Reminds me of the Glomar Explorer, used drill casing to lower a huger underwater claw assembly to raise the bow of a Soviet sub.
I think they will use a combination of a petroleum filled tanker and lifting cable, tanker is filled completely with kerosene or even gasoline, no air pockets, has detachable ballast to sink it,ROV attaches slings to aircraft to tank, drop ballast, weight is greatly reduced, depends on how much lift they need, you can only wind so much heavy lift cable on a winch for that depth.
I’m not a salvage expert but my job involves boom trucks and rigging.
yep at 3 miles cable stretch just from the cables own weight on itself makes it nearly impossible. Many moons ago I logged wells in the oilfield at about a mile and the cable stretch for a 1” cable was ridiculous with only some electronic tools at the end.