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October 13, 2011 - 23:32
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Since the introduction of Scuba diving in the mid 1950s, one of the most hotly debated subjects in the world of technical diving is that regarding the best type of gear configuration. Over the years, many experienced divers, instructors, and training agencies, have all claimed that their method and style of kit configuration is the best.

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Also, a diver may be able to maintain his depth at the bottom by lightly finning. However, finning too hard and for too long could lead to excessive CO2 production. The breathing rate would then increase, and the flushing and exhaling of CO2 would become less efficient. This would then cause the breathing rate to increase even more, producing more CO2 and thus predisposing the diver to a heavy narcotic hit, together with a greater possibility of O2-toxicity problems. This is the well known vicious circle of too much CO2, leading to too much N2, leading to too much O2.

Very deep diving for technical divers will have a different set of considerations for buoyancy compared to the average recreational diver, who may experience depth changes of only just a couple of atmospheres. At 200m there is a great deal of difference, with a pressure change of over twenty atmospheres. At these depths, an over-weighted diver runs the risk of reaching the point of no return, where the ability to inflate is exceeded by an increasing descent speed, as suit-compression and excess lead, or the addition of steel tanks, steel plates and unnecessarily heavy equipment, becomes overwhelming.

Bungee or not?

Another hotly debated subject is whether to have a bungeed or an un-bungeed wing system. Again, much like the Low Pressure Inflator issue, there is no one right or wrong answer. There is only the consideration of what should be used in a variety of environments or diving circumstances. For example, in confined or closed environments, such as cave or wreck penetration, the bungeed wing could result in snagging or entanglement, whereas in open water or ocean diving this problem would not generally occur.

The advantage of a bungeed wing is that, if a diver found himself in an undesirable position where it was difficult to dump gas by adjusting his body to an optimum position, then the bungee would assist in self-deflating the wing by squeezing the gas out from any position. However, that advantage could also turn into a disadvantage in the event of a wing malfunction, such as a split or ruptured bladder. In this scenario, a rapid loss of gas would occur from both the split and by the bungee squeezing away badly needed gas. In the un-bungeed system there is always the option of turning sideways to trap some of the remaining gas inside. This is not for the faint-hearted but is an option none-the-less. So, there is no right or wrong answer, only what is best for the given environment.

Hose routing

This, too, is a subject that has had many a group of technical divers debating in open session for hours on end. In the caving community, a pioneer of configuration protocol is William Hogarth Maine, or Bill Main as this highly respected caving pioneer is called. The term Hogarthian was adopted due to Bill’s philosophy. Originally, this philosophy was based on safety issues in caving, where, if divers used exactly the same equipment and configuration down to even the smallest detail, i.e. if one diver was a replica image of the other, then, in an emergency, other team members would be compatible with the diver in trouble

Incorporated in this style of configuration is a very rigid hose routing, the specifics of which include what side you have your primary first stage and back-up regulators, a 2m primary hose that would be wrapped once around the neck, and the location of additional equipment for the dive. Again, due to differing diving environments, this configuration may not always be the most suitable. For example, in open-ocean do we really need a 2m long hose when one of 1.5m may be sufficient?

In summary, what is fundamentally important is that, no matter what the environment, no matter where the hoses are located and their length, no matter whether your back-up LPI is connected, divers MUST know what they have and where it is situated. This is the only way to resolve a problem in a worst-case scenario, whether it be in a cave, in open water or inside a wreck. It therefore makes great sense to have a tidy, streamlined and neat configuration that is well suited to the given environment and the diver.

This discussion is by no means restricted to the technical diver. Recreational divers also need to consider their hose routings, many of which may have been learned or become a habit, good or bad, over many years of just taking such things for granted. I have seen some recreational divers stow their alternate second stages in various unsuitable places like BCD pockets and restrictive retainers, or even attached to nothing, where they dangle like a dog’s tail!.

Nearly all recreational agencies have a general agreement that the alternate air source is usually stowed in the imaginary triangle between the chin and down and across the rib cage. However, I believe that in an out-of-air emergency, the stressed diver on the bottom will always prefer to take the regulator from his buddy that he can clearly see and knows that it is working.

The alternate air-source in the triangular region may have flashing fairy lights on it, but I can guarantee that in most cases the out-of-air diver will always go for the one in their buddy’s mouth. If I had my way, I would adopt the same philosophy in the recreational community as in the technical community, by breathing off the second stage that would be donated to the out-of-gas diver, and having the back up regulator on a bungee around the neck, where it can be located with ease.

Originally published

on page 77

X-Ray Mag #5

May 22, 2005 - 12:58

The other side of Cayman Islands - Sister Islands - Bloody Bay Wall - Coral Spawning - free diving world record. Cave diving in Siberia. Philippines: Cabilao. Norway: the wrecks at Narvik - one of the biggest naval battlegrounds of WW2. Finding the U-89 off Ireland. Visiting Fourth Element Interviewing Cathy Church, photographer extraordinaire. Sam MacDonald marine metal sculptures. Ecology: tagging whale sharks. Photography: Going digital. Science: Hydrothermal vents

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