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Home , Dive boat, Scuba set

SSteptepping into diving

By

Paul Beenaround

Alex had always been interested in learning to dive with the new breed of closed circuit rebreather’s that had appeared in recent years, so when he was suddenly faced with the choice of a dance weekend in chilly Munich or a week learning to dive with them in the Red it wasn’t a hard decision to make. He was soon on his way with Easyjet flying over the Swiss Alps en-route for Sharm el sheik. Everything went very smoothly and he had soon settled down in the Camel hotel, a slightly upmarket one in the centre of Sharm which was not far from the College where he would be doing his rebreather course. The next day he met Sherif, an impish Egyptian who was going to be his mentor for the combined basic and advanced four day course. After some classroom work he was shown the intricate workings of the Poseidon MK6 rebreather, the only one recognised by PADI for recreational sports divers on their recently introduced rebreather course. It was a very complex piece of kit, largely controlled by computer software, which took away the risk of diver error. This is unlike many other versions on the market that had caused accidents and deaths, usually through making a mistake. As nice as it was to know that it was keeping him alive, the Poseidon rebreather’s had had many software problems that largely prevented you either starting a dive or necessitated aborting a dive halfway through for often non-existent faults. Hopefully, though, these had been rectified with the recently introduced MK7 version. The PADI diving manual even suggested having a spare open circuit handy just in case. Alex’s unit seemed to be ok, but over the

2 coming six days diving he was to see other divers experiencing problems with theirs. Alex’s first two days of diving were from the nearby beach, opposite the dive college where he had first been talked through the complexities of control and bailout procedures, so very different from open circuit scuba. The rebreather unit on first sight looked like a standard divers stabilizer jacket with all the rebeather components attached to it. Once under the surface using the rebreather felt very strange, more like blowing in and out of a paper bag than the power assisted blast of life giving air he had become accustomed to from his scuba set. Added to this was the total silence and just a slight awareness of his breath passing back and forth through the loop coupled with the slight expansion and contraction of the counter lungs on his shoulders which had some similarities to an astronauts life support system. Put simply, he was breathing unassisted through a breathing loop. The loop started from one side of the mouthpiece, from where exhaled air passed through a non-return valve, along a corrugated tube into a water trap attached to a bag called a counter lung, before entering a two litre canister called a scrubber. The scrubber was filled with co2 absorbent that looked like cat litter, which removed the from each exhalation. The air then passed back into a second counter lung and water trap, along a second corrugated tube back to the mouthpiece to provide another life giving breath of carbon dioxide free air. The whole process is driven by the power of the lungs. However, to put it

3 not so simply, the rebreather had sensors that automatically activated injectors that put just the right amount of oxygen back into the breathing loop to keep the life supporting air at a maximum partial of 1.3 or less, depending on depth. This is one of the reasons why rebreather divers can stay down for hours underwater without getting the bends - as the unit is always replacing the nitrogen content of the air with oxygen, the cause of bend attacks, with just the right amount of oxygen falling short of an excess that would cause and a blackout. Alex found the random hissing of the oxygen injectors strange to listen to, something the on-board computer was totally in control of as it did its job. Air was also injected in the same way from a second small cylinder to maintain a full breath in the breathing loop. This could be needed due to either a loss of air from mask clearing or descending to a greater depth. In some non-recreational rebreather’s these actions are monitored and controlled manually by the diver. Alex’s rebreather had a red light mounted on top of the mouthpiece that flashed every five minutes to remind him to check his consul for , cylinder contents and battery life, apart from the usual diving necessities of depth and time down. The battery was contained in a transparent perspex pod along with a computer, effectively the brain of the rebreather. The computer came in different levels of function depending on the kind of diving intended. Alex’s was the most basic one, limited to 130ft with no ability. The two things that the Poseidon rebreather’s couldn’t protect a

4 diver from was an exhausted scrubber unit (The scrubber unit was only good for three hours) or faulty non-return valves in the mouthpiece. In both cases the rebreather would allow the diver unknowingly to continue breathing from the loop without the carbon dioxide being removed, which would eventually lead to unconsciousness and without prior warning. Carbon dioxide sensors are being developed for the future. Before entering the water the final check is a five minute pre-breathing test taken with a pinched nose whilst sitting down, just to make sure that the set is safe to use before the dive. The other big no no when using a rebreather is removing the mouthpiece whilst in the water without first switching over to the built in bailout valve, which automatically closes the breathing loop from any water ingress. Flooding of the breathing loop would destroy the scrubber contents and create an un- breathable caustic cocktail, necessitating an expensive cleanup afterwards. The bailout valve on the mouthpiece is exactly what it says and automatically supplies air from the small air tank incorporated in the unit. Because the capacity of the tank is so small, diving without an external scuba bailout tank is limited to sixty feet, because the small air tank contains just enough air to allow the diver to reach the surface from that depth. This was where the advanced part of Alex’s course came in, though he did start early by carrying an external bailout tank after his first dive. Effectively he was given a seven litre scuba unit without a harness, which was clipped under his arm to the stab

