Sidemount Diving Configuration – No longer just for tech divers.

by Scott Boyd,

Sidemount diving has become very popular with main stream divers of late. It has moved from the realm of the “crazy exploration cave diver” crowd to a configuration that has many benefits for both open water and technical divers. Originally designed to allow cave and sump divers to pass through really small restrictions, the system has become widely accepted and many dive equipment manufacturers now produce and sell sidemount gear.

The primary benefits of a Sidemount configuration (where tanks are slung in a streamlined position along side of the diver) are that it is extremely stable, comfortable and is generally much safer than a traditional back mount configuration. The stability comes from having the two tanks next to your torso, which puts the combined center of gravity of the diver and tanks right in the solar plexus of the diver. This naturally puts the diver in a trim position and allows him/her to swim at any angle desired with no effort. This is so easy in fact that we often swim upside down while in caves so we can admire the decorations on the ceiling without straining our necks. Any of you that have seen the Steve Bogarts videos at would be amazed at how easy it really is.

The increased safety is provided by having two completely independent cylinders of breathable gas that have their own independent regulators attached to cylinder valves which are both easily reached and easily seen by the diver. This makes it simple to handle regulator/valve/tank failures as you can see what the problem is and can easily reach or inspect the tank/valve/regulator. There is no more fumbling around behind your head shutting down a sequence of valves trying to isolate the failed part.

Technical divers normally use the rule of thirds to insure that there will always be sufficient gas to safely exit. This is also applied to sidemount where frequent gas switching (between the two tanks) always insures that even with the complete loss of all the gas in one tank, there will still enough in the remaining tank to exit safely.

An additional benefit to a sidemount configuration is that you can carry your single cylinders down to the water’s edge, one at a time, and then clip them on in the water. This is a very nice feature for us old farts that have bad backs from hauling a pair of steel tanks up and down our local beaches and boat ladders!

When diving in mixed teams of sidemount and backmount divers, most sidemount configurations will include a long hose on one regulator. This makes it easy for the sidemount diver to donate gas to an out-of-air backmount diver. This type of air sharing works the same as your standard s-drill with the exception that the out-of-air diver signals (hand slashing across the throat) and the sidemount diver then hands the diver their second stage with the long hose. They may or may not be breathing from the long hose at the time, so may have to quickly switch regs. Should the out of air diver panic and simply pull the working regulator from the divers mouth, it will still work, but the short hoses tend to be very short, so they’ll be getting up close and personal until the long hose is deployed.

In sidemount only teams, the long hose is often removed since the chance of anyone losing two completely independent systems is so remote that self-rescue is almost insured and the last resort option would be to swap cylinders with a team mate if all else fails (however, this is much more difficult than it sounds). There are a lot of cave specific benefits to a sidemount configuration that don’t translate to open water, so I’ll skip those in favor of some my recent open water experiences.

Shore diving while sidemounting here in the Northwest works very well. You carry your steel (or aluminum) tanks to the waters edge one at a time and then clip them to your harness and have a great time. On exit, you unclip the tanks in shallow water and then can carry them up to the truck one at a time.

Boat diving on the other hand is not the strong suit for this configuration. Clipping the tanks in place on the boat makes you very wide and makes it difficult to fit through transom doors to get into the water. Clipping steel tanks in place while floating in the water comes with its own challenges. Once one tank is clipped on to your side, the heavy weight will make you roll sideways and makes the second tank an uphill battle. Oh and be sure not to ask your wife to help you hook up the second tank. She may think the current is pulling you away from her, and grab your only working regulator right out of your mouth. Just don’t ask me how I know that a quick pop on top of her head will make her release your second stage so that you can recover it and breath again. I guess we never truly stop learning!

EDITORS NOTE: SSI recently started offering recreational sidemount diving as a specialty and the PADI course is coming within days. For more information see the following: and


ScubaGadet welcomes Scott Boyd, our new tec/wreck correspondent. Scott, along with Jeff Carr, is the author of Northwest Wreck Dives. An excellent and enthusiastic photographer as well as scuba diver, Scott’s website,, is a treasure trove of photos, as well as information on diving the Pacific Northwest and locations around the world, cave diving and more.  You can read more about Scott and Jeff here.