The conception, execution, and eventual success of the project to link North America and Europe with an undersea telegraph cable in the mid-1880s was costly, ambitious, exasperating, and arduous, comparable to the Apollo moon-landing project and the atom bomb.
Our world is tightly laced by undersea fiber-optic cables carrying data at rates in the high Mb/sec range. Though it’s hard to get a solid number, estimates are that more than 300 of these cables link and belt around continents in a tight web, with about 1000 landing stations.
The first non-passive cables used periodically spaced electronic boost amplifiers as repeaters, powered by DC sent on their metalized outer layers. Optical cables soon followed these but with electro-optical repeaters. Now, these cables are all-optical systems, with optical amplifiers as repeaters. The laying of these cables is a tightly scripted effort, supported by GPS, sonar, satellite-based weather guidance, pre-installation seabed mapping, advanced test instrumentation, full onboard lab and repair, and more.
But the first undersea cable was a passive interconnect, and was deployed without any of our present-day resources. The mission lacked electric lamps, motors, convenient soldering tools, or the advanced materials on which we rely. The story of how it spanned the Atlantic Ocean, completed in the mid-19th century, is a throw-back “time trip” story to a world we cannot even imagine.
It is a story of financial commitment, abortive attempts and major setbacks, renewed commitment and technical innovation within severe limitations, all leading to an eventual, though long-delayed, success. The 12-year final effort yielded the first message to Europe in July 1866 and shrank the Earth’s distances and associated information time lags in ways that changed nearly everything about commerce, politics, diplomacy, and even war.
Many of the technological, material, and production advances that the cable-laying venture used remain with us today. Manpower, in the literal sense of the word, was key. Although steam engines for power were available, such machines were not suitable for all aspects of the project. As a result, many tasks could only be done by hundreds of laborers working around the clock.
The project was financed mainly by self-made businessman Cyrus Field West and a consortium he put together. He had the idea in 1855 and expected the effort would take a few years and a few million dollars. In fact, the effort required no fewer than four attempts made over more than a decade, and at the cost of tens of millions of mid-19th-century dollars. It’s hard to compare that to 21st-century costs, but it was clearly enormous.
The project technical team included the world’s leading railroad, tunnel and ship designer, Isambard Kingdom Brunel, as well as William Thomson (later better known as Lord Kelvin). There were also thousands of workers at the factories that made the cable. These included those at the plantations that provided the raw insulating substance, master shipbuilders, hundreds of workers who wrapped the miles of cable in the ship’s holds, the electrical engineers and craftsmen who could set up and splice (weld) cable at sea, and large sailing crews.
Little was known about the ocean floor and routes; meaningful charts and mapping did not exist. The estimated maximum depth was said to be about 2½ miles (4 km) with an ocean floor ranging from mud and rock to smooth and sharp. (The actual average ocean depth in the Atlantic about 3.5 km, so on that point they were not far off on the “average.”) However, the steep undersea mountain ranges in the mid-Atlantic which we now know about and have mapped were not known.
The planned ocean route traced a path from St. John’s, Newfoundland, to Valentia Bay, Ireland, Figure 1. The path from New York City to St. Johns would make use of existing land-based cables and several short submarine cables, with similar land-based and short-run submarine links on the Europe side. Navigation was done entirely by compass and star-sighting. As a result, following the planned route and tracing previous locations to find the cable to make repairs, proved to be major challenges.
The sailing vessels
Different ships were used for each of the multiple attempts. The first attempt used modified cargo ship. This was followed by a pair of Navy ships that started from opposite sides of the Atlantic and ended with a mid-sea rendezvous and splice. These failed for a variety of reasons. One major issue was the sheer mass and volume of the cable that resulted in many problems, including organizing the cable in the ship so it could play out smoothly at sea, as well as the effect of the volume of cable on ship stability and handling (several times the ships nearly sank during severe storms).
Finally, there was the SS Great Eastern, the ship that laid the cable on the ultimately successful attempt, Figure 2. She was unlike any other ocean-going vessel, as the ship custom-designed and built for this one task at enormous expense. This iron ship was roughly the size of one of today’s cruise ships: it was nearly 700 feet long, had a beam of 120 feet and displaced 22,500 tons. Rather than use the space-wasting rib-based structure of other ships, it used a double hull for strength and was among the first to include watertight compartments.
A ship of this size and displacement needed a considerable amount of thrust to carry the cable load, especially in strong seas. In addition to sails, the SS Great Eastern had side paddlewheels and a 24-foot stern screw propeller for propulsion. Each had its own steam power plant at 3,800 horsepower for the paddles and 6,800 horsepower for the screw.
Construction of the Great Eastern required nearly all of the heavy plate-steel production capacity in the United States. New techniques had to be developed for assembling and fastening the plates, because the sheer size and required strength of the final ship placed extreme demands on construction. As refrigeration had not yet been perfected, the ship carried live animals to feed the crew of 500. Loading the cable onto the ship took three months (interestingly, that’s about how long it takes to load a fiber-optic cable onto a modern cable-laying ship, as any imperfections or kinks can damage the cable or pay-out, and delay or even cancel the mission.)
Part 2 continues this amazing story, looking at the cable, test and repair, and implications of the final success.
Related EE World Content
Optical amplifiers, Part 1: Applications and considerations
Optical amplifiers, Part 2: Basic implementations
GPS, Part 1: Basic principles
GPS, Part 2: Implementation
- John Steele Gordon, “A Thread Across the Ocean: The Heroic Story of the Transatlantic Cable,” Walker & Co, NY, 2002.
- Chester G. Hearn, “Circuits in the Sea: The Men, The Ships, and the Atlantic Cable,” Praeger Publishers, Westport Conn., 2004.
- “The Great Transatlantic Cable,” (video), PBS American Experience, 2005.
- The Trans-Atlantic Telegraph Cable: 150th Anniversary Celebration 1858-2008
- History Magazine, “The Transatlantic Cable”
- Submarine Cable Systems, “Submarine Cable System History: 150 Year History of Submarine Cables”
- Science Museum Group (UK), “Sending messages across the Atlantic”
- The Museum of Technology, The Great War and WWII, “Telegraphy”
- BT (formerly British Telecom), “Queen Victoria, the SS Great Eastern, 2500 miles of cable and a communications milestone”
- History of the Atlantic Cable & Undersea Communications
- Thomas C. Reed, “At the abyss : an insider’s history of the Cold War” (one chapter tells about highly classified undersea tapping of Russian cables by the U.S. Navy)
- Andrew Blum, “Tubes: A Journey to the Center of the Internet,” (very interesting look at the physical infrastructure of the Internet and how fiber-cables are brought ashore, terminated, and actually connected to the it)
Leave a Reply
You must be logged in to post a comment.