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Sidemount.. It’s not just for Cave Divers Anymore

For a generation, sidemount diving has been a staple for serious cave divers.But these days, more and more cavers, and even non-cavers, are wearing their bottles at their sides.

By Steve Lewis

There are probably a handful of things happening in the dive industry that we could peg as the latest and greatest idea or innovation. I’d add developments in lighting technology, dive computers, and thermal protection to my list, but surely the hottest trend right now has to be sidemount diving (wearing a totally independent cylinder and regulator system slung on each side of the diver’s body). Any technical diver old enough to remember Friends as a new television series may also remember when sidemount was a very specialized technique with a small and almost cliquish fellowship restricted to England’s Mendip Hills and North Florida’s Karst Country. Finding sidemount training and uncovering a mentor to help you progress in the technique was a lot like joining a medieval secret guild; you had to know someone, or have a solid recommendation from an existing initiate; and those outside the circle suspected witchcraft.

In the early days, gear was centered on mostly hand-sewn adaptations of the classic open water stab-jacket style BCD, a few welded bolt-snaps, and lots of bungee cord. And the application was ALL about exploring small silt passages; what a good friend of mine describes as “a mighty tight squeeze.” But that was then and this is now. Times and attitudes have changed. After all, back when NBC first aired Friends, the largest sport diving agency had branded TDI’s popular nitrox courses as too complex for the average diver and decompression diving was totally verboten. Now of course, nitrox is the usual choice for most divers regardless of which flavor C-Card they earned as an open-water diver, and most weekend charter rosters include at very least a couple of divers planning staged deco; and often a full boatload of weekend warriors all planning for a deep, long dive. These days, it seems that sidemount really has come out of the closet. To begin with, gone are the hand-wrought BCs. Mainstream manufacturers such as Armadillo, Dive Rite, Hollis, OMS and Oxycheq are producing beautifully crafted harness, butt-plate, wing combination’s specifically for sidemount diving. Cam bands – used to convert regular tanks to sidemount tanks in an instant – are in several manufacturer’s catalogs. And plenty of stores sell “regulator conversion kits” – essential an assortment of custom-sized hoses and 90 degree fittings designed to help make the transition from traditional backmounted doubles to sidemount a one-step process. Perhaps best of all, sidemount instruction is readily available and several agencies, SDI and TDI among them, offer specialty ratings and sidemount options for their existing curriculum from Intro-to-Tech to Advanced Trimix, in addition to the more traditional cavern and cave.

The real kicker perhaps is that sidemount divers are beginning to pop up on dive boats and at open-water sites. On a brilliant Saturday morning at a popular quarry in Ohio this past summer, there were a handful of “tech divers” wearing sidemount kit. On local charter boats too, sidemount divers are starting to make a showing, especially among divers who are trained to execute wreck penetration. It’s not just for cave divers anymore. Lamar Hires, head of Dive Rite and one of the early promoters of sidemount diving, files the reasons for using sidemount into two main categories – Lifestyle and Mission Specific. Let’s use Lamar’s definitions as a starting point to explore the overall features and benefits of SM diving.

The ubiquitous North Florida Cave Diver’s Rig consisting of a backplate, simple harness, wing and manifolded doubles, began to establish itself as the gold standard for technical divers sometime in the early 1990s. By the time TDI opened its doors in 1994, this kit configuration, with long hose on the right post, backup regulator and SPG on the left, and a generally minimalist approach to gear selection was what technical divers wore almost universally. But its one-size-fits-all approach and promotion as the universal solution to all dive applications, has lost some of its lustre over the years and technical divers have looked at other options with an open mind. With a sidemount configuration, the tanks are carried independently of each other and can be attached to the diver in the water or near to the water. This makes pre- and post dive prep easier on the diver’s back and knees, since the strain of one tank is about half of the strain of two. A good buddy of mine swears that diving sidemount has helped her enjoy dive trips more and use aspirin less! “There’s no way to describe how good it feels to take all my tanks off in the water, attach them to an equipment line and then walk up that boat ladder wearing nothing heavier than my harness and drysuit,” she says.

Also, the sidemount diver’s gas supply is fully redundant and carried in completely separate systems each with a first and second stage plus an spg (and usually a LP hose). This offers similar gas management options as a set of doubles (some argue more options than doubles) but the valves and first stages are within full sight at the diver’s side rather than behind her back. This obviously makes options during either simulated or real situation shutdowns very simple! There is never any guessing which first stage is giving the diver grief… real or otherwise. This alone has many SM divers arguing that theirs is the safer option in the case of a free-flowing second stage, runaway wing inflator, runaway drysuit inflator or other gas leak. Which is a stance I agree with. The final “lifestyle” benefit revolves around the easy of travel and sidemount diving. Number one: A SM harness has no heavy backplate and therefore helps keep luggage within airline baggage allowance. Number two: renting “bottles” at one’s destination is easy since standard scuba cylinders can be got ready for service as sidemount primary tanks quickly and with a minimum of fuss and very little extra gear. The addition of a couple of cam straps to the traveler’s luggage, makes conversion of almost any sized scuba cylinder the work of a few minutes; in fact standard stage bottle kits can be made to work in a pinch

Going back to the genesis of sidemount diving, we arrive at the original reason to move one’s primary cylinders from one’s back to one’s side; low ceilings and flat bedding planes. While this reality has informed the decision making of cave divers for more than a generation, more and more wreck divers feel that sidemount offers real advantages inside a wreck. The interior of most wrecks, even those intentionally sunk and cleaned out ahead of time, present special challenges because of the likelihood of entanglement with overhead cables and other debris. The possibilities of “unfriendly interaction” with all this mess are pretty high, and a staple of the traditional Advanced Wreck class is a session learning the best techniques to free oneself or a buddy from the clutches of a couple of metres of electrical wire and rotting wood caught in the traditional manifolded doubles. Not to say that entanglement in this sort of situation is a non-issue in sidemount, but if we look at it logically, there simply is not the number of potential line-traps behind the diver’s head when he is wearing sidemount kit. I also find the inherent lateral stability against the effect of roll wearing a sidemount setup is a huge benefit when scootering; but perhaps that’s a story for another day.

All this said, it is important to remember that no single kit configuration is right for ALL applications. Sidemount is not the silver bullet and is certainly not the best option always and everywhere. However, a growing number of tech and sport divers are finding SM an interesting and enjoyable way to dive in many different environments. A good workshop is a great way to learn the technique and to find out the best ways to route hoses, hang lights, and configure deco bottles, but having a very flexible alternative to the traditional tech diver’s kit for many divers is worth the extra effort.

Steve Lewis is an active instructortrainer for TDI and a strong advocate for the application of sidemount configuration for ALL open circuit divers who venture into an overhead environment. In addition to running SM courses and clinics on a regular basis, Steve is currently working on a new book about technical diving called Twelve Dialogues with Doppler.

Originally published in the Underwater JournalDownload your free copy now.


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