Re D Und a Nc Y Ethic

Technical Leigh Cunningham is Matters the technical manag- er and TDI Instructor Trainer for Ocean Redundancy ethic? Don’t be dead – be a double bagger! College, Sharm El Sheikh.

Probably best known for his records - Leigh once Leigh held the record for the Cunningham deepest dive in the Red Sea - and attempts of Double Bagging reaching extreme depths, he also has a wide range of teaching credentials to his cur- riculum:

TDI instructor trainer, DSAT Tech for Divers Trimix instructor, PADI MSDT IANTD Technical diver instructor CMAS 3 star instructor. In the world of tech- Better be safe than sorry. This old The meaning of redun- So where is nical diving, a direct adage certainly applies to diving too, dancy In dive-speak, redun- this point? ascent to the surface and in this case redundancy pretty much dancy usually translates into hav- Turning once translates into having a back-up for all ing double tanks, double regula- more towards the Being more concrete So, are there is not an option if you important systems. After all, diving is sup- tors, double this and double that. above definition, no absolute criteria as to when one run into a problem posed to be fun and a means of hav- But what does redundancy really the entire system should wear back-ups? Absolutely! For or emergency. For ing adventures that enrich our lives, not mean? The dictionary give us the refers not just to starters, with any kind of diving that car- something that will make us lose it. following definition. the mechanical ries a decompression obligation, and div- this reason, technical Fortunately, there are a lot of good les- equipment but ing in overhead environment obviously divers are required to sons and readily applicable techniques Redundancy, in general terms, also to the diver, qualifies, as set forth by various training carry back-up sys- to be learned from the world of technical refers to the quality or state of along with his or agencies. But before it comes to that, tems to resolve prob- diving, that can make diving much safer, being redundant, that is: exceed- her training and why not make it a policy always to have without being a real bother or overshad- ing what is necessary or normal, contain- ability to cope with critical situations. For a sensible margin of safety, and always lems associated with owing the experience. Using a seat-belt ing an excess. This can have a negative this reason, when to use then becomes use redundant systems for any diving equipment malfunc- when driving a car has become second connotation, superfluous, but also posi- a somewhat subjective and individual close to the NDL limits or beyond, say, 30 tion during a dive. nature, as is carrying a spare tyre in the tive, serving as a duplicate for prevent- question. It is not, however, just a matter meters? trunk. We will probably never, or rarely, ing failure of an entire system. of what the diver can safely handle but actually have need of them, but when also a question of mental comfort dur- What is needed? Regarding deeper But what about the needed we surely appreciate these sim- The last sentence in the above definition ing a dive. Diving, we should not forget, dives, or dives with long bottom times, rest of us? ple measures. is interesting, because it raises a very is also about having a good time. Simply redundancy means diving with twin tanks But here the similarities between driv- important question, also in terms of div- bringing the extra equipment - even and two sets of regulators. These tanks ing and diving stops. Running out of ing: When is something superfluous, and on dives that do not venture into those may either be independent or, which is gas when driving a car is mostly just an when is it an important safety measure depth zones where conventional wis- more common, connected by a mani- embarrassment and inconvenience, but ‘preventing failure of an entire system’? dom would deem it absolutely necessary fold. In either case, if there is a regulator Text by Leigh for a diver it can obviously have dire Most of us will probably agree that using – means more than just additional safety. malfunction on the bottom, there is a

Redundancy Ethic Redundancy Cunningham conse- quences. a heavy double tank rig for a shallow Just as importantly, the feeling of having back-up system which can be switched Photos: water dive is overkill, and we wouldn´t that extra safety also translates directly to. Craig Nelson be bothered. But as we go gradu- into making the dives far more enjoy- ally deeper and longer, we will also able. Because, while it doesn’t lower any Size matters The tanks should also be approach a point where a double rig alertness, it does remove the latent stress- big enough, not only to carry enough becomes a very useful piece of equip- loading of what if...?. And this is certainly gas to complete the planned dive, but ment and a safety measure worth taking into consideration. also to give an ample reserve supply to

