BREATH OF FRESH AIR Closed-circuit have always been seen as taste of CCR diving – that’d be me, then! So it came to pass that I drove up the A14 something for elite tech divers, but the Poseidon and M1 to Stoney Cove at the beginning of Mk6 Discovery looks set to change all that, December – why when I agreed to do this did I not think of what the bringing an electronic CCR to recreational divers would be like at that time of year? – to hop Text and photographs by MARK EVANS Additional photographs by SIMON MORRIS on a week-long course for a couple of days to see how the unit performed firsthand. The course was being run by well-known et’s make this clear, I am not a cylinder, bunging a first stage on the pillar instructor Jack Ingle, and it diver. I have dabbled in valve, turning it on and jumping in. All that was primarily for other CCR instructors to the past, spending an afternoon in faffing about with O-rings and scrubber swap over to the Discovery, and a pool on the Draeger Dolphin systems just didn’t set my world alight. non-rebreather instructors to get qualified to semi-closed unit and a couple of However, my view on CCRs has been teach with the unit. Jack teaches CCR days with the Buddy Inspiration mellowed by a couple of days spent diving courses on various rebreathers, but it was LCCR with Martin Parker down in Cornwall, the Poseidon Cis Lunar Mk6 Discovery, interesting to hear him saying that he but I have never been fully convinced to which has been launched on to the market thought the Discovery was one of the best take the plunge. The semi-closed circuit aimed squarely at recreational users. on the market, and that certain functions it rebreather didn’t seem to offer much over I was a bit dubious when Simon Morris, has will soon be seen being adopted by my normal open-circuit rig, and the MD of Poseidon Diving Systems, invited me other manufacturers. High praise indeed Inspiration – and other electronic fully up to give the Discovery a trial, but I had from someone of his calibre. closed-circuit rebreathers I have seen but not seen prototypes of the unit at various shows, With outside temperatures hovering in dived – were undoubtedly fantastic, very and the genuine article at Dive 2009, and I the low single-figures, the first day was spent capable units which have been to extreme knew it was hitting the diving world in one of the nice, warm classrooms in The depths, etc, but for me personally seemed to designed to be used by divers in recreational Underwater Centre at Stoney Cove getting require far too much time and discipline on situations. More importantly, it was to grips with the unit. Jack basically started the set-up and break-down stages. I am just supposed to be very user-friendly and great from scratch, opening a brand-new box in used to sticking a BCD or wing on to a for non-rebreather divers to get their first front of us and taking out and discussing

Laying out the pieces;; the full unit; the ‘clever’ bit reather Extremely user-friendly and great for non-reb divers to get their first taste of CCR diving each part until a disassembled but fully major issue while diving), you will hear a scrubber canister. Unlike other units where complete CCR was lying on the desk. There buzzer, feel the mouthpiece vibrate and see a you need to pour loose absorbent into a didn’t seem to be a lot there! With this CCR red light flash on the HUD in front of your canister, here they are pre-packed and just being aimed at recreational divers – it is mask. With my ancient traditional-style slot into place. No need to spend time designed to be used to a maximum depth of twin-lens black-skirted mask, I couldn’t see patting and shaking canisters to ensure there 40m with no – this the HUD, but there was no mistaking the are no air spaces or channels in the ‘sorb, simplicity was a welcome sight. mouthpiece vibration or the sound of the just slide the pre-packed canister into the Once the unit was out of the box, Jack buzzer. With a teardrop-style mask, it was unit. Dive time on a single canister is took us through the assembly process, again possible to see the HUD easily, even with a advised as three hours, and if you have done step by step, and we all basically shadowed black skirt, but it is worth bearing in mind a couple of hours one day and are going to him, following what he did on our own that you might need to get another mask if be diving again the next, you can put the rebreathers. The main body of the unit is yours doesn’t allow you to see the HUD. used canister in a ziplock bag or slot the lids solidly constructed from aluminium and One thing I was impressed with was the back into place and then reuse it for another durable plastics, and it has been well hour the following day. It has been tested thought out – for example, the bottom of Mark finishes beyond three hours, but Poseidon are the Discovery will only go on one way, so running through playing safe by advising users to stick to you can’t get it wrong. Similarly, the head the PST replacing the canisters after three hours of unit, which contains all the fancy electronics use. There is a cost implication in using and sensors, can only slot into place one pre-packed canisters – they