More ramblings.

I once saw a salvor disprove the ping-pong ball method on a TV programme. Even at wet-suit depth they crushed into cup-shapes and lost all boyancy.

I thought that a standard method was to use the tide:
Hitch one sunken vessel to two floating ones at low tide.
Drag the salvee through the water at high tide until it grounds.
Wait for the tide to fall, shorten the hitches, wait for the tide to rise..... have to be not too far to shore, among other requirements.