The most basic element of any technical diver’s equipment is his twin set. The two cylinders he typically carries on his back, but not exclusively, there are times when a cave is too narrow for back mounts and side-mounts are the appropriate configuration.
Up until about three years ago my twin set consisted of two 12 litre 232 bar steel tanks. This set was perfectly adequate for the kind of support diving I was doing.
My twin 18 litre cylinder set, note the home made bands
In 2003, since I was going to need more gas to support Nuno Gomes in his quest to break the 300 metre mark, I upgraded to twin fifteen litre steel tanks, again 232 bar. I’ve found that the twin fifteen litres are (not surprisingly) heavier than the twelve litre ones, but give a very significant amount more air. The twelve litre set gave 220 x12x2 = 5,280 litres, whilst the fifteen litre set gave me 220x15x2 = 6,600 litres. That meant I could spend much longer time exploring caves like Boesmansgat.
You will note that my set has an isolation manifold between them. This valve enables the diver to isolate the right tank from the left one. In the event of a valve failure, I can close the valve that has the problem, reopen the isolation valve, and breathe air from both tanks. The idea of an isolation valve is not new. It goes back to the era of George Benjamin’s expeditions to the Blue Holes in the Bahamas (see “Deep Into The Blue Holes” by Rob Palmer(1997)) . But in recent years we’ve seen the manifold become the de facto standard among cave divers. Particularly thanks to the work of George Irwin, Jarrod Jablonski and the Woodville Karst Plain Project (WKPP) project in Florida USA. They evolved what they termed the DIR or Doing-It-Right approach to technical diving (see website, www.wkpp.org). This was a set of rules to ensure a standard configuration amongst the very large number of divers belonging to the group.
But that is not to say that isolation manifolds are universally adopted. In fact Nuno Gomes does not use an isolation valve. For him the risk of trying to close a leaking valve at 200 plus metres is just too high. He rather takes a separate bail out cylinder. As I recounted in chapter 8, he’s had to switch over to his backup and ignore a malfunctioning valve all together. For Nuno, the simplest solution to a problem with his main regulator is to swap to another one altogether. Personally I find the manifold very helpful, especially in a task-loaded dive like when I’m filming or doing a lot of reel work. The point is that you can breathe air from both tanks without needing to switch regulators. If you opt for independent doubles like Nuno and other members of the team, you have to regularly switch from one tank to the other to balance your gas usage. Once again I stress, I don’t think either method is wrong. They both have good and bad aspects. For me appropriate configuration is very much dependant on the specific environment and the objectives of the dive.
My other set of cylinders of twin seven litres 300 bar tanks, are independent tanks. I’ve used these for much of my open water diving over the last few years. Furthermore, the geography of some cave environments makes the use of a manifold twin set impractical. One need only think of the English cave divers who for years have been using the so-called “side-slung” method of rigging their tanks. The reason for this is that the caves they dive in are simply too small to use twin back mounts like we do here in South Africa or the divers in Florida might use. The “side-slung” system is just what it says; the diver has a harness that allows him to clip two or more cylinders to his hips and thus pass through very narrow constrictions.
The next component of my technical diving equipment is the buoyancy compensator. For most of the last ten years I used two DiveRite Classic Wing BC’s. One acts as a back up for the other. I’ve found this so-called Horseshoe or back inflation BC to be very efficient and very tough. I dived all over South Africa, in the ocean, in caves, in dams and never had a problem. Last year Nuno brought out his own signature model wing type BC and as a member of his team I was lucky enough to get a complimentary pair. I must say that these “Nuno Gomes” wings are really in a league of their own. They are made from very tough material. The inner bag itself is made of material similar to the stuff inflatable boats are made of. Also they have an exceptional amount of lift (in excess of 90lbs of lift). You’ll note that I still use two of these wings for redundancy reasons again. I usually do not dive with a dry suit, so I require the second wing in case my primary wing fails. One difference between the way my old Diverite Classic wings were configured and my new “Gomes” wings is that I used to run both power inflators over my left shoulder. This was simple and easy to get to.
