Case ReportWhile sailing in the Caribbean, three fellow divers and I decided to dive a wreck we had dived during a similar sailing trip a few years ago. I was the most experienced diver (about 25 years) and had assisted with teaching scuba classes for many years while in college. The other three divers had fewer than 10 or 20 dives each.
One diver had a history of an ultrasensitive gag reflex and was uncomfortable with a regulator mouthpiece in his mouth. He had purchased a full-face mask and tried it once before this trip. Should he encounter an out-of-air situation, he would have to completely remove the mask to buddy breathe. I recommended for him to place a regular mask around his neck when diving the full-face rig so if he needed to remove the full-face mask, he would be able to put on a regular mask (something I learned in cave-diving training).
On the day of this particular wreck dive, the diver with the full-face mask did not want to bother with carrying a spare mask. Upon entering the water, the divers were so enthralled with the wreck that they all seemed to go in different directions. I corraled them back together and tried to get the three to follow more closely, but the excitement was getting to them, and they all still wandered a bit far from each other. As the dive leader, I was periodically checking individual air gauges, and all four of us were consuming about the same amount of air. After a few times checking individual gauges, I began to rely on my gauge only to estimate the air for the group.
As my pressure gauge neared 1,000 psi, we were moving along the wreck and gradually ascending from a depth of 80 feet to around 60 feet. I began looking for a mooring line that we could follow up for a controlled ascent. The current on the wreck was strong enough that I did not want to try a free ascent, especially with the number of other boats anchored at the wreck site. I quickly found a mooring line and noted that I was at 900 psi; I thought we all could do a safety stop at 15 feet for a few minutes. As I looked around, I saw the diver with the full-face mask quickly swimming toward me and signaling that he was out of air. I quickly retrieved my octopus as he removed the full-face mask and met me at the mooring line.
Since the diver did not have a spare mask, he had to pinch his nose, close his eyes and concentrate on breathing with water in his face. He was anxious to ascend but was breathing OK, so I controlled our ascent rate. We ascended quickly, but not dangerously so. On the surface he was fine. Upon reaching the surface we saw the other two divers on the mooring line below us making a safety stop.
In retrospect, I should have done several things differently. I should have insisted that the diver with the full-face mask bring a spare mask, I should have forced the group to stay closer together, and I should have been more forceful at monitoring air consumption on all the divers. It turns out that the diver with the full-face mask was consuming quite a bit more air, especially as the tank emptied. On other dives during our trip he was always the first one out of air, and I wonder if using the full-face mask caused a bit higher air consumption.
No adverse effects were noticed by any of the divers, and we made three more dives throughout the week on our boat. On the later dives, the group followed much more closely, and we monitored air consumption quite a bit more often.
CommentsDiving from a small private boat without formal organization when compared with diving in formal groups carries a greater risk of incident, similarly like unscheduled flights on small aircraft in comparison with scheduled flights on large jet airliners. Friends tend to allow more leeway with friends or take more responsibility themselves than what a dive professional would do for a customer.
In this case, the more experienced diver took responsibility for checking the gauges of other divers instead having them do it themselves. He did the right thing in taking on the responsibility of checking his buddies' gauges.
The diver with a hypersensitive gag reflex is at an additional risk of drowning if his reflex occurs underwater. He thought a full-face mask would be a solution, but he did not practice enough using it before the dive trip. In addition, he did not take other precautions to avoid an out-of-air situation. Removing the full-face mask underwater and using another regulator that the diver was not used to could provoke a gag reflex in somebody who is hypersensitive.
Maintaining contact between divers in the group is important, but it does not make up for incompetence of individuals in the group. A diver who cannot read his own gauges should be considered incompetent. An informed risk assessment for the group of divers like this one would have precluded diving in remote locations. Divers failed to assess the risk properly and exposed themselves to undue risk. The fact that "nothing serious happenned" does not justify such behavior.
— Petar Denoble, M.D., D.Sc.