Back on topic, forgot to mention - after torpedo room. If you're an S boat driver no gots one, Porpoise has two after tubes with two reloads, all others have four after tubes with four reloads. I know real life torpedomen have a lot to do (cleaning heads, swabbing decks, chipping and painting
) but ingame they have only one job, reloading tubes. Mechanical and Guns skills control how fast they reload tubes, but in the after torpedo room they only have to reload once after you fire all the tubes, once that's completed they might as well be passengers. The forward torpedo room in Porpoise has 8 reloads, Salmon/Sargo on up 10. Tambor on up has six forward tubes with 10 reloads so six tubes reloaded once, with four left over for a partial reload. Salmon/Sargo have four forward tubes so two full reloads and a partial. Porpoise has two reloads.
However you add it up the guys in the forward torpedo room have more work to do, so when starting a career I put the best rated torpedo POs in the forward torpedo room, after torpedo room gets whatever is left over, since reload speed isn't as important with only one reload per tube. Very rare to fire more than one shot per stern tube in a single battle unless it's a long one.