66 X-RAY MAG : 4 : 2005 EDITORIAL FEATURES TRAVEL NEWS EQUIPMENT BOOKS SCIENCE & ECOLOGY EDUCATION PROFILES PORTFOLIO CLASSIFIED Spare mask can easily be What is technical diving? carried in a pocket Technical Matters Some people define technical diving handle any unexpected problems. How Divers using dry suits might con- schedule outside the primary plan, in order to as diving in “overhead environments” big this gas supply should be depends sider their dry suit a form of back- handle any emergency causing a digression meaning that direct ascent to the sur- not only on the depth and the length of up buoyancy. In this case, divers from the primary plan. Even those face is not possible because of the bottom time, but also on the diver should consider the weight of the divers who use multi-gas computers, and a previously determined breath- diving system (rig), compared might opt for the additional security ing rate. The gas used at the deepest to the comfortable lift capacity of back up tables and plans. parts of the dive may be either air, Nitrox of the dry suit. Swimming up to The down side of multi-gas com- (aka EANx, Enriched Air Nitrox), Heliox, or assist the ascent could be con- puters is, they may encourage tech- Trimix. For shorter or shallower deco dives, sidered appropriate in this type nical divers to rely on the ability to divers might opt for a single tank, with a of emergency, but if the diver make new plans on the fly (during the dive), a decompression obligation requiring redundant valve (Y or H valve), allowing is too negatively buoyant, and instead of making a structured depth and decompression stops and/or a being the diver to use two regulators on a sin- have to fin too hard or for too time plan before the dive. In spite of the risk inside a cave or a wreck. gle tank. long, it could lead to excessive of being considered old fashioned, I think it is If there is a problem at the bottom, the CO2 loading. As the breathing safer to make a structured plan and do the The late Robert Palmer, once one of dive would be cut short, and the diver rate goes up, any narcosis would required calculations using an appropriate the gurus of technical diving, defined would make a controlled ascent, com- intensify, plus an increased risk of decompression software before the dive, and it as “the use of advanced and spe- plete his decompression obligation, and CNS O2 toxicity. consider the deco schedule, as generated by cialised equipment and techniques finish the dive safely. the multi-gas computer, as a bail out option. to enable the diver to gain access to When relying on a drysuit as a Whichever depth, dive time, and specific under- Buoyancy: For divers using wet suits, a back-up buoyancy device, one system you water environments more safely than redundant wing system should be used should take the worst case sce- chose, multi- might otherwise be possible” as the buoyancy device. This means two nario into consideration. For example, a split gas computer, independent bladders, usually in one bladder where all the gas is abruptly lost Depth-timer or outer shell, and with independent infla- from the wing. Would the dry suit support the computer in tors. In the event of a buoy- ancy diver sufficiently to make a safe and control- gauge mode, Mask: This is probably the most unlikely problem, i.e. the regulator led ascent from depth, through a you need at item of equipment you will have a prob- supplying gas to the primary series of decompression stops, least two to lem with. But for any kind of dive that bladder, malfunction, or accurately and without over accurately fin- takes you into deep waters or a decom- a problem with the blad- exertion? If not, the diver ish the dive in pression schedule, you should certainly der itself, or ruptured should consider using a the event one bring two. I can talk from own experi- inflator hose, etc, the redundant wing system. malfunctions. ence, as I once lost a lens during a dive. diver would switch Another important This was due to a hairline crack in the to his back-up question is, whether frame of the mask, which went unno- bladder, make a well worn dry suit Men in ticed at the surface before the dive. a safe ascent, with weak seals will Black? The back up mask came in most useful, complete the be able to retain a enabling me to read gauges, whereby decompression sufficient volume I could ascend at the correct rate, obligation, and of gas for a safe near full tanks. Dump wing gas, and see if perform accurate stops finish the dive. controlled ascent. you can establish neutral buoyancy using and finish the dive If the dry suit has the dry suit alone safely. sufficient lift, then Twin tanks, mani- having a redun- Depth and time monitors fold and two dant wing system (Depth-timers): In this day and age regulators with seems pointless. of multi-gas Air/Nitrox, and mixed gas hoses routed so computers, divers have the luxury of These artistic expres- that both lift and Try to avoid carry- having a continuously re-adjusted sions might seem breathing gases ing equipment, which schedule with them on the dive, funny to some people are always availa- ble - even with one would not be used. based on exactly what they are but it gets to the point first stage closed. breathing,. When using Depth-timers, when required. The boat Hose routening is If necessary, simulate the or computers in gauge mode, divers crew know who the diver is the subject of next problem in shallow water with should carry back-up tables to have a below it, and the face’s and article in the series colors are descriptive.

