The Fine Art of Extreme Exploration Dives
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tech talk The fine art of conducting Extreme Exploration Dives 69 X-RAY MAG : 31 : 2009 EDITORIAL FEATURES TRAVEL NEWS EQUIPMENT BOOKS SCIENCE & ECOLOGY EDUCATION PROFILES PORTFOLIO CLASSIFIED tech talk How to master the complexities of extensive explorations of underwater caves and other overhead environments Our case story will be a recent actual a depth of 200 meter and ranging more exploration where the dive profile posed a than 700 meters from the entrance. On few challenges: the actual dive date we may then find - Distance of 700 meters from the that these preset definitions of depth and entrance to the end point. time do not match up with the actual - The depth of 164 meters at the begin- diving profile, mental and physical fitness ning of the actual exploration and 186 and the equipment at hand. This leads to m at the end. postponements and delays which may run - Duration of the dive which including into a year, or at least several month of deco stops required a run time 9 hours waiting, which is often the case. It is thus and 46 minutes submersed. necessary to stay fit and keep practicing all the relevant technical skills. In this case However, even if this specific dive profile I kept up a regular schedule doing many presented us with some exceptional chal- speleological/cave dives where I could lenges, it wasn’t fundamentally different rehearse practice stage and travel proce- from other technical dives in terms of dures as often as possible, as well as prac- safety and logistic considerations. We do ticing deep and rebreather dive profiles. our preparations and make plans in which In the beginning of May we found our- we try to reduce the number of unknown selves in Egypt. After one week of diving factors as much as possible. between 50 and 100 meters deep with In technical diving “what if..” and “plan stage and trimix, I’ve also made five dives your dive and dive your plan” are all basic to depths between 65 and 180 meters on mantras. It is only the magnitude of the rebreather in order to some build routine undertaking that changes as well as the with real deep dive profiles and to test the levels of complexity. Even for a practiced 150 meter barrier. tech diver who routinely dives his twin 12-li- Physical fitness training was not an issue ters tanks and use ready made table dives as I practice every year around 4-5 times like this are much more complicated. a week by running, swimming and bicy- cling so I simply took a nice break the Preparations week before the actual dive. 1. Defining objectives and means. Knowing the location This cave is quite the labyrinth and has In this case the objective was to explore several levels. So it is a good thing I knew an underwater cave that would take it rather well. A year ago I first dived it to divers beyond the depth of 164 meters a depth of 60 to 90 meters before going before the made it to the end. In this down to 150 meters. And the week before case we planned as if we were diving to the dive I’ve returned with a rebreather, 70 X-RAY MAG : 31 : 2009 EDITORIAL FEATURES TRAVEL NEWS EQUIPMENT BOOKS SCIENCE & ECOLOGY EDUCATION PROFILES PORTFOLIO CLASSIFIED EVERFLEX LIKE A SECOND SKIN. SCUBAPRO EverFlex suits are rich in features and in the way they make you look and feel. Our advanced, extra- comfortable EverFlex line has been stylishly designed for incredible fit and freedom. Its pre-formed dimensional shape and multi-thickness panels provide a superior combination of warmth and flexibility. EverFlex suits move naturally with a diver’s body for unparalleled stretch and comfort. Heliospan lining in the torso area and Glideskin going to the 70 meter mark, just to than 270 meter on a closed circuit inside the cave and the dive bell at seals on the wrists, ankles memorize the route, using a scooter, rebreather. On the other hand, the 12 meters. It was a bit heavy, but in and neck provide added to avoid wasting time when we were closed circuit system (or semi-closed case of a complete failure of the protection and insulation. going to do our exploration. Needless circuit) is the latest trend amid serious closed circuit, it would have allowed EverFlex adapts to a large range of body shapes and to say I had also gone over the avail- underground exploration dives for a me to make it back to the bell area sizes. able topographic information and number of good reasons: from the deep end. This also permit- If you are tired of the struggle reports from