Size Matters

For the past 5 years I have used a VR3 from VR Technologies as my primary diving computer.  I still used it when I bought my Inspiration rebreather which ran on Vision electronics and came with it’s own computer in the form of the  Vision handset which not only gives the readings from the cells within the unit’s electronics, but it also gives information from the temp stick, decompression time  and general dive data.

A couple of weeks ago my VR3 kicked the bucket during a dive to 65 meters ... not the best of circumstances but I turned to the Vision handset and used my back up dive plan from my slate and used the timer to abort the dive and complete my decompression obligation safely.

I started visiting forums and websites reading information and reviews on which dive computers where available on the market.  I wasn’t up to speed with the latest models since prior to the VR failing I wasn’t looking for a computer.  I looked at what new models VR had released and also at Canadian manufacturers such as Liquivision and Shearwater.  All these companies create excellent diving instruments without a doubt - they are the leaders of the Technical Diving Market.

I find it a common occurrence that I set my heart on a dive gadget or piece of equipment but I find out that it only comes in Medium, Large, Extra Large and Extra Extra Large – seriously have these manufacturers every heard of Small – yes, small body, small feet, small wrists ... that’s what I’m made of ... a lot of small body parts I’m a size 34, UK 8, US 6 with feet size 35, UK 3 ½ US 6 pretty proportionate I would say!  So why is it that I struggle to find diving equipment that fit properly? 

What does this have to do with the choice of a computer you ask?  I will explain, the space between my wrist and my elbow is exactly – 26cm (10.23”) that’s not much real estate when you have to fit, one dive computer, one bottom timer and one slate (small).  From the first time I wore the VR3 on my right arm rather than on the left as it had been while tech diving open circuit I realised I wasn’t comfortable with three important items crammed in that small space.  The move was because of the vision handset which needs an arm to itself since it has a thick electronic hose coming from the unit down to the handset.

Now that I’m on the market for brand spanking new piece of kit I’m going to look at size ... because Size Matters!!!  Going back to my short list the VR and Shearwater units are pretty large compared to the nifty little units offered by Liquivision ... John a member of the tech dive team I dive with had recently bought a XEO unit – I was impressed by how small and light it was.  It’s one thing to look at specs and measurements online but it’s another impression to hold something in your hand.  I realised that I could wear the Liquivision with the rest of kit on my right arm without any problems or crowding.  My decision was made.  I contacted Liquivision to enquire about prices for the XEO closed circuit trimix software ... I was floored since it doesn’t come cheap and the quote was in Canadian Dollars ...

Once I make up my mind very little can differ me from my target so I did some math and decided to purchase the XEO.  I was in email correspondence with a member of Liquivision’s staff – they are very helpful and accommodating.  After a couple of days in correspondence I used the website’s online shop to order my unit I chose the XEO CC Kit which included a PC Interface, ZAGG Shield and 3 battery pack option.

Visiting the Liquivisions stand at the Dive2011

While waiting for the delivery of the unit I downloaded and read through the manual, I found the manual very well written and easy to understand how the unit function, even though it hadn't arrived yet.  I couldn’t wait to start tapping away.

When the unit arrived I was like a kid at Christmas ... I installed the battery and the Zagg Shield which I confess took a bit more time than I had planned, I’m not very good with sticky things and straight lines. The first thing I had to do was enter the Pin number, after a bit of a struggle with the tapping, I realised I wasn't tapping strongly enough, I got used to tapping the unit by the time the Pin was complete.  Next it was time for the Gradient Factors and the date, with that data in order the unit was ready to dive and I could go through the menu options.  I liked the idea that the XEO has no buttons, I started to get used to its ergonomic shape and angled display.  The full colour OLED display (which boasts of user changeable colours) has large fonts and displays all the information needed during a dive ([*]with the exception of one particular bit which I will come back to in the dive portion of this post). With the Gradient Factors updated, making sure they matched those set on  the software on the Vision electronics to enable both units to give identical decompression results during my dives.


