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Dublin's Diving Bell
1866-1958

Article and photos from St. Andrew's Resource Centre, Pearse St. Dublin 
and Tony Brennan.

The Diving Bell was built to the design of Dublin Port Engineer Bindon Blood Stoney by Grendon and Co. of Drogheda , Co. Louth, and was delivered to Dublin in 1866.

It was constructed from 25 iron castings with planed joints, bolted together.

George Strype of Grendon and Co. designed the horizontal air pump and air tube which con­nected from the air pump into the Bell, passing down the inside of the lower section of the fun­nel. The surrounding water cooled the com­pressed air before it was fed into the chamber at between 50° and 60° Fahrenheit. In practice, it became unbearably hot inside the chamber on occasions and men could not work for longer than 30 minutes consecutively. Continuous working, therefore, required two shifts, each consisting of a supervisor and up to five men. They worked in an area of 400 square feet, the size of a good sized domestic living room.

South quay 2008

Ladders, both inside and outside the funnel provided access via the airlock at the top of the funnel. The Bell was sup­plied with electric light, although glass panels in the roof of the chamber allowed natural light to illuminate the interior of the chamber so that work could regularly proceed without artificial light. The Bell also had a tele­phone connection with its support vessel, the Bell Float.

The hull of the Shears Floating Crane was built by Harland and Wolff of Belfast, while Courtney and Stephens of Dublin supplied the machinery. It was delivered to Dublin in 1866, at a final cost of £17,058.  

The Diving Bell has a chamber 20 feet square at roof level and 6 ½  feet high inside. It is constructed L from 25 iron castings, with planed joints, which I were bolted together. From the centre of the roof a tube (or funnel), 3 feet in diameter, rises 37 ½  feet. The total height of the chamber and the tube is, therefore, 44 feet. This is the limiting depth at which the Bell was capa­ble of working. The upper end of the tube forms an airlock 6'ti feet high. The total weight of the Bell and access funnel is almost 90 tons.

The Bell was raised, lowered or positioned by lifting gear, incorporated as part of its support vessel, the Bell Float. This vessel, which did not have self propulsion, and, therefore, had to be positioned by a steam tug, was 80 feet in length, had a 30 foot beam with a 8 foot draught and a concrete counter weight located at its bow to bal­ance the weight of the Diving Bell, which was operated over the stern of the Bell Float. When the Bell was out of the water the balancing system left a safe freeboard at the stern of the Bell Float.

It was used by groups of up to six workmen, who levelled the river bed from inside the Bell .

An accompanying float and crane, the Shears Float, then lifted large prefabricated concrete blocks, each weighing up to 350 tons, into place on the prepared river bed. These blocks, each reaching from 20 feet below low water (LWOST) to three feet above, were then bonded together to form the quay wall.

Diving bell  Construction

In its simplest form a Diving Bell is an inverted container, open at the bot­tom, with an access funnel topped by an airlock. It is lowered into the water and, as it descends, a quantity of air becomes trapped between the water and the airlock. The air thus trapped becomes compressed by the grow­ing water pressure as the water level inside the Bell rises.

When the external wall of the Bell rests on the bed of the river or bay, air is pumped via a flexible hoseline into the Bell . The rising air pressure gradu­ally expels the water from the Bell and the walls of the chamber settle solidly on the mud, silt and sand in the area to be worked.

The shaft extends above the surface of the water when the chamber rests on the bed of the river. The shaft provides access for the workmen to the work­ing area on the bed of the river. The air was pumped through a flexible hose from a steam powered unit on board the Bell Float into the chamber to dispel the water.

The Diving Bell has a chamber 20 feet square at roof level and 6Y2 feet high inside. It is constructed from 25 iron castings, with planed joints, which were bolted together. From the centre of the roof a tube (or funnel), 3 feet in diameter, rises 37Y2 feet. The total height of the chamber and the tube is, therefore, 44 feet. This is the limiting depth at which the Bell was capa­ble of working. The upper end of the tube forms an airlock 6½ feet high. The total weight of the Bell and access funnel is almost 90 tons.

The Bell was raised, low­ered or positioned by lift ing gear, incorporated as part of its support vessel,
the Bell Float. This vessel, which did not have self propulsion, and, therefore, had to be positioned by a steam tug, was 80 feet in length, had a 30 foot beam with a 8 foot draught and a concrete counter weight located at its bow to bal­ance the weight of the Diving Bell, which was operated over the stern of the Bell Float. When the Bell was out of the water the balancing system left a safe freeboard at the stern of the Bell Float.

