November 19, 2008: Check out dive for Peter and Bill

Submitted by Robin Ellwood on November 18, 2008 - 10:15pm.

This morning's activities included a check out dive on surface supply for Peter and Bill. We met up with Rob and Steve - the "dive guys" (who run the diving program in Antarctica), got suited up and headed out to the pier in front of McMurdo. Rob reviewed how the surface supply connections were set up, how the communications system works, safety procedures and rules, as well as what to do in case of a diving emergency. We always have a supply of oxygen available in case a diver gets decompression sickness, but it should never really be needed. Everyone dives very carefully and stays within the "no decompression" limits.

Decompression sickness is a concern for divers. As divers go into deeper water, pressure builds up. As the pressure increases, more nitrogen can be forced into the divers tissues. As long as the diver stays within the time limits of the dive tables, decompression sickness should not be a concern. The dive tables tell how long divers can stay safely at each depth without having to worry. Staying within "no decompression" limits means that the diver does not exceed that time limit. In this scenario, the diver can simply do a nice, slow, ascent to the surface with no worries. If, however, the diver stays longer than "allowed," he or she must do a "decompression stop" at certain depths - typically about 10 feet, or just at the bottom of the ice. This allows excess nitrogen that has built up in the divers system to degas safely. Without such a decompression stop (or "safety stop"), if the diver ascended directly to the surface, those excess nitrogen bubbles could be released into tissues and/or the bloodstream of the diver; obviously this would be a bad scenario! There will be NONE of that going on! We dive very safely!