The Diver Is Becoming the Weakest Link

By Bill Nadeau

“The vocabulary evolves. The science improves. The models become more sophisticated. The technology changes. But the fundamental problem remains remarkably stubborn.”

I come to this subject with a somewhat unusual perspective, one that has not only been shaped by roughly four decades of technical diving and instruction, but also by the less comfortable side of the profession. I have worked as a Coast Guard Dive Rescue Specialist, served with the RCMP Underwater Recovery Team and, later in my RCMP career, worked as a Marine Incident and Accident Investigator. That work required me to look closely at serious marine incidents and diving fatalities and, more importantly, at the chain of decisions, circumstances and contributing factors that led to them. Over the years, I have learned that understanding why something went wrong is often considerably more complicated than simply identifying what went wrong.

We have spent decades making diving equipment smarter. Perhaps the uncomfortable question is whether we have made the diver smarter at the same rate.

There is a strange irony happening in advanced diving. We are surrounded by increasingly sophisticated technology.

Closed-circuit rebreathers regulate oxygen electronically. Dive computers model decompression continuously. Heads-up displays put critical information directly into a diver’s field of view. Sensors monitor equipment performance. Autonomous underwater vehicles can map environments before a diver ever enters them. Increasingly, researchers are experimenting with systems that can monitor the diver as well as the environment.

And yet, when something goes wrong underwater, we still tend to discover that the most complicated component in the system is the one between the diver’s ears.

That component is also remarkably old.

Human Factors Didn’t Arrive Yesterday

There has been a great deal of valuable work in recent years bringing human factors, decision-making, situational awareness, communication, teamwork, leadership and organizational culture into the diving conversation.

Gareth Lock deserves considerable credit for the progress being done in the diving world. His work through The Human Diver has helped bring human factors and non-technical skills into a language that divers can understand and, perhaps more importantly, remember. His central challenge to the traditional “bad diver” or “bad decision” explanation is an important one: rather than simply asking what the diver did wrong, we should ask how the situation made sense to the person at the time. That is a profoundly useful question. It is also one I believe the diving community needs to embrace.

Gareth has been exceptionally effective at packaging, branding and communicating a message that experienced divers and other high-consequence industries have been trying to communicate for decades. The fact that he has made it resonate so strongly is a good thing. But it is also worth remembering that the message has a history. Human factors did not suddenly arrive in diving when we gave it a name.

The aviation, military, healthcare, nuclear, offshore and other high-consequence industries had already been wrestling with human performance, decision-making, workload, communication, organizational culture and system failure for decades.

And diving was not exactly sitting around waiting for someone to tell us that humans could make mistakes.

Some of us had been learning those lessons the hard way for a very long time.

The vocabulary changed, the problem did not.

Consider a study published in Human Factors in 1970 by Gershon Weltman, Raymond Christianson and Glen Egstrom. The researchers compared experienced and novice divers performing complex underwater assembly tasks and problem-solving exercises in a water-filled tank and in the ocean. The experienced divers maintained relatively consistent performance while the novices did not. When moved into the ocean environment, the novices became slower at the physical task and their problem-solving accuracy deteriorated significantly. The researchers concluded that psychological stress was a significant factor even at relatively shallow ocean depths (Weltman et al, 1970).

In case you missed that date, it was 1970. Long before “human factors” became a fashionable subject in technical diving. The researchers were already asking a question that remains remarkably relevant today:

What happens to human performance when we take a person out of a controlled training environment and put them into the real underwater world?

The terminology and equipment has changed and the research has become more sophisticated. But the human ‘we’ has not changed nearly as much as we sometimes like to think.

Then consider a 2005 study examining safety culture and accident risk among professional divers and offshore workers.

Researchers presented participants with different scenarios involving safety culture, supervisory quality, worker competency and time or financial pressure. All four factors significantly affected perceptions of accident risk. The study involved 212 professional divers and 108 offshore workers (⁠Adie et al, 2005).

Again, this wasn’t recreational divers sitting around debating whether somebody had good “situational awareness.” This was professional diving research examining the relationship between people, organizations and risk.

And then in 2007, Paul O’Connor, Angela O’Dea and John Melton published research specifically examining human error in U.S. Navy diving accidents. Their study reviewed 263 Navy diving accident and mishap reports. The researchers found that existing human-factors classifications weren’t particularly useful for understanding diving accidents, so they developed a taxonomy specifically for dive-team human error. Among their findings, failures in situational awareness and leadership were the most common human errors identified in the dive teams they studied. (⁠O’Connor et al, 2007).

Again, work done almost 20 years ago. The lessons weren’t new. What was changing was our ability to describe them.

