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Communications Networking The Internet

Undersea Cable Repair Via 19th Century Tech 98

An anonymous reader writes to mention a story going across the wires about an old-fashioned way to fix a modern convenience. Taiwanese boaters are using simple hooks to fish up the fiber-optic cables damaged in an earthquake late last year. The outage that resulted kept millions of users offline in half a dozen countries around the Pacific rim. From the article: "They work 24 hours a day but the weather can hinder their progress. Walters said one ship is waiting for 30 to 40 mile-an-hour winds (48 to 64 kilometres- an-hour) to die down in the Bashi Channel. The winds have stirred up 10 to 12 metre waves ... After arriving at the scene they survey the ocean bottom to assess whether the contour has changed, and the degree of sediment movement. Then the traditional tools are brought out. A rope with a grapnel on the end is played out, down into the depths, and towed over the sea floor until tension registers on a graph on the ship, indicating contact has been made with the cable. Today's fibre optic cables are just 21 millimetres in diameter."
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Undersea Cable Repair Via 19th Century Tech

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  • 21 mm? (Score:4, Interesting)

    by JeffSh ( 71237 ) <jeffslashdot AT m0m0 DOT org> on Saturday January 13, 2007 @03:40AM (#17588348)
    Correct me if I'm wrong, I'm no expert on this subject, but undersea cables certainly aren't 21 mm wide. Certainly they are run in bundles of dozens (maybe hundreds) for a total width of several inches. At work we had fiber cable installed that has 16 or so strands and it was half an inch thick.

    I guess it's just bad writing and I shouldn't be so nitpicky. :)
    • Re: (Score:3, Informative)

      by PerlDudeXL ( 456021 )
      21 mm == 2,1 cm (which is more than half an inch)

      But I can image that those fibre cables are bundled and come with a undersee resistant coating.
    • Re:21 mm? (Score:5, Informative)

      by Bios_Hakr ( 68586 ) <xptical@@@gmail...com> on Saturday January 13, 2007 @04:01AM (#17588464) Homepage
      The don't just have fibers either. There is a central core; usually steel cable. Then they have power feeds for the repeaters. Every 50~100km, they'll have a repeater pod. Finally, they have the fibers and, on top, a thick metal or plastic sheath.

      What's really amazing about undersea cables is that no one outside the industry really thinks about them. Sprint and ATT give everyone the impression that sats take care of most comms. However, the opposite is mostly true. The vast majority of comms are way too time sensitive to allow the the delay imposed by satcom.
      • Re:21 mm? (Score:4, Insightful)

        by Anonymous Coward on Saturday January 13, 2007 @04:51AM (#17588674)
        What's really amazing about undersea cables is that no one outside the industry really thinks about them.

        That's the way any engineering works if it is well designed. Most people don't think too much about how a hydroelectric or coal power plant works either. Nor do most people today care about how an interrupt controller works.

        It sort of sucks for the engineer because you are in the position where you are only recognized if you frack up (and yes I've been in BSG withdrawal). The best type of award you can get for your accomplishments (other than a big fat paycheck) is for nobody to ever think about what you did. Case in point: everyone remembers the dipshit who invented the square wheel, but nobody ever gives recognition to the genius who invented the round wheel.
        • Please mod parent up.
        • by bitt3n ( 941736 )

          It sort of sucks for the engineer because you are in the position where you are only recognized if you frack up (and yes I've been in BSG withdrawal). The best type of award you can get for your accomplishments (other than a big fat paycheck) is for nobody to ever think about what you did. Case in point: everyone remembers the dipshit who invented the square wheel, but nobody ever gives recognition to the genius who invented the round wheel.

          that's a common issue in many professions. for example, in america

          • by SEWilco ( 27983 )
            cornerbacks have the same problem. no one notices them until you snag them with a grappling hook.
        • Now wait just a micron. That's a load of feldercarb and you know it. Now stop playing with your daggot and get to work! Frackin' nugget.
        • everyone remembers the dipshit who invented the square wheel
          And for those who don't, here [20megsfree.com] he is.
    • Re: (Score:3, Informative)

