For 400 years, diving bells were the most common method of working underwater. The practice of lowering large airtight containers underwater, while divers put their heads inside them to gulp air, became common in the mid-fifteenth century. Diving bells (which got their name because large church bells were often used) were open at the bottom and needed to be heavy to overcome their positive buoyancy. They were usually lowered underwater from a ship or specially constructed floating platform, which meant their depth was controlled by the people above.
Improving the Diving Bell
But in 1775, a Scottish confectioner and an English slave abolitionist teamed up to design and build a wooden diving bell that could be raised and lowered by the diver when underwater. Charles Spalding (1738 – 1783) was the eldest child of a Scottish bookseller. He grew to become a successful confectioner, sugar refiner, grocer and wine merchant. In 1768, Spalding married Susannah Small, while his younger sister, Ann, married Susannah’s brother, George, who was a cooper (wooden barrel maker). When, six years after his marriage, Spalding’s attention turned to constructing a wooden diving bell, his brother-in-law was conveniently on hand to build it for him.
It was a shipwreck in the winter of 1774 that drew Spalding’s attention to underwater work. The brig Peggy was on its way to Edinburgh from London carrying a load of merchandise for Spalding. On the night of December 3, the ship was caught in a storm near the Farne Islands. The Peggy and two ships in its company were dashed on the rocks. The crews and passengers of the three ships perished. Spalding expressed interest in salvaging his cargo, and the owners of the Peggy commissioned him to attempt to recover what he could. Spalding immediately began researching diving bells and, assisted by George Small, built one. Spalding’s bell was small and barely came past the diver’s shoulders. It held eight cubic feet (226 L) of air and would have allowed a resting person to breathe for approximately twenty-five minutes. Spalding proposed to replenish air in the bell by lowering barrels of air from the surface.
In June 1775, he tested his bell in the Firth of Forth, just off the beach at Leith, near Edinburgh. He was assisted by his brother Thomas, as well as his brother-in-law, Small. Charles Spalding dived successfully to a depth of fifty feet (15 m). Confident he was ready to dive to the Peggy, he sailed for the Farne Islands, arriving on September 1. The summer was drawing to a close and, unable to find shelter on the islands, Spalding sought it ashore. He found accommodation with the Reverend Thomas Sharp, Archdeacon of Northumberland, in Bamburgh Castle. Also staying at the castle was the Reverend’s brother, the slave abolitionist, Granville Sharp (1735 – 1783). A month passed before the skies cleared and the seas calmed sufficiently to attempt diving. In the intervening time, Granville Sharp and Spalding must have spent many hours in front of a warm fire, discussing the problems of underwater exploration and survival, because Sharp turned his imagination to improving diving bells.
With clearer weather, Charles Spalding went out to the Farne Islands in a small boat, and assisted by others, dove in his bell to attempt to locate the wreck of the Peggy. But he was disappointed when, against his will, his crew hauled him up from sixty feet (18 m), insisting it was too dangerous. Poor weather forced him back to the mainland where, waiting for calm seas, Spalding realized he had neglected his business long enough, and returned to Edinburgh.
During the winter, Spalding and Sharp corresponded regularly, discussing the problems of Spalding’s first diving bell. The main drawback to be overcome, Spalding believed, was that the diver had no control over the ascent or descent of the bell. Only the people in the boat above could raise and lower it, or shift its position. And limited communication—at best tugging on a rope—meant the diver was unable to go where he wished in order to work on a wreck. After his experience of being hauled to the surface by a nervous crew, Spalding wanted to build a bell, the movement of which could be controlled by the diver.
Granville Sharp’s Diving Bell
Sharp proposed an idea whereby a hollow tube ran down the centre of the bell and a strong rope with a weight at the bottom passed through the tube, from the surface to the sea bed. The rope would take a turn around a friction wheel within the bell and by means of foot pedals, one or two men could pedal the diving bell up and down. Spalding wasn’t convinced Sharpe’s idea would work. His main concern was that the rope running through the centre of the bell would become tangled. Instead he suggested a weight could be suspended from a block and tackle arrangement inside the bell. The divers would first lower the weight to the seabed, then pull themselves down against the positive buoyancy of the bell. They could also feed the rope out to return to the surface. Spalding and Sharp also discussed altering the buoyancy of the bell by means of a ballast tank built into the crown. The divers would begin with the tank filled with water, to assist the bell sink. During a dive, a tap could be opened so that the water in the tank emptied into the main chamber, and the reduction in weight would increase the bell’s buoyancy.
Spalding built his second diving bell in 1777. It was larger than his first and was large enough to have two adults sit inside it. It included the ballast tank, while a 300 pound (136 kg) weight was suspended inside by means of a twin block and tackle arrangement. Spalding returned to the Farne Islands to test his second bell and afterwards reported to Sharp:
“I proceeded with Confidence and all caution possible; my success was such that I found I could do anything below the water that I pleased, and proceed with the greatest ease by being rendered half Buoyant myself. Neither did I feel the least tendency in the machine to incline to one side more than the other, although the rope was made quite slack, part of it lying on the ground and dragging after the machine.”
