Speaking of Robert Mitchum...
I just finished watching
The Enemy Below. RM plays a destroyer escort captain playing a cat-and-mouse game in the South Pacific with a German U-Boat helmed by Curd Jurgens. Not as many submarine tropes as your typical sub movie.
The first ten minutes feels stiff as what feels like actual Navy seamen dutifully recite their lines. But then Mitchum comes on screen and suddenly everyone plays to him, and better for it. This was filmed in 1957, when Americans were more worried about the Russkies and the full horrors of the Holocaust weren't widely known. So it was possible to portray the Germans as sympathetic, and indeed, this movie spends roughly half the time aboard the U-boat. Sure, they speak English with German accents to each other, but it was either that or subtitle half the movie, and the American movie-goer has little patience for that.
Indeed, this movie portrays the crews of both sides as practically brothers-in-arms. There's almost no red-eyed hostility toward the enemy, and officers of one side even risk their lives to save the lives of the others once the battle is all but over. Picture two football players putting everything they have into trying to knock each other down, then the victor offers the other a hand up.
I was tickled by some lighter counter-trope moments, as well. In one scene, the crew are ordered into silent running to play the waiting game. An enlisted man reclines in his bunk with a book,
The Decline and Fall of the Roman Empire. Next to him, a lieutenant amuses himself with a
Little Orphan Annie comic book.
If you like Robert Mitchum, give this one a look.