Today, a SCAT video.
No, this isn’t German. SCAT in this case is “Submarine Classification and Tracking”. According to the YouTube notes, this was a proposed system that involved “a mechanical noisemaker affixed to large magnets which, when it attached to the hull of a moving submarine, generated noise that allowed the sub to be easily tracked“. This was never deployed, since there were…shall we say, practical issues with attaching mechanical noisemakers with magnets to moving submarines.
But we do have this vintage 1960s video:
Bonus: “To Catch a Shadow”, more anti-submarine warfare propaganda, featuring the P-3 Orion.