The Perils of Saturation Diving

One of the most dangerous jobs in the oil and gas industry.

the perils of saturation diving

That day in the summer of 1984, I was standing 140 meters on the seafloor of the North Sea. Floating above me and stationed alongside an oil rig is the Dive Support Vessel (DSV) Stadive. Mike Lambert was dive supervisor and in dive control.

The earpieces in my bright yellow Kirby Morgan Superlite17 diving helmet squawked into life. “Ray, we’ve got nearly 130 meters of cable out on the crane, you should be able to see the lights by now,” Lambert’s voice has an element of concern.

I am looking up in the direction of what would usually be the shimmering light of the surface. At this depth sunlight hardly filters down, due to the density of water, light photons are drained of energy and cannot penetrate effectively.

I was intently scanning the blackness of inner space for two chemically

I hear Lambert yell to the crane operator “All Stop, all stop, all stop!”

My vision is now completely gone as a muddy cloud of soft silt rises from the impact of the crane hook. After some time, it settles. The limiting blackness of deep sea is once again my work environment. I examine the crane hook now hoisted to the correct level. Sure enough, there are the chemical lights attached.

the perils of saturation diving

Surface support, the deck crew onboard ship had failed to activate them by breaking and shaking the sticks triggering the light-emitting chemical reaction. The light sticks cost no more than a few dollars each.

This close call is undoubtedly one of many undocumented examples of dangers that are part of the life of the saturation diver working in the oil and gas industry. Pride in their job and monetary rewards with offshore dreams of big houses and fast cars are what drives a man to put his life on the line so that you and I can go about our lives without giving oil any consideration.

Saturation divers do construction and demolition work at ocean depths up to 300 meters and must spend weeks on board ship living in a pressurized habitat, which minimizes the risk of decompression sickness (the bends). Saturation divers breathe a helium-oxygen mixture to prevent nitrogen from becoming narcotic and causing a loss of senses similar to drunkenness. The divers are lowered to the seabed via a diving bell. The bell locks on and off the pressurized living habitat via an airlock system that enables separation of the diving bell from living chambers. Once at depth the diver drops out of the bell via a bottom door. The door opens when the bell pressure is equalized with the sea depth pressure. The diver makes their way to the worksite. Connecting the diver to the diving bell is a 30- to 45-metre-long umbilical, a lifeline of hoses that has the three vital functions, the oxygen-helium supply, the hot water that circulates through the dive suit and the communications cable. Temperatures at depth in the North Sea vary from 4 to 6 degrees Celsius. This an extremely hostile work environment.

Core pioneer divers who worked offshore rigs between 1965 and 1990 were at the most risk of severe injury and death. There were 56 confirmed diving fatalities in the North Sea.

Many others over time have struggled with significant health problems. An estimated 90% were in life-threatening situations at work. Eighty-five percent of those who survived have suffered from decompression sickness in addition to avascular necrosis, pulmonary disease COPD and cancer; 30% have been diagnosed with brain injury; 96% of those studied have had their quality of life significantly reduced; and 23 divers have so far committed suicide.

On November 5, 1983, one of the most serious and certainly most horrific recorded diving accidents occurred on the semi-submersible drilling rig Byford Dolphin. The four divers, Edwin Coward (35), Roy Lucas (38), Bjørn Bergersen (29) and Truls Hellevik (34) were inside the pressurized saturation diving system and were to die instantly when their living chamber explosively decompressed from a pressure of nine atmospheres or 90 meters deep to one atmosphere or surface in a fraction of a second.

Warning: graphic detail

One of the dive tenders William Crammond (32) opened the clamp between the diving bell and living chambers that keep the pressurized atmosphere in the diver’s habitat. He was killed instantly. Coward, Lucas and Bergersen had their blood turn to foam as a result of the explosive decompression, not dissimilar to shaking a carbonated bottle of soda and unscrewing the top. Hellevik suffered a horrible death. He was closest to the open round interior door, which should have been closed and sealed before the clamp was taken off. If sealed, it would have stopped the explosive decompression. The door was not closed and slightly ajar. Forensic pathologists report, “Hellevik, was subjected to the highest-pressure differential and in the process of trying to secure the inner door, the escaping air forced him through a 60-centimeter (23 in.) crescent-shaped opening created by the jammed interior door. Hellevik was violently dismembered, including bisection of the thoracoabdominal cavity, which further resulted in the expulsion of all internal organs of the chest and abdomen except the trachea and a section of small intestine and of the thoracic spine and projecting them some distance, one section later being found 10 meters vertically above the exterior pressure door.” In layman’s terms, he was shredded to pieces.

