WHY DO WE NEED TO COMPENSATE FOR BUOYANCY You may be perfectly weighted for neutral buoyancy near the surface, but as you go deeper the pressure on your neoprene suit increases and it is compressed. You start to displace less water, which means you lose buoyancy. You seem to get heavier.
Your body being incompressible, if you were hardy enough to dive suitless you would need no BC. You would still need one for surface support, however, and to hold your tank on your back.

Function 1: Buoyancy control
Gas has a weight, and at the end of a dive, when you have exhaled most of your supplies into the water, you will be lighter than when you started.
A BC allows you to compensate for these buoyancy changes by putting spare gas into an airtight vest. You put air in to compensate for loss of buoyancy as you go deeper, and let it out as you ascend.
If you wear a drysuit and dive with a single tank, you do the same with the suit, keeping it at constant volume and maintaining neutral buoyancy.
So why wear a BC when using a drysuit Should you become inverted it allows you to add buoyancy at one particular level, returning you upright. It also provides a back-up should the airtight integrity of your drysuit fail.
You need to be able to let air in and out of a BC easily and in a controlled manner. Finning horizontally under water, the air within a BC always goes to the highest point at the back, normally near the shoulders.
Manufacturers supply dump-valves to this end, though diving instructors still teach new divers to dump air by raising the corrugated hose and opening the oral-inflation valve. This lets a lot of water back in the other way.

Function 2: Surface support
The BC is not a life-jacket but it can function like one if you fully inflate it. This is very important while waiting at the surface to be picked up by a boat, or during long surface swims.
Some BCs give a lot of maximum buoyancy but this figure means nothing if the inflated part of the jacket is above the surface of the water.
In our comparison our test diver is identically equipped and weighted when he uses each BC for surface support, and we measure the height of his mouth above the surface. We consider 10cm to be the minimum acceptable ride height
We also measure the maximum lift available when a BC is fully inflated by attaching weights to it in fresh water. Compare our figures with those claimed by the manufacturers.
You should not wear more lead than you need to be neutrally buoyant at the surface, and a few kilograms of lift will be enough to see you on the way to the surface at a rate in excess of what is safe.

Function 3: Tank support
We check how securely the tank is held by each BC camband and judge how comfortable it is to wear while strolling around at the surface.
All BCs provide these three core functions. Then manufacturers start to add features such as pockets, D-rings onto which to clip accessories, the opportunity to mount two or more tanks, and integrated weight-systems.
Integrated weights have to be stored securely but you must be able to ditch them fast in an emergency, or simply to pass them up to a boat-handler.
Some BCs also have trim-weight pockets to help you compensate for the buoyancy of an aluminium tank. These tend to make a BC more expensive.
Some of the BCs we test here are aimed squarely at the dive-centre rental market, so their size is often clearly marked on the outside to allow them to be located quickly on the rack. This may not appeal to those whose size is XXL!
The 16 BCs tested here are entry-level in price and will appeal to those on a budget. We aim to provide the clues as to which will suit your needs best.
Prices range from the best-value £177 Sopras-sub from Eastern Europe to the well-proven but expensive (£307) Buddy made in the UK.
All performance comparisons were made using the same size of jacket, M.

AQUA LUNG WAVE £210

hspace=5 This strongly made yet simple favourite of dive centres has two upper dumps only, one operated by pulling on the corrugated hose and the other by cord and toggle. It has a lower drain plug but nothing to aid quick head-down descents. Simple large pockets are held closed by large flaps with Velcro fastenings. It has a single standard tank camband. The direct-feed hose integrates well with its corrugated hose.
The Wave represents the classic but basic entry-level BC. We were surprised to find that there was no sternum strap to prevent the straps slipping off those with narrower shoulders. It gave reasonable forward support when resting at the surface.

Specs:
Dry weight: 2.5kg.
Torso squeeze fully inflated: None.
Comfort out of water: Average.
Ride height: 13cm.
Max. buoyancy: 17.5kg.
Sizes: Five, XS to XL.
  • Aqua Lung UK (www.aqualung.co.uk)

    BEUCHAT MASTER LIFT SPORT £220

    hspace=5 Another classic design for an entry-level BC,
    this French-made offering has three dump valves, one operated by pulling on the corrugated hose, another by cord and toggle threaded through to the front, and a third positioned at the lower back, useful on a quick head-down finning descent from the surface.
    Comfort is provided by a wide cummerbund. There are two large zipped pockets, a clip-on whistle, some plastic D-rings and a single standard tank camband. We felt that the ride height provided when fully inflated at the surface was best suited to use in less-than-rough conditions because the diver was left so low in the water.

