View Full Version : Bounce Diving

Michael Smart
10-12-2013, 04:42 AM
The following account describes a bounce dive performed by Richard Walker and Dave Abbot in September 1973 in the Ekofisk Field in the North Sea.

On September 14, 1973, Richard Walker was transferred from the pipe-lay barge (Chactaw) to a nearby jet barge called the Cherokee where he made his first bell dive.1 While the Choctaw laid pipe, the Cherokee buried it with a huge contraption called a “jet sled” in order to protect the pipe from anchors and bottom-trawl fishing techniques. Overall the garage‑sized sled was a tubular framework built on a pair of pontoons that supported “the claw,” a pair of vertical pipes studded with water jets whose main business was to cut a trench deep enough for the pipeline to lie in. The sled straddled the pipeline and was attached to the stern of the barge by a towing bridle. As the barge winched itself forward using its anchoring system, the claw carved the trench. Periodically, divers were sent down to check the sled for alignment and to sample the seabed for hardness, and on September 25 Richard was selected, along with a small British diver by the name of Dave Abbott, to inspect the sled which was already in operation on the sea floor.2

In terms of planning, getting Richard and Dave to the bottom of the sea was the easy part; it was getting them back alive that took skill. To do that, the supervisor had to consider three critical elements: the working depth, the “bottom time,” and the breathing mixture. The supervisor knew the sled was operating in 270 feet of water, which was fairly deep water, but not extreme; and he knew that the dive was going to be short, under an hour. Those two factors alone gave him the option to use a technique called “bounce diving,” so called because, under stopwatch conditions, Richard was expected to pressurize the bell to the working depth, lock out, complete his task, and get back inside to begin his decompression schedule before the clock ran out. The whole process was very frenzied and tense; decompression back to surface pressure was accelerated, full of stops at different depths, and fairly lengthy compared to the actual time spent working. For example, in one recorded bounce dive to 500 feet for a mere 20 minutes, the bell team had to decompress for seven hours and ten minutes. Thus, bounce diving made sense for deep, short‑term dives, but for jobs lasting days or even months it was impractical. In that instance, the supervisor would have chosen a different mode of diving.

The depth and duration of Richard’s dive also determined his breathing gas, which was going to be a mixture of helium and oxygen, not air, because, at 270 feet, air mutates into a toxic gas, with the oxygen concentration snowballing far beyond tolerable limits, and the nitrogen content presenting dangerous problems as well. Beginning at roughly 100 feet, it produces a narcotic effect upon the human brain (nitrogen narcosis); at 270 feet, it would have left Richard completely dumbstruck and unable to concentrate on his work. Thus, breathing air at surface pressure is not toxic, but feeding it to a diver at 300 feet is extremely dangerous. So in order to avoid toxicity problems on deep dives, a synthetic gas mixture is supplied where the oxygen concentration is reduced, and helium, not nitrogen, is used as the diluent to carry the oxygen because it causes no narcotic side effect. Thus, the deeper the dive, the lower the oxygen percentage in the dive mix.

Compared to all the different modes of diving, this “Beat the Clock” method is the most problematic to the diver’s health. The rapid changes in pressure, coupled with frequent errors in mismanaging the decompression, causes enormous damage to the diver’s body and produces the most numerous and serious cases of the bends. The more bounce dives a diver makes during his career, the greater the risk he incurs in terms of lifelong injuries to joints, muscles, and nerves. Nevertheless, Richard was willing to endure these yo-yo dives because, like all beginning divers, he wanted to advance to The Promised Land of “saturation diving” where divers remain stabilized under pressure for much longer periods of time and ultimately make more money.

Now, dressed in their dive suits, Dave was already in the bell speaking to the supervisor over the radio and running through internal bell checks when Richard came on deck and stood beside the bell. Like a giant white gumball machine, the four-ton spherical bell sat on top of a five-foot-tall tubular support frame called a stage. There were 15 tiny view ports and two black bumper guards, one running around the top of the stage, the other around the equator of the bell. To keep the divers alive and happy, the capsule was connected to the control van by a 1,200-foot long life‑support umbilical which supplied, among other things, breathing gas, communications, electrical power, and hot water. Ocean Systems called it the ADS-IV.a By coincidence, Richard was not unfamiliar with it. He’d been trained in one at Santa Barbara City College.

