The greatest danger in scuba diving? You may be surprised!
I learned to scuba dive about 20 years ago. I was certified by NAUI (the National Association of Underwater Instructors) in Chicago, Illinois, and did my check-out dive in a quarry in Wisconsin. It was dreary and raining. The water was cold and the scenery sorely lacking: we dove down to the top of an abandoned school bus! I did just fine as long as I had air; strap a tank on me and I can dive for hours.
But take away the air, and make me go underwater, and I want to surface immediately. It was a huge accomplishment for me to complete my surface dive (where you go fairly deep with no air, just a snorkel, then surface and clear out your snorkel to continue breathing on the surface) although I bit through at least one snorkel before I was through! I blamed it on the cold but the truth is that I was very tense.
I did a fair amount of diving before I had children and hung up my fins. I dove the Blue Hole, going down 120 feet and getting “narced” (nitrogen narcosis, where you feel “drunk” underwater). I did open water diving with hammerhead sharks off CoCos Island.
My buddy and I were swept away in a current in the middle of the ocean, but so was the dive master and the rest of the dive team, so the boat followed us and we were just fine. I dove with sea turtles, manta rays, eels, and sea horses. I’ve done night diving, which was surprisingly noisy as the fish nipped the coral as they fed. I loved scuba diving. It was a magical, liberating, beautiful experience. But I never forgot how dangerous it was and that it could kill you if you weren’t careful and aware.
I tend to be fairly risk averse so I did a lot of nerdy research as I prepared for my first real diving trip. I wanted to know all I could about how to avoid a scuba diving accident. I learned something that I thought others might find very interesting: that diving as a threesome is the single most dangerous thing you can do when scuba diving! More dangerous than cave diving, ice diving, open water diving, or diving alone! (If my memory serves me right, this result is based on Canadian data on scuba diving accidents, injuries, and deaths. )
It seems hard to believe at first but I think I’ve got it figured out. For one, it happens fairly often. I’ve seen it on many diving trips: someone comes alone or their buddy can’t dive, so they join up with a buddy team. Dive instructors suggest that people join up in threes rather than dive alone. Or the dive instructor joins a pair.
Two, I think people feel safer in a bigger group. Three, I think that when you are diving alone, or cave or ice diving, you are very aware of the risks and take extra precautions to avoid the dangers. But diving in threes doesn’t “seem” risky, so everyone relaxes. And people tend not to clearly lay out ahead of time who is watching whom at the bottom of the ocean where seconds can make the difference between life and death. And that is likely where the danger lives: with a buddy system, there is no question about who is responsible for whom. I am watching out for my buddy, and he is watching out for me. Period. But when diving in threes, the pairing gets muddled. Are you watching out for two people? Are they watching out for you, or for each other? And inevitably someone gets overlooked. And accidents happen.
So, if you ever take up scuba diving, have a blast! But don’t ever dive in threes!
by Sherry Jarrell
Learning from Dogs 
Exactly! Investing in 3As AAA seems safe so everyone relaxes while when investing in something unrated you are much more careful.
Ergo higher capital requirements for banks for anything that seems to carry lower risks and lower when precaution is self-ordained… just the opposite of today!
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But let’s not hold our breath on the expectation that things will change for the better! Looks like we all have to go through economic collapse stage two for the lessons to really come home.
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This is very interesting post, Sherry. There may be significant opportunities for improvement in other fields through better understanding of the relationship between safety record and the number of people involved.
On the specific point about “buddy systems”, these operate well in other disciplines too: for example, aviation and the police. Perhaps there is information about how these systems perform with larger groups.
In aviation, despite some notable exceptions, it is generally considered that a “team” of three (or more) pilots do not necessarily perform well. Also, they need not all be pilots: not so long ago, many scheduled flights operated with two pilots and a flight engineer; and the military aircraft which operate with two pilots, yet the commander of the aircraft is a third person (think: tank crews; the driver drives!). In aviation, specific training in “crew resource management” in multi-crew situations is required, some of this is directed specifically at the avoidance and the handling of emergencies.
Also in the military, there are examples of systems of pairs, and pairs of pairs, which allow teams of 2, 4, 8 and so on to be assembled rapidly; I believe that this is particularly common in the special forces.
A more general example exists in road safety. A high proportion of the people who die in road accidents are in cars driven by inexperienced drivers. There is also a correlation between the probability of an accident and the number of people in the vehicle. Yet, as far as I know, there are no efforts to introduce restrictions on the number of passengers allowed to be carried by drivers dependent on their experience.
No doubt, this aspect is worth consideration in other situations which are less hazardous but nevertheless important. For example, in software development, there are many advocates of “XP” (eXtreme Programming [not the Microsoft operating system!]) which involves “pair programming”, in which two people work together in two alternating roles, one leading and the other monitoring.
Does anyone know of other fields of application?
John
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