    Specs:
    Dry weight: 2.4kg.
    Torso squeeze fully inflated: None.
    Comfort out of the water: Above average.
    Ride height: 11cm.
    Max. buoyancy: 16kg.
    Sizes: Five, XS to XL.
  • Alpha Distribution (www.beuchat.fr)

    BUDDY EXPLORER £307

    hspace=5 Buddy double-bag-construction jackets used
    to be standard issue in BSAC clubs and are designed for UK diving. Built in a uniquely robust way, this one has a top dump and a lower back dump valve operated by pull-cords and large, easily found toggles.
    Its waist-band is weightbelt-like; it has Buddy buckles that can be unfastened best by using opposing hands; there are hose-wraps for keeping things neat; large forward-facing pockets that are easy to access; and a single standard tank camband.
    The harness offers an uncluttered frontal area with no sternum strap, helpful on curvaceous bodies. Its single-tank camband is not hygroscopic, so does not stretch when wet. There are two over-pressure relief valves. At the surface we found this BC gave the best forward support, and tended to lay the diver face-up.
    Extra ideas include a little line-cutter in its own pocket, an SMB pocket, and the options for an auxiliary cylinder and the Buddy Auto-air alternative breathing system.

    Specs:
    Dry weight: 3.0kg.
    Torso squeeze fully inflated: None.
    Comfort out of the water: Below average.
    Ride height: 18cm.
    Max. buoyancy: 14kg.
    Sizes: Four, S to XL.
  • AP Valves (www.apvalves.com)

    CRESSI-SUB LINE £193

    hspace=5 Three dump valves, including one operated by pulling on the corrugated hose and two others both operated by cords and toggles, with even a forward toggle for rear dump, distinguish this attractively cut BC. We found it gave support where it is needed, low down when at the surface, yet it really suited only experienced divers or those learning to dive in benign conditions, such was the ride height provided.
    This BC is designed to add little drag when swimming under water, which will make it a popular choice with many experienced divers. It has two zipped pockets with hard-to-get-to zips and a couple of plastic D-rings. It has a single conventional tank camband.

    Specs:
    Dry weight: 2.3kg.
    Torso squeeze fully inflated: None.
    Comfort out of the water: Above average.
    Ride height: 11cm.
    Max. buoyancy: 9.5kg.
    Sizes: Five, XS to XL.
  • Cressi-sub (www.cressi-sub.net)

    IST SATURN £250
    hspace=5 Obviously designed with the coldwater diver in mind, this classic-looking BC made in Taiwan looks as if it offers an enormous amount of lift, but looks can be deceiving.
    The diver is certainly wrapped in its large buoyancy cell, but surface-support was disappointing.
    The BC has curved zip-pockets, five stainless-steel D-rings, three dump valves, one operated by pulling on the corrugated hose and the other top dump by a cord and toggle threaded through to the front shoulder facing. It has an integrated-weight system, trim-weight pockets, a zipped key pocket in the cummerbund, two different sets of hose-retainers, and an emergency horn. It has a single conventional tank camband.

    Specs:
    Dry weight: 3.3kg.
    Torso squeeze fully inflated: Slight.
    Comfort out of the water: Below average.
    Ride height: 11cm.
    Max. buoyancy: 14.5kg.
    Sizes: Five, XS to XL.
  • Sea & Sea (www.sea-sea.com)

    MARES VECTOR EPIC £295
    hspace=5 Well-made, with consequent heavy weight, this BC has three dump-valves, including one operated by the corrugated hose, one at the opposite shoulder operated by a cord and large toggle, and one at the lower back.
    It comes with the well proven Mares MRS Plus integrated-weight system; two diagonal pockets equipped with zips and toggles that make them easy to locate; a single stainless-steel D-ring, three plastic D-rings, a hose-clip, and lots of forward buoyancy that gives
    perfect surface support and discourages the diver from falling face-downwards. It has a single conventional tank camband and an elasticated cummerbund.

    Specs:
    Dry weight: 3.7kg.
    Torso squeeze fully inflated: Some.
    Comfort out of the water: Above average.
    Ride height: 16cm.
    Max. buoyancy: 18kg.
    Sizes: Four, S to XL.
  • Mares UK (www.mares.com)

    OCEANIC OCEANPRO FX £299
    hspace=5 This American BC is loaded with ideas. It has three ways to dump air via three different
    valves; large, easy-access top-loading pockets; efficient integrated weight-pockets; and trim-weight pockets.
    An extra idea is the pocket for the Personal Safety Device, a safety sausage that can provide permanent buoyancy by being zipped into a life-ring as well as being used conventionally to mark a divers position.
    This BC has four large stainless-steel D-rings and a single conventional tank camband.
    Good surface support is provided by buoyancy low down. It is welded from 1000-denier nylon and claimed to be exceedingly robust.

