Appeared in DIVER August 2011

WHEN IT COMES TO BUYING A FIRST BC, the choice is daunting. Internet forums don’t help, with their constant recommendations to buy a stainless-steel back-plate and wing. Few divers need that, frankly, even though the reasoning is that you will need one in the end.
It will also set you back about twice the cost of an entry-level BC.
Why do you need a BC anyway If you didn’t wear a wetsuit, you probably wouldn’t need one while you were under water. The human body is incompressible, and so displaces the same amount of water at whatever depth you might be. You simply need to get your overall weight in line with the amount of water you displace.
The problem if you do wear a wetsuit is that it gets compressed as you go deeper, effectively making you feel heavier. In fact what is happening is that you are displacing less water.
You put a small amount of air into your buoyancy-compensator (BC) to counteract this effect. As you come up your suit expands, making you feel lighter, so you need to be able to release the right amount of air from your BC to compensate for that, too. So the BC keeps your overall volume, accounting for you and all your equipment, constant.
A drysuit can be kept at constant volume by the same method – injecting and releasing small amounts of air from it according to your depth.
If you start out neutrally buoyant near the surface and are not wearing more weight than is strictly necessary, you’ll never need to use a BC under water when wearing a drysuit.

SO WHY DO PEOPLE WHO USE DRYSUITS also have a BC Because it allows you to localise this compensating air. It’s all positioned somewhere near the top of the body, so if you find yourself inverted in a drysuit because the compensating air has found its way to your feet, you can inflate your BC and, we hope, right yourself before you hurtle uncontrollably to the surface.
For the same reason, it’s best to inflate the BC when at the surface to use it as a flotation device.
What else does a BC do for you It straps your tank onto your back by means of a thick length of webbing and some kind of adjustable clamp, usually called a camband.
Most conventional BCs also provide D-rings onto which to clip accessories, and one or two pockets for carrying anything you might need during a dive.
What about the style Some BCs can take air only in a chamber at the back, while others allow the front part, low down, to be inflated when inflated fully – useful for stability at the surface.
People sometimes think that a back-inflation BC gives better stability under water.
The truth is that the air within it will rise to the highest point when you are under water, whatever shape it is, so the small amount of air you use for buoyancy compensation will always head high up behind your shoulders.
This is also crucial to know when you operate a dump valve. If it is positioned at the point to which the air naturally rises under water, there will be no drama in getting rid of it when you need to. A back-flotation BC simply allows you to enjoy an uncluttered chest area.
What about the corrugated hose It’s there simply for oral inflation of the BC as a back-up. People are still taught to use it to dump air, because originally a corrugated hose was all any BCs had, but it’s outdated thinking (see panel).
You should rarely need to use the corrugated hose for dumping air. Doing so opens the oral inflation valve and allows water to get back in while you’re using it.
some bcs use an integrated-weight system, to save you having to wear your weights on a separate belt. What’s the advantage The buoyancy in the BC adds an upward force, while the weights provide a downward force.
If you wear your weights separately, it’s your back that takes the strain of the opposing forces. Integrated-weights avoid this, but it must be possible to drop them easily.
When integrated weights were introduced, manufacturers relied on Velcro to keep them in place. This was a mistake, because the Velcro became tired as it got used in sunny and wet conditions. Now all BCs use a system of quick-release buckles.
Trim-weight pockets are often fitted, too. These are normally high up at the back, and their function is to overcome the buoyancy of the lightweight aluminium cylinders commonly encountered at dive centres outside the UK.
The primary function of a BC makes it a lo-tech item. You could use an inverted plastic carrier-bag for buoyancy control, but a good BC makes the whole process more comfortable.
Longevity BCs built from stronger material might last a lot longer and, let’s face it, they do tend to get used and abused.
However, a lightweight BC might pay for itself many times over in the money you save in excess-baggage charges, if you fly to dive.
The dry weight might therefore be an important part of the overall cost.


