I've read several historical books that mention a sub lying on the bottom hearing the sound of cables dragging across overhead, so although it wasn't done often it was done. Not trying to catch the sub like a fish and haul it out of the water, the problem was trying to locate it when it's lying doggo with motors stopped - sonar bottom echos make it real difficult to pick a confirmed contact out of all the returns coming from the bottom itself.
Speaking of sonar, we've noted in game that the IJN escorts seem to be programmed to be deaf to the sub's sonar and fathometer. In Admiral Lockwood's book SINK 'EM ALL he mentions that sub skippers were finding out as early as the summer of 1942 that a single ping was extremely unlikely to be heard by any nearby destroyers, so they frequently used single pings to confirm range to a target throughout the war.
So there's some real life fact behind it, I'm going to start pinging more often.
