page_title: Submarine Telegraph Company
section_title: Manufacturing problems
hierarchical_section_title: Submarine Telegraph Company / History / Manufacturing problems
caption_attribution_description: English: Title: Effect of the submarine telegraph; or peace and good-will between England and France Abstract/medium: 1 print&#160;: wood engraving&#160;; sheet 20.7 x 27.6 cm.
context_page_description: The Submarine Telegraph Company was a British company which laid and operated submarine telegraph cables. Jacob and John Watkins Brett formed the English Channel Submarine Telegraph Company to lay the first submarine telegraph cable across the English Channel. An unarmoured cable with gutta-percha insulation was laid in 1850. The recently introduced gutta-percha was the first thermoplastic material available to cable makers and was resistant to seawater. This first cable was a failure and was soon broken by a fishing boat.
  The Bretts formed a new company, the Submarine Telegraph Company, and laid a new cable in 1851. This cable had multiple conductors and iron wire armouring. Telegraph communication with France was established for the first time in October of that year. This was the first undersea telegraph cable to be put in service anywhere in the world. The Submarine Telegraph Company continued to lay, and operate, more cables between England and the Continent until they were nationalised in 1890.
context_section_description: Early submarine cables had numerous quality problems.  The insulation was not applied evenly leading to variations in the cable diameter and shape.  The conductor was not held on the centreline of the insulation, in places coming close to the surface making it easy for the conductor to become exposed.  The insulation was full of air pockets due to the gutta-percha being applied in one thick coat instead of several thinner coats.  All these issues with the insulation caused inconsistencies in the electrical properties of the cable.
  Quality of the conductor was also inconsistent.  The diameter of the copper was variable, again leading to inconsistent electrical properties.  There was little experience with annealing long lengths of copper.  This resulted in inconsistent mechanical properties with brittle portions in the wire.
  An even bigger problem was caused by the joints.  The copper wire was supplied in short, inconsistent, lengths.  Initially on the 1850 cable, joints were attempted by brazing a scarf joint with hard solder.  However, the heat from the blowpipe softened the gutta-percha which became plastic and dripped off the cable.  An alternative method was therefore used.  Two inches of insulation was stripped from each end, the exposed wires twisted together and soft soldered.  Sheets of gutta-percha heated to a plastic state were then wrapped around the joint and clamped in a mould.  This resulted in a cigar-shaped bulge around the joint which was undesirable for cable laying.
caption: "Effect of the submarine telegraph; or peace and good-will between England and France"
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