# The 1851 Submarine Telegraph Cable That Connected Britain and France Canonical URL: https://www.teknalyze.com/on-this-day/1851-submarine-telegraph-cable/ Published: 2026-11-13 Updated: 2026-11-13 Author: Teknalyze Desk Section: On This Day Categories: On This Day, Technology Primary topic: 1851 Submarine Telegraph Cable, 19th century technology, communication history, international communication Historical event date: 1851-11-13 ## Event summary On November 13, 1851, a new era of international communication began when the submarine telegraph connection between Britain and France officially opened to public service. ## Fact box Event: The 1851 Submarine Telegraph Cable That Connected Britain and France Date: November 13, 1851 People or organization: Not stated in the article Why it matters: Although the cable had been laid weeks earlier, November 13 marked its public opening. ## Key points - Their initial attempt in 1850 had succeeded briefly before the cable failed, but a stronger replacement installed in 1851 finally provided a durable connection. - The successful 1851 project depended on the work of several engineers and manufacturers, particularly Thomas Russell Crampton, who helped finance and design the improved cable. - The installation operation began on September 25, 1851, using HMS Blazer, a former steam vessel adapted to carry the enormous cable. ## Historical context By the middle of the 19th century, electrical telegraph networks were transforming communication across Britain and parts of continental Europe. Messages could travel rapidly between cities connected by land-based wires, replacing journeys that previously depended on messengers, postal services, and physical transportation. ## Article On November 13, 1851, a new era of international communication began when the submarine telegraph connection between Britain and France officially opened to public service. Running beneath the English Channel, the cable linked Dover and Calais, allowing electrical messages to cross a stretch of water that had long separated the two countries. The achievement established the first commercially successful submarine telegraph connection and demonstrated that underwater cables could become dependable infrastructure for international communication. The opening represented the culmination of years of experimentation, engineering setbacks, and financial uncertainty. British entrepreneurs John Watkins Brett and his brother Jacob Brett had pursued the idea of connecting Britain with continental Europe through an underwater telegraph. Their initial attempt in 1850 had succeeded briefly before the cable failed, but a stronger replacement installed in 1851 finally provided a durable connection. Although the cable had been laid weeks earlier, November 13 marked its public opening. The distinction matters because the project’s lasting importance was not simply proving that an electrical signal could travel underwater. It was demonstrating that submarine telegraphy could support a practical communications service, creating a foundation for the international networks that would eventually connect continents. ### The Challenge of Communicating Across the English Channel By the middle of the 19th century, electrical telegraph networks were transforming communication across Britain and parts of continental Europe. Messages could travel rapidly between cities connected by land-based wires, replacing journeys that previously depended on messengers, postal services, and physical transportation. However, bodies of water remained major obstacles. Although Britain and France were separated by only a relatively narrow section of the English Channel, information still had to cross that barrier through conventional transportation unless a reliable underwater electrical connection could be established. The challenge was both technical and commercial. An underwater cable needed to conduct electrical signals while preventing seawater from reaching its copper conductors. It also had to withstand handling during installation, movement along the seabed, abrasion, and potential damage from anchors or fishing equipment. For the Brett brothers, overcoming these obstacles promised more than faster communication between two neighboring countries. A dependable Channel crossing could connect existing telegraph networks and encourage the development of international communication services, opening new opportunities for commerce, government correspondence, and news reporting. The challenge was to transform an experimental concept into infrastructure reliable enough for everyday use, something that had not yet been achieved on a commercial scale. ### The Failed 1850 Cable and the Lessons It Taught The first major attempt to establish a submarine telegraph connection between Dover and Calais took place in September 1850. Working through their commercial venture, the Brett brothers arranged for a cable to be laid across the Channel, demonstrating that telegraphic signals could be transmitted beneath the sea. The experiment was an important proof of concept, but its success was short-lived. The cable lacked sufficient mechanical protection for the marine environment and failed soon after installation, commonly attributed to damage caused by fishing activity. Its failure revealed a critical engineering problem: electrical insulation alone was not enough. Even if a cable could transmit signals while submerged, it also needed physical protection against the forces and hazards encountered during installation and everyday operation. The experience helped shape the next attempt. Rather than simply repeating the original design, the project moved toward a substantially heavier cable with improved insulation and iron-wire protection. This distinction explains why the 1851 connection became the lasting historical milestone. The 1850 experiment showed that underwater telegraphy was possible, while the replacement demonstrated that it could become a viable commercial service capable of supporting regular communication between countries. ### How Engineers Built a More Durable Cable The successful 1851 project depended on the work of several engineers and manufacturers, particularly Thomas Russell Crampton, who helped finance and design the improved cable. Charlton Wollaston also contributed to the engineering and installation effort, while R. S. Newall and Company manufactured the cable. The new design contained four copper conductors, each insulated with gutta-percha, a natural material valued for its electrical insulation and resistance to water. The insulated conductors were grouped together and protected with additional layers, including tarred hemp and an outer covering of galvanized iron wires. This armored construction was significantly more robust than the earlier experimental cable, providing mechanical protection while preserving the electrical separation needed for reliable signal transmission. The resulting cable was a substantial industrial product. Approximately 24 miles were initially manufactured, with additional cable required to complete the crossing. Its weight and dimensions created major transportation and installation challenges, requiring specialized handling equipment and a carefully coordinated maritime operation. Crampton’s financial involvement was also essential because the project required considerable capital at a time when the commercial prospects of submarine telegraphy remained uncertain. His willingness to help fund the undertaking reflected the belief that a