Accident Analysis

Dialogue One (A rejected chapter from The Six Skills, Decompression Curve and Other Discussions)

Chalking the Foul Lines: Dying because of recklessness does not constitute an accident.
Based on a dive safety presentation first delivered 1999

“Too often the shortcut, the line of least resistance, is responsible for evanescent and unsatisfactory success.” Rabbi Louis Binstock (1896-1974)

The Niagara Escarpment is the limestone-capped rim of a huge bedrock bowl running west and north from Rochester, in up-state New York, through the Canadian province of Ontario, across the top of Lake Huron and then curving back into Michigan, Wisconsin and Illinois. On its way from the southern shores of one Great Lake to frame the western shore of another, it forms the cliffs of Niagara Falls, dissects Ontario’s wine county and forms the tree-covered spine of the Bruce Peninsula.

The escarpment submerges there, at the end of the Bruce Peninsula, and for about 50 kilometers, until it surfaces at Manitoulin Island to continue its arc back through the United States, there is a navigable waterway connecting the main body of Lake Huron with the expansive waters and approximately 30,000 islands that constitute Georgian Bay. This waterway is part of the network of commercial shipping lanes that opened North America to European settlers, but more important to divers, thousands of ships, from simple gaff-rigged fishing boats to gigantic steel freighters passed through there, many of them meeting their end in the process.

At the southern end of this gap at the very tip of “The Bruce” is a small fishing village called Tobermory. On Highway 6 just at the edge of town is a sign welcoming visitors to “The Scuba Diving Capital of Canada.” While the local chamber of commerce may be guilty of optimistic overstatement, the clear, cold water off Tobermory, and Fathom Five National Underwater Park, attracts divers to the area by the boatload in the summer and fall. It’s a rite of passage for sport divers from southern Ontario and neighboring American states to make the long trek north to dive on one of twenty or so shipwrecks broken and torn apart on the sharp rocks that ring that coast.

In many spots along the coast of the Bruce, vertical dolomite cliffs take an almost vertical plunge 100 metres or more beneath the waves. Outside the boundary of the national park, there are also a few wrecks far too deep for sport divers but appealing enough to bring technical divers to the village in great numbers. Oddly enough, these deep and somewhat remote dive sites account for very few diver fatalities. The bête noir in this area is a small wooden barque sunk within sport diving’s limits, and a twenty-minute boat ride from Tobermory’s Big Tub Harbor.

Since the discovery of the sailing vessel Arabia in the early 1970s, more than 14 divers have perished on her. Far more than any other wreck in the Province of Ontario and perhaps any single spot in Canada and the USA, including any individual Florida cave or the fabled wreck of the Andria Doria off America’s Atlantic coast.
Every dive season there are countless near misses on this little wreck as well. Divers make ballistic ascents. They lose contact with their dive buddy and panic. They forget to make required safety stops. They get lost, run low on air, and make mistakes that could snuff out their lives and add to the grim statistic that has earned the Arabia the somewhat sexist nickname “The Widow Maker.”

The real challenge is explaining why a rather ordinary wreck sitting in a fairly sheltered spot, with moderate visibility and light current, is so dangerous. Based on the records of diver deaths in this region, deeper dive sites protected by tougher environmental conditions and offering many more opportunities for grief are comparatively benign.

One guess is that too many people are looking for a shortcut and the Arabia is an assessable “challenge” visited by a number of suitably-equipped charter boats and therefore readily available to wreck divers, even those capable of faking a logbook and embellishing their experience. Without doubt the unfortunate history of the wreck exudes a kind of morbid attraction to this last category of fools.

We live in a society promising magic pills to make us fitter, thinner, younger, more attractive, and smarter: so much so that the expression “paying one’s dues” and all it suggests is considered out of touch. Subscribing to a philosophy that promotes earning privilege by hard-won experience and the slow accumulation of skill is considered “old school” and unfashionable.

The diving community certainly has members who are looking for shortcuts to “class dive sites” without prerequisite experience and skill. However, diving is not a pastime for shortcuts, and the Arabia was the stage for one incident that confirmed this dictum with blinding clarity.