After bell checks, Richard ducked through an opening in the stage and climbed inside through a short, cylindrical hatchway called the “trunking” which had two heavy steel doors, a bottom door that opened outward, and an inside door which opened inward. The passageway was tight, only two feet in diameter, and once inside, Richard turned two large levers to “dog” the bottom door closed, but left the inside door open.

This bell, like all working bells, was crammed with gear. Two bulky dive umbilicals were coiled against the wall—one for Richard, the lock-out diver, the other for Dave, the standby diver. Here and there a gaggle of valves, gauges, copper tubing, and electrical cables ran this way and that. Various “penetrators” on the hull allowed the service lines from the main bell umbilical to link up with the support facilities within. Next to the gas panel, a scrubber sat whirling and whining as it cleansed the atmosphere of carbon dioxide. There was also a small O2 analyzer that indicated whether the gas in the bell had enough oxygen in it. Mounted at the top of the bell was a small “horn speaker.” All Richard and Dave had to do to communicate with their supervisor was speak loudly into it. And stuffed in various nooks and crannies were such things as the bell emergency tool bag, water bottle, port cover, extra scrubber canister. Normally the bell came with two seats, but divers routinely ditched one of them to conserve space which there wasn’t much of in this bell. In fact, throughout the entire North Sea, no bell was more claustrophobic than this one. It was only five feet, five inches in diameter.3 Richard was six-foot-three and weighed 190 pounds.

Suddenly a voice over the horn speaker called out, “Okay, here we go; coming up on the bell,” and the gumball machine suddenly rocked off the deck and began to gently sway like a plumb bob. Through one of the ports Richard could see the deck crew operating the davit. Several minutes later the two men were rotated over the side of the barge and lowered into the gurgling sea. Fifteen feet under the surface, the bell was momentarily stopped in order for the duo to check the seal on the bottom door. Outside water pressure and a thick o-ring recessed into the hatch were what kept the water out. With the seal confirmed, topside continued their descent.

Up against the hull, and mounted next to the gas panel, were two depth gauges—one internal, the other external. As the bell descended, the needle on the internal gauge still read zero, but the needle on the external gauge was slowly rotating clockwise—30, 40, 50 feet—then past 100 and beyond 150. The deeper they went, the darker it got outside.

On the way down Dave called out the depth every ten feet while Richard donned a small scuba tank. This “bailout bottle” was connected to his mask and was for emergency purposes only. If he lost his main gas supply (severed umbilical or topside mistakenly closes his supply), then all Richard had to do was reach up with his right hand and open a small valve on the side of his mask to make it back to the bell.

After roughly ten minutes, topside stopped the bell with a sudden jolt. It had reached its destination depth about 30 feet off the seabed where it would remain suspended throughout the dive. By this time Richard had soaped his mask to keep it from fogging up, clipped his umbilical into his harness, and put his gloves on. The two divers were still breathing air at surface pressure, but that was about to change.

Richard then lowered himself into a sitting position on the lip of the inside hatch. With his feet hanging in the well of the trunking, he undogged the door by kicking the hatch levers open. The door still remained closed because the outside pressure at 240 feet was more than eight times the internal pressure of the bell. Checking with topside, Richard and Dave let their supervisor know that they were ready to start the blow down.

When the supervisor gave the okay, Dave shouted into the speaker, “Starting blow down now,” and then he opened the Blow Down Valve. Mixed gas immediately rushed into the bell with a deafening roar. The bell also began to heat up. Compressing gas alone will cause the temperature rise, but helium has enormous thermal conductivity properties, and the change in temperature for divers in a confined space can be dramatic—even fatally so. The helium had also changed Richard and Dave’s speech pattern, so the supervisor had to use a special radio with a built in “unscrambler” to understand them.