successful Channel connection could become the foundation of a much larger communications business. ### Laying the Cable Across the Channel in September 1851 The installation operation began on September 25, 1851, using HMS *Blazer*, a former steam vessel adapted to carry the enormous cable. To create sufficient space, much of its original propulsion machinery had been removed, meaning the vessel had to be towed during the cable-laying operation. Engineers gradually paid out the armored cable as the vessel moved across the English Channel toward the French coast. Maintaining the correct tension and controlling the vessel’s position were essential to preventing damage and ensuring that enough cable remained to complete the route. The operation encountered difficulties when towing and tidal conditions caused the cable to follow a less direct path than intended, leaving insufficient cable to reach the French landing point. Additional cable had to be manufactured and connected before the installation could be completed. The connection was subsequently finished during October 1851, allowing engineers to test the electrical continuity of the line and prepare it for public service. The project demonstrated that laying submarine cables was not simply a matter of lowering insulated wire into the sea. Successful installation required coordination among cable manufacturers, electrical engineers, ship crews, and shore-based workers, along with an understanding of maritime conditions and mechanical stress. These practical lessons would influence later submarine cable projects as engineers attempted longer and more demanding routes. ### November 13, 1851: The Cable Opens to Public Communication On November 13, 1851, the successful Dover–Calais submarine telegraph connection officially opened to the public, marking a decisive step toward routine international electrical communication. The service allowed messages to cross the Channel through an underwater cable rather than depending on a vessel to transport written correspondence. Although transmission still involved telegraph operators and supporting land-based infrastructure, the submarine section removed a major physical obstacle from the communications network. The opening also demonstrated the commercial potential of the technology, particularly for customers who valued speed, including merchants, financial institutions, news organizations, and government offices. This was especially important for time-sensitive information. Commercial decisions increasingly depended on knowing prices, market conditions, and political developments in other countries, while faster communication reduced the delays associated with transporting messages across national borders. The Dover–Calais cable did not instantly create a fully integrated international communications system. Additional land connections, operating arrangements, and network expansion were still required. Nevertheless, its successful opening established a working example that other telegraph companies and governments could follow. The cable proved remarkably durable for an early submarine installation, remaining in service, with repairs, until 1875. ### From the English Channel to Transatlantic Communication The success of the Dover–Calais connection encouraged further investment in submarine telegraph networks. During the 1850s, additional cables began connecting Britain with other European destinations, demonstrating that underwater telegraphy could expand beyond a single crossing. Engineers then confronted a far greater challenge: establishing communication across the Atlantic Ocean. The distances involved were vastly greater than those across the English Channel, requiring improvements in cable manufacture, insulation, electrical signaling, and maritime installation techniques. An initial transatlantic telegraph connection was completed in 1858, but it failed after a short period of operation. Reliable transatlantic communication was finally established in 1866, helping transform the speed at which information could travel between Europe and North America. These later achievements built upon decades of electrical research and engineering experimentation. The Dover–Calais project was not the sole origin of global telecommunications, but it provided an early and commercially successful demonstration of the submarine cable as practical communications infrastructure. Over time, international cable networks expanded across oceans and continents, creating increasingly interconnected systems for transmitting information between countries and fundamentally changing the speed at which news, financial information, and diplomatic communications could travel. ### The Connection to Today’s Undersea Internet Cables Modern submarine communications cables are fundamentally different from the copper telegraph cables of the 1850s. Instead of carrying electrical telegraph signals, contemporary systems primarily use optical fibers to transmit digital information through pulses of light. These fiber-optic networks support enormous volumes of international data traffic, including internet communications, financial transactions, cloud computing services, and video conferencing. Their capacity and sophistication would have been unimaginable to the engineers who worked on the original English Channel connection. Yet the underlying infrastructure challenge remains recognizable. Engineers must still protect delicate transmission components from seawater, mechanical damage, and environmental conditions while installing and maintaining cables across difficult underwater terrain. Modern cables also require specialized vessels, route planning, landing facilities, monitoring systems, and repair operations. Although the technologies have evolved dramatically, the basic engineering task of creating a dependable physical communications link beneath the sea has remained central. The 1851 cable therefore represents an important early chapter in the history of global connectivity. It demonstrated that international communications infrastructure could extend across the seabed, helping establish an approach that would eventually support worldwide networks carrying much of the world’s international digital traffic. ### The Cable That Helped Connect Nations Looking back at November 13, 1851, the opening of the Dover–Calais submarine telegraph connection stands as a milestone in the development of international telecommunications. The achievement followed an unsuccessful experiment, a major redesign, considerable financial investment, and a difficult installation operation. Its success depended not only on the ambition of the Brett brothers but also on the engineering contributions of Crampton, Wollaston, cable manufacturers, and the maritime crews responsible for deploying the system. Most importantly, the project demonstrated that underwater telegraph cables could provide a dependable commercial service, encouraging further international connections and helping establish submarine cables as essential components of global communications infrastructure. **On November 13, 1851, the Dover–Calais telegraph connection opened a new chapter in international communication. What began as an ambitious effort to transmit electrical signals beneath the English Channel helped establish the engineering and commercial foundations of the submarine cable networks that continue connecting the world today.** ## Sources No external source is cited in this article. ## Sources No external source is cited in this article.