Delta P VR3 HD Dive Computer Review

Delta P makes a good quality dive computer, and the latest VR3 is no exception. Their computers are fairly easy to use (once you read the manual!), and the new VR3 HD dive computer ships out with the latest version of the software (G10 mode) enabled, but you can switch back to G3 (three gases), or X10, which is the 2007 version of the software. So that means if you replace an older computer, there's zero learning curve if you don't want to use the new features, like the ability to customize the information you see on the primary dive screen. They also do a little bit of up-selling- when you first open your VR3 it's a color display for three dives, then it goes back to single color, unless you order the color upgrade PIN. Of course if you bought it with multicolor enabled, you should get the pin on a white strip in the box.
The VR3 HD uses a single AA battery, which you can open with a special key that comes with the computer. If you can complete a battery change within 30 seconds, you won't lose any data. The computer has two buttons, and you activate them by either pushing one or both. A short push or a push and hold gives you the variety you need to activate all the functions. The backlight can be set to be on for 10 seconds, on all the time, or off at the surface and on underwater.
VR3 Dive Computers can operate on four levels :-
Level C1: Open Circuit Air / Nitrox
Level C2: Open and Closed Circuit Air / Nitrox
Level C3: Open Circuit Air / Nitrox / Trimix
Level C4: Open and Closed Circuit Air/ Nitrox / Trimi x
On the home screen of the dive computer you can see the current active gas, battery level, and the amount of gas you have left. VR dive computers use a derivative of the Buhlmann ZHL 16 algorithm on all decompression dives, the VR uses 2 minutes stops. You can also upgrade to an alternative algorithm, which uses a variable permeability model (VPM). This may provide a reduced decompression requirement. In general, intermediate stops are longer and shallower stops are shorter. The VR3 has No Stop plan for depths up to 41 meters, so you can avoid decompression stops altogether, provided you following depth/time recommendations. There's also a fly time- which tells you how long to wait before flying to make sure all the gas has cleared.
Options include a gas calculator mode (another PIN upgrade), which allows you to work out partial pressure gas fills. You can also connect a re-breather linking cable to track real time decompression. The VR3 dive computer also has some games you can play on decompression stops, such as Octopus, where you're shooting another octopus with ink. Buddies is a pairing card game, and Wreck find you're looking for pieces of a shipwreck in the sand. An upgrade allows you to download decobooks- the computer will store about 40 pages, loaded as text files. You can download dives to a computer (it stores up to 22 hours before overwriting the old data), and there is a simulate mode so you can practice using the dive computer before you actually get wet.
Once you have entered in your dive gasses, a dive plan function allows you to enter dive depth, time, and surface interval to calculate a set of backup tables. One of the cool features of using a dive computer, and the VR3 is no exception, is that if you have just completed a dive, it remembers your residual gas loading and uses that in the calculations. This is much easier than the tables (of course you should always run the calculations on tables as well, so you have a backup to the computer). The VR3 dive computers provide alarms for ascending too quickly, when to stop on a decompression stop, and when to ascend due gas levels.
Specifications from the manual:
Depth limit 150m (calibrated)
Time limit 9999 mins and 59 seconds
Max deco stop 99 levels
Number of gases 10
Battery life Up to 100 hours
Sleep Approx. 1 year
Dive memory Approx. 80 hours
Record resolution 10 seconds
Logbook dives 99
Find the Delta P VR3 HD Dive Computer at Amazon

Mares Nemo Dive Computer Review

A diving computer can make your SCUBA experience a more memorable and safer one. And when it's time to purchase a diving computer, SCUBA fans should consider the Mares Nemo Dive Computer. This dive computer, which comes in the form of a watch that divers wear around their wrists, is one of the top-ranked computers that SCUBA fans can purchase. That's because the Mares Nemo Dive Computer is packed with several key features. Any dive computer can protect divers from the dangerous, and often deadly, effects of decompression sickness. This sickness strikes when divers ascend to the surface too quickly. In extreme cases, decompression sickness can result in death.

Dive computers, though, track exactly how long a diver has been underwater and also how deep they have dove. Some dive computers emit a series of warning beeps to alert divers when they've missed decompression stops. Divers can also rely on diving computers, such as the Mares Nemo Excel Dive Computer, to review their own diving performances. The computers can store several of divers' most recent dives - this number depends on the quality, and often the price, of the dive computer - that SCUBA fans can then transfer to their personal computers.
Divers can then analyze this data to determine if their SCUBA performance has been improving or deteriorating. They can determine, for instance, if they dove deeper three dives ago than they did during their most descent. The Mares Nemo Dive Computer can do all this and more. The computer boasts four different dive modes. These modes cover the most common forms of diving: air, nitrox, bottom timer and free dive.

The Mares Nemo Dive Computer also comes with an advanced RGBM Mares-Wienke Algorithm. This is key because it significantly lowers the risk of micro-bubbles forming. The RGBM Mares-Wienke Algorithm does this by introducing deep stops. Finally, the Mares Nemo Excel Dive Computer also features a timer-controlled display light that divers can easily turn on with the press of just one button. This makes it easier than ever for divers to see the important information coming from their dive computer.
The Mares Nemo computer also does a good job when it is serving as a traditional watch. It boasts dual time zones, a stopwatch, calendar and a working alarm clock. Finding the right dive computer is never an easy task. It takes considerable research on the part of divers. But those divers who choose a Mares Nemo Dive Computer can rest assured that they've purchased a top-of-the-line piece of diving equipment.

The Mares Memo Sport dive Computer on Amazon: