Proper set-up of your side mount cylinders is essential to maintain proper buoyancy and streamlining. Cylinders mounted on your side must be positioned correctly for ease of use, safety, comfort, and proper swimming techniques. If your cylinders are hanging low and riding on your torso, the ability to navigate tight restrictions is lost and your streamlining is gone. Knowing how to rig your cylinders is essential for keeping them stationary in their correct position on your sides.
The cam strap
The cam strap is used to secure the tank to the lower or butt portion of your side mount harness. The cam strap must have a clip attached, which is used to clip off to your harness. The cam strap must also be positioned properly on your tank. To position the cam strap, slip it over the cylinder and tighten it by pulling the strap tight and closing the cam buckle. The distance from the top of the cylinder valve, where the cam strap is placed, varies depending on your chest length. A good rule of thumb is to measure from your armpit to just below your belt line. Place the cam strap the same distance from the top of the valve.
Proper tank buoyancy is essential for proper trim and streamlining. Some types of cylinders, such as aluminum tanks, become buoyant as they are depleted. For these cylinders, you may need to attach hard weights to the cylinder cam straps in order to compensate for the buoyancy change. Hard weights can also be added to the cylinder cam straps to offset the buoyancy of wetsuits and dry suits. If additional weight is needed due to dry suit buoyancy, a standard weight belt can be used under your harness.
Cylinder bungee and right and left post cylinders
For proper streamlining, your cylinders need to be snug and up and under your armpits. The cylinder bungee on your side mount system is used to pull the valve of the right and left cylinders into your armpits. The bungee or rubber tubing goes over and around the cylinder valves, pulling them tight against side. You may be using rubber tubing or bungee cord to accomplish this, but whichever method you use, make sure your cylinders are properly fitted under your armpits.
For your cylinders to fit correctly under your armpits and to make it easier for you to access your cylinder valves, a right (standard) and left post valve is recommended for side mount cylinders. These are the same valves as used on a set of double cylinders without the cross over bar. The right post valve should be used on your right side, and the left post valve should be used on your left side.
Positioning the right and left cylinders on your body
Hose configuration and placement
Proper regulator hose configuration and placement is also essential for safety, ease of use, streamlining, and access. The diagram below illustrates the proper hose placement for side mount cylinders. A long hose can be used on the left cylinder if desired and pulled up and around the back of your neck.
Ninety-degree elbow adapters can be used on the second stage regulators to prevent jaw fatigue from sharp hose angles.
Custom length hoses for the LP inflators and regulators can be designed to further streamline and simplify the system. Loose hoses should be tucked under the waist belt to further streamline your rig.
The second stage regulator that is not in use should be clipped to the upper left D-ring. When changing second stages underwater, unclip the regulator not in use, exchange, and then clip the exchanged regulator back onto the left upper D-ring.