Reloading, 4 tubes, all that jazz. I intentionally overcomplicated it so that the compartments are easy to redefine so that if I ever get to the point where you can upgrade (or downgrade) boats, it should be possible to reset torpedo configuration easily.
Not that the rest of the game supports that at the moment since the boat mass and torque are hardcoded ... welp. Perhaps I can start looking into the future now. :)
I need to be sure I'm decreasing reload time more specifically rather than just "first found empty tube", but that's the biggest puzzle at the moment. Then, next thing which I think might be sonar - underwater ship detection, that is.