One summer’s day a few years ago, a young man, who we’ll call Bob, decided to pay the wreck of Arabia a visit. Bob had just finished his open water scuba diver certification and the site was not one he had any business visiting. Apparently some friends warned him about attempting the dive, but according to later accounts, he was resistant to the meaning of caution. The site’s reputation as a potentially dangerous one was said to be a huge part of the lure. Bob had visions of diving all the well-known wrecks off the North East coast the following year and this adventure on Arabia was to be a warm-up.

Arabia sits broken but essentially upright in about 32 metres of water… approximately twice the depth Bob’s freshly minted open water card certified him to dive. Outfitted in rental dive gear he unfortunately found a boat willing to take him to the site. Since his was going to be a deep dive, and he’d heard that decompression gas was a good idea on deep dives, Bob strapped a stage bottle of nitrox to himself — a gas he was not certified to use — and, diving alone without the help and support of a buddy, went exploring.
We will never know what he saw or learned on his dive because Bob was found a couple of days later lying on the lake bottom less than a hundred metres from the wreck, long dead.

As truly extraordinary the symmetry of its stupidity, and as sad its outcome, this was not a particularly unique or isolated incident. Another death around the same period, involving an equally inexperienced diver on the Forest City, a deeper more challenging wreck in the same area, illustrates that. Every year there is a miserable list of equally dreadful cases where over-confidence, poor judgment and ill-informed choices result in the thinning of the herd.

And we should remember that such acts of folly are not restricted to beginners. Highly experienced divers seriously injure themselves and sometimes die too.

Jennifer Hunt, in a study published in Psychoanalytical Quarterly in 1996, focused on “Sam,” a pseudonym for a well-know New Jersey wreck diver and author. Her article, entitled Diving the wreck: risk and injury in sport scuba diving, explored Sam’s motivations for continuing to conduct technical dives following a near fatal accident. Sam had suffered a very serious decompression episode the year prior to her interviews with him — an incident he documented as a sidebar in a best-selling book written later. Disregarding the physical injuries caused by the incident, he continued to engage in deep wreck diving in a high-risk environment ignoring medical advice not to.

Hunt draws an interesting and somewhat disturbing picture of how unresolved psychological conflicts may influence a person’s approach to diving. She also teased out of many months of research an explanation of what compels divers to ignore evident risk.

“Like Sam,” she wrote, “a number of deep divers appear to link masculinity to involvement in high-risk activity. This unconscious link between risk-taking and masculinity is given cultural support within the deep diving community.”

I know Sam well enough to believe Hunt’s assessment of him is off the mark. After conversations with him, I read his motivations as having little if anything to do with perceptions of masculinity or influences drawn from his peer group. Sam’s decompression blunder was no accident but the direct result of carelessness and oversight. Sam’s actions were not driven by testosterone-soaked myopia, but a different flavor of foolishness — complacency of the experienced.

I think Hunt drew the wrong conclusion about Sam but I do not think she is wrong in all cases. Certainly her reasoning explains why some divers – experienced and inexperienced – attempt things outside the purview of their personal limits; even when they have full knowledge that what they intend to do is risky.

Some misguided link between “being a man” and taking foolish risks certainly helps to account for the behavior that resulted in Bob’s death on Arabia… but what else is there and what steps can each of us take to manage and control our own behavior in order to lessen the chances of suffering a similar fate? Step one is to identify and then avoid things that cause serious dive accidents.

The simplest way to stay out of the statistics column is to have a realistic grasp of your personal limits and the limits of your gear and then to stay well within those limits. It’s that simple; however, most of us need some help being honest and well-informed about where our limits actually lie.

Cave diving remains the purest form of high-profile, complicated diving. It’s also the branch of diving that offered the original properly organized training and certification for what we now call technical divers. The first recorded scuba dive into a cave in the USA was conducted by National Speleological Society divers in 1948, and the Florida chapter of that organization held the first cave training sessions for divers five years later in 1953. By the late sixties and early seventies, cave diving was being taught actively in North Florida by two groups, the NACD (National Association for Cave Diving) and the NSS-CDS (National Speleological Society – Cave Diving Section).