My twins set with wings attached
Again, for redundancy reasons I always ran one inflator from the left tank and one from the right. Logically enough it did not make sense to run them from one tank only and risk having no lift in the event of a regulator failure. The new wings are designed by Nuno to go one over the left shoulder and one over the right shoulder. This was done to simplify the configuration and leave no doubt in the mind of the diver as to which source of buoyancy he was using at any given time. On the occasions when I do dive in a dry-suit I will usually only use one wing because in an emergency I can use the suit itself as a buoyancy device.
The next most fundamental piece of equipment is the regulators one chooses to use. In cave diving one requires at least two independent regulators. Both should be high quality DV’s or what the US Navy once rated as Class-A regulators. In my opinion most modern manufactures have models with more than adequate specs for most deep diving. My own personal preferences are Poseidon and ScubaPro. I’ve found both these brands to be above average in durability and breathe-ability. They have taken the harsh conditions we have in our caves and in our oceans with no problem. They’ve worked for me on dives ranging from 20-30 metres sport diving down to below 100 metres.
The twin set with my Poseidon Regulators
Notice that my right post (the tank that would be behind my right shoulder) has a DV with an extra long hose on it. This was once again something I picked up from the guys at WKPP. Not that our caves are so tight that we can’t fit two divers alongside each other, (although this is sometimes the case) rather it is just easier and more streamlined to use the two meter hose wrapped around one’s canister light and then up around one’s head. Also, the right post DV has no contents gauge. The logic being that only one gauge is necessary since, under normal circumstances, the manifold between the two cylinders is open. The left post is fitted with a standard length regulator and a contents gauge running down my left side. This DV is attached to a bungee cord and hung around my neck. This arrangement means that even in the dark I know where it is. It also allows the DV to be pulled off in an emergency.
The next piece of equipment that a cave diver needs is a primary torch. This is usually a canister type light, which has a 50 or 100w bulb. Mine is relatively old technology and normally burns for about an hour and a half. More modern ones give hours of continuous use. The standard torch head is the so-called test-tube bulb, but I tend to go with a standard sealed beam halogen bulb. The only down-side to this design of light head is that the bulbs cannot be burned out of the water because they need the water to cool the torch down. If one forgets and burns the torch out of water, then the light head tends to melt. I guess this is one area where I should update my gear with a more modern, longer burning and cooler running light. To back up this primary light I have a secondary torch stowed under my left arm (again I’m following the DIR method here), and three other smaller torches that I carry either in my pouch or on my helmet. You’ll note the primary torch is slid onto my harness belt on the right hand side and secured by the use of a weight belt buckle to hold the torch in place. This very simple idea makes the torch a pleasure to use instead of a real pain to try and keep in one place.
An alternate set up is seen in the next picture with my two ScubaPro regulators, also with a long hose on the right post.
The use of helmets as platforms for torches was adopted by our group quite a few years ago. Although most of the other groups
I know of around the world have gone away from helmets, and even some of our guys no longer use helmets, I still find it useful to have when I’m busy using my hands for other things than holding a torch.
One more piece of gear that no cave diver worth his salt would ever go into a cave without is a line reel and a few line arrows or dorf markers. The designs of these reels have gone from the strange to the ridiculous. I’ve seen big unwieldy type spools that were really a danger just to have in the water. Some floated, some sunk. In general, the simpler spools that had line guides built into the front and were about ten centimetres diameter generally work the best.
Some final comments with regard to equipment configurations; some divers go so far as to tape up their mask straps and fin straps to avoid entanglements of these. I’ve not had any problem so far, and maybe I’ve just been lucky in this, only time will tell. As far as fins go my current pair are ScubaPro TwinSpeed split fins; I’ve found these to be very comfortable and capable of meeting my propulsion requirements whilst not exhausting me. I do however have a pair of Poseidon Forza fins as well and have no complaints about those either.
As far as diving gauges go, I generally dive with two dive computers, again for redundancy. At the moment I use a Cochran Commander Nitrox computer that lets me use two different gases on any single dive and a simple AladinPro air computer. Both have served me well, although naturally when I dive Trimix these are just serving as depth gauges and timers.