This particular Diving Bell was designed by Dublin Port engineer, Bindon Blood Stoney, and was used extensively in the development of the Port from 1871 to 1958.

It was used by groups of up to six workmen, who leveled the river bed from inside the Bell .

An accompanying float and crane, the Shears Float, then lifted large prefabricated concrete blocks, each weighing up to 350 tons, into place on the prepared river bed. These blocks, each reach­ing from 20 feet below low water (LWOST) to three feet above, were then bonded together to form the quay wall.

Working the bell

The crew of the 90 ton Diving Bell comprised up to six men. They daily descended through the air lock of the Bell into the well-lighted,400 square foot chamber in which they worked.

There were complicated regulations which had to be observed during entry to and egress from the Bell . The men entered the airlock in the funnel, closing the door behind them. Compressed air was pumped into the Bell chamber and the airlock. When the pressure equalized between the two areas and the men adjust­ed to the different air pres­sure, they opened the bot­tom door and they descended via the ladder to the chamber. There they worked under a pressure of about 201bs. per square inch. They could walk on the river bed, talk, (even sing on occasion) and communicate with the sur­face by telephone. Sometimes the river bed consisted of mud, up to 2h feet deep. The men wore thigh high waders in these conditions.

On exit from the Bell , the men had to again pass through the airlock, which was their safety valve. They had to spend at least five minutes passing through the airlock. If this precaution was ignored bleeding from the ears and nose could follow. In fact, they might even develop "divers' bends", a painful 'e condition, the only cure for which was to re-enter the compressed air of the Bell again and re-surface slowly.

The most exacting experience for the under­water crew was when they had filled the platform and bins inside the Bell cham­ber with the spoil from the river bed. The Bell was then moved by its support­ing float to a new location within the port area to tip the spoil. This was accom­plished by raising the Bell a few feet above the river bed and towing it to the new location. The com­pressed air prevented the water from entering the chamber, where the crew would have climbed onto the platforms. Initially the water rose inside the Bell but was finally arrested by air pressure, while the crew stood on their plat­forms. However, the cold water coming in mixed with the humid atmos­phere in which the men had been working inside the chamber, resulted in heavy fog forming in which the crew could hardly recognize one another.

Not a job for the faint hearted!

Joe Murphy, last supervisor to work the diving bell 1958.

The Diving bell was an unbelievable piece of engineering ingenuity. In the deep water beds you had to work by the tide. We started diving at half tide, that is three hours after high water. We would do a five hour dive which meant we were back up out of the Bell when the water was about the same level on the next tide.

Sometimes we had to start work at two or three o'clock on a dark and cold winter's morning. Of course, we had electric light and the telephone. However, there were only a very few men who could handle the claustrophobic nature of the work, with the compressed air and the small working area.

With the heavy pressure a lot of men would bleed from the ear and the nose. Ordinary divers, like our­selves, with no diving suits, would go through torture while we were compressing and decom­pressing, if we had even a head cold. I actually had my left ear blocked on three occasions where the eardrum fills up with blood. It is very painful unless you get to a hospital quickly and have it pumped out.

When the Diving Bell was positioned on her marks by the Bell Float, you were brought to the Bell Float by a small launch. A plank was laid between the Bell Float and the chamber of the Bell . You walked across the plank and entered the air­lock. Usually the charge hand would go first with two other men into the air­lock of the chamber. The top door of the chamber was closed over the heads of the men inside. We then turned on the compressed air from the actual Diving Bell chamber below and allowed it to enter the air­lock chamber When pres­sure in the airlock and in the Bell chamber is balanced, the bottom door of the airlock opened down­wards and the men climbed down the ladder onto the staging inside the Bell chamber. The last man going down the access funnel would then close the bottom door of the airlock over his head. This made the airlock available for the rest of the squad to enter. When they decompressed the airlock by an external lever they were able to open the top door. They then went through the same process again and eventually joined their colleagues in the Diving Bell chamber.

