Something most people don’t know is that you can’t just strap on scuba tanks, dive down to any depth, and then shoot straight back up. That would be a fatal mistake.
The air in scuba tanks is compressed and typically consists of oxygen, nitrogen, and sometimes helium. While your body uses up the oxygen as you breathe underwater, the inert gases—primarily nitrogen and helium—get absorbed into your bloodstream. These gases don’t get used by your body. Instead, they sit there, dissolved in your tissues, waiting for your return to the surface.
Now, this isn’t dangerous if you ascend properly.
What Happens If You Surface Too Fast?
As you ascend, the pressure decreases, and those inert gases begin to come out of your tissues and into your lungs, where you exhale them. But this process takes time. If you ascend too quickly, the gases don’t have time to escape gradually. Instead, they rapidly expand inside your body, like shaking a soda can and popping the tab.
This leads to decompression sickness, more commonly known as the bends—a condition that can be incredibly painful at best, and lethal at worst.
To avoid this, divers perform decompression stops on the way up—pausing at specific depths for specific periods to allow gases to safely leave the body.
The deeper you go, the more complex and time-consuming these stops become. For example, coming up from 2,000 feet safely could take over 33 hours. Thankfully, most recreational divers never need to go that deep—unless, of course, they’re saturation divers.
Welcome to the World of SAT Diving
Saturation divers—or SAT divers—are the elite of the diving world. They do construction, demolition, and repairs at extreme depths, sometimes as deep as 2,000 feet below the surface.
But instead of spending 33 hours ascending after every dive, SAT divers are kept under pressure for weeks at a time.
Here’s how it works:
They live in a pressurized chamber aboard a ship or oil rig. This chamber, which doubles as their living quarters, is laughably small—imagine a submarine stuffed into a closet. It contains beds, a bathroom, and enough space for divers to rest between jobs. The pressure inside is set to match the depth at which they’ll be working.
Connected to this chamber is a smaller, pressurized capsule called a dive bell. When it’s time to work, the diver suits up inside the chamber, crawls into the bell, seals the door, and the bell is detached and lowered into the ocean using a crane.
Since the pressure inside the bell matches the ocean pressure outside, divers can simply open a hatch at the bottom and slip out to do their job. Afterward, they return to the bell, seal it, and get winched back up to the surface—where they reattach to the chamber and remain under pressure.
This process repeats daily for weeks. At the end of a SAT diver’s shift—often a month long—they undergo one long decompression process, which takes several days, done entirely inside the chamber.
Danger in the Deep
While this system is incredibly efficient, saturation diving remains extremely dangerous.
Below 700 feet, sunlight doesn’t reach. The divers are in total darkness, and it’s unbelievably cold. Their suits are heated by hot water pumped in through a tether. If that tether fails, hypothermia sets in almost immediately.
Even with flashlights, visibility is poor. The water is thick with sediment—shining a light is like shining into fog. Large fish sometimes approach, seemingly affectionate, but they’re actually hiding behind the divers from something larger, out there in the dark.
But no matter how experienced a SAT diver is, there’s one thing they all fear: a lost bell.
The Terrifying True Story of Richard and Victor
On August 7, 1979, SAT diver Richard Walker was 10 days into a job in the North Sea. He was exhausted, missing his wife and 15-month-old daughter. That night, before his dive, he wrote in his journal:
“Dear God, I just want to get out.”
Soon after, he and his partner Victor Guiel entered their dive bell and began their descent to 485 feet.
But right before the dive, a critical decision was made: the location transponder, used to track the bell’s position, had come loose—and instead of fixing it, they just removed it.
Once submerged, the divers began work on an underwater structure. A few hours later, Richard—outside the bell—heard a strange noise and saw the dive bell tilt. Then his radio crackled: “Get back inside immediately.”
He scrambled into the bell and sealed it shut.
The main cable holding the bell had slipped off. Only a fragile bundle of wires and tubes, called the umbilical, remained connected. It wasn’t meant to bear the weight of the bell—but it was all they had.
They tried to haul the bell up using the umbilical. It snapped almost instantly. The bell crashed to the ocean floor.
Worse still, this dive bell didn’t have a clump weight—a safety feature that would allow it to float if released. The dive bell landed flat on the seabed, sealing shut the only escape hatch.
With no heat, no communication, and very little oxygen, Richard and Victor were trapped in silence and darkness.
A Desperate Race Against Time
Less than 30 minutes later, another dive ship arrived to help. But they hadn’t been prepared for an emergency, so it took three hours to deploy rescue divers.
Without the transponder, locating the bell was incredibly difficult—but after an hour of searching, they found it. At 7:00 a.m., they peered into the porthole and saw Richard and Victor—cold, but alive, giving a thumbs up.
Back on the ship, everyone rejoiced. Richard’s wife was even told, “There’s been an accident, but your husband is okay.”
But the battle was far from over.
Because the rescue ship kept drifting, it took two more hours of struggling just to thread a cable into the top of the bell. With each visit, the divers saw Richard and Victor looking worse—panicked, desperate, and running out of air.
Finally, at 9:00 a.m., they got a cable through and prepared to lift the bell.
The moment they began pulling—it snapped again.
The bell plummeted.
When they found it again hours later, Richard and Victor were still alive—but they weren’t waving anymore. They just stared at the floor, despondent, making peace with what was coming.
Eventually, another cable was secured. The bell was hoisted up and brought aboard the ship. But it was too late.
Both Richard and Victor had passed away.
Final Thoughts
Saturation diving is one of the most dangerous jobs on Earth. It requires courage, resilience, and trust—not just in your team, but in your gear, your training, and the engineering that keeps you alive.
Richard Walker and Victor Guiel’s story is a sobering reminder of the risks these divers take to do the work that most of us never even think about, deep in the dark, freezing corners of the ocean.