previous dives in order to - greater autonomy ted the team to familiarize themselves to get into your suit, Everflex get a clearer picture of equipment - greater gas economy with the cave. is for you. load during the dive, restricted pas- - breathing a much less colder gas The scooter or, as it appropriately sages, currents (what of if it rains the - less tanks to manage termed, the Diver Propulsion Vehicle, preceeding days?),visibility and nec- - Possibility for using helium – in the was also a requirement because of essary permits. In nature it is not any form of heliox - for the entire dive, the distance to be traveled. Several different from when you check the significantly improving the decom- trips starting from the deep end which weather forecast, prevailing currents pression profiles. was 500 meters from the entrance and swell before you go on a dive in helped me to select a model that DEEP DOWN YOU the ocean. My Voyager dive computer has a can really tow, rather than a lighter WANT THE BEST battery life of at least 7 hours, mak- one. The former, although a little less scubapro.com 2. Choice of equipment ing it possible to complete the entire speedy, seemed to me to be more dive, starting from the entrance until maneuverable inside that particular The choice of gear must reflect the the bell-area. My other technical cave. depths and environmental hazards. option was to stick with the usual The deco stations: the possibility of For example when I did my 330 meter open circuit system with complete mounting a deco station was exten- dive it was obvious to go with an redundancy. sively used. The choice was between open circuit system since I had never We had to bring a few 20 liter tanks a mobile deco station – suspended been beyond 150m on a rebreather. inside the cave, between the depth between 11 and 9 meters deep and And no one has ever gone deeper of 110 meters which was 600 meters then again at 6 meters. Or a fixed 71 X-RAY MAG : 31 : 2009 EDITORIAL FEATURES TRAVEL NEWS EQUIPMENT BOOKS SCIENCE & ECOLOGY EDUCATION PROFILES PORTFOLIO CLASSIFIED deco station at 6 meters which is much With the calculations for depth and The diving bell was mounted at 11 meters simpler. The mobile option was then time completed, we opted to go with and since the ambient temperature was chosen as it was capable of staying dry the “full helium” option which only had 18 ° C it wasn’t required to heat the habi- and hot twice as long which in this case 6% Nitrogen without a second thought. tat. meant almost 4 hours instead of the 2 Even the bailout plan an open circuit hours offered by the fixed option. system had a maximum level of 30% Provisions Nitrogen Dealing with dehydration is paramount Decompression strategy We had full sets of tanks with standard to ensure proper decompression - we The dive profiles were simplified as much deco mixes 02/He 20/50, 40/30 and 60% can never drink too much. Lots of water as possible so we opted for a short one O2 which were thoroughly analyzed, with a bit of fructose and a isotonic salt and a long one, for a depth of 180/200 marked twice and pressure verified. Also mixture is ideal. Fruit juices or energy meters at the bottom which was already clips sets, and speleological cable keep- drinks can also be used but with modera- very complex with its several levels and ers for the ropes were checked. tion as the last thing you would want is a great end depth. As an additional For the sake of safety we also had to nausea. Hot drinks such as light sweet option we could use a set of a set of consider the situation where we had to teas or soups are alsi suitable During more conventional tables and 2 multi- perform the dive on open circuit sys- long dives it is also important to eat to gas computers, one connected to the tems and not rebreather. Did we have keep up the energy. Energy bars are rebreather to deal with all the intermedi- enough of each mix? For each depth fine also nut paste or cocoa but go easy ary situations. we had to calculate what was needed on sweets. Put pastes and creams into Simplicity is preferred even if it with an acceptable level of security tubes or syringes. And don’t bring ham demands hours of calculations for differ- Thermal insulation was taken of by a or other meat products into the dive bell ent profiles and using different software. drysuit with Thinsulate 300 undergarment 72 X-RAY MAG : 31 : 2009 EDITORIAL FEATURES TRAVEL NEWS EQUIPMENT BOOKS SCIENCE & ECOLOGY EDUCATION PROFILES PORTFOLIO CLASSIFIED tech talk Stay with the same team if possible.