While the needle on the internal gauge was racing to join its mate, both men wiggled their ears and jaws. In the bell van the supervisor started his stopwatch to track the bottom time of the dive. Richard had about 40 minutes to complete his inspection. The faster he blew down the more time he had for his lock out. And if he couldn’t finish the job (which was a cultural taboo), he still had to scamper back to the bell to begin his decompression schedule.

After a number of minutes both gauges displayed identical depths, and magically the heavy steel door beneath Richard’s feet dropped like a lid on a footlocker, turning the trunking into a small pool of quivering water. It was the gateway to another world.

The last thing Richard did was open his gas supply and pull on his mask. Shaped like a fiberglass catcher’s mask, it was banded to a rubber hood that zipped down the back of his head. A thick neoprene facial guard circumnavigated his head just in front of his ears and under his chin. This rubber barrier, along with positive pressure inside the mask, kept the water out. Richard’s mouth and nose were crammed inside a small oral-nasal mask connected to a demand regulator mounted on the outside. Surface gas was supplied when Richard inhaled. He could also free flow the mask if he chose to, but most divers avoided this because of the noise of the gas rushing into the mask. Two ear speakers and a small microphone allowed him to speak with topside.

Slipping his fins on, he gave a quick comms check. “One, two, three, four, five, how do you read me topside?” he said in a voice pinched by helium.

“Loud and clear,” came the response through his ear speakers.

From a wall‑mounted rack, Dave peeled off a few coils of Richard’s umbilical. Richard took these and shoved them down through the trunking, and then, like an Arctic seal diving through a hole in the ice, he suddenly vanished into the world that Neptune ruled.

In the water, bubbles exploded from Richard’s exhaust manifold and reverberated against his ears. He sounded like a patient on a life‑support machine. The noise was so loud he had to hold his breath to hear topside speaking to him. Despite what most people think, the sea is not a silent world at all. Every gurgle, every murmur and whisper from Mother Nature penetrated Richard’s ears in full‑volume stereo.

In the distance he heard the muffled roar of the jet sled.

“Diver in the water,” he said.

“Roger,” a voice came back.

Richard swung his body from under the trunking and took a quick look around to get his bearings. It was dark, but not pitch black. The bell lights reflected off a primordial soup like headlights on a foggy mountain road. A rope coming from above passed through a shackle on the side of the bell and down to the seabed. This was the “down‑line” and it was attached to the sled.

Gathering the items he needed, Richard wasted no time in telling topside that he was leaving the bell for the job site. “Slack the diver as he goes,” he said.

“Roger,” topside answered.

He took hold of the down‑line and began pulling himself along the rope through a suspension of tiny glassine life. Behind him, Dave was feeding his umbilical out through the trunking.

Hand over hand Richard followed the rope down into the gloom. The growing roar in the water was coming from a cloud billowing neon phosphorescence in the distance and the rope he clung to led right to the heart of it. Richard kicked and pulled. The roar kept getting louder. Seconds later he reached the seabed at the edge of the cloud. For a moment he stopped and looked back to check his umbilical. The image he saw was dreamlike. Against a curtain of black space, the bell hung like a glowing orb in the night sky with an almost divine presence. At 270 feet, it was Richard’s only safe haven if something should go wrong.

Adrenaline was now pumping furiously throughout his body. The roar was the roar of a thousand lions. The sled couldn’t be seen, but he felt its rumbling power through the vibrations in the water. It felt like an earthquake machine and Richard began flashing on the photographs of his objective, its components, the checkpoints, and the areas he was told to avoid. Somewhere within this black blizzard, the claw was slicing the seabed with streams of high pressure water while powerful suction pipes vacuumed up the spoil and blew it out to the side.

In the back of his mind, he felt the supervisor’s clock ticking. Holding tightly onto the rope, he gathered up his courage and with one deep breath plunged into the swirling tornado, his image disintegrating behind him.

