Turtle Bunbury

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'Dublin Docklands - An Urban Voyageis a work in progress, commissioned by the Dublin Docklands Development Authority, and due to be completed in the autumn of 2008. The following tale represents research I have undertaken for the project which may or may not be used in the final book.

Dublin’s Diving Bells

Origins of the Diving Bell

Amazingly, the idea of a diving bell dates back to the Greeks. Writing in the 4th century, Aristotle remarked on how divers were able to breathe perfectly when submerged in a cauldron ‘for this does not fill with water, but retains the air’. In 1535, Italian physicist Guglielmo de Lorena created and used what is considered to be the first modern diving bell. In 1628, a diving bell was used to salvage more than 50 cannons from the Swedish warship Vasa shortly after it sank. In 1690 Edmund Halley - he of the Comet – devised a bell capable of remaining submerged for extended periods of time, and fitted with a window for the purpose of undersea exploration. In Dr. Halley's diving bell, atmosphere is replenished by sending weighted barrels of air down from the surface.

Charles Spalding & the Belgioso Treasure

Considerable advances on the quality of diving bells were made by Charles Spading, a Scottish mechanician who ran a confectionary shop on the Royal Exchange in Edinburgh.[1]. In 1783, Spalding and his nephew Ebenezer Watson suffocated while experimenting on further improvements to the bell in Dublin Harbour. The two men were hoping to gain access to the Belgioso East Indiaman, a Portuguese ship sunk at Kish Bank in Dublin Bay which reputedly had a treasure chest of 60,000 Spanish dollars, as well as valuable cloth and ginseng. Rumour had it that Spalding’s assistant, a rival, deliberately ignored signals to pull them up for fresh air but it seems more likely the signal ropes simply became entangled.[2] Two years later, reports came of ‘a black man, famous for diving into the deepest waters’ being lowered into the sea in a bell in the hope that he might fasten ropes to the iron rings on the legendary treasure chests. The bell was described as ‘a very large bucket turned upside down, with a metal ring in the upper end … across the open end was a strong iron chain on which the diver might sit with his head and body in the bucket and his legs in the water’. To envision such a bell, one author suggested ‘plunging a wine-glass with its mouth directly down into a bowl of milk or ink when it will be observed that though either should cover the glass, none will get inside’. The black man reappeared after 28 minutes ‘in a violent heat’ but would not speak to anyone. He then went back down for a further 15 minutes. At length, redressed in waistcoat and short, a brandy in hand, he told his audience how the ship was nearly covered in sand and that he was unable to break into the ship’s hold with his boat-hook.[3] The treasure presumably remains down at Kish Bank.

Dr Colladen & the Bends

The Scottish engineer John Rennie used a diving bell in the construction of Howth Harbour between 1809 and 1819. In 1820, Dr Louis Colladen of Geneva visited Howth to study this Diving Bell. It weighed about four tons and the upper part was pierced with eight or ten holes into which were fixed very thick convex glasses to transmit light. At the very top of the bell was a hole one inch in diameter into which a long flexible leather pipe was inserted. This pipe would remain above sea level and, by use of a syringe pump, enabled fresh compressed air to be dispatched down to the bell itself. This helped to balance the pressure within the bell itself. Communication between bell and boat was surprisingly easy – the slightest tap on the interior of the bell could be heard above, although no noise made above ever reached the bell. Having mastered the art of squeezing his nostrils and swallowing hard, the courageous Doctor headed down to the water with some men, including his assistant who, to his delight, proved claustrophobic and got the bends. ‘He was pale, his lips were totally discoloured; his appearance was that of a man on the point of fainting … this appeared to me more remarkable as my case was totally the reverse, I was in a state of excitement resembling the effect of some spirituous liquor’. He observed that it was almost impossible to hear anything, not even his own voice shouting. He subsequently praised it to the Royal Society as ‘one of the most useful of machines, not only in the practice of submarine architecture at great depths, but in mining or exploding the rocks which obstruct the entrance of harbours, or in obtaining from the bottom of the sea any valuable goods which may have been lost near the coast’. It was also useful for those seeking to study the fuci, geology and marine animals, or, of course, find treasure.