HOW IT ALL STARTED
It wasn’t so long ago that divers went without the luxury of being able to stay neutrally buoyant, although we did our best.
We used to wear just enough lead to allow us to get down, and then increase our lung volume while breathing to account for the reducing buoyancy caused by the compression of our suits.
This was balanced by the fact that often with the regulators of the time it could become quite hard to get a good lungful of air at depth.
Then came a marvellous device we called the Adjustable Buoyancy Life-Jacket, or ABLJ (pictured). It was passed over the head, and the narrow webbing around the waist was clipped together. There was also a crotch-strap. It looked like a toilet-seat cover or dray-horse collar.
hspace=5 A common error was to pass the crotch-strap through the beckets or grab-ropes while sitting on the tubes of a RIB, with dangerous – if humorous to onlookers – consequences.
As you went deeper, you inflated the ABLJ a little by removing your regulator and blowing air from your lungs into it via an oral inflation valve and a flexible corrugated hose.
The force of the buoyancy provided dwelt on the lowest point of the crotch-strap. It was often uncomfortable. On the way up, you let air out through the same oral inflation valve, raising the corrugated hose to make it the highest point.
One enterprising British company came up with a separate 400ml cylinder to inflate it, using air decanted from the main cylinder before diving. Many divers would over-inflate the ABLJ at depth, with dire consequences.
However, for years you couldn’t buy a BC without this little cylinder. The same company came up with a dump valve that did not let water in as it let air out.
Then a man called Harry Mackenney invented the ABLJ with a direct-feed from the regulator.
There was a continuing fixation about the ABLJ being a life-jacket, and BCs, when they arrived, were criticised for not fulfilling that role.
It was true that an ABLJ could keep an unconscious diver head-up at the surface as long as it was fully inflated first, but would a diver remember to do this before passing out
A rescuer had the option to inflate it, of course, but the same would apply with a BC.
Some insisted that it should be used like a reverse parachute. In trouble at depthInflate it and shoot to the surface!
No wonder diving got a reputation for being a very dangerous sport!


CRESSI START £162
THIS BC MAY at first glance look a little cheap, but that reflects the fact that it’s the least expensive model in this comparison review.
Italian manufacturer Cressi makes a wide range of BCs, but the Start is definitely
entry-level.
Nonetheless, it has good pockets held closed by large slabs of Velcro, and there was no
torso squeeze when it was fully inflated at the surface, thanks to the buoyancy cell mounting that slides on the waistband.
The Start has an effective cushion over the back-pack for maximum comfort in that area.
It represents a basic school jacket, with its size marked clearly on the outside.
We can’t imagine many private buyers going for size XL!
www.cressi.it

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Sizes: XS, S, M, L, XL
Dry Weight: 2.3kg
Max Lift: 15kg (M)
Integrated Weights: No
Pockets: 2
Dump Valves: 3

SUBGEAR BLACK DRAKE £199
THIS PRODUCT MAY have a very low price, but we found that it had enough buoyancy at its back for good control under water.
At the same time, nearly all of the maximum lift available was where you need it when you’re at the surface – low-down at the front. That’s perfect for training.
The Black Drake has unusual integrated-weight pockets in that they are huge vertical pouches held closed by pinch-clips.
The ordinary pockets were accessible, but they were not as big as we expected.
Unusual features include double pinch-clips at the shoulders to give more versatility when fitting to a wide range of diver shapes.
At the risk of revealing our hand early on, the SubGear Black Drake would emerge as our favourite BC in this line-up, considering the integrated weights and the price.
www.subgear.com

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Sizes: XS, S, M, L, XL
Dry Weight: 2.7kg
Max Lift (M): 15kg
Integrated Weights: Yes
Pockets: 2 with zips
Dump Valves: 3
MARES SPIRIT £215
From the highly regarded Italian-based but international manufacturer Mares, this is a classic school-style BC with masses of lift when fully inflated, and the buoyancy is low-down to give good surface support.
The huge pockets are held securely closed by means of Velcro, and there is a choice of camband position to suit either an aluminium or a steel tank.
Novel keepers for both the pressure gauge and the octopus avoid that common problem of new divers dragging such items through the sand or silt.
This proved to be one of our favourite BCs in this comparison test. While we liked the price, however, it might be worth forking out the extra for an integrated-weight system.
www.mares.com

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Sizes: XS, S, M, L, XL
Dry Weight: 2.8kg
Max Lift: 16kg (M)
Integrated
Weights: No
Pockets: 2
Dump Valves: 3
SCUBAPRO T-ONE £215
SCUBAPRO PROVIDES equipment for many diving schools around the world, and this is the BC you are most likely to be furnished with if you hire your kit while abroad.
The T-One represents a very basic school-type BC, with everything you need but nothing more than that.
This model has nice usable pockets that are of a very basic design, plus places to stow an octopus rig and a pressure gauge neatly.
A neat camband arrangement discourages the loose end of the webbing from flapping,
but there was no appreciable padding to the back-pack.
However, this was curved like a good rucksack so that it puts all the weight of the rig onto the wearer’s hips.
www.scubapro.com