For a moment Richard was lost, fumbling through the cloud with his arms outstretched, and then he collided with something hard and metallic. Over the clamor, he shouted into his mask, “On the job. All stop on the diver’s umbilical.”

Faintly, almost imperceptibly, he received a response from topside. “Roger, on the job.”

Inside the swirling vortex, Richard groped around on what he would later describe as “a giant mess of tubular struts, hydraulic lines, and various and sundry protrusions.”4 Moving carefully and deliberately, he measured distances, collected soil samples, checked the towing bridle, the tension on the supply hoses, the sled’s orientation to the pipeline, and reported to topside on the efficiency of the claw, whether or not it was cutting the trench as deep as it was supposed to. Checking all these things by “Braille” was dangerous work. Richard had to be extremely careful not to get himself or his umbilical near the suction pipes or the jetting nozzles around which he took his measurements.

After completing his checks, Richard emerged from the tempest and stood below the hovering bell. In the heat of the dive, there had been no time to evaluate his surroundings or assess its beauty; but away from the sled, the water was much cleaner and his eyes were adjusted now to the darkness. With the bell lights casting a soft glow onto the seabed like a lamp shade, Richard stood there staring at the vastness of his surroundings, letting the breathtaking strangeness of this alien world take possession of his senses. All alone and listening to the sound of his breathing exploding into a gray-black cosmos, it seemed like such an odd place to be. There were no rainbow colored fish, no beautiful kelp forests, no spiny black sea urchins, no frolicking sea lions, no majestic coral reefs, no landmarks, no rocks, no boulders—it was just a barren wasteland as flat as the corn fields of Iowa.

No one had ever set foot here before; Richard was sure of that. The panoramic lack of beauty, the awesome reality of what he was witnessing—its size and dimension so much greater than expected—Richard felt as though he were looking directly into the face of Mother Nature and it humbled him profoundly and filled his soul with a deep sense of peace. Had Neil Armstrong felt this way on the moon? Richard didn’t know, but he was overwhelmed by the universal power it represented. And in an instant, as he gazed through the boundless sea, he knew he had been transformed and that his birth on this new planet had been complete. Without terror or frame of reference, he was the first of his species to arrive. He blinked his eyes in wonder, and then he turned and climbed his umbilical, back to his mothership.

Once inside, Richard and Dave blew the water out of the trunking, closed both doors, and pressurized the bell another ten feet to seal it.

“Ready to leave bottom, topside.”

“Roger, coming up on the bell.”

Like an elevator, the bell was slowly hoisted back to the surface, and because it was sealed, the internal depth gauge remained frozen at 240 feet, while the needle on the external gauge began to reverse itself. At the same time, the supervisor began their decompression schedule by opening an exhaust valve on his control panel. The inside depth was gradually reduced until they arrived at the first decompression stop. The exhaust valve was then closed and the depth held for a prescribed number of minutes, after which the valve was reopened to bring them to the second stop. The advantage of decompressing the divers in the bell was that everything was controlled, the divers were dry, and they were inside the safety of the bell.

More scheduled stops followed and it was in this way—by not allowing the speed of the ascent to exceed the rate at which the blood and body tissues were “out gassing” through the lungs—that the danger of decompression sickness was avoided.

Meanwhile the deck crew had physically brought the bell out of the water and landed it on top of the entrance lock. The two chambers were then clamped together and the trunking pressurized. With no place to go, Richard and Dave just sat inside while the supervisor continued the decompression until they reached the depth at which the entrance lock was pressurized to. At this point one of them reached down and opened a small valve on the inside door allowing the pressure of the bell to equalize with the pressure of the entrance lock. After equalization, Richard and Dave pulled the inside door back, climbed down into the entrance lock, and then crawled through a circular hatchway into one of the living chambers to quickly don oral-nasal masks called Bibs.b These were used to vary the breathing mix to the divers in order to accelerate the decompression. Finally, after two and a half hours, Richard and Dave arrived back at surface pressure with bloodstreams still fizzing from the dive.

a Advanced Diving Systems IV.
b Built-in-Breathing System.