    Specs:
    Dry weight: 4.0kg.
    Torso squeeze fully inflated: None.
    Comfort out of the water: Above average.
    Ride height: 14.5cm.
    Max. buoyancy: 16kg.
    Sizes: Five, XS to XL.
  • Oceanic SW (www.oceanicuk.com)

    POSEIDON BESEA W40 £299
    hspace=5 This can be adapted to be a technical BC later, but if you had to assemble it yourself from
    the knock-down parts supplied, youd probably give up diving long before you got in the water. Once done, its great!
    Its a wing-type BC, which means that it has all its buoyancy at the back. It provides more maximum buoyancy than you could need, which betrays its real pretensions to be a tekkie BC. It can be constructed to fit any person, including allowing for torso length, but is not readily adjustable between divers.
    This BC has very comfortable lumbar support that makes strolling around with your tank on your back before diving less of an imposition than with some other BCs, and it has two tank cambands. There are two ways to dump air from its U-shaped buoyancy cell - pulling on its corrugated hose to operate a valve at its top, or pulling a bottom cord on each side (both of which might have to be used if inverted).
    There are two plastic D-rings and two tank cambands.

    Specs:
    Dry weight: 3.2kg.
    Torso squeeze fully inflated: None.
    Comfort out of the water: Good.
    Ride height: 17cm.
    Max. buoyancy: 24kg.
    Sizes: One size fits all.
  • Poseidon UK (www.poseidon-uk.co.uk)

    SCUBAPRO T-SPORT £239
    hspace=5 Keep it simple is the idea behind this BC that offers a sleek profile to a diver while under water. It has three dump valves, one operated by pulling on the corrugated hose
    or by operating the valve directly, one at the opposite shoulder and one at the lower back. There are large angled pockets and a single large plastic D-ring.
    The unique Scubapro cinch-strap and single camband, which allows for quick switching between same-size tanks, should make this BC popular with the dive-centre rental market.
    It was among the most comfortable of those tested, with passably good surface support.

    Specs:
    Dry weight: 2.5kg.
    Torso squeeze fully inflated: Slight.
    Comfort out of the water: Above average.
    Ride height: 13cm.
    Max. buoyancy: 14.5kg.
    Sizes: Seven, XXS to XXL.
  • Scubapro-Uwatec (www.scubapro.co.uk)

    SEAC SUB PRO CLUB £199

    hspace=5 A conventional-looking BC, Italian-made using tough 1000 denier Cordura, it actually keeps nearly all its flotation at the back, like a wing-style BC.
    Three dump valves - positioned at each shoulder (one operated by pulling on the corrugated hose) and the lower back - make buoyancy control during ascent simple.
    The Pro Club has diagonal pockets, one small stainless-steel and two plastic D-rings, and a clip for retaining a high-pressure hose. It has a single conventional tank camband. We felt that experienced divers might appreciate the sleek lines of this model but that new divers might prefer a greater amount of surface support, because its 10cm ride height left the diver rather low in the water.

    Specs:
    Dry weight: 2.4kg.
    Torso squeeze fully inflated: None.
    Comfort out of the water: Below average.
    Ride height: 10cm.
    Max. buoyancy: 12kg.
    Sizes: Five, XS to XL.
  • Beaver Sports (www.beaversports.co.uk)

    SEEMANN-SUB RESORT PRO £225

    hspace=5 A conventional-looking BC from a popular European manufacturer with an integrated-weight system, the Resort Pro has useful zipped pockets, though the zips looked a little flimsy, and a couple of plastic D-rings.
    A choice of three dump-valves should make ascents problem-free. There were welcome splashes of colour in what is often a sombre type of product and it looked an attractive package.
    It felt very sleek under water, with little to interrupt the smooth flow of water over the diver, yet gave acceptably good surface support when fully inflated and waiting to be picked up. It has a single conventional tank camband.

    Specs:
    Dry weight: 2.4kg.
    Torso squeeze fully inflated: None.
    Comfort out of the water: Below average.
    Ride height: 14cm.
    Max. buoyancy: 14.5kg.
    Sizes: Five, XS to XL.
  • Swanborough (wwwseemannsub.co.uk)

    SOPRAS-SUB PX 420 £177

    hspace=5 This is a relatively new brand in the marketplace, but it seems to hold none of those unwanted surprises. We rather liked it.
    This conventional-looking BC seems strongly made and has the requisite three dump-valves to give a choice of ways to dump air during an ascent, including pulling on the corrugated hose. Two pockets areeach held closed by a Velcro flap, and there is a small key-pocket in a cummerbund that has plenty of adjustment for girth. There is a single conventional tank camband.
    The PX 420 gave the best surface support among the other BCs tested alongside it.
    Under water it worked well. When it was fully inflated at the surface there was no tendency for the diver to fall face-forward, and his head was held well above the water.
    The brand may have little in the way of dive-deck credibility yet (if that should matter to you) but in the water we think it certainly does the job.

