Way back in 1977 Mike Todd, DIVER’s then technical editor, conducted a consumer test of nine state-of-the-art BCs. One was more state-of-the-art than the others, a back-inflation unit, or wing, with integrated weights, called the BCP.
All the others were horse-collar BCs, modelled on inflatable emergency life-jackets used for sea survival. The principles had been modified for diving with the addition of large oral inflation hoses and either one-shot carbon dioxide cartridges or, standard in the UK, mini air-cylinders you filled from your main tank for back-up inflation, and dump-valves to let the air out.
You wore a separate weight-belt and cylinder harness. As you added air to neutralise your buoyancy, it collected behind your neck, pitching your head up and feet down. Your dead weight was taken on a jock-strap. I had my first horse-collar BC when I was 15. For a teenage boy, that jock-strap proved a huge incentive to use the minimum weight possible.
At that time, leisure divers didn’t use back-inflation BCs much, especially in the ultra-conservative UK. The horse-collar BC, considered to be a life-jacket, was presumed rather optimistically to be able to float you face-up if you had the presence of mind to inflate it before passing out.
The mini-cylinder also provided an independent supply of air that could be breathed through the bag in an emergency.
It even doubled up as a linebacker when riding to and from the dive-site in small boats.
Divers simply ignored the sloppy buoyancy characteristics of horse-collar BCs when submerged.
Of the BCP, Mike noted presciently: “It was found to be the most comfortable system for adjusting buoyancy while diving.” Wings would remain largely the preserve of cave-divers until the 1990s saw the emergence of technical diving, and the wing slowly migrated from cave to tech and on to recreational users.
It’s easy to associate early back-inflation BCs with small specialist cave- and technical-diving brands and think the big scuba manufacturers climbed aboard the bandwagon only recently, but that’s not the reality.
Because in 1977 the BCP wing, with its built-in weights and so far ahead of its time, was made by one of sport diving’s best-known companies, Scubapro.
Some 40 years down the line, what does Scubapro’s Hydros Pro back-inflation BC offer to tempt recreational divers?
The Hydros Pro is a high-end BC designed for single-cylinder diving. It uses a single-bladder air-cell made from 420-denier nylon-coated PU, providing 16-18kg lift depending on size.
The air-cell is the doughnut type rather than a horseshoe, so air can circulate around it regardless of your position in the water.
If you’re head-down, the air will collect where it is easily vented through a single bum-dump.
Hydros Pro weight release.
Horseshoe air-cells don’t connect at the base, where technical divers often want to use the saved space to carry light canisters, for instance, so they might have two bum-dumps to allow either side of the wing to be vented when you’re head-down.
Both doughnut and horseshoe cells have their advocates, so it’s probably reasonable to assume that neither is significantly superior to the other for most sports divers.
To help keep the wing streamlined when only partially inflated, three sets of bungees collapse the bladder. These are mounted internally, rather than wrapping around the outer air-cell, where they could create a snag hazard.
Along with Scubapro’s time-proven balanced power inflator, with its oral-inflation/dump, there is a rapid exhaust-dump activated by pulling down on the oral-inflation hose, shoulder-dump and bum-dump.
Two quick-release side-pouches take your main weights of up to 4kg each. Trim-weight pockets holding up to 2kg each are mounted at the rear. Scubapro uses its regular stainless-steel buckle for the tank camband and provides a loop for setting the height at which you want your cylinder to sit. There are no accessory pockets, but two small and four large stainless-steel D-rings are provided.
Instead, the Hydros Pro is factory-prepared to accept a choice of accessory mounts that attach through holes above and below the weight-pouches. Scubapro uses these not just for bolting on a knife but also to fit additional screw-on D-rings and bungee loops.
The designers of the Hydros Pro aren’t wild about BC pockets (some are made for the Hydros, though I suspect somewhat under protest). The feeling is that they can be difficult to use when movement is restricted by a dive-suit, and sit over loaded weight-pouches.
Instead, tech-style, they prefer an external place for everything, and everything in its place and in easy reach.
These Hydros Pro system accessories were not supplied for test but they look efficient.
The harness shoulder-buckles have a swivel action to encourage them to assume the most comfortable position as you move around, and have pinch-clip releases. They attach to the backpack with hinges that allow you to fold the shoulder-straps flat for packing.
Hydros Pro rapid exhaust and shoulder-dump.
When the BC is deflated, they also help to hold the straps open for you to make it easier to don. A sternum-strap, again closed with a pinch-clip, can be adjusted for height to accommodate different torso lengths, prevent interference with a drysuit direct-feed or for comfort for women (Scubapro has produced a version tailored for the female form). There is no cummerbund, only a waist-strap with another pinch-clip buckle. A jock-strap can be added.
If you don’t want to use the weight-integration pouches, you can quickly replace them with a simple belt, also equipped with a pinch-clip release and stainless D-rings. It’s included, and you can switch back and forth in seconds by removing a clip – no tools required.
Small weight-pouches are available as an extra. The idea is that when using a lot of lead to offset a coldwater suit’s buoyancy, the bulkier weight-pouches are really your best choice, but when visiting the tropics, where a couple
of kilos might suffice, you can dispense with these in favour of the more compact waist-strap and smaller and lighter weight-pouches. This seems a good concept.