As to the future of my diving hardware, I intend going on a rebreather course in the future, if only to get a first hand understanding of this technology. And I think before too long I’ll be acquiring a Trimix dive computer. I’ve seen these machines first hand and I believe they are definitely an improvement on the standard single gas air computers that most divers are familiar with.
B. Other cave diving references.
CDG (1990), “Cave Diving”
Chowdury. Bernie (2001), “The Last Dive”
Exley. Sheck (1994), “Caverns Measureless to Man”
Exley, Sheck (1986), “Basic Cave Diving- A blueprint for survival”
Farr, Martin (1991), “The Darkness Beckons- History and Development of cave diving”
Finch, Phillip (2008),”Raising The Dead”
Mount.Thom & Gilliam. Bret (1993), “Mixed Gas Diving”
Palmer, Rob (1994), “An Introduction To Technical Diving”
Palmer, Rob (1997), “Deep Into The Blue Holes”
Stone, William & Am Ende Barbara with Paulsen, Monte (2002), “Beyond The Deep”
Van Schaik, Verna (2008),”Fatally Flawed-The Quest To Be Deepest”
C. Glossary of terms
Argon – A dense gas pumped into dry-suits by technical and commercial divers to help insulate them from the cold of long submersions.
Buoyancy Compensator (BC) – An air bladder that divers use to maintain neutral buoyancy
Closed Circuit- So called because it describes underwater breathing equipment that recycles the exhaled air from the diver, and adds oxygen from time to time. Based on a level of oxygen set by the diver usually around 1.4 or 1.6bar.
Counter-Lung- Every rebreather system has to have a bag from which the diver breathes and into which oxygen and Diluent are added throughout a dive. Every breath the diver exhales is sent via a scrubber back into this bag to be re-breathed.
Demand Valve (DV)- The two-stage regulator scuba (self-contained-underwater-breathing apparatus) divers use to breath underwater. The first stage reduces the tank pressure from 200b to about 10 bar above ambient and the second reduces it to ambient, enabling the diver to breath on demand.
Diluent -Close and semi-closed circuit divers use a dilutant gas to ensure that they have an acceptable level of oxygen in their Counter-Lung as the machine adds more oxygen when they use up more and more of the oxygen in their mixtures.
EANx- Enriched Air Nitrox, or Nitrox is oxygen enriched air. Normal air has 21% oxygen, 79% nitrogen. By using EANx divers can stay down longer and have to do less decompression because the gas they breath has less inert gas (nitrogen) and more oxygen. The x denotes the percentage of oxygen in the mix eg.EAN32 has 32% oxygen.
Full-Face Mask- A mask designed for use in very cold water or because of the risk of oxygen seizures, on dives where very high percentage of oxygen is breathed. Also often used by Police/Recovery divers when they are using full exposure suits.
HeliAir – Any mixture of helium and Air, generally used in technical diving when special equipment required to boost gas from one tank to another is not available. It is a simple way of making Trimix, although you do not have the same freedom to mix any combination you might want because of the pressure rations. Generally used for extreme deep diving.
Nitrogen Narcosis- So called “Rapture of the Deep” by Jacques Cousteau. Under pressure nitrogen has a narcotic effect in humans. Effects can vary from almost nothing to unconsciousness and death.
Nitrox- See EANx
Open Circuit- So-called ‘normal’ Scuba diving apparatus, exhaled gas is vented into the water and wasted.
Oxygen- Most important gas to human respiratory cycle. oxygen makes up about 20% of air and is metabolised (used up) by divers as they breathe it in their air or other breathing gas.
Rebreather- See Closed Circuit
SCUBA- Self Contained Underwater Breathing Apparatus
Scrubber- Term used to describe that part of a rebreather unit that is used to trap Carbon Dioxide exhaled by the diver. Normally takes the form of rough granules that have a limited Carbon Dioxide absorbent life.
Trimix-The preferred gas for extreme deep diving, it is any combination of helium, oxygen and nitrogen. Depending on the level of Narcosis the diver wishes to tolerate they can mix an appropriate Trimix for the job.