    Specs:
    Dry weight: 2.5kg.
    Torso squeeze fully inflated: Slight.
    Comfort out of the water: Average.
    Ride height: 17cm.
    Max. buoyancy: 17.5kg.
    Sizes: Five, XS to XL.
  • Euphoria Leisure (www.euphorialeisure.com)

    TIGULLIO SEARIDER £199
    hspace=5 This is a simple-looking product that seems to have everything you need, including the three standard ways to dump air via dump-valves, a solitary diagonal zipped pocket, and main and lower-front plastic D-rings. It has a single conventional tank camband.
    This model felt a bit small compared with the other BCs ranged alongside it, though all were size M. Close-fitting, it was sleek in the water but we thought this to be more of a travel jacket that would suit an experienced diver and entry-level in price rather than for a new diver, because surface support proved minimal. The one thing it was not was a sea rider!

    Specs:
    Dry weight: 2.3kg.
    Torso squeeze fully inflated: Some.
    Comfort out of the water: Below average.
    Ride height: 11cm.
    Max. buoyancy: 15kg.
    Sizes: Five, XS to XL.
  • Beaver Sports (www.beaversports.co.uk)

    TUSA LIBERATOR £248

    hspace=5 Like all Japanese products, this well-finished BC comes with every conceivable extra, including an extra-long corrugated hose. It has an integrated-weight system with a unique release system, and trim-weight pockets too. It has upper and lower dump valves, one operated by pulling on its corrugated hose; a hose clip and an additional accessory clip; and two large zipped pockets augmented by a single large stainless-steel D-ring.
    It has enough forward buoyancy for secure stability while waiting at the surface - although less than we expected - and a single conventional tank camband.

    Specs:
    Dry weight: 2.3kg.
    Torso squeeze fully inflated: Slight.
    Comfort out of the water: Average.
    Ride height: 12cm.
    Max. buoyancy: 17kg.
    Sizes: Five, XS to XL.
  • CPS Partnership (www.cpspartnership.com)

    TYPHOON ELEVATOR £289

    hspace=5 At first glance this may look like a conventional BC, but in fact all the buoyancy is provided at the back in the way of a wing-style BC that wraps around the tank when fully inflated.
    The Elevator has three dump-valves, with one operated by pulling on its corrugated hose, allowing you to take care of controlled ascents. There is an integrated-weight system and well-hidden trim-weight pockets.
    Its zipped pockets proved awkward to use but these are augmented by three large stainless-steel D-rings.The waist-belt and cummerbund offer a lot of adjustment for girth and the sternum strap is elastic. Reflective panels add safety. It has a single conventional tank camband.

    Specs:
    Dry weight: 4.2kg.
    Torso squeeze fully inflated: Slight.
    Comfort out of the water: Average.
    Ride height: 12cm.
    Max. buoyancy: 12.5kg.
    Sizes: Four, S to XL.
  • Typhoon International (www.typhoon-int.co.uk)

    ZEAGLE SCOUT £279
    hspace=5 The Scout is unashamedly a wing-style BC.
    It has two tank cambands, a buoyancy cell discouraged from flapping under water by being restrained by a threaded bungee cord, and a simple bodice-type harness. There are two well-hidden utility pockets but also two plastic D-rings for dangling accessories.
    An upper dump-valve operated by pulling on the corrugated hose and a lower dump with a toggle for dumping air when head-down do the job. The integrated-weight system consists of two pockets with Velcro-covered flaps at the lower end and two large fabric tags to be ripped open in an emergency. Dont do this before handing your set up to a boatman or youll give the divers below a headache!
    The Scout is obviously intended for divers who like to dive in an Alpinist way. It has two tank cambands. We found it incredibly comfortable in the water but ride height is low and it definitely pushes you onto your front at the surface.

    Specs:
    Dry weight: 2.3 kg.
    Torso squeeze fully inflated: None.
    Comfort out of the water: Better than average.
    Ride height: 10cm.
    Max. buoyancy: 12.5kg.
    Sizes: Five, XS to XL.
  • OceanDive (www.zeagleuk.co.uk)