Cave diving, as with any form of extreme sports, carries considerable additional risk on top of the list of commonplace ones attached to the ordinary, everyday version of the sport… in this case, open water scuba diving. As the popularity of cave diving grew, so too did the number of diver fatalities in Florida’s caves. Pretty soon, cave training programs included modules on Accident Analysis, during which students and their instructors, in an attempt to avoid a similar fate, engaged in detailed discussions about divers going into caves and dying in there.

This “accident analysis” segment of diver training was radical stuff… a complete departure from the candy-coated puff being delivered to the mainstream dive-industry customer.
In his seminal writings on dive safety, Basic Cave Diving: A Blueprint for Survival, Sheck Exley was among the first to identify that most fatal and near fatal incidents in caves are the result of people ignoring one or more of the five safety procedures. Exley, pioneer cave diver and explorer, originally recorded these five principles or best practices as: Training; Guideline; Gas; Depth; Lights. (A mnemonic to remember them is Thank God, Good Divers Live.) This translates into: Do not exceed or ignore the limits of your training (and experience by implication); Always maintain a continuous guideline to open water / the surface; Plan dives around adequate gas volumes and oxygen partial pressure; Stay within the working depths of your equipment, your level of concentration, nitrogen partial pressure, and comfort zone; Carry backup lights to preserve safety and comfort in the event of primary light failure.

In a 1992 article in Aquacorps Journal, Michael Menduno, the magazine‘s founder and editor-in-chief, used Exley’s accident analysis technique to pick apart eight diver deaths that had occurred in the United States dive community inside a 12-month period. The fatal sites were a mix of caves and deep wrecks and one deep open-water location.

At Alachua Sink, considered an advanced Florida cave dive, a newly certified cave diver became lost in the cavern zone and drowned. An experienced cave diver suffered a CNS (Central Nervous System) oxygen toxicity episode diving Devils Eye, also in Florida. The wreck of the Andrea Doria claimed two lives in separate incidents; one diver simply ran out of air, the other became lost inside the wreck‘s maze of cabins and companionways. On the Arundo, a wreck off New Jersey, a diver experienced an oxygen toxicity event and died. The Chester Polling, off Massachusetts, claimed the life of an experienced wreck diver conducting a dive to 52 metres (170 feet) on air. And two buddies attempting a 75 metre air dive (250 foot) wearing only single 11 litre cylinders (aluminum 80s) and with only sport-diving gear and training, died in La Jolla Canyon, off California‘s southern coast.

Menduno, who is credited with coining the term technical diving, wrote “Unfortunately in most of these cases, experienced divers violated one or more basic safety principles and died as a result.”

He went on to explain “the predominant causal factor was the lack of a “continuous guideline” (line system) to the surface that serves as a critical navigation device in the overhead environment of a cave or wreck and an important staging tool during open water staged decompression. Even in the absence of rough sea conditions executing a five to ten stage open water hang in the absence of a decompression line is hazardous and tricky particularly when using hyperoxic mixtures for decompression where depth control is critical.”

He identified that the second most predominant factor in the 1992 deaths was “inadequate gas management,” and stated that in the instance of one Andrea Doria incident and the ridiculous depth attempt at La Jolla, divers entered the water with insufficient gas to conduct the dive safely and handle an emergency.

“They were,” Menduno wrote. “In effect conducting suicide missions.”
A couple of months following the publication of Menduno’s article, and ironically during a workshop on diver safety that boasted a panel made up of many of the top advanced divers and dive-trainers of the period, came news of deaths nine and ten: those of Chris Rouse Senior and his son Chris Rouse Junior on the wreck of the U-Who, later identified as the U869.

