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When Martin Parker's closed-circuit rebreather, the Buddy Inspiration, went on sale in 1998, it revolutionised the market.
It was good, but some would say it was not always good enough for the abilities of certain of its users, and a few fatalities ensued. Martin was determined that he could make something better, something more foolproof.
A number of divers also wanted a unit that was smaller than the Inspiration. They didn't necessarily want to go deeper, but to be able to stay long enough at depths at the limit of air-diving to do what they wanted, without paying the price of long decompression stops.
The new electronics and design of Ambient Pressure Diving's Evolution answer both these requirements, and while its electronics are available for use in upgraded Inspirations, the Evolution is available for the travelling diver who does not need the onboard gas supplies of the full-size rebreather.
The Evolution has, says APD, better ergonomics, better hose routeings, simple catches and twin 2 litre cylinders. It is also available with different specifications, including a choice of conventional BC with integrated-weight system, or wing.
Task-loading is reduced in comparison to the Inspiration Classic. For example, set-point switching from low to high and back again can be automatic, with a manual over-ride.
The set-points are adjustable but default to 0.7 bar for use at the surface and for the descent, and to 1.3 bar for the bottom and ascent phases of the dive.
They automatically switch back to the low set-point at the 100% oxygen depth (3m if using a high set-point of 1.3 bar). This helps with buoyancy control near the surface.
The redesigned scrubber unit takes 2kg of Sofnolime and is good for two hours. An important option is the scrubber temperature-measuring stick, which indicates on the handset which part of the scrubber is being used and so helps the user understand its depletion.
It measures temperatures throughout the profile of the stack and is claimed to compensate automatically for depth, work-rate, water temperature and part-used scrubber material.
The Evolution uses the same proven oxygen-controller as the Inspiration Classic, but there the similarity ends. There is easy access to the O2 cells, redesigned in conjunction with Teledyne, and these have improved co-axial connections.
It is now deemed OK to unscrew a cell without disconnecting it.
There are four LEDs, two for each oxygen controller, in the lid of the scrubber unit. They are equipped with fibre-optic cables that take their message to the Head-Up display (HUD) attached to the mouthpiece, which looks to be an elegant solution to the waterproofing problem.
A system of red and green lights imparts information that is repeated in detail on the wrist-mounted handset.
The brightness of the lights can be adjusted to suit ambient light conditions.
Apart from monitoring and controlling ppO2 in the mix, the on-board computer now does a lot more. It is available in three versions, from the entry-level Dive Timer model to the Nitrox and Trimix versions, which take into account decompression requirements. These versions feature user-selectable levels of conservatism (Nitrox) or adjustable gradient factors (Trimix).
A choice of up to six diluents can be programmed in and called up, either under water or on land. The dive computer can also be switched to open-circuit mode for bail-out decompression calculations, again with six user-adjustable gases. The Trimix version is CE-approved to 100m.
The two electronic oxygen controllers are independent of each other and have separate power supplies, with battery-status indicators on the single handset. The three buttons on the handset are designed to be intuitive to use and are identical to the Inspiration Classic in function.
The Vision firmware is designed with the future very much in mind. Using the APD Communicator software supplied, it can be upgraded to trimix at a later date, or the owner's details can be uploaded so that the front-end screen is customised, helping to secure against theft.
A new program can be uploaded later to accommodate further developments in deco software or rebreather practice.
The APD Communicator also allows dive data to be downloaded and analysed using the APD LogViewer program. This should give a comprehensive "black-box" facility.
The unit's supply and service history is also recorded for further use. Software is available in all major languages.
One thing that has not changed - the user still needs to switch the rebreather on before diving!
Next month reports on our test of the APD Evolution, which costs from £4695, according to specification.
Ambient Pressure Diving, www.apdiving.com/evo.htm
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Inside the Evolution, with its redesigned scrubber unit and twin 2 litre cylinders
the compact shell
front view
how it all fits on the diver
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