History of the Atlantic Cable & Undersea Communications
from the first submarine cable of 1850 to the worldwide fiber optic network

Cable Recovery
by Bill Burns

Cable recovery techniques were developed soon after cable laying began in the 1850s. Accidents during laying meant that cable ends were occasionally lost to the sea bed, and existing cables needed to be retrieved and repaired when damage occurred through manmade or natural causes.

To aid in the maintenance of cables, and to avoid conflicts with the routes of existing cables as new ones are laid, the route of each cable is surveyed, and the track of the cable as laid is precisely charted. Compare these two surveys from 1890 and 1973, which show how improvements in technology have aided this task. In 1973 the best satellite navigation equipment allowed an accuracy of about ± ¼ mile; now GPS satellite systems make the surveying and charting of new cables and location of existing cables even more precise, with accuracy of just a few feet.

Cables have been recovered by grappling for over 150 years, an operation aided today by the use of Remote Operated Vehicles (ROVs). The first successful deep-water operation was the recovery in 1866 by Great Eastern of the lost 1865 cable.

When an existing cable has to be recovered, the location of the fault is calculated by electrical measurements made from the two shore ends, and the position is found on the cable chart. The repair ship then sails to the position of the fault and retrieves the cable. Once the cable is located on the seabed it may be hauled up intact in a bight (in shallow water), or it may be necessary to cut the cable and haul up the end of the good section. This is then buoyed, and the operation repeated on the other side of the fault. A new section of cable is spliced in and the repaired cable is released back to the sea bed.

This article shows how cables were spliced about a hundred years ago. Similar techniques were used on copper cables until they were superseded by fiber optic cables in the 1980s. Here's how repeaters were spliced into a coaxial copper cable in the 1970s.

When cables are recoved for repair, especially if they have been in position for some years, they are often found covered with marine growths. The type of growth depends on the geographical location, the water temperature,and the depth of the cable.

This cable section, now in the Science Museum, London, was recovered in 1909 by CS Colonia from the 1869 French Atlantic Cable laid by Great Eastern:

This section of armoured cable from the Pan-Jam (Panama-Jamaica) cable was recovered from about 1000 meters of water in the Caribbean several years ago, having been submersed for about 15 years:

This sketch shows a section of the 1870 Penang-Singapore cable, recovered during the repair of a fault in 1871. The cable was damaged in 30 fathoms of water by the tooth of a swordfish, which pierced the cable.

Research Material Needed

The Atlantic Cable website is non-commercial, and its mission is to make available on line as much information as possible.

You can help - if you have cable material, old or new, please contact me. Cable samples, instruments, documents, brochures, souvenir books, photographs, family stories, all are valuable to researchers and historians.

If you have any cable-related items that you could photograph, copy, scan, loan, or sell, please email me: billb@ftldesign.com