Midnight Templar Greatings!!!! mate
you can change the realizm settings in the naval academy,
all you need to do is go to the single player missions in the main single player menu just go to the realizm settings and turn the manuall TDC on - save you new setings and go back to the naval academy and start a mission.
When you start a carrer just before the start patrol screen simplly change TDC back to automatic - (I am sorry my English need improvment

)
Thats all
I am leard about month how to play with 100% realizm settings,
count the target speed by using the chronometr (3min.15sec) with some usefule mods like pato 1500 km bearing mod and so on....
If you have any aditional questions you may feel free to ask me and others ho hade beter expirience in the game
Good luck and good hunting