With the difference in pressure from the surface to saturation depth, anything blocking the opening would be exposed to a force of up to approximately 25 tonnes by the air trying to escape.

Pioneer diver Stephen Florence (63) from Yorkshire spent over four decades as a saturation diver. He considers himself “quite fortunate” having started work on the offshore oil rigs in the late 1970s. With diving personnel “dropping like flies” in those pioneering days, Stephen recalls many close calls.

On one such occasion, he was on the seabed, 90 meters down. He and his buddy were using airlift bags to raise a 3 ft. diameter pipeline. They had to bolt the two ends of the flanges together and tighten them with hydro-jacks. The pipe was kilometers long. Lift bags were every 5 meters to take the enormous weight.

“I had to get my head underneath between the pipeline and the seabed to tighten up the bottom bolts,” he said.

One of the airbags had an undetectable leak, and like a slowly deflating balloon, the weight of the pipeline was to gradually and silently pin his head to the seafloor.

“I could hear this creaking and realized it was my helmet being crushed. I couldn’t see or move. I was trapped for over half-an-hour, the weight bearing down on me,” he said.

That’s how long it took his dive buddy to get the air hose and top up the deflating bag so Stephen could free himself.

“I thought, I don’t like this at all, you must hold back the panic and stay calm. Saturation diving is a roller coaster. You can’t wait to get in saturation and earn great money. Then you can’t wait to get out, go home and breath fresh air again. The highs and lows are bound to affect you mentally,” he said.

Diving Supervisor of the DSV Seven Pelican, Phil Kearns (59) from Cheshire has been in the industry for 35 years. Phil was drawn to the adventurous lifestyle and the camaraderie. But never far away is the money.

Although not directly involved, he recalls a diver trapped in a gas pocket of hydro-carbons as a result of leaking manifold at a depth of 120 metres.

Above the diver was a canopy, an overhang, the leaking hydro-carbon gases began collecting under the canopy and building up a bubble. Eventually, the diver unwittingly ignited the large bubble of hydrogen and oxygen gas mixture. The subsequent underwater explosion killed him instantly, breaking his neck.

In his time, he has seen a shift in the safety culture by the oil companies. From the hypocrisy of paying lip service to safety issues of the pioneering days to a welcome legislative change.

He concludes that major accidents like the Piper Alpha production platform where 167 workers were killed, and the Deep-water Horizon drilling rig with the death of 11 and cleanup cost of $62 billion (USD) forced governments to review the safety culture of the oil and gas industry.

The mantra now is, “If you think safety is expensive, compare it to the cost of an accident. Public sentiment is on our side. The public will not accept an industry that routinely kills people,” he said.

Saturation diving by most employment standards is a strange one. It is certainly not for those who have a fear of confined spaces, the dark, the ocean, flying in helicopters, putting your life in the hands of another, the unknown, or a dislike of physically arduous work.

For all the pioneer divers who died, a debt is owed to them, not that they would ask for anything in return. They led the way in laying and maintaining the pipelines and offshore oil rigs that work 24 hours a day, seven days a week, 365 days a year so you can drive your car up to the petrol bowser and fill your tank up.

People from all walks of life are prone to error. Today, oil companies do their best to mitigate the dangers of working in the oil and gas industry. But accidents still happen.

People are not infallible. Anyone could have made the mistake and forgotten to break and shake the light sticks.

the perils of saturation diving

About the author

Ray Sinclair graduated Bachelor of Journalism. Actor. Aspiring Poet. Former Special Forces Royal Navy Clearance Diver. Falklands Veteran. HMS Coventry Salvage Team.