Index
Affrox 43
Air Products 43
Aliwal Shoal 79
Badgat 30, 31, 39, 74, 75, 77, 79, 101, 112, 123, 124, 141, 144, 145, 154
Bass Lake 13
Bauer 43
BC 13, 22, 23, 31, 53, 57, 59, 60, 105, 120, 130, 193, 207, 214
Beresford, Mike 38
Blue Hole 119, 168, 178, 182, 183, 184
Boesmansgat 10, 11, 34, 35, 39, 40, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 55, 57, 58, 59, 60, 63, 68, 71, 72, 73, 74, 75, 77, 82, 89, 90, 91, 92, 93, 94, 95, 97, 100, 107, 123, 126, 132, 133, 141, 143, 144, 145, 146, 149, 150, 154, 185, 199, 205
buoyancy compensating 12
Cairo 162, 163, 164
Calypso 12
cave diving 6, 11, 15, 16, 19, 20, 21, 26, 32, 36, 38, 40, 42, 48, 71, 73, 74, 75, 76, 85, 90, 92, 99, 100, 112, 123, 125, 134, 143, 147, 152, 204, 209, 213
CMAS 13, 15, 16
Coelacanth 16, 156
Cousteau, Jacques 15, 25, 168, 202, 215
Czarnecki,Leszek 34, 90, 94
Dahab 117, 119, 162, 163, 164, 165, 168, 171, 176, 178, 181, 182, 183, 198, 200
DAN 15, 17, 22, 96, 97, 106, 109, 110, 113, 118, 156
decompression 6, 15, 16, 17, 18, 22, 25, 36, 37, 38, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 60, 67, 85, 90, 92, 94, 95, 97, 98, 99, 101, 103, 104, 105, 106, 109, 119, 120, 122, 123, 135, 137, 146, 147, 152, 157, 158, 168, 179, 184, 185, 192, 194, 196, 197, 215
decompression illness 17, 50, 52, 58, 60, 97, 106, 109, 147
EANx 32, 215
Egypt 41, 117, 161, 162, 163, 164, 189
Emmanuel, Joseph 1, 6, 42, 66, 89, 124
Exley, Sheck 19, 21, 60, 63, 64, 90, 143, 144, 204
Gomes, Nuno 6, 15, 28, 29, 32, 38, 40, 41, 43, 61, 64, 66, 72, 94, 143, 144, 146, 156, 167, 196, 201, 203, 205, 206, 207
Guinness Book 63, 199, 203
Guinness Records 201
Harding, Dennis 16
HeliAir 32, 55, 93, 102, 107, 215
High Pressure System’s 43
hyperbaric oxygen therapy 15
Kahn, Craig 23, 29, 41, 66, 67, 68, 73, 89
Komatie Springs 30, 144
Kwa-Zulu Natal 7
9
Kwazulu Natal 14
Leopard’s Cave. 19
lightning 92, 93
Liquid Air 43
Miracle Waters 156, 157, 158
Mount Carmel 40, 43, 46, 51, 63, 73
NAUI 13
Newham, Craig 28, 36, 41, 47, 56, 59, 66, 73, 89
Nitrox 32, 35, 37, 57, 76, 78, 94, 95, 113, 131, 151, 166, 189, 212, 215
Police Sign 81, 159
Polish Expedition 90, 92, 95
record 6, 15, 35, 40, 41, 42, 43, 55, 63, 64, 66, 67, 72, 73, 74, 76, 79, 83, 85, 100, 111, 112, 115, 117, 120, 124, 126, 127, 131, 133, 135, 138, 139, 141, 143, 145, 146, 147, 149, 150, 155, 156, 166, 176, 177, 185, 188, 190, 192, 194, 198, 201, 202
Rian Bower 16
SAUU 13
Shaw, Dave 72, 131, 134, 143, 145, 146, 147, 150, 152, 153, 154, 155
Shirley, Don 101, 124, 127, 131, 134, 143, 144, 146, 147, 150, 152, 155
Smilowski, Witold 90
Into The Deepest And Darkest Page 17