. Thats all most divers need to know.
By pressing the button, it also shows the dive duration and a percentage for CNS toxicity that might occur with elevated levels of oxygen in the breathing mix.
The maximum depth achieved and water temperature come up as alternate displays. You just keep pressing the button.

OTHER COMPUTERS TO CONSIDER:
Suunto Gekko £185
Aladin Prime £235
Oceanic Veo100 £185



Divernet Divernet
SPECS
MARES PUCK COMPUTER
PRICE
£160
FAST ASCENT RATE WARNING Yes
OTHER WARNINGS MOD exceeded. Omitted deco stop. No deco limit. Deep-stop suggested
NORMAL IN-WATER DISPLAY Depth. No-deco time remaining. %CNS. Dive duration
ALTERNATE DISPLAY INFO 1 Deep-stop. Max depth. Personal caution level set
ALTERNATE DISPLAY INFO 2 Water temperature
ALTERNATE DISPLAY INFO 3 %O2 set. Type of water set
DECO INFOSTOP DEPTH & TIME. Deep-stop
DEEP STOPS Yes
SAMPLING RATE 20sec intervals
DIVE PLANNING Yes
LOGBOOK 40hours record
PC INTERFACE USB
DIVING MODES Air, Nitrox, Gauge
BATTERY CR2450
CONTACT www.mares.com
DIVER GUIDE width=100% width=100% width=100% width=100% width=100% width=100% width=100% width=100% width=100% width=100%