      Today's fibre optic cables are just 21 millimetres in diameter.
      what author probably wants to highlight is that today's ONE optic cable is 21mm thick. Nowhere its mentioned how many cables are lying out there. May be they wont want to reveal it either.
      But given the bandwidth capacity of the routes, we should be able to find it. It cant be rocket science in undersea anyway.
      • Re:21 mm? (Score:4, Interesting)

        by StikyPad ( 445176 ) on Saturday January 13, 2007 @12:43PM (#17592676) Homepage
        There's tons of information widely available about undersea cables, if one cares to look. In general, though, they just lay one cable at a time, and only lay a new one when capacity is getting low. This may be surprising, but even a 2.1cm cable takes up a lot of room on a ship when it's 10,000 miles long.
    • Re: (Score:3, Informative)

      by grementas ( 1050664 )
      Actually, there is also a 17mm version of the cable. Those diameters are for the cable used in the deep-sea portion of the cable system. Any cable layed near shore has additional "armoring" layers of steel wires to protect it from anchors and what not. This armoring brings the diameter up substantially. By the way, there are only either 4 or 8 fibers pairs in a single cable. Even so, these systems transmit incredible amounts of information (10GB/s) per fiber pair. You'd be amazed at how many of these system
    • Re: (Score:1, Interesting)

      by Anonymous Coward
      Actually I work in underground telephone plant construction. there are new fiber optic cables that use flat bundles of 12 fibers out there. We placed a few runs of 144 and 288 fiber cable last year. the 288 is about 1" and the 144 is about 3/4". It's amazing what they can cram in those small cables now.
    • No. These undersea cables have just a few fiber pairs (2-4), plus several layers of armor. 21 mm sounds credible.
  • Did I just get FP? (Score:4, Interesting)

    by OmnipotentEntity ( 702752 ) on Saturday January 13, 2007 @03:42AM (#17588364) Homepage
    Anyway, with all this wind and water moving, how do they find a 21mm cable 2.5 miles down? A rope that far would bend under air resistance, let alone water resistance. I think some high technology went into this somewhere. Kudos on not making it too complicated. KISS at work.
    • It's "just a rope and grapnel"...connected to some GPS aided computer telemetry.

      So they still use hooks to pull something up. Great. I still use wheels when I travel. I don't revel in the marvels of ancient wheel technology just because of that.
    • by Cally ( 10873 )
      Long, superb Neal Stephenson article on laying FLAG [wired.com]. If you don't know what FLAG is but you're interested enough in cables to be reading this far down the comments, you really should read it. I never knew long wires were so interesting until I read this, and it's still a classic I refer people to when cables come up at work (so to speak) - fairly often, my employer's in over a dozen data centres round the world. Oh, the fun we had between Christmas and New Year's Day thanks to this earthquake (one of the DC
  • huh (Score:3, Insightful)

    by mastershake_phd ( 1050150 ) on Saturday January 13, 2007 @03:51AM (#17588406) Homepage
    They can find a cable using just a rope and a hook. And shipwreck hunters with modern equipment have a hard time finding ships when they know where they went down.
    • Re:huh (Score:5, Interesting)

      by amorsen ( 7485 ) <benny+slashdot@amorsen.dk> on Saturday January 13, 2007 @04:13AM (#17588532)
      It's reasonably easy to find a cable. At those depths the cables lie directly on the sea floor, and if you run a hook across the sea floor from one side of the cable to the other, you'll cross it by definition. Sure you might then end up some distance from the break, but they are apparently reasonably good at handling that. Such techniques don't work with shipwrecks -- and even if they did, there may not be anything the right shape for a hook to catch.

      Anyway, there's an old but interesting article on undersea cables [wired.com] by Neal Stephenson.
      • by dsanfte ( 443781 )
        I tried to read that and grimaced. The narrative is just terrible. Was he a former writer for Chatelaine or something?
    • by osu-neko ( 2604 )
      If ships were thousands of miles long, they'd be easy to find with a rope and hook, too. But they aren't.
    • by Duhavid ( 677874 )
      I dont know that they know where the ships go down.

      What they have is the estimate of the location of a ship that
      was with a ship that went down, and an estimate of how far and
      in what direction that ship was. From there, you dont know
      that the ship will go straight down. The various parts of
      hood and titanic, for instance, ended up quite far from each
      other, as I recall.
  • by dangitman ( 862676 ) on Saturday January 13, 2007 @03:51AM (#17588410)
    What, are they Amish or something? Every modern company uses sharks with friggin' lasers to repair optical cables.
    • Ironically the cables are armoured against the sharks (with or without the frickin lasers); so they have to use grapples instead.

