Despite what Internet diving forums might suggest, single-tank, open-circuit diving is still one of the most popular formats for our pastime.
Setting off for a brief excursion around some of the most southerly islands in the Bahamas, with excruciatingly mean weight-limits for checked-baggage on inter-island flights, I chose the new lightweight Biolite back-flotation BC to take with me.
This BC weighs only 2.5kg, which includes an integrated-weight system. So I didn’t even need to pack a weightbelt.

In Detail
The Biolite is one of those modern designs that puts all the flotation at the back. The buoyancy cell is restrained from flapping and trapping air in the wrong places by a long length of elastic strap, threaded between loops in the cell and the main part of the harness.
There is a concession to a hard backpack in the form of a panel a mere 20cm deep. This is held in contact with the tank by a single camband. There is no second stabilising strap as such, though there is a loose strap that is used to tie around the tank-valve, and this goes some way to doing the same job. A slim cushion keeps the tank away from the diver’s back.
The waist-strap is closed by a conventional over-sized pinch-clip and is elasticated, so that there is a degree of self-adjustment as your suit contracts due to the pressure of depth.
The main integrated-weight pockets are attached to this waist-strap, and I expected them to make it difficult to do it up when climbing into the BC in the boat, but I was wrong. The sternum-strap mountings slide up and down a novel track to help you avoid uncomfortable positions.
On the right shoulder-strap facing, a series of fabric loops double up for more conventional D-rings, and a locking karabiner is supplied, presumably for dangling a reel or other accessory.
These shoulder-straps terminate in large pinch-clips. These are connected to wide webbing, which returns to the harness in a rucksack style that leaves the diver’s chest area totally uncluttered.
A couple of plastic D-rings, both supplied with hose-clips, dangle from the lower edge of the harness.

Integrated Weights
With my height I need a lot of Neoprene to cover my body, even when wearing nothing more than a 3mm suit.
Alas, the main integrated-weight pockets positioned at the sides of the Biolite take a maximum of only 3kg of ditchable lead each, so I needed to stow extra weight in the zipped pockets mounted on the tank camband.
Luckily, these pockets were good for an extra couple of kilos each, so I was still able to use a larger tank, as is my habit.
The main pockets have an inverted design with zips at the top for stowing the weight in individual packets, and large flaps held closed by pinch-clips that are individually released to drop the weight-packet in an emergency.
The Biolite is obviously designed for use with the type of aluminium tank commonly encountered in the tropics.
I would guess that the positioning of the weights at the sides combined with a heavier steel tank would be less than satisfactory for a comfortable horizontal position in the water, but I didn’t try this.

Buoyancy Control
Under water, buoyancy-compensating air always rises to the highest point regardless of the design of the BC. This tends to be high up on the diver’s back, near the shoulders.
Air is fed into the buoyancy cell of the Biolite via a conventional direct-feed and corrugated hose. I dispensed with the heavy rubber direct-feed hose supplied, and substituted a lightweight Miflex one.
I didn’t notice any tendency to flap my wing but other divers, casually observing, disagreed. They told me that the wing tended to wrap around my tank. This might have been expected to make it difficult to release air while horizontal in the water, but it didn’t seem to do so.
A sharp tug on the corrugated hose was all that was needed to tweak open the valve at the shoulder to release air when I needed to, during an ascent.
At no time did I think that air was getting trapped within the cell. As long as I was facing upwards, there was no problem.
There is also a bottom dump mounted inside the buoyancy cell. I would have liked to have used this for fast head-down progressions away from the surface, but the cord and toggle proved difficult to operate, because it inevitably became entangled with the elasticated strap that restrained the buoyancy cell.
Eventually I removed the toggle, and got into the habit of feeling directly for the valve and its protruding cord. It would have been much better all round if this dump valve had been mounted on the outside, and I’m still waiting for any manufacturer to explain to me the reasoning for this inner position that is so commonly employed.
My only other gripe was the lack of any sort of pocket. I like to stow small things away, rather than have them dangle Christmas-tree-style on D-rings.

At the Surface
I never felt I was lacking in comfort while waiting at the surface. I never felt insecure. There seemed to be masses of support once the buoyancy-cell was fully inflated.
Handing up the weights to the boatman at the end of a dive proved quite difficult. That’s because the weight pouches are intended simply to be dropped in an emergency, rather than being accessed once they are installed.
Getting them out without dropping them proved too fiddly, so I opted either to climb the ladder with my set on and the weights in place, or float it and pass up the whole thing complete.
Packing afterwards to come home was a joy.
I had used the Biolite on a trip with multiple dive destinations and several flights and had got used to rolling it up to go in my backpack.
It did me royally!

COMPARABLE BCS TO CONSIDER:
Cressi Air Travel, £287
Mares Hybrid, £450
Aqua Lung Zuma, £272

SPECS
D4i
PRICE £390
SIZES XSM, SM, MD, LG, XL
MAX LIFT IN SIZE MD 15kg
DRY WEIGHT 2.5kg
CONTACT www.oceanicuk.com
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