come in at way. All the hoses to link the cylinder first around £20 each – but the piece of mind stages to the rebreather are coloured coded you get from knowing these were so you don’t end up getting an one professionally packed in the factory that on the diluent, and vice versa. The BOV makes the absorbent, along with the ease of mouthpiece is, according to Jack, the use, helps offset this to an extent. best-designed and most-comfortable Once the Discovery is assembled, the available. It does sit extremely well in your really clever part kicks in, which is the mouth, and switching from open circuit to automated pre-dive system PST (power up closed circuit, and back again, is simply a self-test). You turn on the handset, or case of moving a lever 90 degrees. In the ‘paddle’ as it is referred to, by wetting two event of an emergency or the unit not being contacts on the back, and then the unit happy with something and wanting you to starts running rapidly through a series of bail out on to open circuit and go to the checks. Once it has reached a certain surface (basically the unit’s to any stage, you are finally asked to do something – turn on the oxygen. Once it has Mark returns monitored both the oxygen content and the fill from his first of the three-litre cylinder, it asks you to turn on pool session the diluent – in this case air, other gases will be with the CCR online in 2010 (see later) – and again checks the , etc. It then asks you to take a couple of breaths, and then is it off again on another series of checks. Watching your unit buzz, light up, vibrate and inflate and deflate by itself is slightly unnerving, but it shows how advanced the electronics are in this rebreather. Finally it will ask you to turn the mouthpiece to closed circuit, then back to open circuit, and last but not least, breathe the loop on closed circuit for a few minutes to ensure it is maintaining the right PPo2 level. After that it is a case of turning the mouthpiece to open circuit and that’s that, you are ready to go diving. Written here, this PST seems to take forever, but in reality it is all over and done with in a matter of minutes. For our first foray into the water, we went down to The Underwater Centre’s indoor pool. The Poseidon Cis Lunar Mk6 Discovery has captured my imagi What the future holds... nation While the Poseidon Cis Lunar Mk6 Though the water is lovely and warm, we to – on open circuit you are able to control Discovery CCR has entered the market went in with our drysuits on, so that we your by in or breathing aimed squarely at recreational divers, a could get our sorted out. out, here it makes no difference as the air in full decompression software package will One by one we got into the water and your lungs just goes into the counterlungs, be available from next February or Jack worked with us individually to get us or back again, so there is no change in your March, and then will be offered at submerged and weighted correctly. Just buoyancy whatsoever. Once you’ve achieved the end of 2010, making this unit just as getting underwater in a rebreather takes a lot , and you are just hanging capable as all the other electronic CCRs more weight than I use on open circuit, and there with no sound or bubbles, it is an currently on sale. So, it is good to know while Jack did say that as your experience awesome feeling, but it does feel very alien. that if you start out with the Discovery in grows, you can drop some, you will always We all spent an hour or so in the its guise, it can develop and grow use more weight as, in his words, ‘a CCR is pool, getting used to the feel of the unit, with you as your experience builds. just a big bag of wind attached to you’. moving up and down in the water A long-time open-circuit diver, I am used column, switching back and forth from swimming up and down the ledge, from the to breathing out and sinking, but with the open circuit to closed circuit, and Viscount cockpit to the Nemo sub, fine- Discovery, I had to get used to changing my monitoring the read-out on the ‘paddle’. tuning our buoyancy now we could achieve buoyancy by venting air through my nose, Once Jack was happy that we’d all got the a bit more depth, and running through a so it bubbled out of the skirt of my mask. I hang of it, it was time to move on. few drills, including switching back and think that was the hardest thing to get used A coffee and some essential diver-fuel later forth between open and closed circuit, going – bacon-and-egg cobs are up and dropping down a few metres, and the way forward – and we emptying the loop of any gloop that had were ready to get into the gathered during our breathing cycles. Cove. We all ‘booted up’ We ended the session with a quick swim our units again and ran down the ‘road’ to 15m, which gave us through the PST before another chance to work on our buoyancy we walked down to the both descending and ascending, before water’s edge and made heading back to the surface for a debrief. our way into the chilly As I was just joining for a few days to get a waters. Once in the water, taster on the unit, this was where I left off, Jack checked that we but the couple of hours I had spent were all comfortable and underwater