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Sizes: XXS, XS, S, M, L, XL, XXL
Dry Weight: 2.4kg
Max Lift: 17kg (M)
Integrated Weights: No
Pockets: 2
Dump Valves: 3
AERIS EX100 £229
THIS BC IS PART OF A LARGE US-made range that is squarely aimed at the new diver, with prices to match.
Details include a waist-strap that is easy to find when dressing, thanks to Velcro keepers on the cummerbund.
The Aeris EX100 also has a very neat and secure Cousteau-designed trident pinch-clip to hold it shut.
Also supplied is a very flexible corrugated hose, and pockets big enough to carry a PADI wheel.
The integrated-weight system includes trim-weight pockets that can carry 2.5kg each side,
and have effective drainage holes.
An ergonomic back-pack cushion gives comfort, but there is precious little padding at
the shoulders.
www.oceanicuk.com

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Sizes: XS, SM, M, L, XL
Dry Weight: 3kg
Max Lift: 17kg (M)
Integrated Weights: Yes, plus trim-weights
Pockets: 2 with zips
Dump Valves: 3
BEUCHAT MASTERLIFT SPORT 2 £240
With probably the easiest access to its pockets of any of the BCs listed here, there was no torso squeeze found on the Beuchat Masterlift Sport 2 when it was fully inflated, thanks to a sliding buoyancy cell mounting on the waist-band.
There was not a lot of maximum lift available when fully inflated at the surface, but the amount was probably enough for most divers.
There was little or no padding covering the hard back-pack, and both parts of the waist strap and cummerbund terminate at the inner end with Velcro fastenings.
Beuchat has a big manufacturing facility near Marseille, and the brand is well-known on the Continent. Its new distributor promises to make it as popular in the UK.
The Masterlift Sport 2 certainly represents a good club-style BC.
www.beuchat.fr

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Sizes: XXS, XS, S, M, L, XL
Dry Weight: 2.4kg
Max Lift: 12kg (M)
Integrated
Weights: No
Pockets: 2 with zips
Dump Valves: 3
SEAC RESORT £246
ANOTHER BASIC BC intended for school use, this one from another Italian brand, Seac, features two positions for both the tank camband and for the sternum strap on the harness.
It gave good access to big pockets, and there seemed to be no torso squeeze when it was fully inflated at the surface, thanks to the sliding mounting of the buoyancy cell on the waist-band webbing.
The Resort had really good padding throughout, which promised to make it very comfortable for the diver who might prefer to do without a wetsuit in warm tropical conditions.
We felt that it would be worth paying the extra to get the version with the integrated-weights system.
www.seacsub.com

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Sizes: XXS, XS, S, M, L, XL
Dry Weight: 2.7kg
Max Lift: 15kg (M)
Integrated
Weights: No
Pockets: 1 with zip
Dump Valves: 3
AQUA LUNG PRO LT £270
THIS IS ONE OF THE LEAST EXPENSIVE Aqua Lung BCs to feature the integrated-weight system with pouches held secure with patented Surelock buckles.
Its pockets concertina outwards so that the enclosed weights do not affect their capacity.
There was no torso squeeze encountered at maximum inflation, and low-profile dump valves ensure that there is no possibility of them getting caught on anything on a dive.
We noted the four unusual flat metal D-rings for accessories, and a back-pack covered with plenty of self-draining padding to provide maximum comfort.
The camband and waist-strap terminate inside with Velcro fixings. This product represents a lot of BC for the money.
www.aqualung.com

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Sizes: XS, S, M, ML, L, XL
Dry Weight: 3kg
Max Lift: 13kg (M)
Integrated Weights: Yes, plus trim-weights
Pockets: 2 with zips
Dump Valves: 3
TIGULLIO SEA TRAVEL £281
TIGULLIO DOES MAKE a school-style BC, but it was not available from the British importer.
So the Sea Travel is the manufacturer’s least expensive offering in the UK, but its unique selling proposition is its light weight, and this BC comes into its own at the airport check-in counter.
The low packing weight is achieved by employing incredibly lightweight materials.
This BC has a camband fitted low down that works with a Velcro-fitted stabilising strap with trim-weight pouches attached.
It includes six pretend-metal D-rings for clipping on any accessories you might need, and usefully large pockets.
An elasticated waist-strap takes care of any suit compression at depth, but the diver
is separated from his tank only by a very thinly constructed back-cushion.
www.tigullio.co.uk

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Sizes: XS, S, M, L, XL
Dry Weight: 1.9kg
Max Lift: 13.5kg (M)
Integrated Weights: Trim weights only
Pockets: 2 with zips
Dump Valves: 3
BUDDY COMMANDO ESCAPE £327
MADE IN BRITAIN, the Buddy jackets made by APValves hold a special place in the affections of British club divers, and the Commando Escape looks like a Buddy.
However, in a departure from the company’s usual tradition of a double-bag construction, this lightweight BC employs a heat-sealed buoyancy chamber, but still features the big pockets we have come to expect from this brand.
Another innovation that has clearly been added to meet the demands of modern divers is the pull-dump fitted to the top end of the corrugated hose.
The Commando Escape has a very nice cushion covering the hard back-pack, too. The second waist-strap is too low to be called a sternum-strap.
www.apvalves.com

