But in reality special training is needed for many other types of diving as well. Nitrox, deep, ice or wreck all require training beyond basic open water to be safely accomplished. Gear Modifications - One of the first exercises in cavern diving training is to have the instructor evaluate your gear. Remove or minimize any items that can catch lines and cause entanglements. Add a safety reel to each diver, and a larger primary reel for each dive team.
Basic reels are best for the job.
Various Sizes A 7' hose on the primary regulator is required. Old standards allowed 5', but 7' is the normal configuration. It allows your buddy to lead you out of a cave, through narrow openings, while breathing off your air. The hoses and guages must be routed to avoid problems sharing air. An air sharing or 'S-Drill' is conducted repeatedly during the course to verify no problems exist in deploying the backup reg.