You might think, given the title, that you are the Submarine pilot in this game.
Actually, is that job called a Submarine Pilot? Submarine Driver? Submarine Person who makes it go through the water and then maybe up out of the water and then down into the water again?
Anyway, you’re not the person who moves the submarine. You’re the boat. And you have to drop depth charges onto the submarine before it shoots a torpedo up at you. The reasons for this skirmish are not revealed, so I’m going to assume that it’s a fight between two people who had an argument over whether Yasmine Bleeth or Pamela Anderson was the best in Baywatch (obviously it was Yasmine Bleeth), and they have never let it go, and now spend their days trying to blow each other up.