IF IN 1999 YOU HAD TOLD ME that in 10 years time I would be sitting at home having a Skype face-to-face conference with Doug Krause of Oceanic in California, watching as he took me through the operation of his company's new diving computer on his desktop PC, I wouldn't have believed it.
It is amazing how much computing power can now be packed onto a wrist. However, some basic philosophies can still make a difference when it comes to computer calculations, and diving computers are no exception.
For years I railed against the algorithm used by many US-made computers, including those of Oceanic, and got used to receiving strongly worded letters from the lawyers.
At one American DEMA trade show, I was bracing myself for another such confrontation with a manufacturer when Bruce Wienke, the man who wrote the decompression software for Suunto, turned up unexpectedly, and proved to be an unassailable ally.
The problem was that these US computers were aimed at warmwater leisure divers with short attention spans. They were for divers who don't go very deep, and tend to be out of the water quickly, asking to go somewhere else.
The algorithm accommodated this by being aimed at no-stop diving no deeper than 30m. Alas, distributors in other countries insisted on trying to sell these instruments to divers with very different diving habits, in which case the instrument defaulted to a vindictive table that would really punish them for going beyond those simple parameters.
These computers had what I called at the time a Jekyll & Hyde character.
When you have a massive home market like the States, what some journalist says in a small island in the north Atlantic may not matter, but the diving market is getting tougher, and Oceanic is casting its eyes farther afield.
Im told that, at the launch of the new dual-algorithm OC1 at the last DEMA show, my name was mentioned!
You can now opt for either the old Pelagic DSAT no-stop divers algorithm, or use the new Pelagic Z+, which appears to perform very much like the algorithm familiar to divers in Europe. Our recent side-by-side test (A Sense Of Algorithm, October) put it firmly alongside the Wienke one used by Mares.
The only problem I foresee is that owners of these computers must choose which algorithm to use. Perhaps astute retailers will set them for them.
The Pelagic Z+ uses the Buhlmann ZHL-16C database, designed to meet the more rigorous demands of repetitive, coldwater deco-diving at altitude. It is available only in the flagship OC1 at the moment, but watch this space!
As old stocks dwindle, Im sure we will see it installed as at least an option in all replacement Oceanic models as they come on line.
The OC1 is a nitrox-enabled computer-watch that can be wirelessly integrated with up to three different gas supplies according to the number of transmitters employed, and this can include your buddys main tank.
It has a digital compass, and the whole lot is contained within a smart titanium case that can be worn as a day-to-day watch.

The OC1 has four push-buttons that seem quite intuitive to operate, though you have to get used to the difference between short and long pushes. I found some of the abbreviations used in the Quick-start guide hard to fathom at first. It really needs a key.
Once I had worked out that NDL Basis meant algorithm choice, I was up and running.
You can opt for deep stops if you wish, and there is a more conservative setting, too. You can also choose one of three sampling rates.
The Oceanic worldwide website has a marvellous tutorial with lots of eDiving virtual diving video clips, so if you get yourself one of these computers I suggest you study the tutorial at home before getting into deep water.
It uses imperial measurements, but naturally there is a metric setting on the OC1 itself.
No penalty is given if the diver skips the deep stop, but it is strongly recommended that a shallow safety-stop be made with or without the deep stop, in keeping with the experiments of Pilmanis (1975).
Once into deco, deep stops are cancelled, as Oceanic believes that ample experimental data since 2007 indicates that this practice often produces an increase in DCI risk. Safety stops are adjustable for time and depth.

Display Legibility
All the information is there, but I found the type difficult to read at times, as an awful lot of information is squeezed onto the display.
The top half is devoted to no-stop or deco information, while the bottom half gives tank pressure and air-time remaining.
An alternative display provides less pertinent data such as maximum depth achieved, and a second alternative display allows access to the watch functions. I found no need to use either.

In the Water
Oceanic sent me two OC1 computers, so that I could directly compare the dual algorithms.
My tests suggest that if you use the Pelagic Z+ rather than the DSAT, you wont find yourself hanging on a line, eking out your remaining air supplies, while your mates are enjoying lunch.
When using more than one gas, it was simple to press the Mode button for more than two seconds to enter the gas-switching menu.
Press Advance to scroll to an alternative gas, and Select to choose it. Press Select again to confirm your action.
The compass must first be calibrated to your global position. This includes declination for a known longitude. I found the compass slightly more complex to use than that of some other similarly equipped computers.
When it comes to those annoying audible alarms, one push-button acknowledges and deactivates the current one.

Planning & Logbook
The planning mode lists no-stop times for a variety of depths. Logbook can list up to 24 dives in the unit, but by using the computer interface and software provided, dives can be downloaded to a desktop computer.

Suunto D9, £990 with one transmitter

PRICE £1055 including one transmitter
ALGORITHM Dual (Pelagic DSAT & Z+)
FAST ASCENT WARNING Variable by depth
NORMAL IN-WATER DISPLAY Full info via three alternative/secondary displays
MODES Watch/Gauge/Nitrox (multi-gases)/Free Dive
BATTERY Factory-fitted (approx 300 dive hours) CR2450
CONTACT www.oceanicworldwide.com
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