And Then There Was a Book Called Technically Speaking©

I find this particularly interesting because recently I went back and reread the opening chapters of a diving manual I wrote years ago. It was called Technically Speaking©. I wasn’t using the language of contemporary human-factors education. I certainly wasn’t calling what I was writing a human-factors framework. But I proposed many of the same questions.

In the opening pages I wrote that progressive diver development needed to introduce certain fundamentals “from day one,” including breathing techniques, survival skills, stress management and risk evaluation. I then divided the fundamental elements of diving into three areas:

Environment. Equipment. Activities.

Change one, and we may need to change the others. Increase the complexity of one, and the other elements have to remain in balance. That concept eventually became what I called the Ranges.

I wrote:

“Each ‘Range’ must be balanced in equilibrium with the other two ‘Ranges’ in order for a dive to be conducted safely.”

And:

“As a diver increases the complexity of one or more of the ‘Ranges’, so must the other ‘Ranges’ be adjusted to maintain the balance.”

Looking at it today, I recognize that much of what I was trying to describe was really an early attempt to understand diving as a system, rather than simply a collection of skills.

That distinction matters.

Certification Isn’t Competence

Another concept I wrote about was the difference between being certified and actually being competent. That distinction seems obvious now, but it remains one of the most persistent problems in diving. A certification card tells us that somebody met a particular training standard. It doesn’t tell us what happens when that person is cold, tired, stressed, task-loaded, disoriented, unfamiliar with the equipment, dealing with an unexpected current or trying to solve two problems simultaneously.

In Technically Speaking©, I used an example of a diver who had successfully learned to remove and replace a mask in a controlled training environment.

Then I changed the circumstances. The diver was now cold, wearing gloves and a hood, in limited visibility drifting along a wall at 25 meters when their mask and regulator unexpectedly got knocked out of position. The question wasn’t whether the diver had been certified to perform the skill. The question was whether the diver was competently prepared to deal with the situation.

Those are very different questions, and they remain very different questions today. It is also why my personal training philosophy has evolved around a simple distinction: what I, as an instructor, am responsible for teaching is fundamentally different from what the student is ultimately responsible for learning. I expect my students to internalize that knowledge and, ultimately, apply it for themselves, continuing to explore and develop their competence while appropriately expanding their capabilities and remaining conscious of their limitations.

Ability Is Not Static

Perhaps the idea from the book that I find most relevant to this discussion now is the concept of ability.

I wrote:

“Ability is forever in a state of fluctuation.”

I argued that ability is affected by external factors such as weather, environment and other divers, as well as internal factors such as a diver’s physical and emotional condition at that particular moment. That seems almost self-evident. And yet we routinely behave as though diver capability is a fixed commodity. You have the certification, the experience and the equipment. Therefore, you are capable.

But human performance doesn’t work that way. A diver can be highly competent and still have a bad day. An experienced diver can become overloaded. A highly trained diver can become disoriented. A team can become complacent. A piece of sophisticated equipment can introduce additional workload rather than eliminate it. And a diver can be completely within their certification limits while being well outside their personal ability on a particular day.

This is where human factors become so important. And it is also where I think the next generation of diving technology presents us with a fascinating problem.

The Technology Problem

We have spent decades making the equipment better. And there is no question that diving is safer because of it. Take modern CCRs for example, they are extraordinary machines compared with the early rebreathers that preceded them. Dive computers can perform calculations that would have seemed absurdly complicated to the diver carrying a set of tables and a pencil. Modern sensors can detect changes in equipment performance before a diver may recognize them. HUDs can place information directly in front of the diver. AUVs can map an environment before a diver enters it.

Artificial intelligence is beginning to offer the possibility of interpreting enormous amounts of information that no human could reasonably process alone. All of this can make diving safer. But there is a catch.

"A warning is not the same thing as a decision."

Information isn’t the same thing as understanding. Automation is not the same thing as competence and equipment capability is not the same thing as human capability.

In fact, the better our technology becomes, the easier it may become to hide the limitations of the human using it.

The Paradox of Automation

In Technically Speaking© I proposed that this created an interesting paradox. The better our equipment becomes, the easier it can become to believe that we are better divers. But those aren’t necessarily the same thing.

A sophisticated CCR can automate some functions of life support. A dive computer can calculate complex decompression models, sensors can tell us something has changed and alarms can tell us that something is outside a predetermined parameter. But none of those systems knows what the diver knows. And none necessarily understands what the diver doesn’t know.

That’s an important distinction.

Automation is extraordinarily good at doing what it was designed to do. The problem begins when the real world presents us with something that wasn’t in the design assumptions. That is when experience, judgment, adaptability and leadership become more important, not less.

The Diver Is Becoming the Weakest Link

So perhaps the question isn’t whether diving technology is becoming smarter. It unquestionably is. The more interesting question is:

Are we developing divers at the same rate that we are developing their technology?

