A. Purpose
- This Program is designed to develop wreck and cavern diving skills within the limits of light penetration and to insure that divers are aware of self-responsibility and capable of risk management in overhead environments. The Program may be taught using either air or EANx.
- If combined with the EANx Diver Program, or if the student is already qualified as an EANx Diver, the student may use a mixture of EANx in the range of 21% through 40% oxygen.
- If combined with the Advanced EANx Diver Program, or if the student is already qualified as an Advanced EANx Diver, the student may use a mixture of EANx in the range of 21% through 40% oxygen as a dive gas, and safety or required decompression stops may involve EANx mixtures of up to 50% oxygen.
B. Prerequisites
- Must be qualified as an Advanced Open Water Diver or equivalent.
- Must provide proof of a minimum of 10 logged dives.
- Must be a minimum of 15 years of age with a parent or guardian authorization, or a minimum of 12 years of age for Junior Diver qualification, or a minimum of 18 years of age without guardian approval.
C. Program Content
- A continuous guideline that allows for a safe exit to the entrance will be in place at all times during training in a wreck or cavern environment.
- A minimum of 90 minutes of bottom time must be completed in the overhead environment within 4 to 6 dives.
- Land Drills:
a. Use of guide lines.
b. Following guide lines with and without vision.
c. Simulation of silt-outs, etc.
C. Equipment Requirements
- A dual-outlet (H or Y) valve is recommended.
- A 2-meter long hose is to be attached to one of the second stages on the primary gas supply.
- It is recommended a long hose (1.5 to 2 meters in length) for gas sharing be carried by each diver.
- Primary reel and/or safety reel.
- Two lights.
D. Program Limits
- There may be no more than 4 students per Instructor inside the overhead environment.
- Unobstructed exit/surface light must always be visible.
- No dives may be conducted to depths greater than 130 fsw (39 msw).
- The Rule of Thirds must be applied from the point of entering the overhead environment until safe exit from the overhead environment portion of the dive.
- All appropriate safety or required decompression stops must be performed.
E. Water Skills Development
- A confined water session must be completed before conducting any dives in an overhead environment.
- Become proficient in the following propulsion techniques: modified flutter, modified frog, modified dolphin and standard shuffle kick.
- Swim a distance of 75 feet (23 meters) without a mask.
- Swim in a simulated out-of-air situation (without breathing, and exhaling slowly) for a distance of at least 45 feet (15 meters), and commence gas sharing. While gas sharing, continue to swim for a distance of at least 200 feet (60 meters) while maintaining a swim rate of approximately 60 feet (18 meters) per minute.
- For wreck dives, practice deployment of lift bag.
- Determine SAC rate and RMV.
- Practice use of reel and line.
- In the overhead environment, practice running the line and making tie wraps.
- With eyes closed, follow a guideline in the overhead environment.
- Share breathing gas while following the guideline, both with eyes open and with eyes closed.
- Perform an "S" drill prior to commencement of all dives.