Pre-Dive Diver Negligence

The possibility of equipment failure haunts every sport diver, but the annual DAN report regularly reveals poor maintenance is the cause of most equipment failures. For example, here are a few recent cases with a range of equipment failures that show even the most experienced divers can make a life-threatening error if they fail to check every last element of their gear.

Two cases involved divers using doubles. In one, a very experienced diver found that one of the two screws that secured his wing to his backplate was not tightened sufficiently, causing the whole rig to risk coming apart at depth. Another diver using doubles dived with the manifold closed. While his pressure gauge was attached to his left tank and constantly showing almost full, save for what he used to inflate his BC, he was breathing from the right tank.

And then there are self-induced hose problems. During a dive, a diver found that her 13-year-old high-pressure hose had developed a hairline crack along its length. Since there is a restrictor in the high-pressure port of a first-stage, the gas loss was not as dramatic as with a regulator inter-stage hose failure. But that happened to another diver who discovered the problem only when his regulator hose ruptured close to the second-stage. His buddy reported it had not looked right before the dive, but they had done nothing about it.

One diver turned her tank valve off, then opened it a quarter of a turn, the result of having been taught a bad habit that came back to bite her. The pressure gauge fluctuated as she breathed, and breathing became more difficult as she descended. At 55 feet she couldn't get air, resulting in an air-sharing ascent with her buddy. It's a problem that has been reported more than once. Always open a tank valve fully.

One diver had to abandon a rented regulator and resort to sharing air to make an emergency ascent from 141 feet. Marty McCafferty comments on behalf of DAN, "Some dive shops do not maintain their rental equipment well, and some regulators [intended for training] do not perform well at depth, even if they are perfectly maintained."

Another diver had an O-ring fail on an inexpensive third-party swivel connection to his regulator's second stage, with a consequent dramatic loss of air.

When a diver had regulator problems during his first dive of the day, he used another regulator for the second. Both regulators had computers attached, and the second computer had no way of tracking his nitrogen absorption from the first dive. He thought that because it was an identical computer, it wouldn't matter. So much for understanding computer theory.

Casualness leads to error. A diver reported starting a dive with an empty tank, thanks to no pre-dive check -- a page one mistake.

Air sharing can have unintended consequences, too, as two divers found out when their hoses became entangled when one diver with a Hogarthian [long hose] gear configuration helped an inexperienced diver deal with a free-flow. Instead of having the donating diver pass the hose over his head, the less-experienced diver pulled on it, causing the donating diver's secondary regulator to become entangled and difficult to reach.

A diver had a BC inflator stick open, resulting in a rapid ascent, luckily without ill effect. Another had a similar problem while diving under ice, and the cold prevented him from disconnecting the hose. He suffered a ruptured eardrum. A corroded auto-inflator stuck open and caused another diver's involuntary ascent.

A diver made an unexpected rapid descent when the inflator control became separated from its corrugated hose, thanks to a defective single cable tie. Any air he blew into the hose simply siphoned out.

In these cases, the divers handled the problem and survived. Divers who can't handle the problems and panic don't survive. As Peter Buzzacott observed in the DAN case summaries, "Rarely does a single issue lead to a near miss."

- John Bantin