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Diving bell

technology Maturity 11-13 Next article →

A diving bell is a rigid chamber used for underwater work. It transports divers from the surface to great depths.

L-Taucherglocke
L-Taucherglocke

These devices are not submarines. Occupants cannot steer or control them independently. Instead, a bell is suspended by a cable. A winch on a surface platform lowers and lifts the bell. This system allows humans to perform complex tasks in open water.

Dykkerklokke
Dykkerklokke

There are several distinct types of diving bells. The most common is the wet bell, or open bell. This structure has an airtight canopy that remains open at the bottom.

Dykkerklokke
Dykkerklokke

It serves as a base or transport for a few divers. A second type is the closed bell, also called a pressure vessel. This is a sealed container for human occupancy.

US Navy 010707-N-3093M-003 Diver Transfer Capsule
US Navy 010707-N-3093M-003 Diver Transfer Capsule

A third type is the rescue bell. These are used to save people from sunken submarines. These bells must withstand high ambient pressure while maintaining an atmospheric internal pressure.

To understand how a wet bell works, imagine an upside-down cup in a sink.

CarlStraat Köln
CarlStraat Köln

As the bell is lowered, water pressure traps air inside the canopy. This creates an air-water interface at the bottom. The air space is at ambient pressure, meaning it matches the water pressure outside. As the bell descends, hydrostatic pressure increases. This pressure compresses the air inside. To prevent the bell from filling with water, gas compressors at the surface provide fresh gas. This compensates for the volume reduction.

When the bell rises, the pressure drops. The expanding air spills out from under the edges.

A closed bell operates using a different mechanism. It is a pressure vessel that maintains an internal pressure higher than the water outside. To allow divers to enter or exit, the bell features a hatch at the bottom. This hatch must open inward. This design ensures that the external water pressure holds the hatch tightly shut.

Clump weight bell
Clump weight bell

In saturation diving, the closed bell is used as a transport. Divers travel from a living chamber to their job site in the bell. The bell can lock onto a hyperbaric chamber at the surface. A pressurized trunking allows divers to move between the bell and the chamber. This system keeps the divers under pressure during the entire process.

Humanity has explored the depths with bells for centuries. Aristotle described the use of a cauldron to trap air in the 4th century BC.

Alexander the Great diving NOAA
Alexander the Great diving NOAA

In 1535, Guglielmo de Lorena tested a bell near Rome. His bell allowed a diver to stay submerged for one to two hours. The limit was fatigue and cold rather than a lack of oxygen. In 1691, Edmond Halley designed a bell with a window.

Charles Spalding Diving Bell, The Saturday Magazine, Vol. 14, 1839
Charles Spalding Diving Bell, The Saturday Magazine, Vol. 14, 1839

He planned to replenish the atmosphere using weighted barrels of air from the surface.

Many engineers have improved these designs over time. In 1775, Charles Spalding added balance-weights to help with raising and lowering.

Charles Spalding Diving Bell, The Saturday Magazine, Vol. 14, 1839
Charles Spalding Diving Bell, The Saturday Magazine, Vol. 14, 1839

He also added ropes for signaling the surface crew. In 1789, John Smeaton used a force pump to manage air. These improvements made diving safer and more efficient. However, the work remains dangerous. Charles Spalding and his nephew, Ebenezer Watson, died during salvage work in 1783.

Diving bells are essential for modern maritime operations. They allow for the salvage of sunken vessels and the maintenance of underwater structures. For example, in 1687, Sir William Phipps used an inverted container to salvage a Spanish galleon. This operation recovered 30 tons of silver. The silver alone was worth over £200,000 at that time. Today, these tools connect us to the deep ocean. They allow us to study and work in environments that are otherwise impossible for humans to reach.

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🖼️ Images & Media (13)
File:Alexander the Great diving NOAA.jpg
Alexander the Great diving NOAA.jpg
File:Charles Spalding Diving Bell, The Saturday Magazine, Vol. 14, 1839.png
Charles Spalding Diving Bell, The...
File:L-Taucherglocke.png
L-Taucherglocke.png
File:Dykkerklokke.jpg
Dykkerklokke.jpg
File:Clump weight bell.png
Clump weight bell.png
File:Bell umbilical section 20151203 132411.jpg
Bell umbilical section 20151203 132411.jpg
File:US Navy 010707-N-3093M-003 Diver Transfer Capsule.jpg
US Navy 010707-N-3093M-003 Diver Transfer...
File:Caisson Diving Bell Barge BF73 001 079 060 (cropped).jpg
Caisson Diving Bell Barge BF73 001 079...
File:CarlStraat Köln.jpg
CarlStraat Köln.jpg
File:Diving bells - Dyckarklocka.JPG
Diving bells - Dyckarklocka.JPG
File:Alberto gianni.jpg
Alberto gianni.jpg
File:Bathysphere in museum Windstärke 10 (Cuxhaven).jpg
Bathysphere in museum Windstärke 10 (Cuxhaven).jpg

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