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Michael Smart
10-12-2013, 09:25 PM
By late May 1976, five divers had already died while working on oil and gas projects. One case in particular bears special attention because it demonstrated how the role of safety could be subjugated by the interests of a powerful oil company and that diving from a heaving ship was infinitely more perilous than diving from a stable barge.

For a second time the incident involved drop weights, with the fatality resulting from another accidental bell surfacing of the kind that killed the two Ocean Systems’ divers in 1974, and by a chilling coincidence it occurred on exactly the same day, January 17.

Under a contract to provide diving services to Hamilton Brothers in the Argyll Field, Comex Diving Limited installed a portable saturation system on the stern of a small supply vessel known as the Smit Lloyd 112. The stern was a convenient location from which to launch the bell, but it was also an area most susceptible to heave. By late August 1975, the ship had arrived in the field to commence work,1 and as the winter months approached, rough seas repeatedly caused diving operations to be aborted due to the difficulty of getting the bell through the splash zone as well as it bouncing on the end of its lift wire like a yo-yo.2 To get the bell through the air/sea interface more rapidly, Comex officials authorized the dive crew to add additional weight, but this, too, proved ineffective.3

Unhappy that their work schedule was being adversely affected, Hamilton Brothers began to apply pressure upon Comex to remedy the situation.4 A meeting was called to discuss the situation, and according to the Comex Diving Safety Manager, the oil company “demanded” that the diving system be adapted to allow operations to continue in more marginal sea conditions.5 The client’s basic concern, the project manager would later testify, “was to get a system with increased efficiency as quickly as possible.”6 To Comex, the message was clear: either fix the problem or get off the job.

With the threat of losing a lucrative contract looming, Comex decided to take a completely unorthodox approach to solve the problem of the yo-yo effect. Instead of suspending the bell over the job site, the company decided to allow the crew to modify the bell to set it directly onto the seabed, a procedure never used in the North Sea before. To counteract the effect of a heaving ship on a slack bell wire, Hamilton Brothers instructed another company to build and install a heave compensator to act as a shock absorber for the system.7

Like most diving bells of that era, the one on board the Smit Lloyd was fitted with a drop weight which was flat and doughnut‑shaped and rested like a steel collar around the perimeter of the trunking just inside a protective bumper guard. When work began on the modifications, the doughnut weight was removed and replaced with a heavier 2.2 metric ton weight tray which was slung beneath the bell by two wire strops. These strops were attached by lengths of chain to a pair of drop weight release pins mounted on the hull of the bell.8 The new weight tray now functioned as the drop weight, and when the system was in operation, it would rest upon the sea floor while providing ballast for the buoyant bell floating about six feet above. Unfortunately, when Comex constructed the lead‑lined tray, it neglected to provide holes in the bottom to negate whatever suction force the seabed might impose upon it as well as the more vulnerable release pins.9



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By October, the tray was installed, but the heave compensator had not yet been fabricated. Nevertheless, Comex was prepared to dive the bell without it, and did so. On a routine dive that month, the ship was pitching up and down like a hobby horse as the crew began lowering the bell with Derek Bannister and a man named Brorurd inside.10 At about 30 feet or 30 meters from the surface, Bannister couldn’t be sure, he felt a “sudden jolt.”11 The next thing he remembered, the bell was on the surface and he was looking through one of the lower portholes at a pair of broken chains. The weight tray had come free. No one was injured apart from “the odd bruise,” Bannister said, because the bell had remained sealed with the inside door closed.

Shaken by the accident, Bannister went on leave while Comex built an identical weight tray (the original was abandoned on the seabed) and equipped it with stronger, more fortified sling components. By the time Bannister returned to the ship in mid‑January, the heave compensator had been installed and tested, at which time Hamilton Brothers discovered that a pipeline connection near one of its subsea satellite wellheads was leaking oil. They instructed Comex to repair it. A young Texan by the name of Clay Ellis and John Mallin were originally slated to make the dive, but by the afternoon of the 17th, Bannister volunteered to take Mallin’s place.12

One of the guiding principles of safe diving is to keep the bell above seabed obstructions at all times, particularly subsea wellheads which are box‑kite‑shaped structures that tower 20 to 30 feet off the mudline. For this reason, the decision by Comex to conduct a dive that put the bell into direct contact with the seabed and in close proximity to a wellhead was a dangerously ill-conceived plan. It may have served the interests of Hamilton Brothers, but it deliberately and unjustifiably put Bannister and Ellis at greater risk. If the Smit Lloyd suddenly dragged her anchors or was mistakenly moved in the wrong direction by an order from the diver, the bell could impact and snag on the wellhead with potentially disastrous results.