1 Letter from Richard Walker to Mary Ellen Fletcher, September 16, 1973.
2 Letter from Richard Walker to Mary Ellen Fletcher, September 26, 1973.
3 US Navy Diving Manual, 1973, Section 12 p. 26. In terms of volume, the bell was only 80 cubic feet or 2.26 cubic meters.
4 Letter from Richard Walker to Mary Ellen Fletcher, September 26, 1973.

10-12-2013, 09:41 PM
Hi Michael

I'm enjoying reading the articles you have posted. I think others on the Forum might be interested to know the sources of these. Did you write them originally? They are well-written but they don't sound like you just wrote them for this Forum :-)

Perhaps you could post in the Introductions Forum and tell us a bit about yourself?

Sent from my GT-P5110 using Tapatalk 4

Michael Smart
10-12-2013, 11:52 PM
Hi Michael

I'm enjoying reading the articles you have posted. I think others on the Forum might be interested to know the sources of these. Did you write them originally? They are well-written but they don't sound like you just wrote them for this Forum :-)

Perhaps you could post in the Introductions Forum and tell us a bit about yourself?

Sent from my GT-P5110 using Tapatalk 4

Thanks for the reply.

The source of these articles comes from a book I wrote about an infamous diving accident that took place in the Thistle Field in the North Sea in August 1979. What you are reading is some of the background material leading up to the accident. I would mention the name of the book, but the administrators of this website took down my initial posting when I revealed the name of the book (shameful plugging I suppose). But anyone using a good search engine will be able to discover the name of the accident and the book title just by typing in Richard Walker and Skip Guiel, or even my name.

My background is fairly common: Naui/Padi diver, underwater photographer, Padi instructor, then on to oil field diving in the North Sea in 1979-1986. I retired from commercial diving in 1988. The rest about me is presented in the Preface of my book.

11-12-2013, 07:08 PM
I have the book and it makes to some very interesting reading, half way through the book at the moment, very difficult book to put down

Drop me a pm if you want the title or obviously Michael

19-12-2013, 01:06 AM
i treasure this book like few other and will always recommend it to my friends and diving colleagues. if you are a diver and you haven't read this book yet, then do yourself a real favour and go order a copy. you can even download it as an e-book these days. believe me, you will treasure this book like few other.

i am sure the admin of this diving forum would like to join me in thanking michael smart in person for posting a few excerpts from his book on their worldwide diving forum for free. this enables and empowers many disadvantaged people around the world who can not afford to buy the book themselves. now at least they will be able to read some of it online for free. seems to me the diving world already owes a huge debt of gratitude to michael smart for his sheer determination and resolve to get the sad truth behind this sorry tale published and out there at last. so now all of us can own that truth.

then you will know the truth and the truth will set you free. John 8:32

but first it will seriously piss you off.

with thanks and deep respect to michael smart

rip richard and skip

Chris Brown
19-12-2013, 01:59 AM
Awesome! No wonder the commercial guys think we are crazy doing mix dives and deco floating intend open ocean:)

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Michael Smart
19-12-2013, 04:21 AM
Chris, Jonat1--
Thanks very much for the compliments.

11-09-2017, 12:22 AM
I just stumbled across this thread while doing research for an article about oil rigs. (I'm a journalist.) Your account of bounce diving in the North Sea is gripping, Michael, and fascinating for me because I was a rigger aboard the Cherokee for a year, from May 1973 through June 1974, and I remember Richard Walker. Chances are I would have been on deck on the day you describe, helping to prepare the bell and keeping the umbilical untangled as the bell was raised and lowered from the sea bottom. I always admired the divers; a brave and funny bunch. Now I'm planning to order a copy of your book.

11-09-2017, 06:18 AM
I am glad this thread popped up. I've been looking for a new diving page turner :)

Alex Denny
12-09-2017, 06:13 AM
So have I! I will definitely check the book out...