5 jacket and used on all future dives. He never did like carrying it, even though it was essential on all dives over sixty feet, as well as to provide a backup for his buddy diver. It was uncomfortable to carry as it often banged against the other equipment and sometimes made his position in the water lopsided. It was also difficult to remove and replace underwater, which he was made to do often as part of the training course. He spent half of his second beach dive learning the skills that required for him to go on to the bailout cylinder without a facemask and then ascend to the surface. He was then taken on a short tour of the nearby reefs where he saw an enormous five-foot black and white grouper, but had no camera. It didn’t all end once the days diving was over as he had to spend each evening studying the PADI dive manual in preparation for the two written exams he would have to take. On day three he graduated to diving with a mixed crowd of divers using rebreather’s and scuba equipment, and their first dive was on Woodhouse in the Tiran straits. Assembling the rebreather on a rolling boat with the distraction of other divers was a lot more difficult than doing it back at the dive centre. He had a very long to follow, much like a pilots, and if interrupted he had to start again. Alex’s set had fifty five self analyzing checks to do whilst expecting him to acknowledge and respond on request by way of the monitoring consul, after he had analysed the gas contents in each of its two small cylinders to make sure the contents were correct before turning them on. If any of these checks failed Alex had to go over the whole assembly and start

6 again. Usually this only happened when he had missed something out or done it in the wrong order, but at least it was keeping him alive even if it often looked like it was trying to stop him from diving. Perhaps a short prayer and the sign of the cross should have been added to the checklist. The very last check to do was the pre-breathing one, which was left until just before the dive. The was clipped on before he jumped off the boat. After entering the water each diver had to do a complete rotation at twenty feet as his buddy did a bubble check on him, and if a leak was found the dive would be terminated. Sherif had told him to bring his camera, but even though he took it once he had no chance to use it as he was kept busy repeating the same survival skills over and over, including the difficult bailout tank removal and replacement whilst hovering over a drop-off. He quickly learnt to remove the bailout tank before returning to the boat ladder, as on his first attempt whilst holding the ladder in a choppy sea he nearly got pulled under the boat. Sherif had been using an old membrane which seemed to let in more water than it kept out as he had not been able to find anyone in Egypt to service it. Alex had always had a dislike of these suits, which were totally unnecessary in the warm waters of the Red Sea. They did a second dive on the way back to Sharm where once more he had to repeat the same skills all over again, but by this time they were becoming automatic as was intended. On the journey back Sherif started him off on his seventy five question exam, which he completed at the dive centre.

7 He only had half a dozen answers wrong and Sherif discussed the correct answers with him until he was sure that they were understood, and so he was then declared officially qualified to dive rebreather’s to sixty feet. The next day, the last one of the course, was intended for external bailout bottle skills which he had already covered, so Sherif made it more of a leisure dive with just a few reruns on bailout bottle use. They did the first dive at the nature reserve of Ras Mohammed, but as the was running in the wrong direction they only briefly saw the wrecked remains of the Yolanda cargo as they drifted by. Their second dive was on the nearby stingray station, only on this occasion there were none to be seen which was disappointing as he had his camera with him. On all of his training dives they had been accompanied by Pascal, a retired French lawyer who was acting as a safety backup and observer, using his own Poseidon rebreather. Once back at the dive centre Sherif had him doing a final twenty five question exam which he mostly got right followed by a picture for his certification cards. The last two days diving cost him a jaw dropping £145 a day (as opposed to £50 a day for scuba), but as he wanted to get his hours up he paid with a smile, for just like the flying that he used to do he wanted to get his hours up by adding four more dives to his logbook. This made a total of eleven, which seemed a little paltry compared with the thousands he had already logged on scuba. Alex had been assigned to Abdul who looked like the main character in the Mummy films and Pascal