Exley’s ideas had gained general acceptance and had stood for several years unchanged and unchallenged but shortly before his own tragic death in April of 1994, exploring a deep cave in Mexico, Exley revisited his work on accident analysis and expanded his safety procedures to reflect massive changes in the world of technical diving and to accommodate the widening appeal of technical diving with divers outside a cave environment. In addition, a veritable who’s who of advanced diving adding their input and suggestions to Exley’s framework, and the results now, almost a generation later, is a Risk Management Process intended to help prevent unnecessary deaths, and to help drive home to a growing audience of enthusiastic divers, all ready and willing to push the envelope, that while technical diving is fun, it is totally unforgiving of the foolhardy.

Risk Management is the identification, classification, avoidance and mitigation of risk. In order for it to work, it requires honest and detailed answers to some straightforward questions and following some common-sense guidelines organized into eight categories: Attitude, Knowledge, Training, Gas Supply, Gas Mix, Exposure (the combination of Decompression and Depth), Equipment, and Operations… let’s take a look at them.

The fundamentals of diver safety really all boil down to attitude. If we pick through the cascade of events that led to a diver’s death or serious injury we find common mistakes and rash decisions were the catalyst for disaster. In the majority of cases, these events began and decisions where made before the dive took place and were the result of recklessness (Sam’s example) or machismo (Bob’s example). Before every dive, a technical diver should ask themselves this question: “Why am I doing this?”

There is no room for a cavalier attitude. There is no time for bullshit. And technical diving is no place for people trying to prove their manhood. If you recognize these traits in your attitude, take up golf and stay the hell away from technical diving.

Mark Twain said that it ain’t what you don’t know that gets you into trouble. It’s what you know for sure that just ain’t so. That’s pretty succinct, because most of the targets in diving are moving rather than stationary, and there’s more alchemy than science to it. And so it follows: No dogma; No absolutes; Only an open mind.

Knowledge is also understanding that you need to have options when things don’t turn out the way you expected. And wisdom is having the insight to choose the option most appropriate for whatever the current circumstances may be.

Both knowledge and wisdom also contribute to the technical diver’s mindset, which accepts that there is always more to learn and often a better way to accomplish one‘s goals.

Stay within the limits of your training and you will weight the odds in favor of survival; exceed or ignore your training and the odds very rapidly swing in the opposite direction.

Scuba diving is a pastime built on and driven by training. It starts with certification as an basic open-water diver and progresses from there. Technical training is an ongoing process and never stops. A diver never “has enough” training. In this regard the situation is similar to training for an athletic event.

Graduation from a formal course is a good first step, but it is only a first step and carries no guarantee that a diver is prepared to make a specific dive. There’s more to technical diving than holding a c-card. One key element in a diver’s development is practice. Well-directed and well-accessed practice builds muscle memory, familiarity and competence… it is what prepares a diver for a particular dive.

Experience is the other key component. Exposure to specific environmental conditions is the only preparation that counts towards preparing for dives in that environment. For example, extensive wreck diving experience does not qualify a diver for cave diving and visa-versa

Even the most cursory glance at the growing list of dive “accidents” tells us that any recreational dive can morph into a nasty situations when someone attempts a dive they are not trained to do in an environment that is unfamiliar to them. A workable analogy would be attempting Parkour off a three-storey balcony to see if the sport’s to your fancy. Either option is going to land you in the emergency department.

In a cave this simply means that a dive team must maintain a continuous guideline to open water: think Ariadne, Theseus, the Minotaur, a ball of string and the Labyrinth. Explored caves — that’s to say the vast majority of caves visited by recreational divers — have a network of permanent lines in their passageways. These guidelines are placed strategically throughout the cave’s main tunnels and branch lines. At regular intervals, markers — usually plastic, but metal or tape in rarer cases — are attached and indicate the distance to and direction of the nearest exit. Cave divers also carry reels of line with them to gap any breaks in the permanent lines — intentional or otherwise. By following this rule, a cave diver always knows where he and his team is in relation to open water and fresh air. ‘Loosing the line’ or not having one to start with, has been a contributing factor in many, many cave fatalities.

The same guideline rule holds true for wreck divers penetrating wrecks, with the difference that wrecks seldom have fixed permanent lines so wreck divers install as they go and retrieve as they exit. But the comfort and security of a continuous guideline out of the overhead is paramount.

