What does H.E stand for?
 

Ahoy there!

Just recently watched a video about the sinking of U-864 by HMS Venturer. In it there's a bit from the Captains patrol log, where he states:

"09:32: Picked up very faint diesel H.E bearing 340 degrees. It then faded"

I was really curious as to what H.E stands for? Hydro-acoustic something perhaps?

Here's the link if anyone's interested :)

https://www.youtube.com/watch?v=I8URUdS04M0

I know this might be the wrong place to ask this but I have to start somewhere :hmmm:

Hydrophone Effect