Significations et usages de Sidemount

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  Technical diver with decompression gases in sling mounted stage cylinders, similar in configuration to sidemount.

Sidemount is a scuba diving equipment configuration which has diving cylinders mounted alongside the diver, below the shoulders and along the hips, instead of on the back of the diver. It is a popular configuration with advanced cave divers, as smaller sections of cave can be penetrated and tanks can be changed with greater ease. Sidemount is also growing in popularity with divers who have difficulty handling the heavy double tanks commonly used by cave divers^{[citation needed]}.

  History and development

Sidemount diving began in England, where it was originally used in partially submerged caves.^{[citation needed]} It was an easier method of transporting diving gear between totally submerged sections of the cave (sumps). Americans began using sidemount in the mid seventies for the same purpose.^{[citation needed]} In the early eighties, Wes Skiles, and other Florida cave divers began to use sidemount^{[citation needed]} to explore cave passages that were too low for conventional back mounted tanks. They quickly found that the British style of sidemount didn't work well in low passages, and slowly developed a "Florida style" form of sidemount. Today, the British refer to this "Florida style" diving as "American sidemount".^{[citation needed]}

Most sidemount rigs used to be home-made as there were no commercial production of kits like there were for standard scuba rigs. One of the later "pioneers" of sidemount diving was Bill Rennaker, who started making kits available with sidemount accessories such as a custom butt plate.^{[citation needed]}

Dive Rite released the Transpac which was able to be converted for sidemount diving, and then later followed it up with the Nomad.

Expansion of tec rec sidemount into recreational and open water courses now occurs in several countries.^{[citation needed]} Note that sidemount configuration is not just a positional concept only - correctly matching technical (or even recreational) rigs together with sidemount harnesses is different from merely shifting tank positions using standard recreational gear for convenience, (which is not true sidemount).^[vague] Sidemount may be split into basic sidemount (single tank - left or right positioned, but nominally left), and advanced sidemount (dual redundant tanks and regs, one left post and one right post).^{[citation needed]} "Recreational" sidemount unmodified rigs should not be used for tec rec activities, particularly in overhead environs.^[vague] Further, standard reg configurations, split-fins and other recreational equipment is unsuitable for profile manoeuvres, S-drills and other safety skills which necessarily require advanced sidemount configuration.^{[neutrality is disputed][citation needed]} Instruction in sidemount is not just for skilled enjoyment, but for diver safety. This is further explained in a number of international instructional sites.^[vague]

  Configurations

Various harness configurations have been used to side mount cylinders, including:

  Backplate and wing harness

Rigid Hogarthian style backplate and harness systems may be modified by adding butt-plates and optional special sidemount buoyancy compensators. Cylinders are attached to the chest D-rings and either D-rings mounted on the waist belt as for sling mounting, or special purpose loops on the butt plate.

  Specialised sidemount harness

Specialised sidemount harnesses are available^[1] Some of these are only suitable for sidemounting, but others can also back mount a cylinder or twins.

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  Combination sidemount/backmount harness. Front view

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  Combination sidemount/backmount harness. Back view

  Minimalist webbing harness

  Minimalist sidemount harness showing webbing, sliders and D-rings, buoyancy compensator, integrated weight holders and cylinder.

A webbing harness with shoulder straps, waist belt and crotch strap, supporting a variety of sliders and D-rings for attachment of cylinders and accessories, with or without integrated weighting or separate weight belts, and with or without a back mounted buoyancy compensator, which may be attached to the harness, or directly to the diver. Cylinders are usually attached to a shoulder/chest D-ring and waist belt D-ring on each side> Additional accessories may include canister lights and clip-on pockets for small equipment. This style of harness may be off the shelf from an original equipment manufacturer or retailer,^[2] or home made, as most of the parts are freely available or relatively simple to make.

  Comparison between the British style and Florida style configurations

  The original British cave diving belt style sidemount harness and developments

In the UK, cave diving was an additional skill learned by cavers to explore flooded parts of a cave system, rather than divers choosing to explore caves. The early equipment was little more than cylinders fitted with belt loops and slid onto the standard caver's belay or battery belt along with any extra weights needed to achieve neutral buoyancy, and a caver's belt mounted battery pack.^[3] This simple sidemount configuration was particularly low profile and suited to small cylinders, and worked well for low visibility, usually fairly shallow dives, which were often more of a crawl or wriggle though tight confines than a swim.

As penetration distances into caves increased, the basic belt was replaced by a more sturdy harness with shoulder straps and padding on the waist band to distribute the load more comfortably.

A disadvantage of this arrangement is that the cylinders and lead weights must be fitted to the harness before it is put on. This usually required the diver to lie down to fit the harness, and if the cylinders were large, to be assisted to a standing position.

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  Belt loop on cylinder for sidemounting in the British cave diving style

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  Diving cylinders set up for British cave diving sidemounting

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  The original belt style British sidemount harness, with cylinders, weights and battery canister mounted.

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  A diver putting on his belt style sidemount harness. Getting up afterwards often required assistance.

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  A diving cylinder ready for use on a British cave diving sidemount harness.

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  Back view of the modified British sidemount harness.

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  Front view of the modified British sidemount harness.

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  Front view of the modified British sidemount harness with cylinders.

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  British cave diving style sidemounting harness, side view, with cylinders, weights and battery pack

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  British cave diving style sidemounting harness, side view, with cylinders, weights and battery pack

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  Helmet used for British style cave diving.

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  Simplified British cave diving sidemount harness, front view.

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  Simplified British cave diving sidemount harness, back view.

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  Simplified British cave diving sidemount harness, side view.

  Florida style sidemount harness

  Procedures

One of the advantages of the sidemount system is the easy access to cylinder valves, and the protected position they occupy in comparison with most back mount systems, where the valves are relatively vulnerable to bumping against an overhead and being "rolled off" (closed by rubbing against the overhead).

The standard arrangement for sidemount is that all cylinders are independent, and each is provided with a single demand valve, an SPG, and on one or two, a low pressure inflator hose for buoyancy compensator and, if used, the drysuit. This implies that if gas is shared in an emergency, the recipient will be breathing from a different cylinder to the donor, unlike the more usual arrangement with backmount, where both divers breathe off the same set.

In the case of recreational sidemount, with only one cylinder, the regulator would have an octopus demand valve for air sharing and the procedures would revert to much the same as for a single back mount cylinder.

  Compatibility in mixed configuration team diving

The basic sidemount configuration requires different techniques for sharing air to the Hogarthian back mount configuration.^[4] This means that a single set of standardised safety procedures is not possible while diving with team members using Hogarthian back mounted tanks. The UTD Z-system^[4] provides an approach to deal with this problem by quick-connecting two primary gas supply sidemount cylinders to a manifold block mounted behind the shoulders on the Z-system harness, from which long hose primary and necklace secondary demand valves are supplied, reducing the demand valve arrangement to a functional approximation of the standard Hogarthian configuration at the expense of additional complexity of components. Additional stage cylinders are side mounted with independent regulators.

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  Sidemount diver in fairly tight space

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  Left side view of sidemount diver in cave

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  Top view of sidemount diver

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  Sidemount diver front view. Holding reel and DSMB

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  Sidemount diver: detail of top of cylinder

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  Sidemount diver in cave showing 2 cylinders and BC back view

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  Sidemount diver operating cylinder valve

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  Sidemount diver pushing a cylinder in front

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  Sidemount diver near surface

  References

  External links

• http://www.simplysidemount.com
• http://www.gosidemount.com
• http://www.diveph.com
• http://www.sidemount.com.au

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