In an open water, non-overhead environment, ‘Guideline’ can be translated to mean three things: the first always having a bearing on the preferred exit — such as a friendly shoreline or boat — which is a case of knowing where to surface rather than where the surface is.

Secondly, it is knowing where the team is at any moment in relation to the planned route, including entry and exit points. Since there is no actual line and no specific markers with distances to the exit written on them, this exercise can be more complex in open water than in a cave, because there is no easy or apparent ‘map’ to follow. However, natural navigation and noting distinct landmarks helps immensely.

Lastly, complex decompressions in open water are made less stressful, and more controlled, with the simple addition of an ascent line. This can be fixed in place and have contingency gases staged at various points in the water column. It can be a DSMB (Delayed Surface Marker Buoy) deployed by individual divers or by the team, or it can be a full-blown decompression staging platform complete with contingency gases, surface supplied oxygen, refreshments and piped music.

Getting lost in a cave is usually fatal. Getting lost on a dive in the open ocean, on a wreck or otherwise, can be equally serious. Currents, big seas and fog can make surfacing at the wrong end of a 120 metre wreck more than embarrassing. The simple and most supportable solution is to use an upline.

There are lots of bad things that can happen underwater but the worst thing of all is running out of something to breathe. Where there is no direct access to the surface — such as in a cave or when there is a decompression obligation — this is a total show-stopper.

It follows then that technical divers make sure there is a sufficient volume of gas for everyone to get back to the surface, and there is some redundancy built into each diver‘s gas delivery equipment. For this, they use techniques originally developed by cave divers.

In its simplest, unmodified form, The Rule of Thirds (one third of the staring volume for entry, one third for exit, and one third for contingencies) is a bare minimum approach to gas volume management, and not by default the best option in a hard overhead environment. For example, if a cave diver looses back gas just as he and his buddy reach thirds — the worst-case scenario — they will most likely not make it out of the cave, but will exhaust their gas supply within a short distance of the cave entrance. The logic here being that the journey out will require slightly more gas than the journey in on account of several factors, such as one or both divers being stressed — breathing harder — the journey taking longer since both divers are tethered by a long hose, and silt-outs are a distinct possibility with one or both divers distracted by the stress of sharing gas for a longish swim.

But the rule of thirds is a fine starting point to plan from. In essence, there should be sufficient reserves for the dive team to exit safely in the event one diver suffers a catastrophic gas loss. In open water this means the plan should include contingencies for all the team to reach the first gas switch with a comfortable cushion. Generally, this is accomplished by the team’s penetration or bottom time being governed by the gas volume of the team member carrying the least number of litres or cubic feet. This volume is used in gas supply calculations.

The situation with decompression gas is similar in that contingency volume must be planned for. The consensus seems to be that each team member carries sufficient deco gas to allow two divers to complete the optimal decompression schedule.

Except in exceptional circumstances, an open-water technical diver must carry all the gas he will need for the dive. Unlike his cave-diving buddy, there are few options for reliably staging primary gases in open water.
Having gas and not being able to access it accomplishes nothing as so in addition to gas volume management, technical divers dive with a gear configuration that provides a backup gas delivery system. In the open circuit arena this may be a set of doubles with two first stages, a stage bottle of bottom gas with its own regulator, or a sidemount rig. When diving a rebreather, this means carrying an independent bailout cylinder with its own regulator.

The next to worst thing that can happen to underwater is only having something inappropriate to breathe or breathing a gas that is ‘toxic’ at depth. For example, breathing a mix delivering an oxygen partial pressure higher than convention dictates… which is a maximum of 1.6 bar. This also covers breathing mixes that have high narcotic loading, are hypoxic — deliver a low oxygen partial pressure — or — in exceptional exposures — mixes that may encourage counter diffusion issues.

The rule is to always dive the safest possible mix(es) for the planned dive; always analyze and label gas before making the dive. Above all, make sure that you know what you are breathing and that you are sure of its Maximum and Minimum Operating Depth(s).

