Buddy Nexus

A Finnish-made computer that is sold mainly to those using the closed-circuit AP Inspiration rebreather, and thus suited to use in closed-circuit constant ppO2 mode, the Buddy Nexus can also be used as an open-circuit two-gas-mix nitrox computer with either pre-set auto gas-switching or manual gas-switching by means of a less than positive tap-switch.
  It uses wet-finger contacts which can be rather hit and miss until you get the hang of it, and there are many options to set.
  We wanted to know how its algorithm measured up to its open-circuit-type rivals and used it set for less-cautious normal rather than harsh conditions. Although it was slightly less cautious than most of the other computers in the normal setting, we were confident that the information it displayed was generally in line with the mainstream.
  Our main criticism is that the peripheral information is displayed in such a minute type-size that it proved hard to read for those of us with less than perfect eyesight. If you use a CC rebreather it represents a good-value choice, but much of its display is too small and so hard to read for serious open-circuit diving. £349


Cochran Commander

Previous experience told us to set up this US-made computer with a 50% safety factor, the maximum available, to bring it closely into line with the other contenders.
  The computer is set up by a combination of wet-finger contact and contact with a metallic object (a dime is included for the purpose).
  The Commander had a large and clear display and there was no denying that it went into deco-stop diving mode almost as soon as, if not before, any of its rivals but it would often rack up stops at ever-deepening depths rather than lengthening time at one depth.
  It then shed those stops on the way back up and before we got there, and sometimes rather prematurely in our view.
  Invariably it was long back into masses of no-stop time available when, with one notable exception, the other computers were still insisting that we had to wait around for at least five minutes at 3m (plus a safety stop in some cases).
  The Cochran Commander offers many functions and different possibilities but is rather more suited to those who love tinkering with electronic animals than those who want to get into the water with marine ones. To this end, its manual is supplied in the form of PC mini-discs. from£269


Cressi Archimede We liked the look of this Japanese-made computer very much. Its display was probably the easiest to read of all of the models tested, with its big bold figures. Its three buttons were easy to operate and its menu instantly understandable.
  Previous experience tells us that it uses an algorithm identical to the Dive Rite Nitek single nitrox-mix computer which we believe is made in Japan by the same manufacturer, and we anticipated that it would present identical information, albeit in a more easily read manner.
It was possible to choose a wide range of maximum ppO2 settings and nitrox mixes (Head to Head, January 2002). In the event, the example sent to test was faulty and simply went into Error mode under water. It was a great disappointment and extremely bad luck. Sorry, Cressi. 321

Dacor Darwin (also Mares M1) Made in Italy by Mares, this computer is quite bulky but still sleek and attractive in its own way. Apart from information being arranged in a slightly different layout on its LCD, and slight differences in the appearance of its casing, one can assume it to be identical in performance to the Mares M1 computer.
  We had problems setting it up until we realised that one needed to press the mode button for several seconds to activate it - not immediately apparent from the two seconds said to be all thats needed in its instruction book. After that, all became clear.
It has a secondary display activated under water by again pressing the mode button but we found that the primary display told us all we needed to know.
It ran out of remaining no-stop time when we expected it to and asked us to make deco-stops in line with the mainstream, adding a safety stop only after we had ascended past the 5m depth mark - which was often some time after it had returned to no-stop diving mode. This came as a bit of a surprise sometimes.
  We would be confident to use this computer, whether Darwin or Mares M1, to monitor our deco for this type of diving, with the proviso that we treated the safety stops as mandatory. £200

