Computer Dacor Darwin
Many people think that Charles Darwin conceived the notion of evolution. Not so.
     His scientific masterpiece, snappily entitled The Origin of the Species by Means of Natural Selection, or The Preservation of Favoured Races in the Struggle for Life, concentrated on the theory that the survival of any life-forms was due to their being most fitted to the prevailing circumstances and conditions. So it was not really evolution so much as survival of the fittest.
     He was equally interested in the fact that some animals were unable to adapt, hence the modern habit of alluding to Darwinism at work when someone is witnessed doing something extremely foolish and fatal.
     Putting aside the joke that this computer works on a Darwinian principle, lets assume that the good people at Dacor were thinking along the lines of its design surviving because it was the fittest for the purpose and was able to adapt to changing circumstances.
     First glance at the Dacor Darwin gives away its family connection to the Mares M1. No surprise here. They come from the same factory, so comparisons are inevitable.
     I have to say that the Darwin is better-looking. By some simple changes to the moulding and colour scheme of the outer case, the manufacturer has lost the somewhat brutish appearance of its older brother. However, it isnt one of the smallest computers currently on the market.
     The layout of the LCD display has been reorganised too, but without any obvious advantages added.
     Its a nitrox computer. You can set it to give the deco requirements for the mix of nitrox you are going to breathe, from air all the way to 50% O2, and for those not yet familiar with the use of devil-gas, you can simply keep it set for air.
     You can also set the level at which a warning for the maximum ppO2 operates, and that varies from 1.2 to 1.6 bar. As expected, it also monitors any oxygen toxicity that might build up within the diver.
     If you are using a bottom gas other than nitrox, it will double as a depth-gauge and bottom-timer. Audible alarms can be switched on or off to order.
     Once you run out of no-stop time, when using it as a computer, it sounds off in an alarming way and displays the deepest stop depth and the stop time. I found the way it alternated between your actual depth and your maximum depth (and water temperature) slightly disconcerting but I liked the fact that it always gives an additional safety stop of 3 minutes once you are clear of deco-stop time and between 3 and 5m deep.
     The Darwin uses a variable ascent-rate and monitors this by displaying a bold graphic which represents a percentage of the ascent-rate according to depth, and the display has its own integral illumination.
     Once you are at the surface it starts counting and displaying surface interval. Time to fly is always 12 hours in the case of no-stop dives or 24 hours for deco-stop dives, or the total desaturation time if that is the longer. The unit is said to be good for use down to 150m, although I didnt bother to check this.
     The manufacturer has always been a little coy in the past about the algorithm it uses but this one is said to be a deterministic-exponential 11- tissue algorithm with M-values derived from Rogers and Powell studies.
     The important figures it throws up seem to be broadly in line with other European manufactured computers. Some peripheral information is so small on the LCD that only those with 20/20 vision need look.
     At the surface, youll find all the usual modern functions including logbook, dive-planning no-stop limits, calendar and clock, and simulation modes.
     Simulation allows you to get to know your computer before you find yourself in deep water. All settings are achieved by operating two buttons while at the surface, and you can use a button to turn it onto dive mode, although the whole unit is activated automatically after less than 30 seconds once it makes contact with water.
     PC integration for downloading your dives later is done using an optical connection. The computer logs data with a point profile of 20 seconds during the dive.
     The two-button system of manipulating the unit to provide the setting changes I wanted took a little more understanding than the instruction manual could provide. The frustration I went through in simply setting a nitrox percentage and a ppO2 level took me back to the bad old days of wet-finger contacts and profanity. Its certainly not as simple as they like to portray.
     The whole thing runs on a couple of easily obtainable AAA batteries housed in their own integral watertight section. Follow the instructions and you can change these easily without losing any computed information. If you were to foul up on replacing the sealing O-ring, only the battery compartment itself would be flooded, not the computer.
     Something I spotted in the instruction manual that should interest most people diving in British waters is this: Never use the Darwin or any other dive computer for repetitive square-profile dives deeper than 18m. Not a lot of people know that!
     The Dacor Darwin costs £235 wrist-mounted or £250 in a console.
  • Hydrotech 01455 274106, www.hydrotech.co.uk

  • Divernet
    + A Mares M1 for the style-conscious
    + Regular European-style deco requirements
    + Fit your own AAA batteries

    - Two buttons not as good as three
    - Bulky compared to some others