At 1722 the launching of the bell went according to plan and Bannister and Ellis came to rest in 256 feet of water approximately 10 to 15 feet from the wellhead.13 Argyll oil at that time had only been flowing for about six months so the surrounding seafloor was still covered in drill mud, a thick, gooey substance used during drilling operations. Twenty‑year‑old Ellis exited the bell, traveled down the pipeline at the full length of his umbilical but could not reach the leaky connection. He could see it, but he couldn’t reach it.14

He had to move the bell.

Communications through his mask was poor so Ellis returned to the bell and stood on the bottom door with his head inside the trunking. He took his mask off and instructed topside in which direction the ship should move. Topside then disengaged the heave compensator and began hoisting the bell. It took some force to break the weight tray out of the mud—one engineer would later calculate as much as “20 times the maximum force that the release mechanism could withstand.”15

This action, along with the shock applied to the bell wire from the heaving ship, sheared one of the bronze release pins and completely bent the other connecting the weight tray to the bell.16 There was a loud bang and Bannister called out for topside to stop what they were doing. Seconds later there was another bang. With no ballast securing the bell to the bottom, it started to shoot to the surface, main lift wire and umbilical trailing behind.

As the bell soared to the surface, expanding gas bubbled noisily out of the trunking. Ellis lost his footing and would have fallen out had Bannister not managed to grab him and pull him inside. With the atmosphere fogging from the rapid decompression, Bannister was still struggling furiously to close the inside door when the two men arrived on the surface forty‑five seconds later. Eventually he got the door closed and started to re-pressurize the capsule, but in the desperation of the moment something had fallen across the face of the hatch preventing a seal.a Moments later the two men blacked out from the lack of oxygen in the now‑depressurized atmosphere. When Bannister regained consciousness hours later, he was paralyzed from the chest down and Ellis was dead.17

Clay Don Ellis was “mad about diving” his mother would say to reporters,18 and he was the 27th diver to die in the North Sea since the government began collecting statistics on fatalities. Immediately after the accident, Comex reinstalled the doughnut weight.19

Strangely, the Department of Energy, the agency responsible for investigating diving accidents, did not make an official inquiry into Ellis’s death, having been persuaded by Comex that current safety regulations did not cover diving operations on subsea pipelines.20 To close this apparent gap in the legislation, new regulations were quickly drafted and by July 1976, the Submarine Pipe-lines (Diving Operations) Regulations were put into effect. For the next five years, they would set the minimum standard of safety for diving in the North Sea.


a Bannister suggested in court that it might have been a glove.

Endnotes:
1 Ellis FAI (Fatal Accident Inquiry Transcript), p. 198.
2 Ellis FAI, p. 198.
3 Ellis FAI, p. 261.
4 Ellis FAI, p. 228.
5 Ellis FAI, p. 47, 204.
6 Ellis FAI, p. 264.
7 Ellis FAI, p. 355. There was no mention in court records about compensating the bell umbilical as well.
8 Ellis FAI, p. 233.
9 Ellis FAI, p. 80-81.
10 Ellis FAI, p. 302.
11 Ellis FAI, p. 302-303.
12 Ellis FAI, p. 412.
13 Ellis FAI, p. 321.
14 Ellis FAI, p. 306.
15 Ellis FAI, p. 112.
16 Ellis FAI, p. 113, 121, 124, 165, 169, 181.
17 Carson, W. G., The Other Price of Britain’s Oil, p. 69.
18 Press and Journal, January 19, 1976.
19 Ellis FAI, p. 242, 379.
20 Ellis FAI, p. 297.

Baron015
11-12-2013, 12:49 AM
Interesting story. What is a glove, in this context ?

GLOC
11-12-2013, 12:58 AM
Interesting story. What is a glove, in this context ?

"Eventually he got the door closed and started to re-pressurize the capsule, but in the desperation of the moment something had fallen across the face of the hatch preventing a seal.a "

Third last paragraph.

Regards

Michael Smart
11-12-2013, 01:01 AM
Interesting story. What is a glove, in this context ?

A neoprene glove, part of the hot-water suit. But after it goes under pressure many times, it loses a lot of its body. Not much insulating power then.