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Undersea Cable Repair Via 19th Century Tech
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."
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.
Libertarian Leaning Political Discussion Forum.
And weird E and R switched in meter metric!
Meter == device for measuring stuff. I.e. volt meter, etc.
Metre == measure of distance (the distance travelled by light in absolute vacuum in 1/299,792,458 of a second.)
Just because Americans can't spell doesn't mean the rest of the world has to adopt your broken spelling.
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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.
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.
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.