Appeared in DIVER March 2008

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.


THOSE INTREPID COUSTEAU DIVERS from the Calypso managed to get by without BCs. Even I, and Im not as old as them, learned to dive without one. Then I was told to get an ABLJ, a sort of toilet seat you wore round the neck, but used exactly as you do a modern BC.
When I taught diving, I would demonstrate buoyancy-control technique with an inverted carrier bag. It worked just like a BC, only it was that bit trickier to let the air in and out as needed. BCs are designed for the job, which includes holding the tank on your back, and most work well. They are basically lo-tech items, yet I am lent ever more complex ones to write about for these pages.
Manufacturers continue to add features to give added value at the point of purchase. The result is that packing my bag becomes a chore. I am always well overweight at airline check-in desks. That simple plastic carrier bag would have doubled neatly for use with my carry-on!
Cressi has thought about this. It has come up with a BC that has a minimum dry weight. It cant be used as a carrier bag, but it does fold into a tight bundle that weighs only a couple of kilos. It makes buying a BC especially to take abroad a viable financial concept - provided it works well.
Constructed in lightweight nylon material, we felt the Flex looked rather flimsy at first. The trim-weight pockets, held closed by push-studs, didnt look as though they would take the wear of carrying a couple of lead weights.
This BC is clearly not intended as a heavy-duty item, and you wont see many full-time dive-guides using them. But if you take one diving holiday a year, it should last you a long time and see back the money you might have spent on excess-baggage charges.

I lent the Cressi Flex to Simon Gardner (right), a dive-guide from the liveaboard Royal Evolution. He fell in love with it, and I had difficulty getting it back. Simon had been using a wing with a metal backplate with a single-tank adaptor, so this really was a change for him. He never noticed the absence of any sort of backpack with the Flex when in the water.
He said he couldnt get over the light weight whenever he donned his equipment. A single camband might allow the tank to twist about on the divers back, so a second Velcro-covered belt to add stability supplements this.

The Flex is a BC with a conventional format for its buoyancy cell, so there were no surprises. It worked faultlessly.
Simon said he liked the pockets. He hadnt used a BC with pockets in a long time.
The two large pockets are held closed with zips that operate the right way for easy access, and a couple of large shoulder-mounted metal D-rings take care of dangled items.
Two other similar-sized D-rings are mounted at the end of the adjustable shoulder straps, and two little ones along the lower edge of the jacket. The trim-weight pockets were perfect for use with the typical 12-litre aluminium tank commonly encountered abroad.
The zipped pockets contain small net pouches that could be used as non-ditchable weight-holders for an integrated-weight effect.

Control of Ascent
Though the Flex is minimalist in many ways,
it offers a full range of methods to dump air during the ascent. You can pull on the corrugated hose to open the dump valve at its top or operate a toggle pull dump on the right shoulder. A nice feature is the way the toggle for the lower rear dump is threaded through to the front of the BC, so that there is no fumbling for it on fast head-down descents.

Surface Support
The Flex is a lightweight BC, not one of those super jobs to which one could almost fit a small outboard motor and drive back to shore.
On the other hand, for the properly weighted user it offers sufficient support to be comfortable at the surface in large seas.
A maximum lift of 10kg (size M) may not sound much, but how much weight do you add to your belt to become neutrally buoyant
As a rule of thumb for the single-cylinder diver, you dont need more lift than this, and because much of the buoyancy is positioned low down, all of that 10kg takes effect to sit you nicely at the surface.

Ease of Removal
It took only moments to unclip the waistband buckle and one shoulder strap to slip out of this BC in the water. Pick-up boat drivers appreciated its low weight when it came to heaving the set aboard, or would have done if the pockets had drain holes.
Instead, they dredged up as much as half a kilo of water each, which also made climbing a boat-ladder harder than it might have been. But there is nothing else like the Flex.

Divernet Divernet
Dump valve
Weight pocket may be flimsy
Bottom dump toggle is at the front

PRICE £260
STYLE Conventional
INTEGRATED WEIGHTS Trim-weights only
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