Repairing the cable
This is an interesting read:
So, they grapnel one of the broken ends up, off the seabed (that could be somewhere between 1km and 7.6km below the surface).
I guess they have to move the ship "backwards" (along the line of the cable), as there is unlikely to be any slack in the cable to allow it to be raised straight up that far !
The cable end is brought onto the repair ship and they test/check if the fault is there. Then they attach a buoy to it, and set it to sit on the surface, awaiting for it to be spliced onto the other end eventually.
Then they move off and find the other end and do the same.
So, once the two ends have been checked/repaired, those two ends could be maybe a few km apart (where before they were "joined" to each other).
I would imagine they then have to splice in a new long section of cable to take account of this increased distance between the two ends..and once spliced, they then drop the cable back onto the seabed...but they'll be a long "run" of cable that is now looping around on the seabed...but at least the connection will be working.