      It's been like that for ages. They kept finding shark teeth embedded in the cables.

      • How did the sharks know that optical fiber is a tasty snack? I'm chewing on a strand right now.
        • Sharks can sense electromagnetic fields and they often chew on stuff that generates fields. There's power running down the cable; to power repeaters.
  • No Electronics? (Score:5, Informative)

    by SageMusings ( 463344 ) on Saturday January 13, 2007 @03:52AM (#17588418) Journal
    I beg to differ. There are devices known as OTDRs (optical time-domain reflectometers). Essentially, you shoot a pulse of light down the carrier and start a high-speed counter. The difference in refraction (say, a break in the cable or the end of the cable) causes a reflection that is detected at the device. Using the elapsed time, you get the distance to the break.

    Check out this link http://en.wikipedia.org/wiki/Optical_time_domain_r eflectometer [wikipedia.org]

    I also saw a documentary on the Science channel about these ships. The whole process of fixing the break is sterile and professional. They use fusion splicers, which fuse the two ends with an electric arc. Fascinating stuff.
    • Re:No Electronics? (Score:5, Insightful)

      by rjforster ( 2130 ) on Saturday January 13, 2007 @05:07AM (#17588756) Journal
      Disclaimer: I used to build the pump lasers for the submarine repeaters so I know something about this. I also have a fibre optics PhD and have made more fusion splices than I care to count.

      OTDR only works if there are no isolators in the path. (Gizmos which let light pass in one direction only)

      In some submarine cable designs at each repeater there is a return path (ie a fibre loops back) going back the way the light came. I seem to remember this being at an out of channel wavelength (so it passes through some wavelength dependent isolators). Anyway, once you know how many repeaters you do get light back from along this return path you know more about where the break is.

      I was surprised by the comment about the cable thickness for working at 2.5 miles depth. The repeater chassis I've seen are steel, coffin sized, and the walls are 21mm thick.

      I also have a feeling that todays technology is the same as that of 4 or 5 years ago. There hasn't been that much investment (or new jobs) in new submarine cable tech since the dot-com crash. Maybe it's picking up again now but it will take a while to get the momentum back that we had in the R&D team 6 years ago.

      • Re:No Electronics? (Score:4, Interesting)

        by mike_in_nj ( 1050678 ) on Saturday January 13, 2007 @08:20AM (#17589912)
        Disclaimer: My father worked for several firms involved in the manufacture, laying, and operation of submarine cable systems in the 80s and 90s. I've seen and handled the cables and have toured the type of ship shown in the photo.

        The cable size (21mm) sounds correct. They are much smaller than the repeaters. I've seen some samples mounted on display plaques so that you can see how they are constructed. Each cable contains a small number of tiny fibers (the ones I've seen had 6). The construction is a solid metal (steel?) core for strength, then some sort of thicker plastic layer around it that contains the fibers embedded within it, then a copper shield layer, and then more of the plastic material. I've probably missed a layer or two.

        On the deep sea floor, that's all there is. Just one of those cables (not bundled or armored) with the big repeater casings every so often. At shallower depths, they can be armored to prevent damage from sharks. (Sharks like them, don't know why.)

        The ships are pretty amazing. They have large bow and stern thrusters and can hold position in some pretty rough water. They have huge, round vertical cylindrical holds into which the cable and inline repeaters are fed in and spooled from the factory, and then fed back out when laying them at sea. There's a giant conveyor mechanism that runs from bow to stern to facilitate deployment or recovery of the cable and repeaters. This conveyor clamps onto the cable from above and below it, but it can also widen dramatically to accommodate the repeaters as they pass through.

        Interesting that they use a line and a grapple to find and recover the cable, but they do have very precise survey maps to work from that were created when the cable was originally laid, so they probably don't have to look very far to locate it.
             
