Search for a tool called 'Wolfie's Tweek Pak' here at SubSim download section. It allows you to change TC at all modes in SH3. But mind you that one of them also affects the crew fatigue TC, but I'm not sure which one. So don't change all of them to 4096, as your crew will be dead in seconds...
This also inlcudes a tool to preset the torpedo loadout of all subs. A must have if you feel like me, and think it's unfair to spend all your renown on the good torpedoes (I doubt the captains got less famous if they chose to put in a FAT or two...). If you select torpedoes that didn't exist for the current time period they won't appear though, so that's good.