Sidemount Stage Rigging for Cave Diving
Why Stage Cylinders Behave Differently in Sidemount
Problems with Poor Rigging
Why Trim Changes During Gas Use
Why Stage Cylinders Behave Differently in Sidemount
Most divers use standard AL80s for stage cylinders. They are lightweight and only add 4 pounds/1.8 kg of negative buoyancy. However, they are also very bottom light when the gas inside of them is breathed. The valve and 1st stage regulator add weight to the top of the cylinder, but there isn’t anything to do the same on the bottom. Some divers use weights along the cylinder body, but that comes with its own issues.
Problems with Poor Rigging
Rigging stage cylinders properly is the most effective thing you can do to get them to behave properly. Many divers start out using standard stage cylinder rigging. That only results in cylinders that are not streamlined. They either hang too low, or they float up and risk damaging the cave ceiling. The cylinders must be firmly secured to minimize movement away from the body.
Why Trim Changes During Gas Use
Gas has weight. A full AL80 has about 4 pounds/1.8 kg of gas in it. That means that as you breathe from the cylinder, the cylinder becomes more buoyant. While the cylinder may lay flat on the bottom when heavy, if you remove your cylinders in the water, you have probably noticed that it sits vertically at the end of the dive. This is happening throughout the entire dive as you breathe from the cylinder.
Where to Learn the Full Rigging Method
The full step-by-step stage rigging configuration is covered in detail in Sidemount Diving The Almost Comprehensive Guide
Related Articles
How to Choose Sidemount Cylinders
How to Properly Manage Gas in Your Cylinders
How to Choose Proper Hose Lengths
Sidemount Cylinder Rigging: What Matters Most
How to Rig Top Mounted Stage Cylinders
Common Modifications of the Dive Rite Nomad
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