67 X-RAY MAG : 4 : 2005 EDITORIAL FEATURES TRAVEL NEWS EQUIPMENT BOOKS SCIENCE & ECOLOGY EDUCATION PROFILES PORTFOLIO CLASSIFIED Double bagging Technical Matters There are several explanations for where the expression double bagger comes from, but it is actually a piece of British Army slang. The idea is, that if a lady is hard on the eye, you need to put a paper bag over her head before you can get inti- mate with her. If she is really hard on the eye, you will want to have a second bag close at hand, in case the first one breaks. So, a double bagger will always have two bags ready – just in case. Not very PC, but it’s history.

two SMBs. One SMB to let the sup- redundancy might be used in the port team know the dive is running form of a pony bottle, i.e. clamped according to plan, and one as an to the side of the main tank, or a emergency signalling device. When small spare air cylinder clipped to the doing drift decompression in the BCD. However, a word of caution open ocean, it would be wise to take seems to be appropriate here. Divers a back-up reel too. are often seen to be putting more and more distance between buddy Lights: In overhead environments, teams during a dive, or pushing Reel and SMB (Surface Marker where dive-lights are necessary, past the accepted depth limit of 40 Bouy). These are very useful tools in back-up lights would fall under the meters set forth by most recreational all environments but let’s talk open redundancy ethic. scuba agencies. They are, perhaps, water. For open ocean drift decom- relying on these stop-gap measures, pression diving, deploying the SMB In short, any item of equip- which are of questionable value, if during the ascent, the diver creates ment used to conduct the not outright inadequate, should any a form of reference along which spe- real emergency occur. In such situa- cific ascent rates and a complicated dive safely, and which could tions, nothing can substitute the men- deco schedules are much easier to possibly malfunction, should tal readiness stemming from having carry out accurately. The divers sim- undergone some sort of advanced ply hangs under the SMB by being be duplicated with a appro- training and using redundant systems. slightly negatively buoyant, and reel- priate back-up system ing up at the right time. The SMB also Think about it! ■ allows the boat and support team to Summing it all up For the recrea- track divers doing a decompression tional community, where divers are Next issue: Kit configuration, drifting under the buoy. staying within no-deco limits (NDL), streamlining and hose routing In an emergency, an SMB could the redundancy ethic does not also act as an emergency signal- apply with the same degree of ling device. For example, a red SMB necessity as it does for the techni- could be a signal to the surface sup- cal or decompression diver. The port team that everything is OK. If the non-deco diver can always, at diver suddenly has little or no gas, a any point during the dive, make differently coloured emergency SMB a controlled ascent directly to the could be sent up as a signal for a surface without stopping. However, support diver to bring additional gas while there are no clear-cut crite- in the water, or to see what the prob- ria as to when a diver should start lem is. to carry redundant systems, it is The reel is also very useful on the certainly something the advanced bottom to ensure a safe return to a recreational scuba diver should specific ascent point in low visibility. look into as means of improving The diver simply ties the end of the both safety and technique. In line to the anchorline or downline. the event that a diver runs low, or out of gas, while his dive buddy Minimum. A minimum require- is outside comfortable swimming ment would be at least one reel, and range, an intermediary form of

68 X-RAY MAG : 4 : 2005 EDITORIAL FEATURES TRAVEL NEWS EQUIPMENT BOOKS SCIENCE & ECOLOGY EDUCATION PROFILES PORTFOLIO CLASSIFIED Tried

