Gizmodo
Not a week after two massive undersea telecom cables were snapped—according to BBC News, most likely due not to Godzilla but a single tanker "dragging its anchor along the sea bed"—and the repairs are well underway. But how in the hell do you repair a nine-layer steel-reinforced cable located deep beneath the surface of the Mediterranean?
The first thing you're gonna need is an Optical Time Domain Reflectometer. Engineers on shore use it to send light pulses down the cable, which reflect back at the breakage point, providing a measurable delay that can translate to distance within "tens of meters."
Once you get your location guestimation, you posse up your team of about 50 people and pile them onto—what else?—a cable ship. This ship will need remotely operated vehicles ROVs (see James Cameron) that you drive down to the sea floor, roving around until you spot your breakage.
When the ROV finds the affected cable segment, it may snip off the nasty bits (just leaving them there to become part of somebody's new habitat) and bring up the two new ends. On board the ship, operators can splice a new segment between the cleanly trimmed ends of the cable break, and drop it back down.
Sometimes the ROV can't find the segment, or can't get the right grip on it. In these cases, the technicians send down a centuries-old device called a grapnel. The grapnel snags the cable wherever it can, and yanks it up to the boat for the end trimming and the repair job.
The cable itself is a tricky fix, because it is made up of nine layers, which you can see in the BBC's diagram below. If you are an experienced undersea-cable repairman who would like to add anything to this admittedly brief primer, I encourage you. And for the love of Pete, don't try any of this cable repair stuff at home! [BBC News]
Comments
The answer to your question is that you make the captain of the ship that cut the cable to swim down there and fix it. You beat him until he does.
Nice post. I've been wondering what exactly goes into this.
anyone have an idea as to how thick in diameter these bad boys are?
That must require a wicked pair of crimpers.
...I have a feeling the part where lots of duct tape is used was left out intentionally.
What, no duct tape?
They're about 2" thick, and *very* inflexible, at least in short lengths. I observed one that was about 3 feet long, and I could have used it as a baseball bat.
Can they really just splice in some new fiber? Wouldn't the joins affect the signal? (On the otherhand, I don't see how they could add a repeater device either.)
@rekoil:
that's disappointing, I was expecting something at least a few feet in diameter. they really should add just for dramatic effect, if anything
I am a certified undersea cable repairman, and I can tell you that the BBC image leaves out the most important aspect of the cable: the centermost cluster actually consists of yummy, yummy red vines.
Anyone know how deep we're talking?
This seems like a good way to stop outsourcing jobs to India....more tankers please!
Does any one know..... is the copper sheath layer used to transmit anything?
@Geisrud: That's deep, deep
Jacques Cousteau pockets deep.
@discounteggroll: According to part of this article: [news.zdnet.com] a TAT-8 or TAT-9 connection is a bit thinner than the average persons wrist (2nd paragraph of the section labeled "New Jersey to Britain").
Anyone surprised about the tar-soaked nylon yarn? Are we waterproofing a pirate ship in the 1800s or building a 21st century data conduit here?
@The Lab: heh.
What next?
Osama (not Obama) commandeers a subtilla of ROV's "Turn over Bush for trial or we chop off your hoses!"
/how vulnerable we are!
@mthrndr: Why *not* use it? We have over 200 years experience with it. We know how it ages. We know when and why it breaks down. We know how water affects it over very long periods of time. The same CANNOT be said for polyethylene. It's not as though they're sheathing the cable with it; as a 'back-up', I think it's genius. Sometimes old ideas really do work best.
@The Lab: Old tricks are the best tricks sometimes!
@mtopper: I imagine the copper sheath probably is used for monitoring. So they can get a general idea of where the cut is, without having to travel a few thousand miles and looking for a cut.
They send a signal through the copper, or even the fiber, and the roundtrip it takes to get back to them should tell them where it is cut.
I don't know why, but I find it amazing that most of the internet provided to 1/3 of the world is carried on just a few cables the width of my wrist.
I was curious how deep the water was around there. The cable broke in the straight of Sicily (between Sicily and Tunesia. According to some maps I found, the water is between 200m and 400m deep (600 - 1200'). If the theory holds up, thats a mighty long anchor chain if you ask me.
Okay, dumb question. How do you lift both ends that need to be spliced into one ship? Those ends will be pivoting at some point along the cable (on the seabed) and as you lift them then they'll spread further apart. Does the repair actually involve two splices and a length of new cable to bridge the distance between the two open ends?
@mtopper: The copper transmits DC to power the repeaters that are needed to get the signal all the way across the water. By itself the optical signal only goes about 50 miles, so there's a set of repeaters in watertight casings that are dropped down along with the fiber.
There's a story about China stealing a couple of erbium-doped fiber amps from fiber runs coming out of Taiwan back in the 90s, knocking out much of the island's phone service in the process.
If you really want to know about the nuts and bolts of this stuff and you have a couple hours to spare, read Neal Stephenson's "Mother Earth, Motherboard" Wired Magazine feature. Good stuff.
@tundraboy: Yes, they add a length of fiber to the run which goes into something of an S-shape when they drop it back down.
Check out this presentation for more info...
I hate to be the conspiracy theorist here, but this is undeniably suspicious. Four cables in two different seas in one region being severed in the same week? There haven't been earthquakes or the usual suspects involved here, and we've had four to five different explanations from the according governments.
Mediterranean Sea
"There has been wide speculation that the cuts were caused by ships' anchors dragged along the bottom of the sea in stormy weather. But Egypt's telecommunication ministry said Sunday no ships were registered near the location when the first cut in the cables occurred, north of the Egyptian port of Alexandria."