        • Re: (Score:3, Insightful)

          by tuxicle ( 996538 )

          Sharks like them, don't know why
          Sharks sense electric potential generated by their prey through receptors on their nose [wikipedia.org], maybe they detect the fields from the power feeds for the repeaters?
        • Re: (Score:2, Funny)

          by Dr_DTHP ( 132769 )
          Disclaimer: I am an undersea fiber-optic cable.

          All of the above opinions and bits of information on me and my kind are completely incorrect. I am insulted!

          Take that, progressively-more-expert-series-of-experts!

  • I thought modern browser technology was supposed to prevent fishing?!?!
  • Actually... (Score:5, Informative)

    by kamapuaa ( 555446 ) on Saturday January 13, 2007 @03:58AM (#17588456) Homepage
    Actually, it didn't keep people offline in Asia. It just made international Internet connections incredibly slow. Using the Internet for national sites, which is the vast majority of Internet use, was barely effected. Here in China, nobody at my American-owned computer company even cared, except that MSN chat was pretty spotty for a couple days.
    • Re: (Score:2, Informative)

      by Vinegar Joe ( 998110 )
      Uh......friends of mine in Shenzhen were unable to send or receive email for a week and today I was *finally* able to make a call to Indonesia from Taipei. Many, many websites in the US simply timed out. Things are finally getting back to normal.
    • Re: (Score:1, Interesting)

      by Anonymous Coward
      Well, I provide support for a retail chain who has stores located in the Asia Pacific. Since the earthquake 75% of all calls to Asia result in a 103T error. Asia has had no issue calling us although its always fun to try to explain "We can't call you back" without an interpreter.

      Thankfully, it has gotten better over the past week or so. The funniest thing to come out of this is the director of IT for Asia operations lives in Singapore. Every night when I send my report to notify that we still can't contact
    • by Hadlock ( 143607 )
      My American friend in Beijing was without internet for almost a week, the week after that he would be randomly disconnected for a few minutes every 10-15 min. All the while he was getting slower than dial-up speeds(0.9KB/s).... in the last week his AIM connection died completely. We keep up via gmail and google talk. This from a connection that pre-break was getting 30kb/s for bit torrents from the US. I'm currently setting up a private TOR server in the US for him to see if he can get some normal speeds so
    • Where were you and what kind of connection did you have? I live in Shanghai with a DSL connection and I couldn't access most international sites at all for a few days (I made it work -barely- by passing my internet connection through a Japanese proxy after I noted to my surprised that some Japanese websites still worked). It's getting back to normal, but it sucked. Lucky you.
    • Actually, it didn't keep people offline in Asia. It just made international Internet connections incredibly slow.

      +5 Informative???

      It kept plenty of people offline in Asia. The existence of some people in Asia who weren't kept offline doesn't mean that it didn't keep people offline.

      Here in Malaysia, the greater internet was pretty much inacessible that first night for anyone on the main TMnet [tm.net.my] backbone. It came and went [lowyat.net] over the next week, and it's really only yesterday that things are more or less back

    • by fabs64 ( 657132 )
      ugh, you got lucky, I'm in Australia and [unnamed massive company that I work for] has their email server somewhere in asia. Emails all delayed for about 5 hours for two weeks, YAY!
  • by Anonymous Coward
    Very charming are the noble savages who use such primitive technology to repair these so-called Optikal-Phybers. Who can imagine what these presumably sacred artifacts mean to these tribesmen?
  • by Josef Meixner ( 1020161 ) on Saturday January 13, 2007 @05:06AM (#17588752) Homepage

    When a method works well, there is not really a need for something else, it will only be used when it is superior. So what would those alternatives be, that are cheaper overall?

    A submarine robot repairing on site is probably not possible (I have problems believing it would be able to fuse the fibers), so you only could use it to more quickly find the cable and perhaps make it easier to get the hook onto it as you can see what you are doing. But honestly, how much faster would it be, I guess a hook and the cable for it can just be tossed into the water, an expensive robot probably would take a bit longer to reach the ground. And it probably has limitations on the depth it can operate. Additionally I am quite sure they don't just drive out there and plow the sea bed, they probably have a very good idea where the cable is supposed to be. And don't forget, to find a very long cable is much simpler than finding a wreck. I don't have to find a particular piece, any piece before and after the break is ok, as I can just pull the part up and then follow it, no need to exactly grab the end.

