Appeared in DIVER February 2007

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BC  Coltrisub Zero Tech Evolution VC9
THE COLTRISUB ZERO TECH EVOLUTION VC9 is one of those BCs that have, besides a very long name, every feature that could be loaded onto what would otherwise be a simple inflatable bag.
It looks very technical but you would have to remove the backpack and single camband and replace it with a steel backplate if you went in that direction. It has the holes already.
Instead, I simply played the part of wannabe tekkie, which I do very well nowadays.
The VC9 is a hybrid jacket, in that it attempts to combine a back-flotation design with a conventional waistcoat-style BC.
It has a little wing, restricted from flapping by an elasticated bungee cord threaded through it, and has trim-weight pockets each side that can take up to 2kg of lead each. I found these very useful when diving with a large aluminium cylinder.
The weights are kept in place by flaps closed by pinch-clips. Its a simple matter to unclip the buckles and let the weights drop out when the time comes.
The main jacket also inflates, and has an integrated-weight system with three pouches held closed and in place by the old-fashioned Velcro method. I have never been keen on this system, because I have had bad experiences with weights falling out unexpectedly, but I was careful to install the pouches myself each day and nothing untoward happened.
Dont leave this to anyone else, no matter how helpful they are trying to be.

I WAS USING THE FULL 4KG OF WEIGHT that each of the three pouches could take. I agree that12kg seems a lot, but
I was wearing a large 5mm semi-dry suit and using a dustbin-sized aluminium cylinder with the Zero Tech Evolution, both of which displaced a lot of water.
The VC9 seems to be strongly made. Its a bit of a bruiser,
in fact, so bulky and heavy that I nearly had second thoughts about taking it to Sharm el Sheikh, but I threw myself on the mercy of the BA check-in staff, and a very nice lady chose to ignore my 30kg of excess baggage and gave me a legroom seat to boot! BA has instantly become my favourite airline for that particular destination.
The buoyancy-cell of the Zero Tech Evolution has different compartments, so needs several dump valves. There are simple pull-cord dumps at the lower rear of the wing part on one side, and on the lower part of the other side at the front of the wing, operated by a toggle and pull-cord threaded through to the front of the BC harness.
Another dump valve above the right shoulder is operated by a toggle and pull-cord threaded through to the front shoulder facing on that side. These shoulder straps carry five large steel D-rings, two of which are movable along with the webbing.

AT FIRST I PLANNED TO USE THE DUMP VALVE operated at the left-side shoulder by pulling on the corrugated hose.
I tucked this through the sternum-strap, as is my wont, before making my first dive with the VC9. But once under water
I found that either the direct-feed hose was too short or the corrugated hose too long to achieve this.
Pulling on the corrugated hose merely resulted in me trying to pull the direct-feed hose off the regulator, and no valve was opened to vent off the excess air.
So I had a few concentrated minutes of trying to find all those other toggles, by now well tangled on their long cords.
If I owned this BC, I would shorten both the cords and the corrugated hose, or invest in a longer direct-feed hose.
Anyway, uncontrolled ascent averted, I made my way safely to the surface, where I was able to give myself plenty of armchair comfort by inflating both the wing section and the forward section of the buoyancy cell fully. As the Duke of Wellington might have reflected, it had been a close-run thing.
The VC9 has a backpack thats adjustable for length and a harness thats adjustable for girth, so there is no reason for it not to fit you perfectly. In the water it seemed a lot less bulky than when I had tried to pack it.
It has two large side pockets, with zips that run the right way to help you find them without a struggle. These and the pocket for the safety sausage (or Floating Visual Indicator,
as the manufacturer likes to call it) make the BC seem more cumbersome and bulky when you try to squeeze it into a dive bag, or even a dive-centre crate.
Neither do I like it that the Coltrisub designers have decided to label everything so boldly. This wouldnt be so bad if they were in tune with how I rig my gear. I brazenly clipped my pressure gauge to the D-ring labelled Octopus and stashed my octopus rig on its long hose under a bungee round the tank. The D-ring labelled Pressure Gauge went unused.
No one could have been in any doubt as to how to release my left-sided weights, should it have been necessary, for the left integrated-weight release toggle was clearly marked by
a large arrow and the words Ballast Release. Strangely, however, the other side was left to a rescuers initiative. Should that rescuer have approached me from behind, the rear trim-weight pockets were also clearly marked. I felt like someone driving a signwritten panel van through a royal park, waiting to collect a fixed penalty fine.
A little knife is fixed to the outside of the right pocket. Its illegal to carry a dive knife within Ras Mohammed marine park, so that led to an embarrassing moment when a busybody dive guide from another boat tried to confiscate it from me while under water.
He found it as difficult to remove from where it was stowed as I had before the dive - which is why I had left it there in the first place.
After some minutes of gesticulating and struggling, he gave up and went off to bother someone else for looking at the coral too closely. There was certainly no danger of me using it, or
I might have been tempted to slice through someones (naming no names) hp hose with it. At this time my Camel Dive Centre shepherd Ray had drifted off to cook some coral with the enormous 250W GreenForce lamp I had loaned him.
My diving done for the week, I rinsed the BC, but found that it took quite a lot of fiddling to eject all the water that had made its way into the complex buoyancy cell. I had to inflate and rotate the jacket several times before I could manoeuvre the water to an evacuation point.
Im sorry, Mr Coltri, if your BC still had signs of seawater about it when you got it back. I did my best.
The Zero Tech Evolution is available in sizes S, M, L and XL and costs 323.
  • Submarine Manufacturing & Products, 01772 687775


  • Divernet
    Integrated-weight
    Integrated-weight release toggle
    buoyancy
    buoyancy cell kept neat with elastic cord
    safety
    safety sausage in its pocket
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    + Loaded with features


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    - Unnecessarily heavy and complex
    - That sign-writing!