Dangers of Commercial Diving and How to Stay Safe

Dangers of Commercial Diving and How to Stay Safe

The number one priority of any diver operator is safety.

For every diver there is a support team hundreds of thousands of dollars’ worth of diving equipment.

All of this personnel and equipment has one fundamental goal, to keep divers alive while they undertake the underwater tasks assigned to them.

Teams and Equipment

Commercial divers often used mixed gases for breathing when working deep underwater. Whether gases or surface supplied air, a commercial diver needs a team of people to help him stay alive.

A typical support team for a single commercial diver comprises of a diver supervisor, a life support technician, several tenders, a backup safety diver, and a backup safety diver tender.

Along with these professionals, specialized equipments that keeps divers safe includes a diving bell, a decompression chamber, and life support equipment.

Chamber on DIT’s MV Response

Dive operators don’t take chances with diver’s lives.

So why all these people and equipment for one or two divers? Well, let’s take a look at just how many things can go wrong.

Hazards Of The Deep

Guess what! People are not meant to survive underwater. There are literally thousands of ways divers can get into trouble in the deep, dark ocean.

Running out of air

No matter whether a diver is breathing air from a tank or from a surface line, from time to time the air can stop flowing.

Faulty equipment is usually to blame.

Commercial divers conducting deep dives can end up trailing hundreds of meters of oxygen hoses behind them. These can easily get pinched or even cut on underwater obstacles.

Such dangers are particularly prominent during underwater salvage dives where sharp pieces of metal often protrude from wrecks.   

It is for this reason that divers have backups for their main systems.

A typical diving bell, for example, has several gas backup systems that are available for divers to use should their main fail. The dive team backup diver is also available at a seconds notice to bring down a backup gas umbilical should the main diver need it.

Decompression Sickness

Also known as the bends or DCS, decompression sickness is a real danger to all divers.

DCS occurs when bubbles form inside the body. This is a natural process, but gasses formed under pressure expand when divers come back to the surface. Milder cases of DCS might result in joint pain and rashes; however, more severe cases result in paralysis and death.

At the depths that most commercial divers operate, DCS usually has severe consequences.

DIT student in the chamber.

Fortunately, dive operators have all the tools to hand to prevent DCS.

Divers must follow strict decompression procedures to ensure their safety. Deeper descents, including saturation dives, rely on special decompression chambers that allow divers to be slowly and safely decompress on the surface.

It might not be much fun stuck in a small chamber for hours upon hours, but such procedures are essential.   

Nitrogen Narcosis

The dreaded rapture of the deep can strike at any time when divers are below a depth of 100 feet (30 m).  Certain gasses cause an anesthetic or intoxicating effect on humans under high pressure.

The mildest form makes divers feel as though they have had a few drinks that they shouldn’t have had. A more severe case of nitrogen narcosis can result in divers losing consciousness completely, something which can result in them running out of air and drowning.

To help reduce the risk of this condition occurring, for divers descending below 190 feet, a trimix consisting of oxygen, nitrogen and helium is used. Divers experiencing nitrogen narcosis are trained to ascend to lower depths where the effects are reversed.  

Delta P

Two out of three commercial diving fatalities result from Delta P. When two bodies of water meet that are of different pressures, a force is generated as the high-pressure water tries to run into the low-pressure water.

If you have ever held your hand over a swimming pool vent you will have experienced the effects of Delta P. Deep underwater, this can cause divers to get trapped in position.

If they are unable to free themselves, from a force that can sometimes be strong enough to lift a small car, divers can run out of oxygen or drown.

Not a nice way to go, that’s for sure.

Currents And Sharks

There is a heart-stopping moment when a diver spots a dangerous sea creature coming towards them. Though very few encounters have resulted in injury, divers still need to be careful.

Another more real danger is strong underwater currents. When working underwater, divers must take care to conserve their energy. If divers are required to move large distances, currents can make swimming a huge challenge.

A current of just 2 to 4 knots will result in divers expending most of their energy simply to move. Problems can quickly arise if divers are required to undertake tasks under such conditions.

Two Is One, One Is None

When divers get into a situation that is outside of what they were expecting, panic can take over. While panic is a natural reaction for all of us humans, under these conditions, it can be a killer.

This is where a diver’s training comes in.

Learn Safety First

Schools such as The Divers Institute of Technology spend hour upon hour training divers how to do things safely.

DIT students working topside while students are diving to 165 feet.

At every stage of their commercial diving course, instructors drill students over and over until they are able to react safely to any possible scenario.

If a diver gets into an unexpected situation, such as a communication failure in the dive bell, they will automatically turn to the backup systems to overcome the problem.

Seemingly without thinking, a well-trained diver will re-establish communication through the speaker in the bell or failing that, tap or pull on the bell wire to alert the top side team of a problem.

Good training makes this intuitive.

A key safety protocol for divers is the “two is one, one is none” rule. If a diver has both their main and backup systems online they are good to go. If their main fails and they are left with only one, safety becomes a priority and they abort the dive.  


Aran Davis, Writer for Water Welders


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