Some Remarks by Neal Stephenson

Author:Neal Stephenson
Language: eng
Format: epub
Publisher: HarperCollins

HAZARDS

Dr. Wildman Whitehouse and his 5-foot-long induction coils were the first hazard to destroy a submarine cable but hardly the last. It sometimes seems as though every force of nature, every flaw in the human character, and every biological organism on the planet is engaged in a competition to see which can sever the most cables. The Museum of Submarine Telegraphy in Porthcurno, England, has a display of wrecked cables bracketed to a slab of wood. Each is labeled with its cause of failure, some of which sound dramatic, some cryptic, some both: trawler maul, spewed core, intermittent disconnection, strained core, teredo worms, crab’s nest, perished core, fish bite, even “spliced by Italians.” The teredo worm is like a science fiction creature, a bivalve with a rasp-edged shell that it uses like a buzz saw to cut through wood—or through submarine cables. Cable companies learned the hard way, early on, that it likes to eat gutta-percha, and subsequent cables received a helical wrapping of copper tape to stop it.

A modern cable needn’t be severed to stop working. More frequently, a fault in the insulation will allow seawater to leak in and reach the copper conductor that carries power to the repeaters. The optical fibers are fine, but the repeater stops working because its power is leaking into the ocean. The interaction of electricity, seawater, and other chemical elements present in the cable can produce hydrogen gas that forces its way down the cable and chemically attacks the fiber or delicate components in the repeaters.

Cable failure can be caused by any number of errors in installation or route selection. Currents, such as those found before the mouths of rivers, are avoided. If the bottom is hard, currents will chafe the cable against it—and currents and hard bottoms frequently go together because currents tend to scour sediments away from the rock. If the cable is laid with insufficient slack, it may become suspended between two ridges, and as the suspended part rocks back and forth, the ridges eventually wear through the insulation. Sand waves move across the bottom of the ocean like dunes across the desert; these can surface a cable, where it may be bruised by passing ships. Anchors are a perennial problem that gets much worse during typhoons, because an anchor that has dropped well away from a cable may be dragged across it as the ship is pushed around by the wind.

In 1870, a new cable was laid between England and France, and Napoleon III used it to send a congratulatory message to Queen Victoria. Hours later, a French fisherman hauled the cable up into his boat, identified it as either the tail of a sea monster or a new species of gold-bearing seaweed, and cut off a chunk to take home. Thus was inaugurated an almost incredibly hostile relationship between the cable industry and fishermen. Almost anyone in the cable business will be glad, even eager, to tell you that since 1870 the intelligence and civic responsibility of fishermen have only degraded.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.