COMPUTER Suunto Vytec
Diving at Bikini atoll is mainly in the 50m-plus range. You might been one of those outraged to read recently that I got into the habit of strapping on an unused Suunto computer for each separate dive on Bikinis wrecks.
What a very silly thing to do, you might have thought, and you might have been right, had I not been monitoring the weeks diving with a DiveRite Nitec3 three-mix computer and using each Suunto only as a back-up.
The problem was that, although we were using air as a bottom gas, we were using nitrox 80 as a decompression mix, which really peeled off the stop times. But I had no way of informing any Suunto that merely had a one-mix program. Each one had to presume that I was using air all the way.
So on the first dive I stayed in until my Suunto had cleared its air deco-stop. On the second, the stop was much longer, so I made a note of the time and left it tied off to the deco bar until it was clear.
By the fourth dive, the admirably safe Suunto RGBM program had kicked in, and none of the other divers was prepared to wait it out, even though they were sitting comfortably up in the boat. So I hauled it in, bent it and replaced it with another computer for the next dive. I went on to bend that on the next dive, and so replaced it with yet another. I bent that and was able to replace it with the first, because 24 hours had elapsed by then; and so on.
I got away with that because the Nitec3 was my primary guide. So what to do if you dont have a Nitec3 Use the new three-mix Suunto Vytec, of course!
The Vytec looks very like the Vyper. The display seems familiar too, but there are differences. The display lights up when any audible alarm sounds, and you can change the battery yourself. However the main difference is that with the Vytec you can programme in three different nitrox mixes for one dive, telling it when you change gas as you go. It will track your deco requirements admirably.
You simply press one button to tell the computer that you want to change to a different nitrox mix, choose one of two other mixes predetermined before diving by pressing another button, then confirm your choice by returning to press the first button again.
You dont have to pre-plan the depth at which you change, although it will not accept a mix that gives a greater ppO2 at that depth than the ppO2 previously chosen by you as a maximum.
The Vytec will give you all the repeat diving benefits of the standard Suunto RGBM (100) program and still get you out of the water in time for lunch. And if the RGBM is too cautious for your taste, you can opt to use the less-cautious RGBM 50 alternative when you set up the Vytec with your personal preferences before diving.
The Vytec does everything you would expect from a modern full-function deco-stop computer, but it does something extra, if you are prepared to pay the price. You can opt to buy a high-pressure sensor/transmitter unit that will plug into your regulator and give you a wireless gas-integrated computer.
This displays tank pressure and remaining air time and (I am told) uses an analogue signal and a particular wavelength which appears never to be blotted out by your body getting in the way, or an underwater flashgun recycling nearby.
It updates tank-pressure information every few seconds, so even if you did lose the signal it would be back before you noticed its absence. A permanently flashing icon confirms that the wrist unit is getting the message from the transmitter unit.
If you cannot afford this feature initially, you can always upgrade by buying the transmitter unit later. You can change the battery in this yourself, too.
I had been looking forward to spending a few hours of a plane ride figuring out from the instruction manual how to use the Vytec, but I was able to watch a movie instead. Because it is menu-driven with three push-buttons, it is very easy to understand. In this respect, it scores heavily over the Nitec3.
I had it all sorted with my personal preferences and three chosen nitrox mixes within about five minutes. It remembers what you set for mixes two and three, and after a couple of hours defaults to air-only or mix No 1. This saves all the embarrassment of having to return to the surface because the unit forgot your chosen mixes in the time between setting them and hitting the water.
Another unique aspect of Suunto computers is that not only do they give you a decompression ceiling through which you should not pass, but they also indicate a decompression floor. That is the depth at which your off-gassing begins to be faster than your on-gassing, and this proves very useful when you want to use your valuable decompressing time in the shallows, on a reef for example, rather than ascending higher than perhaps is strictly necessary.
The Suunto Vytec represents the ultimate in diving-computer technology achieved by this high-tech Finnish company to date. Watch out for revolutionary electronic developments from Suunto in the fields of golf, sailing and other sports too.
It costs £390, plus £300 for the optional wireless gas-integration transmitter.
  • Suunto UK 01420 587272, www.suunto.com

  • Divernet
    + Designed for use with up to three nitrox mixes
    + Wireless gas-integration option
    + Everything you could need in a nitrox computer

    - Ever innovative, Suunto might come up with something even better!
    - Not cheap, though cheaper than a Nitec3