As I note a lot of discussion here about aircraft parts sinking thousands of feet to the seabed I thought taht I would offer some ancedotal evidence I came across years back.
Apparently the US Navy was doing a recovery years ago of an F14 that was sitting about 10000 ft down at the bottom. Their submersibles at the time were manned and even after locating the scattered wreckage they would have a difficult time going from one end of the field to the other, since they really didn't know precisely (enough for vision) which way they were heading and where the ends of the field were.
The mother ship with its gear did know where it was on the surface but not where the submersible was. I'm sure today the technology is a lot different. What they did back then was to take a whole bunch of 55 gallon drums, paint numbers on them, then cut holes in the drums then align the mother ship in a line somewhere (they hoped) over the expected debris field and then put the drums over the side of the ship at time intervals while underway.
The drums sank to the bottom (10000 ft down) and presto even with the various currents they were found later by the submersible strewn out roughly in a line that transversed the debris field (in a random drection).
Now I'll leave it to the reader to draw any inferences they care from that experiment
