Appeared in DIVER July 2007

John John Bantin has been a full-time professional diving writer and underwater photographer since 1990. He makes around 300 dives each year testing diving equipment.


A FINNISH COMPUTER MANUFACTURER, BENEMEC, made a talking computer. It used a sense, hearing, that is otherwise redundant for divers under water, so it seemed a good idea.
No one bought it. It seemed that macho divers were never going to wear anything so sissy.
Head-up displays are altogether different, probably due to films such as Tony Scotts Top Gun. Head-up displays (HUDs) are almost de rigueur if youre a rebreather diver. Its the military connotation that makes it acceptable.
Now the US company Oceanic has introduced a mask with a built-in computer and a head-up display. It has been developed from one designed for use by Special Operations. Ill bet you boys will be queuing to buy one.
The Oceanic Datamask unit I took to the Maldives was the only one available in the UK, and there was no instruction booklet. With the help of several phone calls to Oceanic SWs headquarters, I managed to get it set up for my kind of diving, by giving its two buttons either long or short pushes, and paired it with its transmitter.
Is it gas-integrated You wouldnt think of buying a head-up display computer mask that wasnt, would you Its very appealing. Everyone who saw it wanted one.

Im always suspicious of the algorithms of US-made computers. Thats because I am so often under water waiting out a deco-stop demanded by a European-made computer, while my American diving buddies are back on the boat using all the hot water for their showers, scoffing all the snacks and drinking all the hot chocolate.
That cant be right, surely I set the Datamask with a personal caution level so that it offered similar no-stop times to those European ones in which I have confidence.

Display legibility
The in-built display has a variable brightness that you can adjust to suit ambient conditions. In the Maldives I had it turned up to 55%, but for a night dive or a dive in the UK you might find 15% more suitable.
Despite needing glasses to read a book, I was happy to note that I seemed able to focus on the little TV-style window inside the mask.
Obviously the optics are so arranged that the visible image is at virtual infinity. Alas, this made it virtually impossible to get a good photograph of the full display while under water!

These are just like most other nitrox computers in that you can set the fraction of oxygen (up to 100%) and the maximum ppO2. As with other computers, you can set the time of day and date, too. This is useful in logbook mode, which includes a tissue-loading graph.
You can set an alarm for halfway tank pressure setting, and an end-of-dive tank pressure. In common with other US-made computers, you can choose to have this one water-activated or not. You can also choose both a depth and duration for a safety-stop.

After the main display, a push on a side-button activates the first alternating display. The top button activates the second and third alternating displays. At the safety stop you can see depth, tank pressure, time counting down, tissue-loading graph and the STOP icon. In Deco mode the display shows full information regarding stop-depth and time. The computer can also be used in Gauge mode and Freediving mode, with timings in minutes and seconds.
I found that needing to push a button when my hands were full of camera equipment was rather onerous.

The mask
This is where the product was let down. Obviously this mask weighs a bit more than a conventional one, because it includes a computer. I found that I had to strap it on fairly tightly, or it would droop and let a steady stream of water in. I spent a lot of time during the first dive clearing this water out.
Without prescription lenses, I fixed a couple of Dive Optix temporary lenses inside the glass so that I could see to set and use my camera during a dive.
This had nothing to do with the other snag I found, that the front glass is quite far in front of the eyes so that, by the time space is taken up for the head-up display, the remaining field of vision seemed quite limited.
The opaque skirt didnt help, either. I felt I was looking through a couple of cardboard tubes, and had to constantly scan around to find other divers I was meant to be photographing. The right-hand side has a smaller glass than the left.
I dont know how those Navy SEALs got on.
I would have thought that this limited vision would have put them at an operational disadvantage.

Divernet Divernet Divernet
COST Anticipated at 700-800
ASCENT RATE Variable according to depth
WARNINGS Option of audible warnings; max depth; tank pressure; MOD exceeded; ascent rate exceeded; dive time remaining; tissue-loading bar graph; elapsed dive time
NORMAL IN-WATER DISPLAY current depth, remaining no-stop time, tank pressure, remaining airtime, and tissue-loading graph
ALTERNATING DISPLAY 1 Max depth, dive duration, airtime remaining
ALTERNATING DISPLAY 3 Time, temperature
DECO INFO As above, plus stop-depth and countdown timer
SAMPLING RATE 2-60sec. Variable
LOGBOOK Yes, with history
DIVING MODES Air, Nitrox 22-100, Gauge, Free
OTHER NITROX MIXES Three with individual transmitters
BATTERY User-replaceable. 2 x CR2 plus transmitter CR2
CONTACT Oceanic,
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