Clear labels stating MOD should be visible on both sides of any stage bottles taken into the water. Permanent labels and touch identification on regulators for conditions of zero visibility are all well and good but are secondary to clear markings based on analyzed contents.

Keep oxygen partial pressures lower than 1.4 bar for the working phase of a dive. On deeper dives, knock this back to 1.3 or 1.2 bar. During decompression, increasing oxygen levels to a maximum of 1.6 bar must be done with care and attention to stay within 80 percent of NOAA’s oxygen single exposure limits. In the event of multiple dives over multiple days, track daily/24-hour limits as suggested by NOAA. Do not exceed them. There have been several ‘unexplained’ CNS toxicity incidents that seem to point to issues with these particular limits.

Keep nitrogen partial pressures within supportable limits. Personal comfort zones may vary depending on the type of dive and environment, but 3.1 to 3.5 bar is becoming a standard acceptable narcotic dose.

Decompression Sickness (DCS) is a predictable sidebar to all forms of scuba diving. The potential for risk of DCS is greatly increased during the sort of deep and long dives typical of technical exposures. Prudent technical divers always use proven decompression methods and the most up-to-date tools for dive planning. They dive conservatively and make ample allowance in their ascent schedules for working dives, dives in cold water, exceptionally deep dives and dives using helium. They carry tables for lost gas contingencies, and use hyperoxic mixes (either nitrox or high-oxygen content trimix) for decompression, never bottom gas, and optimize their final stops (at 6 and 3 metres) by breathing pure oxygen or something close to it. Air is an inefficient decompression gas and has a poor record at reducing decompression risk (Vann, 1992), so they avoid its use in all but the most extreme circumstances.

Another good practice many adopt is keeping detailed notes of decompression schedules and their ‘health’ after their dive compared to the way they felt before the dive. They refer to these notes when planning future dives.

Thanks to decompression planning software, personal dive computers actually intended for use during staged decompression, and a growing data set cataloging successful dives in the top-end range of 75 metres (about 250 feet), the number of serious decompression incidents among technical divers at these depths is surprisingly low… far from totally acceptable but nevertheless the risk is tolerable to many weekend divers. However, technical divers have to accept that dives deeper than 100 metres (about 330 feet) seem to engage a whole new level of vulnerability to DCS, which puts dives to these depths beyond the scope of all but the most careful of divers, and those who have planned dives with the additional security of in-water and surface support.

In conditions where there are strong or variable currents, cold water and the possibility of limited visibility above or below the surface — when wreck diving for example — bottom times should be kept as short as practical to ensure that total in-water exposures do not add factors such as thermal stress and the possibility of losing contact with the surface support to the risk .

Better expressed as Personal Depth Limits, this rule primarily reminds divers to factor into their plans the effects of narcosis, and a variety of other issues that negatively effect their personal performance.
To the majority of experienced divers, deep is a relative term, and one used with some caution. For example, deep in cold, murky water with strong currents begins when the reading on a depth gauge is much shallower than it does in warm, clear, calm water. A very well-known cave explorer says that deep is any water he cannot stand up in and breathe fresh air. Deep can actually be shallow, it just depends.

The same can be said for the Count Dracula of tech diving — narcosis — because it too is a relative term.
The biophysics of inert gas or nitrogen narcosis are pretty much solid state. The actual changes made to the nervous system would suggest a constant effect that while not completely understood would most likely be linear. But narcosis is wildly variable and its effects oddly unpredictable. The function of partial pressure — expressed in bar and increasing at a steady rate as a diver sinks further beneath the surface — does not account fully for the dramatic variations in the risk and severity of narcosis that divers experience. The only logical explanation is that factors aside from nitrogen partial pressure play an important role in narcotic loading. These factors certainly include stressors such as cold, poor visibility, carbon dioxide retention, mental stress, task-loading, tiredness and poor cardiovascular fitness. All these exacerbate narcosis and work independent of depth. Helium is the crucifix and garlic necklace that can combat narcosis, but thinking it alone makes deep diving ‘safe’ simplifies a complex issue and trivializes other important factors.