The user can set alarms such as maximum depth, time, descent and ascent rate. Should an alarm trigger during the dive it will keep on persisting until the situation is corrected, with the exception of time, since that is something the diver cannot change.


I waited patiently for the weekend to arrive to get the XEO wet ... and boy did we get wet.  I got wet before I got into my drysuit because it was raining.

Unusual View of Cirkewwa from the Ferry

The plan was to dive at Cirkewwa with one of my  buddies to test the XEO and also test the Dry Suit.   Cirkewwa is a site we like to dive when testing new equipment it has easy entry and exit and usually boasts good visibility and a lot of fish life, there is also a huge area of sandy bottom which is perfect for running skill circuits.  When I got in the water my buoyancy was pretty off due to the dry suit,  once weights and buoyancy where sorted I glanced at my wrist and there it was “enlightened” yeah.

All the information I expected was present;

ü  Maximum Depth
ü  Dive time in minutes & seconds or hours, minutes & seconds
ü  TTS or Time To Surface
ü  NDL or No Decompression Limit
ü  STOP at depth
ü  FOR time to remain at that depth

On Closed Circuit;

ü  CC mode and the Set Point
ü  Current depth
ü  Battery indicator
ü  Temperature

My buddy had a VRX the latest model from VR Technologies and we where comparing our screens when we realised that [*] one small detail was missing from the CC screen ...

û  Chosen diluent mix for the dive

Images of the XEO in OC & CCR mode
[images from Liquivision user manual]

During dive mode the menu options available are;

1. Emergency
• Bailout/Undo Bailout (when diving CCR)
• GFs off/Undo GFs off
• Lost Gas (when diving OC or on Bailout)
2. Silence Alarm
3. Change Setpoint (when diving CCR)
4. Change Gas (when diving OC)
5. Review Runtime (reviewing a previously saved runtime, the XEO highlights how far into the dive the diver is)
6. Display
• Brightness
• Auto Dim

All the information shown is important and I wouldn't know which bit to sacrifice to include the diluent mix being used, but I definitely think it should be visible throughout the dive.  As it is shown on the Vision and also on the VR3 & VRX.  When diving the XEO on OC the breathing gas is always shown and it appears instead of the Set Point.

The alarms and warnings are shown in Red on a black background while the standard text is in Yellow and Green – I didn’t not change the colour set up to the XEO.

Images of the XEO in OC & CCR mode showing errors
[images from Liquivision user manual]

When I got home I was eager to see what the dive would look like on the Liquivision Dive Logger software.  I had previously downloaded the software and drivers for the wireless PC connection.  After I rinsed and dried the XEO I aligned both the unit and the connection, set the XEO to "PC connect" while the software searched for the connection.  Both gadgets connected and “communicating to each other” my dive was downloaded and presented in front of me as seen in the print screen below.

Print Screen of the first dive - the vertical red line is the sample used to fill the fields

The software allows the user to input Location and Dive site, a field for comments and notes is also available, the rest of the data is downloaded from the XEO, usual stuff such as; total time, surface interval, start and end time, max dept, average depth, min and max temperature, the CNS and OTU information.  The red vertical line across the graph is the sample I used for the print screen.


I am very happy with the choice of buying the XEO and looking forward to logging a lot more dives.  I wrote an email to Liquivision regarding the missing diluent mix and I was told that it was something they will be looking into.  So who knows in a future software updated the change might be included.


While at Birmingham Dive 2011 event I had a chat with the staff at VR Technologies and handed in my VR3, a few days later, Leyla Gurr emailed me informing me that it had a fault with the PCB board which VR do not repair any more, however they offered me a brand new NHeO3 replacement at a very heavily discounted price.  Needless to say I took Leyla's offer and in a matter of days I received the NHeO3, I have not had the opportunity to dive since then.   Will be writing about my thoughts on that in a few weeks.