When CCR divers and open circuit (OC) divers dive together, they are referred to as a mixed team. OC divers are often shy about asking a CCR diver how procedures may differ so it is up to you to ensure that gas management and emergency procedures are clear prior to entering the water.
1. Orientation
Show how the rebreather is donned and how it can be removed. Demonstrate how the wing is inflated and, if it is attached to an onboard cylinder, discuss how this limited supply could be easily exhausted during a rescue. Determine whether oral inflation of the wing by the buddy is possible. Discuss various warning lights, especially those that indicate life-threatening oxygen levels and discuss how developing problems can be recognized. Describe the significance of a vibrating mouthpiece, if applicable. Describe how and when it might be necessary to close the loop and why preventing a loop flood is critical for buoyancy.
2. Gas Planning
Inquire about the air consumption rate of the OC diver and plan appropriate gas volumes to ensure safe ascent using your bailout gas. Select bailout gas that is compatible with the OC diver’s decompression plans and plan decompression gases to accommodate all emergency scenarios.
3. Complete a Safety Drill
Describe what to look for during the bubble check, then rehearse gas-sharing scenarios prior to entering the cave. Determine whether sharing a long hose or passing off a bailout bottle will be a better decision.
Conclusions
If CCR divers strive to maintain a high level of conservatism and independence with their bailout gas, then safety and flexibility are benefited. Self-rescue is assured and buddy rescue of a CCR or OC diver is also probable. The goal of the orientation is not to teach the OC diver how to run a rebreather, only how to share gas and handle emergencies that may occur.