One factor that is a real concern for ’deep’ diving is concentration… by which is meant being focused on the task at hand. Of course concentration can be negatively affected by narcosis but if there is little attention paid to being focused to begin with, the situation can get out of hand quickly. One can regularly see divers who have plenty of helium in their mix, but who are as incapacitated as the regulars at a Grateful Dead concert as soon as their heads disappear under the water.

Being unfocused and letting one‘s concentration drift around like a ten-year old in Hamleys Toy Shop seems to signal every venerable piece of kit to loosen, break or fall off… or so it seems. The poor diver is brought back from his reverie to find the first stage of his deco regulator floating off into the abyss or something even worse.

Concentration, like buoyancy control and a reverse frog kick, is a learned skill and can be worked on… should be worked on just like any other. Car racers are big on concentration because of the importance of being focused as you approach a 90-degree corner at killing speeds. Their rule is that an additional 10 miles per hour requires 20 percent more concentration. That’s not a bad rule for divers: 10 feet 20 percent more focus.

Under Exley’s original safety guidelines aimed at someone diving in a cave, light was an essential. Without light, finding the way out would be a serious challenge. Because of this, cave divers each carry one primary light and two backups. A dive is aborted if a primary light fails.

Within the expanded guidelines, lights is code for equipment: specifically having the right gear for the job and appropriate backup.

A diver’s equipment is his life support system. It should be treated with respect. Most divers who want to avoid surprises, have gear serviced at least as often as recommended by its manufacturer, and inspect their dive gear before every dive, paying particular attention to hoses and Orings. All regulators, lights, and subsystems such as spools and surface signaling devices should be tested before the start of every dive.
In technical diving, there are no accessories. If a piece of kit is carried into the water, it’s because it is an essential tool for the dive, so it must be inspected and tested. Everything that’s essential should be backed up: either carried by the diver himself or as part of his buddy’s kit.

The primary mission of all technical dives is that every member of the team finishes the dive in no worse shape than when they started it, and so it follow that safety is always the first priority.
The most successful technical divers look at their dives as complex entities that require some considerable degree of organization that includes, planning, preparation, the correct equipment choices, teamwork, efficient execution, and the capacity for any and all team members to respond to any emergency effectively and immediately.

Above all, technical diving is a team activity. The buddy system works OK for sport diving, but technical diving often goes more smoothly with a team of three or more. A team extends to those left on the surface, which includes, in the case of boat diving, a minimum of the captain and crew. For complex dives, support divers may be required as well as additional surface personnel. Communications within this group at all phases of the dive is vital. Often, complex dives require an operations manager or a ‘diving officer.’ This person oversees diver safety, sees that protocols and procedures are followed, keeps records and, in the event of a mishap, takes charge of the response.

At no time should any diver be pressured to attempt to dive outside their “comfort zone,” and each diver carries the responsibility for their own safety. Because of this, the cardinal rule of all technical dive operations is that anyone can call a dive for any reason without fear.

Fatal dive accidents frequently have multiple and complex, often interconnected, root causes. While each accident has unique qualities about it – in part because of the individuals involved – most accidents can be characterized as a chain of events that lead to disaster.

This chain of events very often starts with a minor challenge… a failure in communications, a broken strap. But like dominoes, one event triggers something more serious, and this in turn results in more escalating calamities until all the dominoes have all fallen down. Technical divers need to get pretty slick at removing a domino early on and breaking the chain. Often something as simple as calling a dive early, before anyone gets close to the edge, can change the outcome radically and turn a nasty epiphany into a positive learning experience.

Unfortunately, the more challenging the dive and the greater the distance between it and mainstream sport-diving limits, the more risk is involved. This is the price we have to pay to experience something out of the ordinary and truly exceptional. No amount of training, experience, equipment or good luck will completely mitigate this risk, and sometime sooner or later, many of us will get our fingers burned. We do well to remind ourselves often that if we participate in technical diving, there is always a risk of serious injury or death.


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