Depth under keel ping

[UKönig]

Originally Posted by danasan

You can ping all day and night, no escort will hear that - in the game.

I'm not sure about that, I have used the echo sounder for shallow depth keeping to test if the escorts -so long as they are actively looking for you- will home in on your depth checker.
I don't play dead is dead, so I tested it out deliberately to provoke them into coming closer. It seemed to work. They had to be fairly close already, and searching for me. Which is true enough to historical. It's the same kind of technology that they use in sonar, just pointed at the ground. They could hear your sonar beam if you pinged it off their hull, they way they do with you.
It would probably sound like an ASDIC ping to their hydrophone operator.