    Also the strong winds and high waves probably would make fusing the cables very hard as well, even if they could bring up the cable. So the only thing 'old fashioned' I can see is, that they use a hook. The rest is probably quite up to date and the hook is simply the easiest, most reliable and cheapest way. Why use expensive technology if something simple is perfectly adequate?

  • by andrewdotcoza ( 981693 ) on Saturday January 13, 2007 @05:25AM (#17588822) Homepage
    I don't want to seem overly flippant, but is there really something significant about mariners using hooks to pull stuff out of the sea? I'm not really clear what the alternatives were. I'm expecting "Man Digs Hole With Spade" and "Tech Professional Presses Distant Button With Pointed Stick" as future headlines. OK. I admit that was overly flippant.
  • Superglue? Hairpins? Teleporters? IT'S AN UNDERSEA CABLE. Sheesh...

    And yes, BTW: No one exects the Spanish Inquisition! :) (Sorry, couldn't help it)
    • And yes, BTW: No one exects the Spanish Inquisition! :) (Sorry, couldn't help it)

      What, they actually have cardinals in nice red uniforms tying the cables down with a rack? That's actually older than 19th century tech!
  • You mean undersea fibre links are just cables laying on the sea floor?! I don't know what I expected, but somehow I'm disappointed.
  • by Anonymous Coward
    My father worked in the cable industry in the 1950s and 1960s. He tells an interesting story from the start of the second world war.

    Immediately after Britain declared war in 1939, a cable ship was sent out into the North Sea to dredge up the German cables, which ran from Hamburg through the North Sea and out into the Atlantic. They found the cables using a hook, exactly as described in this story, and cut through them.

    Of course it would be easy for the Germans to go out with their cable ship, dredge up th
    • Of course it would be easy for the Germans to go out with their cable ship, dredge up the two ends, and join them back together again - if they knew where to look for the break. And it's not hard to find out how far along the cable the cut is, as a pulse will be reflected from the break. This had been well understood for a hundred years.

      Knowing this, the British engineers made some sort of contraption full of capacitors and coils that they could fix on to the end of the severed cable before dropping it ba

  • by Eravnrekaree ( 467752 ) on Saturday January 13, 2007 @12:36PM (#17592592)
    Ive always wondered how, or if, they repair cables which are located several miles underwater and continue for a thousand miles. How would you ever hook onto such a cable, and pulling it to the surface seems rather difficult to me and would put a lot of stress on the cable. I just assumed if the cable went bad, they would have to lay all new cable.
    • Simple answer: Like hung electric lines, they're built to take the stress. Slack is left in the cable, and only enough is pulled up to make the repair. You don't have to pull the whole thing up, just a couple thousand feet, depending on depth. Oh, and water bouyancy would help too.
  • Uh, undersea cables ARE 19th century tech.
  • I've lost track of the number of pre-20th-century inventions I've used just this week.

    Pencil, all-natural-fiber clothing, unprocessed foods, the light bulb, and many other things.

    If it works, use it.
  • 30 to 40 mile-an-hour winds, 10 to 12 metre waves, undersea cables that always break. Isn't there some other country they could be writing software in that doesn't have all these problems?

  • my question is why do all the cable systems seems to pass the same path? some would say that the path is the "safest." look what happened now. it's not as safe as they think.

    most providers are boasting of diversified systems but at the end, all their cables pass through the same area. if only i have enough money to establish my own telecom company.

    a rant (a little off topic) - i'm from the philippines and my isp, then connected to a carrier, globe telecoms has not yet been able to recover much after all
  • I read a book from 1896, Wilkinson's Submarine Cable Laying and Repairing. I was pretty impressed with the complicated grapnels they had back then--capable of scooping up a delicate cable, slicing the cable as appropriate. I was so impressed that I typed up the grapnel chapter, scanning in the illustrations: http://lahosken.san-francisco.ca.us/frivolity/wilk inson/I_3.html [san-francisco.ca.us]
  • I've always wondered about underseas cables (and haven't really found an answer)... they lay on the bottom, so what happens when you come to an underseas trench? Surely they don't go down the cliff to the bottom of a 20-000 foot trench.... but does that mean they suspend it across? Or do they go hundreds of KM out of their way to avoid trenches altogether?

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