Dive Rite brought out the Nitek HE, but its plastic case made it unappealing to those who saw merit in a full metal jacket. Now the Florida-based company has introduced the Nitek X, and this gas-switching trimix computer in brushed aluminium certainly looks the part.
We got our hands on one of the first examples in the UK, and I took it diving. My test was flawed, in that I had no instruction manual for what promised to be a very complicated bit of kit, but I was assured that it was intuitive to set up, and it certainly seemed to be.
It did, however, seem odd that I had with me a 45-page manual for a new snorkel, but almost nothing for this very expensive technical item.
The Nitek X comes with a full spec, so there are no upgrades or complex PINs to enter. This comes with the penalty of a high purchase price of almost £1500.
First, I took the Nitek X on some nitrox leisure dives. I soon found that I could easily configure it for an open-circuit dive, using the appropriate percentage of oxygen and zero helium.
Once I had got used to using it in this way, I set it up for a trimix dive in closed-circuit mode. Technical diving instructor Gary Fox (right), from Dive Action in Helston, kindly took it in for a 90m dive with his Evolution rebreather at Thomas Reef in the Red Sea.
It does have a socket for connecting to the fourth (calibrated) cell of a CCR, but we had to use it as a stand-alone application.
Naturally, Gary had the full back-up of his Evolution's own computer.
Algorithm
The Nitek X appears to use the standard Buhlmann ZH16 algorithm, which is freely available in the public domain and hence a favourite of small independent diving-computer manufacturers. There are three degrees of conservatism, plus the option to pre-program your own chosen gradient factors.
Settings
The unit is set up using two large buttons, with the option to give single or double, short or long pushes. In open-circuit mode there is only the option of a maximum ppO2 of 1.4 or 1.6 bar.
It appears to allow you to set three different mixes for one dive, with oxygen percentages varying from 8-99%, and helium from 0-92%.
I use the word "appears", because the sales blurb says it is a seven-gas-mix switching computer. You can opt for maximum depth alarm within the constraints of the gases you set, and it has the option of a dive-time alarm too. For closed-circuit diving, we set a gradient factor of 15/85 and a diluent mix of 09/55. Set points can be varied between 0.4 and 1.6 bar.
Display Legibility
Although the display is very legible, I found that the figures were a bit on the small side. It has a very good autonomous backlight that really helps in low light conditions.
In The Water
Although I could see dive time and depth, there appeared to be no indication of reducing no-stop time, apart from a graphic display that built up a line of blocks and started flashing once deco-stop diving was pending. Gary checked with his buddy Mark Bown that he had the Nitek X set on closed-circuit diving for his dive with it, but once he got to 45m it just switched off. He thought it was "good night nurse" for the Nitek X as he headed on down to 90m.
However, once he ascended back to 45m it switched itself on again, and continued as if the deep part of the dive hadn't happened. We could have done with an instruction manual!
I guessed that the unit must have gone into open-circuit mode and turned itself off in protest at being taken far beyond the MOD of the last nitrox mix I had set - but that's a guess.
We'll never know, because it also appeared to have failed to log the dive. At least it hadn't said "Missed stops. Use tables"! I had to take the battery out to get it back into a usable state.
After the Dive
The Dive Rite Nitek X stores dive details including graphic profiles of up to nine dives. There is a PC interface for downloading. We'd like another go with this computer once a proper manual has been written.
DIVER GUIDE Insufficient information
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