Delta P VR3

This British-made computer is said by its manufacturer to be the only computer you will ever need. At the price it sells for, lets hope thats so!
  In full spec, the VR3 comes knee-deep in options and possibilities. I had been using it previously in conjunction with a closed-circuit rebreather but we returned it to single-mix (air) open-circuit conventional scuba mode for this test. We set no percentage for caution.
  Initially, the display is hard to read because there is, quite simply, too much information available.
  George Buxton had brought his own VR3 with him and, although he had used it extensively, he discovered during our tests aspects of the VR3s display which he had never noticed before!
  The VR3 allows you to choose the depth of the shallowest stop computed for, and to bring it in line with the other computers we chose 3m. It requires deepwater stops and we often saw stops come up as deep as 28m on our max-depth 50m-plus dives.
  If you miss one of these stops, the VR3 displays a large down-pointing arrow and counts down the 60 seconds it gives you to get there. If youre not quick enough getting back down to the stop you have passed, the VR3 sulks and will display the words: Use Tables.
  With 10 other computers to watch, I was not quick enough to redescend the few metres for a 16m stop on an early dive and got rewarded in this way. But even though I had bent it, the VR3 still allowed me to use it fully on the next dive.
  Stops are displayed with the additional graphic of a diver passing up a line to reveal the possibility of continuous decompression within a certain depth range. Its quite fun to watch.
  Multi-level dives on a reef present no problem to this way of diving, provided you dont creep up the reef too much. On a line, coming up after a square-profile wreck dive, things might be different.
  The deepwater stops properly undertaken meant that the VR3 presented shorter mandatory deco-stop times than some of the other computers once in the shallows.
  This is a good choice of computer if you have the money to buy it and the time to get to know it.£499-1000


Dive Rite Nitek He (also Nitek and Nitek3)

Japanese-made, although this is a multiple-mix nitrox and trimix computer aims squarely at the technical diving fraternity, we used it with a single gas (air) setting and obtained results we might have got with its much cheaper little brother, the Nitek.
  Its display was by no means the biggest to read, but all the information was there clearly enough. In past comparison tests we have found the Nitek to be the most cautious of computers, because it doesnt seem to shed the final minute of a displayed 3m stop until the diver actually reaches that depth.
  The instruction booklet is written so that the user must read it from page one (you cannot simply dip into a subject area) but provided us with a clear understanding of how to use it. It offers a choice of only 1.4 or 1.6 bar ppO2 settings.
  The button A/button B system is easy to use both at the surface and under water, should one actually use the Nitek He for its intended technical-diving purpose including gas-switching, and its algorithm seemed to be either the first or second most cautious of the computers compared here. A sensible choice for this type of diving, whether it be the single-mix Nitek or the seven-gas trimix Nitek He. £1029 (others from£257)


Mares M1 RGBM Identical in every other way to the Dacor Darwin and Mares M1, the new Italian-made Mares M1 RGBM uses Bruce Weinkes modified Mares algorithm to put in optional deepwater stops, and thereby credit the diver with less time required in the shallows.
  RGBM stands for Reduced Gradient Bubble Model. By avoiding sub-clinical micro-bubbles forming at depth, the risk of symptomatic bubbles forming in the shallows is reduced.
  The multi-level nature of the diving we were doing meant that although we occasionally saw a one-minute deepwater stop displayed at around 18m, this proved no impediment to our progress towards the surface. The M1 RGBM returned to no-stop diving mode a couple of minutes before its more traditional sibling, the Dacor Darwin, on every dive.
  I would be very content to use this unit for this type of diving, provided that I treated the 5m safety stop as mandatory. £245

Oceanic Veo 250 (also Versa and Versa Pro)