Even with the successful trials of his innovative bell, Spalding appears to have lost interest in it, because he did not dive again for five years. When he was lured underwater again, it was out of concern for the safety of his brother, Thomas. The event that triggered Spalding’s return to the water was the sinking of HMS Royal George on August 19, 1782.
The Royal George was a 100 gun warship of the Royal Navy, and when it had been launched in 1756, was the largest warship in the world. It was undergoing routine maintenance when, embarrassingly for the navy, it keeled over and sank at its moorings. Eight hundred people drowned, including many women and children were on board visiting the crew. The massive ship came to rest in eighty feet (24 m) of water, with the top of its mast still showing, and was an impediment to shipping in the busy port. The Admiralty wanted to recover what cannon it could and smash what remained of the wreck.
By coincidence, Spalding’s brother Thomas, who had assisted him test his first bell and was now a ship’s surgeon, was at Portsmouth when the Royal George sank. Thomas Spalding immediately approached the Admiralty and suggested they build a diving bell along the lines of his brother Charles’ design. The Admiralty wasted no time and within three weeks of the sinking, its carpenters were putting the finishing touches to bell with a block and tackle inside, from which hung a 336 pound (152 kg) weight that could be lowered to the deck of the Royal George. The royal Navy’s bell measured five feet (1.5 m) in diameter at the bottom, three feet six inches (1 m) at the top, and was slightly taller than Spalding’s bell. Two smaller diving bells were to be used to send air down to the larger one.
Thomas Spalding wrote to his brother to inform him the navy had constructed a bell similar to his design, and that he intended to operate it. Thomas also invited Charles to come to Portsmouth and assist him. In a letter to Granville Sharp, Charles Spalding expressed his concerns about the dangers of diving in a bell amongst the rigging of a sunken ship:
“I know not what to do! My brother engaged in Honour, and unacquainted with the service, may very rashly lose his Life, in an attempt that requires the greatest coolness and experience; it is so dangerous to venture along side of a full rigged wreck that I would not venture myself without a friend here Mr [George] Small who has always been with me in all my trials and Experiments in the large improved machine.”
Thomas Spalding dived the bell to test it on the evening September 6, and stayed underwater for thirty-seven minutes. The next day he was taken by boat to the Royal George. Thomas Spalding, along with a former African slave, John Winer, who was reputed to be a good swimmer, was lowered thirty-six feet (10 m) to the deck of the sunken ship. Thomas Spalding and Winer made a series of dives on the Royal George over the coming two weeks. Most dives lasted more than an hour and the maximum depth reached was forty-two feet (13 m). But they achieved little, other than to prise free bloated bodies, which floated to the surface.
Thomas Spalding went back to his work as a ship’s surgeon and, on October 2, his brother Charles, along with George Small, arrived to take over the operation. Charles felt the Admiralty’s big bell was cumbersome, and could easily become tangled in the Royal George’s rigging, so he converted the navy’s two smaller bells, which had been used to replenish air, into one-man diving bells. The smaller, more maneuverable bells allowed the divers to work more readily. By the beginning of November, Charles Spalding had recovered cannon and other valuables from the wreck.
He also suggested, in a prophetic letter, that it might be possible to compress air to thirty atmospheres in a ten-gallon (37 L) copper vessel and use it to replenish air. It was not an idea that was followed through, but nevertheless, Spalding had suggested air be compressed on the surface before it was lowered to a diver.
Spalding also complained of cramps in the legs after long dives and put the symptoms down to the cold, but he was possibly experiencing mild decompression sickness.
Salvaging the Royal George eventually ceased for the winter, and the following spring, Charles Spalding learnt that his services were no longer required. Instead, the Admiralty had hired a William Tracey, who lived in Portsea, to salvage the Royal George. Tracey, along with other local salvors, made attempts to raise or destroy the wreck the following summer, but failed.
Meanwhile, Charles Spalding’s interest in underwater work had been reawakened and, disappointed he had not been invited to return to the Royal George, he cast around for other potentially lucrative salvage jobs. He fixed his attention on the wreck of the Count de Belgioso, which had recently gone down with an expensive cargo near Dublin Harbor, Ireland. Spalding chartered a ship and took his diving bell to Dublin.
He started diving the wreck with his nephew, Ebenezer Watson, on June 1, 1783. On the first day he made three dives to forty-two feet (13 m). The next day Spalding and Watson went down again. After more than an hour the surface crew became concerned and hauled the bell up to find Spalding and Watson were dead. Why they died has remained a mystery. It appeared they had made no attempt to cut the rope attached to the ballast weight and float to the surface. That pointed to the fact that Spalding and Watson had died instantly, rather than through slow suffocation. Some people have suggested that the rotting bodies on the wreck, or the rotting cargo of ginseng plants, released toxic hydrogen sulphide, and the occupants of the bell were poisoned.
Charles Spalding, with intellectual input from Granville Sharp, had developed a wooden diving bell that could be controlled by the occupants, but at a critical time his invention had failed to save his life.
Charles Spalding’s Diving Bell is an edited extract from the book, The Frontier Below: The Past Present and Future of Our Quest to Go Deeper Underwater by Jeff Maynard (HarperCollins). It is available at booksellers and online.