Newer divers to the sport may be mistaken in believing that rebreathers are a modern invention, however the concept of rebreathers has been around a long, long time. Leonardo da Vinci was an incredible renaissance visionary, whose sketches have depicted various modern machines which regrettably required technologies not to be contrived until several hundred years later. Drawings of the helicopter and the submarine have been found, and, yes, you've guessed it - a rebreather too! But it wasn't until 1878 that the first successful rebreather was designed by Henry A Fleuss, an Englishman.

Rebreathers have evolved significantly since then, with several players entering the game over the years, including Dräger, the much respected Grandfather of rebreather design and construction. Dräger launched the first semi closed rebreather (SC RB) specifically created for the sport diving market. Most of you will be aware of the Atlantis and subsequent Dolphin, now they have launched the RAY.

The new RB is very simple, being purely a mechanical device - there are no sensors, complicated computers, battery packs or other electrical devices to malfunction. Very briefly, the diver breathes through the dual hose mouthpiece, with the exhaled gas going through the exhalation hose into the exhalation bag. Being a SC RB a small amount of gas (approximately 20% of every breath during light work) is released through the adjustable relief valve rather than scrubbed for carbon dioxide (CO2). The remaining exhaled gas flows through the scrubber cartridge unit and the alkaline scrubber material to remove the CO2. It then flows into the inhalation bag where additional pre-mixed gas from the cylinder is also introduced at a set rate.

The jacket comes in one size only and I can appreciate the thinking behind it, as this size will suit most divers. It was not a problem for me, being an average sized girl, and was quite snug and comfortable to wear, thank you. However, for chaps with a fuller figure, regrettably, the fit and subsequent dive is not really that successful. The jacket can end up spread almost flat across the diver's back with the straps taking, in some cases, the not inconsiderable strain. It didn't look comfortable, and it is a shame that the 'fit factor' or lack of it will inhibit some divers from having the freedom of choice. Coming from the Dräger stable, the technology behind the Ray is obviously very well established and tested. It currently utilises a 50% Enriched Air Nitrox (EANx) mix. Running an EANx 50 mix, the Ray has an operating depth of 18 metres with a 1.4pp O2, at 1.6pp O2 the MOD is 22 metres. However, I understand from Dräger that there are plans for the Ray to eventually run with EANx 32, thereby giving the diver more flexibility in his dive planning. I look forward to this development.

The Dräger Technicians understand the dark side of rebreathers, and took these factors into consideration when creating the Ray. It has been specifically designed to be a very simple and effective SC RB, just remember the three C's - care, concentration and checks - at all times, for example during assembly and pre-dive testing.

A disappointing point is that a diver should consider that they are diving without a means of stowing or securing equipment. When Dräger first launched the Atlantis - father to the Dolphin - it had clips, pouches and pockets galore. With the Ray, Dräger have ventured down the minimalist path. The lack of 'D' rings or clips is intensely frustrating and there is a real need for additional sensibly placed 'D' rings to help bungy in hoses and gauges to reduce the flap.

On the weighting front, Dräger have been thinking logically, and taken into account the fact that these days divers are trying to lose some lead off their belt. They have mindfully constructed weighting pockets, with the result that lead pouches can sit round the scrubber canister snugly. Divers should also consider additionally placing a 1kg lead sachet beneath the breathing bags on each shoulder - the Ray's in-water performance significantly improves.

The Ray is a brand new product and as such the recreational diving industry will naturally wonder about its durability, as there is no track record. The benchmark that divers can happily refer to is Dräger itself. The Ray is typical Dräger and therefore a well made quality built RB. I can say this with great confidence and from personal experience, having worked with the Ray extensively on the Dräger European Dive Roadshow this summer. Along with the other international crewmembers we prepared, dived, cleaned and maintained the units, on a daily basis, over a period of 31/2 months, in 8 different countries. We didn't treat the Rays like bone china, nor did we jump up and down on, or systematically abuse them. We drove over 23,000kms on the Tour, with 50+ divers diving the 12 units on a busy day, (the record was 126 divers in 10 hours), so the working schedule on the Tour was punishing. A pretty rigorous evaluation. The tour Range Rover was quite ill by the end of the roadshow, the Rays just looked as though they had had a busy weekends diving at Stoney!

For further details about rebreather training or any Dräger product - the Dolphin, Shark or the Ray contact Sea & Sea: (01803) 663012

Review by Rosemary Lunn