This new and attractively designed US-made computer has an easy-to-read display and is simple to set up by means of its two-button menu-system.
  During the test dives it offered information regarding deco-stops needed that was completely unlike that displayed by all the other computers.
  It went into deco-stop diving only once we had passed 50m, some time after all the other units sitting alongside it had done so, and was generally back into no-stop diving as soon as we got up anywhere near 9m. The amount of no-stop time then offered seemed enormous.
  But we could not say that the Veo 250 was incautious. It revealed a Jekyll and Hyde character in that at times it seemed to be working with two entirely different algorithms.
  In contrast to excessive no-stop times, twice during our weeks diving it demanded stops at 3m far longer than the others. These stops were in the order of 20 minutes longer, sometimes more.
  The long shallow stops were probably triggered when we did a 50m-plus dive in a series after a 30m-plus dive, or when the surface interval was less than three hours.
  On one occasion when it wanted us to stay at 3m for 26 minutes after all the others were soundly and finally back into no-stop mode, we resorted to tying it off on a rope hung with an emergency air-tank under our boat, rather than let our skin go any more crinkly in the water, and pulled it up later.
  This is definitely not the way to use a computer properly.
  We would like to say that the Veo 250 is unsuitable for the sort of diving we were doing. However, we cannot say that it was either too cautious or incautious because we could never anticipate which of the two it was going to be.
  The Veo 250 seems ideal for basic (down to 30m) leisure divers, who are, of course, the majority. £269 (others from£149)


Scubapro Uwatec Smart Pro (also Smart Com)

This Swiss-made computer offers five levels of micro-bubble suppression, but if you use it straight out of its box, it simply works as all previous Aladin computers do, with the regular Buhlmann ZH-L8 algorithm.
  This algorithm might now be less cautious than currently thought totally safe by some, whereas others have been successfully using it for years.
  We activated the setting Micro-Bubble Suppression Level 1 before using this instrument. The instruction manual offers little in the way of guidance as to which level anyone should use, apart from suggesting that those suffering from a PFO use level 5.
  We used it at level 1 to take advantage of its modern micro-bubble suppression possibilities.
  The display gives lots of information, laid out in a very easy-to-read way. We half-expected to see some deep stops displayed during diving, but what the manufacturer calls level-stops (as opposed to deco-stops) displayed were always at 6 or 3m which, to us, seemed no different to extended deco-stops.
  We suggest new users start using the Smart at micro-bubble suppression level 2, where level-stops might be displayed at more obviously deeper depths.
  Setting up the computer needed a little intuition, not to say dexterity, as it had rather old-fashioned wet-finger contacts, and the important setting-up icons were very small and less than easy for middle-aged men to see clearly.
  One disadvantage of this computer over all its rivals here was the lack of a user-changeable battery facility.
  Even so, with its bubble-suppression program in operation, it represents what we believe to be a computer that is safe to use for this commonly undertaken type of diving. from £375


Suunto Gekko (also Stinger, Mosquito, Vyper)

A new entry-level computer from this popular Finnish manufacturer, the Gekko uses the Suunto RGBM 100 algorithm common to all its contemporary siblings. It proved to be probably the most conventionally conservative of all the computers tested here, with long stops at 3m consistently indicated on every dive.
  All the latest Suunto computers are very easily set-up for use, with the aid of three push-buttons and a menu-driven system. We used the Gekko set for its least cautious mode or personal setting, and its clearly designed display indicated total-ascent-time and stop ceiling depth when in deco-mode. £199
  It also adds in a three-minute safety stop in the shallows once up past 6m and this is included in the total ascent time.


Suunto Vytec

This top-of-the-range Suunto offers computations using three different nitrox mixes which are easily changed to suit during a dive. It can gas-integrate, with mix No 1 giving tank-pressure display and calculated remaining air-time with the aid of an optional high-pressure transmitter unit that fits to the regulator first stage.
  The reason that we include it here, however, is that it also gives the option of both Suunto RGBM 100 and the less cautious Suunto RGBM 50 algorithm.
  We set our test unit to the latter for comparison.
  Used in the least cautious of its possible personal safety settings, in the event there seemed to be little difference to the decompression required by its similarly set sibling Gekko (RGBM 100), with only about one minute in 10 being shed from total deco-times even after a long series of dives in the 50m-plus range within which we were diving.
  Suunto is at present deservedly the brand leader in leisure-diving computers and its products are very user-friendly, with easy-to-set-up and clearly understood displays. from £430