Guys,
Let me Tell you something, and please don't take me wroung...it is just
Explaining something to you that you are forgeting...
You have to be able to see the difference between A modern sonar
sound and a 40's sonar sound!
So far what I see here posted by you, is sound of Modern Sonars
and not the sound back on the 40's Submarines and Warships...
You have info here:
http://en.wikipedia.org/wiki/Echosounder
I think you are going in the wrong direction and mixing Modern with
old sounds!