& Tested nificantly, they were warm and underwear I could imagine many tropical applications where diving in just the Thermocline would not only be possible, but also desirable from the point of view of comfort Edited by and neutral buoyancy. It would Andrey Bizyukin Who’s testing? Thermocline also make a very good pool Kevin Gurr has been a lead- & Peter Symes Fourth Element launched itself was really interested to see how waterproof yet breathable mem- suit for training situations, being ing figure in the technical div- into the diving industry in 2001 they would have modified their brane. This membrane makes the breathable above the surface ing community for more than By Kevin Gurr with the intention of developing approach and keen to test them Thermocline fabric windproof and and warm in the water. a decade. He was the the first an innovative range of technical as part of my cave diving equip- warm. I tried the Thermocline in two technical and cave instruc- clothing designed to combat the ment. caving stuations. The first was in tor to be qualified in Europe New undergarment from problems of thermal regulation On initial inspection, the Antimicrobial the Red Sea on fairly long dives of and headed the IANTD in Fourth Element has been in scuba diving. After lengthy Thermocline garments have a The fabric has an antimicrobial up to ninety minutes. I wore the UK 1992-2004. Authored the research and development, their more glamorous look to them treatment to resist the build up Thermocline underneath a knack- acclaimed Technical Diver heralded as not less than first product was the Xerotherm, a than the black Xerotherm. Shiny of odours, but the garments are ered old Cressi semi-dry which has Student Workbook with Tom a revolution. Well, is it? drysuit base layer undergarment or rubbery, they look like some- machine washable, making them more holes than it should. Much Mount as well as two workbooks that was extremely well received thing from a Bond movie. The easy to keep clean and smelling of the insulation work was being for the Technical Diver and the Productshots are supplied by technical and sport divers designers at Fourth Element have fresh. The Thermocline garments done by Fourth Element’s under- Normoxic Trimix programs. by Fourth Element alike. obviously put some time into have two different outer finishes garments and I was extremely Leader of numerous successful the design of these gar- on top of the membrane. The comfortable and warm. The neu- diving expeditions that include I have been using the Xerotherm ments so that they look shell finish has a woven nylon tral buoyancy of the fabric meant the Britannic and the Pilar for the past few months and took good, but it is in their use of outer face similar to that of that I needed no extra lead and Project, Kevin Gurr also heads to it instantly. It is well designed the fabric that the innova- double lined neoprene and had no changes in buoyancy up Delta P Technology, manufac- and very warm and uses high tion shows. the skin finish has a with changing depth due to turer of the successful VR3 and performance fabrics to keep the smooth surface rather changes in the fabric. VR2 air and mixed gas dive wearer’s skin dry from perspiration Polartec fabric like rubber, which computers. www.vr3.co.uk and any suit leaks. It’s four way Fourth Element has Fourth Element says is stretch gives complete free- used another high ideal underneath a dom of movement and it performance fabric wetsuit or semidry as is an excellent next to the from Polartec, spe- it gives a very good skin layer whose warmth cially developed for seal against the belies its weight. I also water sports. Weight inside of a suit. used it under a wetsuit for weight, the fabric There are sev- on a recent expedi- has the equivalent eral garments in the tion; even in a situ- Thermal performance Thermocline range ation where it was of 2.5mm neoprene, including short completely wet, it yet it is neutrally sleeved tops, vests, performed very well, buoyant. This is sig- shorts and even a keeping me signifi- nificant for all divers ladies’ bikini. I tested cantly warmer and looking to add some extra the short sleeved rag- more comfortable. thermal protection without lan top and the men’s So, when I was the need for additional shorts. asked to review lead. It has a fleece lining The Thermocline gar- Fourth Element’s against the skin which has ments were extremely products designed similar wicking properties comfortable and gave specifically for use to the Xerotherm fabric excellent freedom of underneath wetsuits, I but this is bonded to a movement. Most sig-

69 X-RAY MAG : 4 : 2005 EDITORIAL FEATURES TRAVEL NEWS EQUIPMENT BOOKS SCIENCE & ECOLOGY EDUCATION PROFILES PORTFOLIO CLASSIFIED Tried & Tested

After the dive, the speed at which garments. Caving in Swildons gested to him developing a long the undergarments dried was fan- Hole in the Mendips, I used the sleeved and long legged product tastic. By the time I had got out same arrangement of the Fourth to give more protection to the of my wetsuit, the inside of the Element undergarments under my arms and legs. A long sleeved top Thermocline had dried. The fleece Cressi semi-dry. In air temperatures will be available soon, he assures is made using a hydrophobic poly- of 15ºC and water temperatures me and full length legs will follow. mer which does not hold water, of about 5ºC, I was much warmer Until then, the Thermocline which runs out under gravity. With than I had anticipated, I did not Raglan top and shorts are an so much less water next to the skin feel the cold of the water and excellent way to increase the ther- there was much less wind chill and I have to put that down to the mal protection of the body core the garments had dried within 15 Thermocline as I know all too well and the vest and shorts combi- minutes or so of wandering around that my old semi dry has lost its nations would also provide core the boat. integrity. warmth with just a little more free- The breathablility of the fabric dom of movement in the arms. I should not be underestimated Criticism believe this would be an excellent when out of the water – it is much My only criticism of the Thermo- addition to most divers thermal less sweaty wearing a Thermocline cline range is perhaps in the sizing protection systems, from technical top than a neoprene vest or which is a little on the tight side cave divers to those who prefer shorty wetsuit so you can keep it particularly around the shoulders more tropical conditions and just on between dives. It is also easier – anyone thinking about buy- want the best in comfort and per- to keep clean. Simply rinsing in ing it would do well to get some formance. fresh water and hanging it up for good advice about sizing from the Sample prices a few minutes is all that is required manufacturers or retailers before M Thermocline long sleeve top £65.00 during a dive trip and afterwards purchasing. I raised this with Jim M Thermocline shorts £45.00 the Thermocline garments can be Standing at Fourth Element and he W Skin Thermocline vest £48.00 washed in the washing machine. said that they would be working W Shell Thermocline short £35.00 The second test was a little more on making the sizing more consist- www.fourthelement.com demanding of the thermal per- ent for future products. formance of the Thermocline At the same time I also sug-

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70 X-RAY MAG : 4 : 2005 EDITORIAL FEATURES TRAVEL NEWS EQUIPMENT BOOKS SCIENCE & ECOLOGY EDUCATION PROFILES PORTFOLIO CLASSIFIED