8 carried on as backup. They went back to the Tiran straits to dive on Jackson reef with Abdul sporting a new membrane dry suit and an upmarket American rebreather. During the dive Abdul had trouble with the dry suit, and whilst Pascal was helping him Alex slipped down to 130ft where he had been told not to go, which was the absolute limit for his rebreather to find out what would happen. Sure enough, within a minute of being there the consul started bleeping and flashing until he returned to a shallower depth. The silence was broken every so often by a gurgling sound that could be heard coming from the breathing tubes. This was caused by condensation building up in them from the warm moist air of the diver’s breath. This condensation could be cleared by shaking the tubes above the head with the mouthpiece closed, though Alex found that doing a barrel roll whilst exhaling hard did the same job with less inconvenience. In the meantime Abdul had sorted out his dry suit only to have his upmarket rebreather fail when it went into a high oxygen partial pressure mode, leaving him to finish off the dive on his bailout bottle. Later on they dived on the nearby Gordon reef with Abdul now wearing a less troublesome and breathing from a dependable scuba set. They had only been in the water for a few minutes when a white tip shark swam by, and Alex got some excellent pictures of it. On this dive they were drifting in a strong current which took them over a huge turtle that was sheltering in the coral. Alex had to swim quite hard to stay on station to photograph it, which at least proved to him that the rebreather was

9 capable of supplying enough air when the going got tough, something he had had doubts about. On the last day they dived on the Far Garden reefs and saw an even bigger shark than the previous day, followed by two huge eagle rays gliding over the burnt out wreck of a former . Towards the end of the dive Pascal’s rebreather went into an abort mode and no matter how many times he switched between the bailout and closed circuit mode it would not change its mind. Back on the boat he couldn’t find anything wrong with it, and then it decided that his oxygen cylinder was too low when it wasn’t. On fitting another tank it still wouldn’t change its mind until he had repeated the whole process twice. Despite these constant anomalies Pascal like the other rebreather divers on the boat were madly enthusiastic about their rebreather’s, which made Alex think of them in the same light as the pilots in the 1965 film, Those Magnificent men in their Flying . On the way back the boat made an unexpected stop so that the boat crew could say their prayers. Because Alex’s rebreather had been left on the boat at the end of each days diving he was saved from the laborious task of disinfecting all the breathing parts from bacteria that was usually done after each days diving. Added to this was the fact that the expensive scrubber canisters had to be discarded after twenty four hours, whether they had been fully used or not. All in all Alex had enjoyed the experience, but he really couldn’t see any advantage for himself in with the huge costs and on-going

10 maintenance and reliability problems, though for deep mixed gas dives they came into their own as opposed to the old style wasteful techniques of carrying half a dozen open circuit scuba tanks, three under each arm, which an Easyjet pilot on the boat had just been training for to see what it was like. However eight months later he was back again to do the PADI rebreather tech 40 course, for which he had had to do a PADI rescue divers course in Thailand before even being allowed to enroll. He went back to the Red Sea College to do it, whilst staying at the nearby Camel hotel. However this time he had not been sent the course manual by PADI UK several weeks in advance as they had done before, and he was totally unprepared for the course. He was then told by the dive centre that he would have to use a CD-rom which had replaced the manual and was totally useless as he wouldn’t have been able to answer the written questions on a computer. Added to this he had to have a medical with the local diving doctor before they would let him start the course. As it happened he had to do a one day refresher course as it was over six months since he had last used a rebreather. Since then Poseidon had changed their Mk6 unit to a Mk7, one which was not exactly as user friendly as the Mk6, due to attempting to make it look better. That aside, he was using the technical version as opposed to the recreational one. The technical version had two manual controls attached to the new style counter lungs, one for oxygen and one for air, which enabled the diver to sort out any occurring problems underwater rather than bailing out to the surface with the bailout bottle, as a recreational diver

11 would. Unlike the recreational version, on the technical version the small gas tanks were mounted upside down, giving easier access to the on/off valves, which was essential for the skills needed for the tech 40 course. The head up display on the Mk7 mouthpiece was mounted on top of it and was almost impossible to see. For some reason the mouthpiece assembly felt much heavier than the old one and was not as comfortable to use as the Mk6 was. A carrying handle had been added that made it almost impossible to remove the electronics module, which had to be passed through a narrow gap in the handle with all the wires and hoses trailing behind it. This was topped off with an impressive clip on cover. On the plus side the integral system had been ditched and a normal weight belt was worn instead. The D-rings for the bailout bottle had been improved, thus making it easier to fit and remove as well as being more comfortable to dive with. His first dive was off the beach in Naama bay, and the intense heat from the promenade and sand burned his feet on the way to the sea. Abdul, the instructor who he had dived with on his last visit, was to be his mentor who went on to take him through the previously learnt skills before going on a leisurely dive around the bay. Alex was finding the mouth-piece uncomfortable and heavy in his mouth causing him to support it with one hand to ease the burden. Halfway through the dive his air supply suddenly ceased in both the breathing loop and the open circuit bailout. After several failed attempts at switching back and forth he was