Because if we aren’t, we may eventually create a peculiar situation in advanced diving:

• A machine capable of monitoring dozens of parameters.

• A computer capable of processing thousands of calculations.

• An autonomous vehicle capable of mapping an environment.

• An artificial intelligence capable of identifying patterns.

And a diver who is still trying to figure out which alarm is actually important. That isn’t an argument against technology. It is an argument for better humans.

Perhaps We Need to Stop Calling It New

This is where I think the current conversation about human factors deserves both recognition and a little historical humility.

Gareth Lock has done something valuable. He has taken a body of knowledge that existed across aviation, military operations, healthcare, engineering and safety science and made it accessible to divers. He has helped move the conversation away from simply blaming the diver and toward understanding the system in which the diver operates. His work explicitly emphasizes systemic learning, psychological safety, non-technical skills and the question of how circumstances made sense to people at the time (Lock, 2019).

That’s really, really good. But perhaps we should be careful about confusing the arrival of a new vocabulary with the arrival of a new idea. The researchers studying underwater performance in 1970 were already examining stress, experience and performance. Professional diving researchers were examining safety culture, supervision, competency and organizational pressure in 2005. U.S. Navy researchers were examining situational awareness and leadership failures in diving accidents in 2007.

And long before I ever heard the term “human factors” used in the way it is today, divers were teaching other divers about stress, complacency, judgment, preparation, limitations, teamwork and personal responsibility.

We didn’t necessarily call it human factors. We called it good diving.

I have also learned this lesson in a much more personal way. Over the years, I have lost several good friends to diving accidents. These were not reckless divers or people who didn’t understand risk. They were experienced, capable divers who knew how to plan a dive, assess conditions and consider their own limitations. Yet in each case, somewhere in the sequence of events, there appears to have been a moment when the perspective that normally served them so well became temporarily distorted. A limitation was overlooked, a circumstance was interpreted differently than it should have been, or a decision was made with a degree of confidence that, in retrospect, the situation did not warrant.

Those experiences have made me reluctant to accept the comforting idea that accidents happen simply because someone was inexperienced, poorly trained or careless. Sometimes the diver knows better. Sometimes the diver has demonstrated for years that they know better. And sometimes, for reasons that are difficult to understand even after the fact, they simply fail to apply that knowledge at precisely the moment it matters most.

The Next Generation

Perhaps that’s actually the most important lesson. We don’t need to diminish the people who are bringing these ideas forward today. Quite the opposite. We should listen to them and we should learn from them. We should become better at understanding human performance. But we should also recognize that diving has a long history of people wrestling with exactly these problems.

Soo the vocabulary evolves, the science improves and the models become more sophisticated. Basically the technology changes but the fundamental problem remains remarkably stubborn:

Put a human being into a hostile environment, give them a complicated task, introduce uncertainty and pressure, and eventually human performance becomes part of the risk equation.

That isn’t new.

What is new is the extraordinary amount of technology we are now putting between the diver and the environment and that creates a different question for the future. If the machines become capable of doing more and more of the work, what exactly should we expect the human diver to be capable of doing? Perhaps the next generation of advanced divers won’t simply need to be better equipment operators.

They will need to understand systems and recognize when automation is helping and when it is creating complacency. Divers (people in general) will need to manage information rather than simply receive it and more importantly they will need to understand their own cognitive and physiological limitations. Divers will need to learn how to communicate better and they will need to challenge assumptions.

And perhaps most importantly, they will need to know when the machine is telling them something important and when their own observations are telling them something the machine hasn’t yet figured out.

Technology can extend our reach, extend our bottom time, depth, perception and it can even extend our decision-making capability but it cannot automatically extend our ability. That still belongs to the diver. And perhaps, as we build increasingly intelligent machines to accompany us underwater, the most important question we can ask is not:

"How smart can we make the machine?"

It is:

“How capable do we need the human to remain?”

Safe Diving - Bill

References

Adie, W., Cairns, J. A., Macdiarmid, J., Ross, J. A. S., Watt, S., Taylor, C. L., & Osman, L. M. (2005). Safety culture and accident risk control: Perceptions of professional divers and offshore workers. Safety Science, 43(2), 131–145.

Lock, G. (2019). Under pressure: Diving deeper with human factors. Human in the System Consulting.  

Nadeau, W., (2005). Technically speaking. A comprehensive guide to effective underwater exploration. DeepFathoms, v-xiv, 2-44, 51-71, 266-280 .

O’Connor, P., O’Dea, A., & Melton, J. (2007). A methodology for identifying human error in U.S. Navy diving accidents. Human Factors, 49(2), 214–226.

Weltman, G., Christianson, R. A., & Egstrom, G. H. (1970). Effects of environment and experience on underwater work performance. Human Factors, 12(6), 587–598.