Comment Re:No Electronics? (Score 4, Interesting) 98
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.
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.
