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| Early type of cable | Another type of older cable |
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The Cables Originally they were all analog telegraph followed by telephone cables now they are mostly fiber optics that can transmit many types of signals at a high speed. The cables are built to withstand pressure and the rigors of the ocean floor. Repeaters are located at regular distances along the cable. These underwater amplifiers boost the signal along the way. There are several types of cable in use. They can damage each other if they are not handled properly or come into rough contact with each other. The handling of the cable is a relatively slow process. The cable is stowed in specially constructed holds. Cable can only be loaded at the place of manufacture or from another ship. The ships stability is controlled by a computer while she is laying or loading cable. |
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How cable was laid at one time. Repeaters were used to boost the signal. Damage was frequent and the ships were kept busy repairing them. |
Ploughs can be used for burying cable so it is less likely to be damaged by fishing vessels usually down to 1000 or 2000 meters. The ships can use a variety of other tools such as jet sleds and tracked remotely controlled track jetting equipment to bury cable depending on the depth and type of bottom. |
They can operate in anything from soft mud, clay or rock. Rock saws are used for cutting up to a four meter trench in bedrock. The cables have come a long way from the first one laid between England and France around 1850. It was a simple copper wire covered with gutta-percha. It lasted one day. Later a more successful cable was laid with separate insulated conductors. Analog (coaxial) telegraph and telephone cables were being laid until recent times. Some are still in use. By increasing the number of voice circuits and using higher frequencies they could get a lot more traffic along a cable but there was a limit. The thicker cables that were needed caused a problem as well. Repeaters along the cables were used to bring transmission levels up to standard. |
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| Arktis Mayflower delivering cable. Cable must be delivered in ships or loaded at the factory | |
| Fibre optics used in modern cables are not a new idea. Charles Kao the ”father of fiber optics” originated the idea in 1987. Since that time the speed of transmission has increased dramatically. More wavelengths on the same fibre as well as more speed is obtainable to day. A pair of fibres are used for two-way (duplex} operation and a single fibre for one-way operation as often used for TV and Radio. The technology is quite complicated requiring modern electronics. The latest submarine cables use fibre amplifiers instead of repeaters. They still must be protected from a harsh environment by strong outer coatings. |  |
| Cables are stowed in circular bins. This keeps the cable in good shape. |
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| This man is one of the people that splices the cable. Notice how small the fibers are. All the communications travel along these fibres. |
Cable
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