Sometimes weird things happened during this procedure. I remember one of our squad, Jack Fagan, had a small bottle of milk in his pocket with a cork in it. The next thing was the cork flew out of the bottle in his pocket. On another occasion, Gerry Hardy had a packet of cigarettes - Gold Flake, they were, if you remember them, they were before the filter tips. The packet was only about half full. When he got down to the Diving Bell chamber, the packet was flattened. At one end he had cigarettes and at the other end was nothing. We had a great crew in that Diving Bell. As well as Jack Fagan and Gerry Hardy, we had Jimmy Allen and Sonny Lee. They were the squad that worked with me in the Diving Bell and they were a really great crew.

On another occasion we were asked to take a man from Trinity College down with us in the Diving Bell. We were due to dive at 4a.m. that morning and when I arrived on board the Bell Float the skipper, Jem Clancy, said I had a visitor down below. I went down to the fo'c'sle and this man, in a white trench coat, white shirt and brown shoes introduced himself to me. He had been deep in conversation with some of the Diving Bell crew who were there ahead of me.

When the time came to go to the Diving Bell, Jack Fagan and Gerry Hardy said to me that they were not feeling up to it. I argued with them and it turned out that our visitor had been telling them about the effect of com­pressed air on the internal parts of the body and on the brain. Anyway, they relented and we all went ahead, including our visitor.

I asked him if he had ever dived before. He said he had not, but he had read a lot about it. I told him he was now going to see the real thing.

We instructed him what to do in the airlock cham­ber. However, about mid­way to compression our visitor began wriggling all over the place. We informed him that we could not decompress - we had to go the whole way. We had to hold him down and he began bleed­ing out of his nose and one ear. We were dressed in sea boots and dungarees, while he was still dressed in his white trench coat and shirt. So we com­pressed and decom­pressed. We got him out of the airlock chamber back on board the Bell Float.  Jem Clancy called up the Pilot Station, we got a launch out, took our visi­tor ashore and brought him to hospital. We never heard from him again, except we know he recovered.

On another occasion two of our electricians were asked to attend a doctor. When one of them discovered it was to the Diving Bell (having steamed open the doctor's report to the Chief Engineer), he said he would not risk it. The other electrician, Jimmy Gaffney, said he would give it a go. Four or five hours later, he arrived back at the electricians' shop, bleeding from one side of his nose. When he was asked what hit him he said he got a belt of com­pressed air. He had opened the valve too quickly - it was stiff and he had jerked it open. The regular divers were accustomed to deal­ing with it.  
Johnny Reilly had been the shipwright diver supervisor in the Diving Bell before me. When I got involved with the Bell , Johnny began diving wearing a diver's suit and the old CB Gorman cop­per helmet. He would have a support boat with him and had to wear lead boots. When the Diving Bell and Bell Float were laid up in 1958, I took over diving wearing the suit, helmet and lead boots from Johnny Reilly, who had been promoted to foreman shipwright.

The Bell Float, with its heavy lifting gear capable of lifting the Diving Bell, also did a lot of general lifting around the port. She was used to lift dock gates. She could lift a complete Arrol crane, ballast weight and all. When she was scrapped, I saw contractors come into the port to move cranes. They had to dismantle them (nuts, bolts, beams, girders, the lot) then transport them to the new location where they would reassemble the crane. This was a job that could previ­ously be carried out by the Bell Float in one opera­tion.

The last job on which the Diving Bell was engaged was the construction of the new lead-in jetty, on which work began in about 1953. The bucket dredger Deepworker came in to dig the trench in which the caissons were to be laid. Using a bucket dredger meant that the trench was full of ridges. The Diving Bell and crew were brought in to level the ground to dead flat.

A caisson was towed in, put on its marks, the valves opened, the caisson sank onto the levelled ground, with about two feet show­ing above low water. Uprights were bolted to this and shuttering panels put up to build the upper section of the quay wall.

A caisson, by the way, is a large concrete box built on a slipway, launched and towed into position before being sunk onto a prepared riverbed. In Dublin caissons were usually 50 feet long, 30 feet wide and 10 feet high before launching. They were then floated and towed off to a construction jetty where they were topped up to whatever was the necessary height. This was sometimes up to 42 feet high to enable the top of the caisson to be fin­ished off as an acceptable quay wall.

The shortest job I ever recall or heard of with the Diving Bell was just before it was laid up. The Bell was brought in to work for one day only on the cill of No. 1 Graving Dock, the older dry dock at Dublin Port. "

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