I just finished watching Greyhound, the new movie with Tom Hanks. The German u-boats sent antagonistic messages twice essentially telling the Americans that they were going to die. Did this happen? Or was this just added drama for the movie?
Anyone with further insight on the matter is welcome to contribute if they're capable, so don't take this post as discouraging such.
As it happens, that particular aspect of Greyhound has come up before. u/thefourthmaninaboat looks at just how likely the prospect is.