What makes diving in overhead
THe Single Greatest safety factor in open-water diving is that, no matter what happens (equipment malfunction, loss of breathing gas supply, loss of buddy, etc.), open-water divers always have the option of making independent, controlled emergency-swimming ascents (ESAs). Two factors make this possible:
- Open-water divers who remain within the recommended depth limits for recreational diving are usually less than 100 feet from the surface and never more than 130 feet from air. Making emergency swimming ascents would be significantly more difficult if recreational divers ventured further than this.
- With the exception of certain recreational-level specialty diving activities (cavern, wreck and ice diving), open-water divers are never under overhead obstructions that would prevent them from making an immediate and direct ascent to the surface.
Obviously, any time divers place a barrier between themselves and the surface, they compromise their ability to make controlled emergency swimming ascents. Thus, by entering overhead environments, they deprive themselves of recreational diving’s greatest safety factor.
Note: NSS-CDS and NACD training standards actually allow Cavern Diver course students to penetrate as much as 200 feet from the cavern entrance. This was done to account for the size some of the huge caverns found in Mexico’s Yucatan Peninsula. These caverns, however, have numerous air pockets in their ceilings. So, while a cavern diver at these locations might be as much as 200 feet from the cavern entrance, he or she is never more than 130 feet from air.
ow do cavern and cave diving differ from one another? »