Scuba Drowning Deaths And Those Who Survive

On the surface, panic or loss of consciousness rarely leads to death, but underwater, death from drowning is often the result. In fact, panic and loss of consciousness account for up to 80 percent of recreational scuba diving deaths.

Some Australian researchers, Drs. Carl Edmonds, Douglas Walker, and Brian Scott, felt there was more to learn about the causes of these dive deaths and ways in which they might be prevented. They analyzed 100 drowning deaths and 48 neardeath accidents in which the diver survived. Their report, which appeared in the South Pacific Underwater Medicine Society Journal, forms the basis for this article. We’ve included the facts from their analysis while adding some of our own commentary.

Water Conditions

More than half the drownings and 60 percent of the near-drowning survivals occurred in calm water, although in 4 percent of the deaths, these calm conditions later deteriorated. Moderately rough seas were associated with 25 percent of deaths and 40 percent of the survivals, and very rough conditions — hardly ideal diving conditions — were associated with 15 percent of the deaths. Currents were associated with 46 percent of the deaths and 31 percent of the survivals. Almost two-thirds of the deaths occurred at depths of ten feet or less; half occurred on the surface or while ascending.

Air Supply

In all but the most extreme circumstances, there is no reason for a diver to allow his air supply to get unnecessarily low or to run out of air. Yet 60 percent of the divers who didn’t survive either were completely out of air or ran so low on air that they were unable to make a safe ascent. Survivors were more likely than non-survivors to have retained enough air to cope with an emergency. Sadly — or even stupidly — it was common for divers in both groups to ignore or pay little attention to their air gauge. (I’ve often thought that one way to prevent this is to ask divers who sign up for scuba classes if they’ve ever run out of gas while driving. Answer yes, and you’re promptly shown the door.)

Eight percent of deaths and 13 percent of survivals were attributable to divers failing to turn on their tank valve. Although the diver had plenty of air, it was not available. Some divers who either jumped off a boat or kicked down from the surface descended as much as 10 feet before they became aware that they couldn’t suck air. In none of these cases had the diver breathed from the regulator before getting in the water, nor had there been an equipment check or a buddy-check of equipment prior to descent. In a few cases, after checking the tank pressure and turning it off, divers failed to fully turn their air back on, resulting in a partial restriction of the air supply that became obvious only later in the dive or at depth.

Buoyancy Compensators

A filled BC can keep a diver from drowning: a floating diver with his head out of the water does not drown. Yet, sizable numbers in both groups (52 percent of deaths, 32 percent of near-drowning survivals) failed to inflate their buoyancy compensators. In a few instances, the buoyancy compensator failed to inflate for mechanical reasons; this accounted for 5 percent of deaths and 8 percent of neardrowning survivals. However, it is noteworthy that 12 percent of the deaths involved divers who had inflated their buoyancy compensators, and in the survivor group, the BC was inflated by the victim or rescuer in twice as many cases as in the fatality group.

Weights

Study after study has found that divers are reluctant to drop a weight belt. After all, they cost money, and the divemaster or guide may chide divers who drop a belt. But a dropped belt may mean a fast ascent and could prevent drowning. In this study, 86 percent of the deceased divers and 74 percent of the survivors had not dropped their belts. A few unfortunate divers dropped their belts but then became entangled (deaths 3 percent, survivals 2 percent).

When the victim and buddy were both in difficulty (usually because of an air shortage), the overweighted diver tended to be the one who died, even if he was not the one whose problem developed first. Out of 14 such cases, 12 of the survivors were the buoyant diver.

— Ben Davison

Next issue: Solo Diving, Buddies, and Buddy Responses