No more than TC32 when in an area where enemy planes might be flying. Otherwise will go as high as TC1024 when:
- transitting or,
- between sound checks in a patrol area where I can run surfaced, or
- in a patrol area where I need to stay submerged.
I'm trying to maximise the chance of being sighted while minimizing the chance of finding prey. While this sounds like the opposite of sensible, I'm trying to compensate for the game making it too easy to find merchants.
Since I am beginning to think there might be too many aircraft as well as too many merchant ships, I am considering running at higher TCs than 32 most of the time.
I try to run at TC1024 at multiples of 12 hours as it means my crew fatigue and watch status remain unchanged.