12 becoming desperate for air and went on to follow his training procedures by quickly grabbing the demand valve from the bailout bottle before taking a much needed breath of air as he made his way back to the surface. Abdul couldn’t understand what the problem was and after fiddling around with the re- breathers controls it suddenly started to work again. Back at the dive centre, after burning his feet once more whilst crossing the beach, he was told that the dive centre were not able to print a copy of the manual from the CD-rom to help with his studies. Once back at the Camel hotel he did a copy and paste of the first chapter on his own computer and put it on to his memory stick and then got the hotel reception to print it out for him. Abdul had promised to lend him his own manual the next day. Alex then went on to spend four or five hours in the evening working through the first part of the course in preparation for the next days diving, something he should have been able to do weeks before in the UK. The next day Abdul took him once more over the hot beach to practise the first of the tech 40 diving skills. This was easy enough to start with, until he got to what was called a ‘diluent flush’ which required him to perform a multitude of actions whilst operating the various controls of the re-breather. The purpose was to flush out a suspect gas mix in the loop or to check on a faulty oxygen sensor. To do this Alex had to close the oxygen cylinder valve, purge the oxygen supply line, open the over pressure valve, lean to one side in mid-water whilst maintaining

13 buoyancy, then hold the diluent button down for four seconds, thereby replacing the gas with clean air whilst rapidly breathing from the loop and exhaling through his nose at the same time. His first attempt wasn’t exactly a success. He had to do it again in the afternoon with some extra added skills to try. However, before he had even had a chance to start, the air supply cut off again and once more he had to return to the surface on the bailout bottle, and once more it was coaxed back in to action by Abdul. As the dive continued Alex was becoming less and less confident in the equipment. This time he made a better job of the ‘diluent flush’ before going on to demonstrate his ability to release a delayed . On the next dive he repeated the same exercises again before attempting two new, more complex ones. The first was a semi-closed three breath procedure which he completed successfully. This exercise is used for real out-of-air situations at depth when decompression stops were still needed. He then went on to make a complete mess of the next exercise, which required him to manually inject oxygen into the loop to artificially raise the prescribed oxygen set point of 1.3 by watching the computer display and holding it there for the rest of dive. Easier said than done. Alex felt that these intricate exercises would be attainable given the time to practise them rather than the whistle stop tour he seemed to be locked in to. In addition to this Abdul was less than satisfied with his buoyancy skills, which only improved when he started using a heavy repackable scrubber and was able to ditch his weight belt.

14 That evening he made full use of Abdul’s course manual, spending another four hours reading and writing in an attempt to catch up with the diving side of the course. The following day Abdul discovered why Alex’s air supply had been cutting off. It was all down to an on/off free flow switch that Poseidon had added to the mouthpiece. It was just an unremarkable looking black sleeve mounted on the mouthpiece connecter, which Alex had unknowingly moved whilst supporting the heavy mouthpiece with one hand and Abdul had unknowingly moved back again. Two dives later he was still having trouble performing some of the more complicated tasks, and he decided whilst still underwater to abandon the course and use his last three days doing some real diving, albeit still on a rebreather. Abdul told him that he would make it look as if he was still doing the course, as otherwise the office would be sure to want to charge him for it. As it happened it was a good move and on the first day’s diving, after climbing up the boat ladder, he saw an Oceanic white tip shark swim up behind him. Abdul had no intentions of letting him off certain aspects of the course and he was shown how to refill the scrubber canister. Alex was surprised at the amount of heat coming from it, which was all due to the chemical process extracting the heat from his breathing. On the second day they dived on the Tiran straits, with Abdul taking him halfway down the famous ninety-meter canyon on Thomas reef to a depth of 140ft; so at least he had managed to half accomplish

15 one of the things he had hoped to do with the tech rebreather courses. On the third and last day they went to Ras Mohammed on a boat that was bristling with rebreather divers. Alex was secretly feeling relieved that this was to be his last day as after six days of it he had had enough of this form of diving and was looking forward to returning to the carefree

world of open circuit scuba. Up to this point there had been a general lack of fish about, but Ras Mohammed made up for it, though it still not as good as he had seen in past years. That last day was a very hot one and Alex was beginning to feel left out as he no longer shared the others enthusiasm for rebreather diving. He still had to perform one last chore back at the dive centre - the disinfecting and washing off of the various dismantled rebreather parts. Once this was done he left the dive centre feeling that he was no longer welcome there, having declined to embrace the rebreather as the others did, and it was only Abdul who he had spent six days diving with who gave him a genuine parting handshake.

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