[ap.google.com]
Indian Ocean
"The Falcon cable was cut 56 kilometres (35 miles) from Dubai, between Oman and the United Arab Emirates, according to its owner FLAG Telecom, part of India's Reliance Communications."
[www.physorg.com]
I can't find the story now, but sometime in the last couple of weeks there was an article showing a group of photos of things few people have seen. One photo showed two non-descript cables coming out of a floor and running up a wall. They were the landfall ends of two undersea cables. Anyone remember also seeing that and where it was? I'm thinking it might have been Wired.com, but I can't find it now.
@packetsniffer: Now 5!!! See quicklink I just posted.
Found the photo. [www.wired.com]
Transatlantic cable emerges at Avon, NJ.
I worked with a guy that did repair on fiber optic cable a few years ago...it was really a pain in the ass job, and we were working with cable that had MANY MANY less fibers than this. We'd spend half a day trying to get the repair to reflect a certain % of light back.
@The Lab:
Tar-soaked yarn is a great insulator. Like @strider_mt2k: said, just because it's old technology doesn't make it bad technology.
I've got half of the power in my house going through Tar'd cables that are 80 years old. That's a more-than-reasonable lifespan for underwater cable, is waterproof, and I image may even be able to reseal small cuts in the insulator. (The tar will just flow back together)
And before anyone starts screaming. Yes, the tar'd wire is one small step above post and knob wiring. It does scare me. And the only reason HALF my house is on it is because I haven't finished replacing that half yet!
OT, but is the photo caption an "Amazing Race" reference?
@Wilson Rothman:
Geez. Okay, this is really getting out of hand.
What is in the photo in the first place?
The tar might also taste nasty, to dissuade critters who've nibbled on the cable from biting any further. Terrestrial cables, both aerial and buried, use a gel known as "icky-pic" for moistureproofing, but I suspect that underwater, something more serious is needed.
@lulable, do some reading about "optical fusion splicing" and be amazed.
Essentially, to make a splice, you cleave the ends as flat as possible, then nudge them up very close to each other but not actually touching. Then you bring electrodes to either side of the gap and start an arc between them, so the arc melts the glass at the tip of each fiber. Then you turn off the arc and touch the molten faces to each other so the glass sticks. It cools almost instantly.
A moment later, you shine some light through the fiber to see if the splice exhibits low enough loss. If not, you cleave out the middle and try again. When you end up with a good splice, melt a tiny tiny piece of glue-filled heatshrink tube over the joint for reinforcement, and move on to the next strand.
Of course, that's just the glass. Undersea cables have electrical power running over the copper parts to power the inline repeaters, and all that needs its own repair procedures. But you get the idea.
I hope someone gets a video crew onboard one of those repair ships!
i'd take the godzilla, cloverfield explanation
@Limekiller: I saw that photo in a Taryn Simon exhibition in Frankfurt last year. Had to think of it too when i read the posting. She has made a lot more very good photographs, check them out at [www.tarynsimon.com]
I think it's hilarious that a cable that transmits some million people's communication across the world has to be only a bit larger in diameter than the one I use for copying some files from one computer to another in the same room. On the other hand, if such a cable would have to be proportionally larger to the amount of data it carries, we would have a problem.
@n/a: hey, nothing wrong with knob and post wiring. in fact, it's better than romex, because them damn norwegian roof rats won't start a freakin wall fire with knob and post.
@aphex:
Then you will likely find it even more amazing that the internet provided to the other 2/3rds of the world is actually carried in your wrist. Please be careful.
@hanswurst0815: Our everyday usage never uses the full bandwidth of our household copper cables. Also, your printer cable is thicker due to increased insulation. Cut an old one in half and you'll be surprised to see that the actual conductor isn't very large.
I imagine these undersea cables are moving data closer to their maximum capacity.
@aphex: Size matters not...
Shouldn't that be like Sea Captain 101?
Lesson 3: Anchors.
If you dont want to move: drop them.
If you do want to move: raise them.
Lesson Review:
1) You want to move your boat at some kind of velocity. You should raise your anchors. True or False?
*NOTE: If you miss this question, you should think about maybe not being a captain of any kind of boat, ever.
Long live space race!
How weird would that be to say to someone else?
"What do you do?"
"Im a certified undersea cable repair man. I fix yer internets."
"...What?"
@theespacepope: No joke!
Best. Photo. Caption. Ever.
@theespacepope: LOL!i laffed really hard at the lesson review!
We played around with the fusion splicer that came out to do our building's fiber. I can't imagine how much more complicated the thing that fixes this is >.>
I don't know, but I hate the fact that calling has been reduced to staticy noise and hiss as crosstalk hits like never before.
@Saboth: We got a brand new fusion splicer for work about a year ago and I can tell you that they've come a long way. I could strip the cladding, prep and fuse a splice in less than a minute with an average loss of .01dB.
"The first thing you're gonna need is an Optical Time Domain Reflectometer"
WTF???
They should just replace it with Monster cable so the data looks and better. Anything less would be an unacceptable compromise...
You want real conspiracy?! The amount of computing power in a given volume depends on the surface area of the box, not it's volume. This is Physics 101. Well, graduate level 101. Which god thought we'd never run into this weirdness, that our 3D world is really just information projected from a 2D one? Or that only computers can we predict where three stars that orbit around each other will be in a million years, since equation exists that can capture that "oh, I'm Mr. Star, I might go left-or-right as I have just stopped being flung out and am starting to fall back into the group, but now even the slightest quantum fluctuation might determine my decision."
@mthrndr: Mr. Pibb + Red Vines = you know!
I saw something on TV once about the repair of these, I think it was on Discovery. It was pretty cool but they didn't get into the advanced fusion stuff. I know that they cover the spliced area with an even thicker and tougher sleeve that protects it from further damage.