Question: Throughout the film you can see that Tank, played by Dave Power, has funny-looking thin black scars on both cheeks. Was this a makeup effect for the character (and if so, why did they do it), or does the actor really have these scars on his cheeks (and if so, what from)?
Question: At first we learn that Tyler is not getting his own submarine, but then a few scenes later and he's being fired from the navy. What happened?
Answer: Technically he's not getting fired, but Dahlgren did not recommend Tyler for his own command, and he won't get a promotion without Dahlgren's recommendation. Therefore, Tyler's only choices are to keep being an executive officer (which is possible but not what he wants, not to mention Tyler feels betrayed by Dahlgren and isn't sure he wants to continue working with him), or leave the navy entirely.
Answer: The scars you see on Tank's face are fake, pure makeup. They wanted the character to have a gritty look.