Johann from Das Boot
 

could anyone tell me what this chap is doing when he puts that instrument to his ear and to the engine?

Listening to the strikes of the pistons. I reckon that it's a way to tell if something is cracked or not. IUt;s the same ting that railwaymen do, wheb they hammer the train wheels.

Yeah, listning to the tappets and for any odd knocking :know:

The actors website:
http://www.erwin-leder.com/biographi...x_english.html
He also act as "Singe" in the Vampire movie "Underworld" :D