on the Poseidon Cis Lunar Mk6 that we were monitoring Discovery had captured my imagination, our ‘paddles’ and then we and I can see myself signing up for a full The pool session slowly descended and course in 2010… I allowed the divers to made our way down to sort their buoyancy the 6-7m ledge. We spent Sport Diver’s technical expert the next 35 minutes Mark Powell gives his opinion... Mark makes his way to the NOW FOR water’s edge ANOTHER VIEW… Sport Diver’s tech guru Mark Powell has dived on various rebreathers, including the Inspiration, rEvo and KISS, and here he gives his opinions on the Poseidon Discovery Mk6 rebreather. One was interested in and is working fully without photography and saw a rebreather as depending on the user to remember to Text and photographs by MARK POWELL a benefit. In each case the existing do the pre-dive checks. If any of the models of rebreather had not tests fail then the unit will not go into hen I was asked to appealed to them and dive mode and so prevents the user try out the Poseidon seemed overly difficult, it was diving when there is a problem. WDiscovery Mk6 I only the Discovery that had The Discovery does have some very expected to hate it, because seemed practical for their clever features. For example, the almost everything about it style of diving. Gradually, I controller regularly validates each of seemed to be counter to began to see why for them a the oxygen sensors during the dive to standard practice on every other CCR such as the Discovery detect any problems. Air is flushed rebreather. The fact that it only would offer some benefits. over the sensors at regular intervals to used two oxygen cells instead Once we got round to check that the reading is as expected. of the more-common three, the diving the unit it was no Existing rebreather dives refer to this fact that it made all the Mark surprise to find that it is very as a diluent flush, where the whole decisions for you, and the fact descends easy to set up and use. breathing loop is flushed with the that there was no way for the into the Cove Putting the unit together is diluent gas so that can check very straightforward, that their cells are reading correctly. ught although to be fair, no Doing this manually has a number of I certainly respect the tho easier or faster than some disadvantages. It uses up valuable of the better tech CCRs. The use of the diluent gas, it takes time, it can affect and attention to detail that Extend Air cartridges, rather than buoyancy and finally it depends on the having to pack the scrubber diver being able to calculate the yourself, saves time and effort, but readings they expect to see at has gone into the design works out slightly more expensive whatever depth they are at. However, than packing it yourself. the Discovery does this automatically user to control what was in the wanted to build one that appealed to The Discovery runs through over 50 every five minutes using only a tiny breathing loop were all things that recreational divers. The most-common self-checks when you turn it on which amount of gas. This allows the unit to went completely against conventional answer to my questions was “but this tests everything from buzzers and constantly monitor the behaviour of rebreather logic. Now sticking to is a recreational rebreather”. It took electronics through to checking for the cells. All of this is invisible to the conventional logic is not always a me most of the day to get my head leaks in the breathing loop. It also diver and they are only alerted if the good idea, but most of that have around this concept. To begin with I prompts the user whenever they need unit thinks there is a problem with the grown up around rebreather design wasn’t even sure what a recreational to do anything. This is designed to cells. It is this constant validation of have arisen for very good reasons. rebreather was, or whether there was ensure that the unit is set up correctly the cells that allows the Discovery to The day started with Simon from even a market for a recreational CCR. use two cells rather than the Poseidon giving me an overview of the I was sitting in on a course and traditional three or more cells. unit and allowed me to ask questions talking to the guys that had bought After two days of diving the unit I about the design decisions they had the unit gave me an insight into why certainly didn’t hate it as I expected made. What quickly became clear is they had gone down this route. Two of and I respect the amount of thought that the Discovery has adopted a them were single-cylinder divers who and attention to detail that has gone very-different approach because did not want to go down the twinset into the design. I’m not sure how big Poseidon wanted to build a route but wanted to extend their the recreational closed circuit very-different rebreather. They did not diving by giving themselves a new rebreather market is going to be, but want to build a rebreather that would challenge, the other was a twinset Mark returns from a successful whatever the size, the Discovery is well appeal to technical divers, but instead diver who had resisted the idea of a dive on the Poseidon CCR placed to satisfy that market.