That and likely more blindingly obvious statements coming to you courtesy of this discussion of The Enemy Below!
Robert Mitchum plays the new captain of a destroyer escort in the South Atlantic. Curt Jurgens is a U-Boat commander on a mission to pick up a code book from a raider and return said book to Germany. Jurgens is sick and tired of war, and drinks to get to sleep. Mitchum has had two boats torpedoed out from under him, including a merchant freighter that his wife was on. She died, but Jurgens' son died in the war as well. Which man has more pain?!
The destroyer escort comes across the U-boat running on the surface, and doggedly pursues. Mitchum is able to anticipate Jurgens' every move, but only because Jurgens is so stubborn about staying on course 1-4-0. Mitchum is able to count on the sub always returning to that course eventually, and work accordingly.
There are a few things I want to bring up for consideration:
Jurgens is discussing submarining in the Great War, and how it was a lot of guesswork and luck to actually hit a ship with a torpedo. Now the periscope tells you course, distance, and speed, and a computer figures out everything else. He complains that they've removed humans from war. I figure that's bunk because you're still killing humans with the torpedoes whether a computer tells you when to fire or the captain just guesses at it.
There's a subplot in the movie about some of the crew being uncertain of their new captain, especially as he starts his command in his cabin, seasick. It doesn't really go anywhere, because once he steps out of his cabin, Mitchum's performance never gives the crew reason to doubt him. He's always able to anticipate what Jurgens will do, or if he's been given the slip, figure out where to meet him again. That and the bit about Mitchum's wife having died from a U-Boat seem like elements added, but the scenes that were going to expand or follow up on them were cut.
There's a sequence where the ship proceeds to drop depth charges around the sub every hour, trying to hound them into surrendering. One of the crew of the sub loses his nerve and tries to climb out, and when stopped by the rest of the crew, grabs a wrench and starts swinging. Everyone backs off and Jurgens strides in. He basically makes the boy give up the wrench by sheer force of will, standing there, asking if he believes in his captain. Then he tries to lift the crews' spirits with a rousing song. Which was pretty cool except for how indicative it was of the strain they were feeling. Of course, the dedicated Nazi was the only officer to want to surrender. Everyone else (presumably just Germans) believed in Jurgens. And he nearly pulled them through.