A. Purpose
1. 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.
2. 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.
3. 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
1. Must be qualified as an Advanced Open Water Diver or equivalent.
2. Must provide proof of a minimum of 10 logged dives.
3. 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
1. 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.
2. A minimum of 90 minutes of bottom time must be completed in the overhead environment within 4 to 6 dives.
3. Land Drills:
a. Use of guide lines.
b. Following guide lines with and without vision.
c. Simulation of silt-outs, etc.
C. Equipment Requirements
1. A dual-outlet (H or Y) valve is recommended.
2. A 2-meter long hose is to be attached to one of the second stages on the primary gas supply.
3. It is recommended a long hose (1.5 to 2 meters in length) for gas sharing be carried by each diver.
4. Primary reel and/or safety reel.
5. Two lights.
D. Program Limits
1. There may be no more than 4 students per Instructor inside the overhead environment.
2. Unobstructed exit/surface light must always be visible.
3. No dives may be conducted to depths greater than 130 fsw (39 msw).
4. 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.
5. All appropriate safety or required decompression stops must be performed.
E. Water Skills Development
1. A confined water session must be completed before conducting any dives in an overhead environment.
2. Become proficient in the following propulsion techniques: modified flutter, modified frog, modified dolphin and standard shuffle kick.
3. Swim a distance of 75 feet (23 meters) without a mask.
4. 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.
5. For wreck dives, practice deployment of lift bag.
6. Determine SAC rate and RMV.
7. Practice use of reel and line.
8. In the overhead environment, practice running the line and making tie wraps.
9. With eyes closed, follow a guideline in the overhead environment.
10. Share breathing gas while following the guideline, both with eyes open and with eyes closed.
11. Perform an "S" drill prior to commencement of all dives.
