• 46 BCs on test.
• Feature chart
• BC Care
• BC suppliers list.

Then came the adjustable buoyancy life-jacket, the ABLJ. It was a device like a toilet-seat cover which you wore around your neck and to which you added air as you went deeper, to make up for the air that was getting compressed elsewhere. As you came shallower you had to let that air out again, if you were not to find yourself being propelled upwards at an ever-increasing rate. Modern BCs are used in the same way. ABLJs revolutionised diving. They allowed the scuba diver to enjoy the thrill and relaxation of neutral buoyancy, just like a fish. They also allowed the user to float without effort at the surface. Of course they were not perfect. They needed to be dressed on to the diver. They put the buoyancy bag high up round his neck (ideal as a life-jacket), which obstructed his vision and made him swim vertically and in a very unfishlike way in the water. Gentlemen had to decide which side to dress. The crotch strap was never entirely satisfactory when fully inflating the ABLJ and trying to swim up with a hard-won porthole! Some divers preferred to do without the inconvenience and stayed with their former seabed-crunching techniques. The early models needed to be filled by mouth. You took a breath of air from your regulator and blew it into the mouthpiece of the ABLJ. This was not always a good idea for those divers ill-at-ease removing a mouthpiece underwater. These same divers were usually rather overweighted, and inevitably found themselves crashing downwards. They needed to make this essential manoeuvre at a time when they were probably out of breath from desperately trying to maintain a depth by actively finning up, and otherwise distracted. Then came the revolution of the little 400ml auxiliary bottle. It was filled with high-pressure air from the full scuba cylinder and provided a ready reservoir for squirting into the ABLJ as and when needed. It was an excellent idea, but these cylinders needed the same care and attention as their full-size brothers. Few divers gave them that. The other problem arose from clumsy application. Divers opened the cylinder's valve and forgot to close it again. The 80 litres of "free air" contained within it was enough to fill the ABLJ several times over, and when accidents happened divers, doing impressions of Polaris missiles, would arrive at the surface with their lungs hanging out of their noses. So ABLJ divers needed special training.
	ABLJ
	Waistcoat style BC
	Coventional BC
	Wing style BC

At about the same time, on the other side of the Atlantic, an enterprising diving-equipment manufacturer came up with an alternative method - the direct-feed hose, which fed medium-pressure air from the main scuba cylinder via the regulator first stage. The effect was less dramatic than using air at 200 bars, needed less finesse to use safely, and now every BC is filled this way.
That is not to say that the 400ml bottle has died. Enshrined in the training principles of British diving clubs, many divers in this country swear that they would never go diving without one - in addition to a direct feed.
It is an extra source of air but it needs lots of practice and a cool head to get access to it. In the event of a diver passing out under water, should his last act be to remember to crack open that little cylinder's valve he would die happy in the knowledge that his dependents would have a body floating inflated on the surface for the benefit of any life-insurance claim!
"Redundancy" is a key word in the vocabulary of the technical diver: basically it means having two of everything. The 400ml cylinder went some way towards that goal, but now twin-bladder BCs with two direct-feed hoses from separate main cylinders have largely superseded that particular solution for those who want it.
The next development was the waistcoat-style buoyancy compensator (BC). It put the buoyancy comfortably where you needed it, held your tank on your back, and even looked stylish! It was refined by different manufacturers in various efforts to gain a marketing advantage.
Gradually, the front buoyancy cells of waistcoat-style BCs began to be removed in favour of straps - to give what could be considered as today's "conventional-style" BCs. Various pockets, clips and buckles were also added, but the overall effect was mainly the same.
ABLJs were misnamed. They were never really "life-jackets" but would support an unconscious diver head-up at the surface. Many waistcoat-style BCs did not, but then their manufacturers always went to great pains to deny that they were in any way to be used as life-jackets. Back in 1972, the Watergill At-Pac was vilified as a killer BC because it put all the buoyancy at the diver's back, which was perfect under water, but would do nothing to float an unconscious diver on his back at the surface. The latest innovative BCs of the late 1990s are similarly wing-style. These have proved very popular with technical divers - and those who admire them. They tend to position the buoyancy perfectly for a face-down, horizontal swimming position, and leave the diver's chest uncluttered by the BC and with plenty of space for cluttering with peripheral equipment instead. They have become very fashionable, which is not to say they are necessarily ideal for every application.
When you choose a BC you must consider your individual needs and priorities. The ABLJ was uncomfortable for everyone but it worked. It was certainly better than nothing. Both waistcoat and conventional-style BCs (but not wings) must be the right size to be comfortable. All BCs must give you the appropriate amount of lift, and in the place where you need it. How much is that?
As a guide, assuming you are a normal, neutrally buoyant human being, you should need no more lift than you have lead on your belt, plus the in-water weight of any other equipment such as the scuba tank(s), torches or cameras that you might take diving with you.
This lift must be positioned low enough to hold your head out of the water at the surface and you should be supported at this time in a way you like. You certainly should not carry too much lead. You should be able to stay at the surface without resorting to putting air in your BC.
Overall buoyancy figures are irrelevant to surface support if any of the inflated volume is actually above the water-line. We compared BCs in size medium, checking for overall maximum buoyancy and measuring the height of our test diver's mouth above the surface, during which time he stayed vertical and held a maximum breath. (New Euro standards are being developed along these lines.)
Larger-size BCs usually have more lift, smaller ones less. However, if the jacket is not a snug fit and is too big, you may well find yourself, at the surface, dangling low from the arm-holes of a very buoyant jacket.
We also checked to see whether a jacket tipped you forward when fully inflated at the surface or laid you firmly on your back.
It must be easy to get the air in to the BC and out again when required. We generally found this was not a problem if the BC was used intelligently. Pockets must be easily accessible underwater. Straps should be secure but readily adjusted. We checked how easy a BC was to don and take off again by doing it in the water.
Not least important, each was subjected to the same test-swim under water, to see what attitude the diver most easily achieved, whether he was perfectly horizontal or head-up, or indeed uncomfortably forced to swim almost vertically.
You might still want the 400ml auxiliary cylinder but only a few BCs provide this facility. Most designs now rely solely on the direct-feed from an MP hose (apart from oral inflation). The little CO2 cartridge sometimes seen in use for emergency surface inflation seems to have gone out of favour too. It was a method which was somewhat unreliable - and lethal if a diver took a breath from a BC which had been inadvertently filled in this way.
Needless to say, the BC as a whole should also be attractive and durable, as we believe all the products reviewed here are.
This year's in-vogue colour seems to be black. This is obviously in deference to those who want at least to look like technical divers. It must be said that black is probably the least safe colour for a lost diver when people are searching for you.
Our test results might differ from manufacturers' own figures but ours are fair in that they are comparative. They were made with the same test- diver, in the same way. He used a 4mm wetsuit and 4kg of lead to give him perfectly neutral buoyancy in fresh water with a normal inhalation of air. The test scuba tank was a typical 12-litre steel cylinder weighing 18kg (full) out of the water.
Products were tested in a random order although, in this review, we have grouped them alphabetically by make for your convenience.
We also look at the usefulness of and access to pockets, D-rings, and the manner in which the scuba tank is attached to the BC. Plus, how much space a particular BC will take up in your dive bag. A bulky one will add to your total buoyancy, with the implication that you will need more weights to compensate in the water.