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Sizes: S, M, L, XL, XXL
Dry Weight: 3kg
Max Lift: 17kg (M)
Integrated Weights: No
Pockets: 4
Dump Valves: 3
IST ALPHA £335
TYPICALLY, THE TAIWANESE add as many value-added extras as they can for the price, and this BC is loaded down with features.
If a BC could have it, the IST Alpha has! There are no fewer than nine D-rings, an effective back-pack cushion and a choice of two positions for the mounting straps of the parachute-style harness to make it feel very comfortable in use.
We found that the Alpha had surprisingly capacious pockets, despite the space taken up by the integrated-weights, although their shape could lead to small items getting lost inside.
We felt unsure about the extra-secure integrated-weight pockets, because they needed an exceedingly strong pull to release them.
If you want a lot of features for your money, the Alpha is well worth investigating.
www.sea-sea.com

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Sizes: XS, S, M, L, L-XL, XL
Dry Weight: 4.3kg
Max Lift: 16kg (M)
Integrated Weights: Yes, plus trim-weights
Pockets: 2 with zips
Dump Valves: 3
ZEAGLE ESCAPE £400
THIS IS A TRUE WING-STYLE BC, with its buoyancy cell tidied by means of an elastic cord threaded through it.
The harness employs a proper Bergen principle, in that when properly rigged it puts all the weight onto the hips. The sternum strap has a choice of two positions.
The integrated weights on the Zeagle Escape can be dumped in an emergency by releasing the buckles, and the trim-weight pockets are unusual in that their weights can be dumped in the same way.
Another feature that is not mainstream is the single top dump, which is operated by pulling on the corrugated hose.
This is combined with a choice of two lower kidney dump valves, operated by toggles.
The Escape is made in the USA, a fact that is reflected in the price.
www.typhoon-int.co.uk/zeagle

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Sizes: S, M, L, XL
Dry Weight: 4.5kg
Max Lift: 16kg (M)
Integrated Weights: Yes, plus trim weights
Pockets: 2 (+ 2 hidden)
Dump Valves: 3 inc. two bottom dumps


COMPARABLE BCs TO CONSIDER

CRESSI START PRO £191
This version includes an integrated-weight system with drop-weight pockets held closed by pinch-clips.
Sizes: XS, S, M, L, XL
Dry Weight: 2.6kg
Max Lift: 15kg (M)
Integrated Weights: Yes
Pockets: 2
Dump Valves: 3
www.cressi.it

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AERIS EX LITE £269
Wing-style BC with buoyancy cell kept compact when not inflated by elastic cord. It’s a lot of BC for £269.
Sizes: SM, M, L, XL
Dry Weight: 2.5kg
Max Lift: 14.5kg (M)
Integrated Weights: Yes, plus trim-weights
Pockets: No
Dump Valves: 3
www.oceanicuk.com

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MARES PRESTIGE MRS £269
This is Mares’ least expensive BC featuring the well-regarded MRS integrated-weight system.
Sizes: XXS-XS, S, M, L, XL
Dry Weight: 4.4kg
Max Lift: 14kg
Integrated Weights: Yes, plus trim-weights
Pockets: 2
Dump Valves: 3
www.mares.com

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SEAC RESORT SWS £319
A version of the basic school-style Resort, this one includes a simple integrated-weight system.
Sizes: XXS, XS, S, M, L, XL
Dry Weight: 3.4kg
Max Lift: 15kg (M)
Integrated Weights: Yes
Pockets: 2 with zips
Dump Valves: 3
www.seacsub.com

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AQUA LUNG DIMENSION i3 £430
A full-specification BC that employs integrated-weights and the buoyancy control system that dispenses with the corrugated hose.
Sizes: S, M, ML, L, XL
Dry Weight: 3.2kg
Max Lift: 22.5kg (M)
Integrated Weights: Yes, plus trim-weights
Pockets: 1 (small) with zip
www.aqualung.com

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HALCYON ECLIPSE 30 £479
It may be phenomenally expensive but this represents the entry-level BC among those bearing the hallowed Halcyon brand.
Sizes: One size fits all
Dry Weight: 5.4kg (aluminium backplate)
Max Lift: 18kg
Integrated Weights: Optional extra
Pockets: No
Dump Valves: 1
www.silentplanet.info

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