The Exploding Tactic

Rennie’s bell was designed to hold a half-dozen men at one time. In the case of exploding rocks, the tactic was for three men to go down in a bell, bore a hole, insert a tin cartridge full of gunpowder, solder a tin pipe to the cartridge lid, and keep extending the pipe until they were all back above sea level and on board. Another man then scuttled out to the pipe in a boat, dropped a red-hot bit of iron down the pipe and rowed away quick as he could before the gunpowder ignited and blew up the rock.

Hardy Conditions

These men were often down for five hours a day without coming up for air, irrespective of season, temperature or tide. Dr. Colladon noted they tended to be ‘rather relaxed in their bowels’ which he assumed to be ‘owing to their feet being constantly wet and cold’. He also noted that none of the men he met had become deaf and suggested that it might even be a cure for such a malady. He described the workers as stout and healthy, living on three substantial meals a day with tea, bread, butter, eggs, bacon, potatoes and fish as their common diet. He felt they were ‘not particularly addicted to spirituous liquors ... a little is very necessary for them, and it would require a good deal to affect them much’.[4]

The North Wall Diving Bell

In 1864, Bindon Blood Stoney, Chief Engineer of Dublin's Port and Docks, was given the go ahead to proceed with the North Wall Extension. His plan was to use 350 ton super-blocks of prefabricated cement, to be put in position by means of a special floating crane and diving bell. In October he accepted a tender from Harland and Wolff, the Belfast firm, for the shear float, and that of Thomas Grendon & Co of Drogheda, Co. Louth, for the diving bell. Both bell and float were delivered in 1866 and work finally commenced on the project in 1869.[5] Stoney’s 90-ton bell was lowered into the water by cables from a floating bell crane. The bell was designed by Stoney and constructed from 25 iron castings with planed joints, bolted together. A horizontal air pump and air tube, designed by a young George Strype (1847 – 1898) of the Grendon Foundry, connected to the Bell, passing down the inside of the lower section of the funnel. This enabled the compressed air to be cooled before it was fed into the chamber. However, the bell chamber invariably became so hot that men could not work in it for more than 30 minutes at a time. This translates unfavourably when compared to the five hour shifts the men were working in Rennie’s bell forty years earlier. Continuous work require two shifts, each consisting of a supervisor and five men, levelling the sea-bed and preparing it for the prefabricated cement blocks. The pressure was particularly tortuous for anyone with a headcold; ears were frequently to be seen bleeding. Few men could handle the claustrophobic nature of the work, between the compressed air and the small working area.

The area the bell covered was, in fact, a relatively large 400 square feet, about half a tennis court. The funnel had a diametre of 3 ½ feet and rose 37 ½ feet high. The height of funnel and chamber combined allowed the men to get 44 feet down. To get in, the men, clad in dungarees and sea-boots, clambered up a ladder on the funnel, into an airlock chamber and, once the pressure balance was in order, down the inside of the funnel by another ladder. The bell chamber was 20 feet square at roof level and 6 ½ feet high inside. The chamber was illuminated by an electric light and glass panels in the roof. There was also a very basic telephone connection to the float above. Stoney’s bell continued to be used until 1958. One of its last jobs was work on the cill of No. 1 Graving Dock, the older dry dock at Dublin Port.[6] It now stands nobly upon the side of Sir John Rogerson’s Quay, close to The Ferryman.

[1] London Encyclopaedia; Or, Universal Dictionary of Science, Art, Literature & Practical Mechanics, Thomas Tegg, Vol. XX, p. 716 (London, 1829).

[2] Dublin: A Cultural History, James Higgins, Siobhán Marie Kilfeather, (Oxford University Press, 2005), p. 64.

[3] Stories for Short Students, Or, Light Lore for Little People, the Rev. Edward Mangin, p. 151 (John Harris, London, 1829). Finding the treasure was also an ambition of John and Frederick Braithwaite, a father and son team who had considerable success hauling anchors and ordnances from ships sunk at Portsmouth and Gibraltar. John Braithwaite was a fire-engine maker in London and had devised a new mechanism by which the bell was connected to a boat above by a leather tube down which fresh air was pumped. However, he was too late for the Belgiano; that contract had already been awarded to another man.

[4] Dr. Collaton’s Narrative of a Descent in the Diving Bell, The Edinburgh Philosophical Journal 1821, p.8.

[5] 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.

[6] Dublin's Diving Bell (1866-1958), Tony Brennan, St. Andrew's Resource Centre, Pearse St. Dublin. http://www.irishships.com/dublins_diving_bell.htm




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