ahoy.
played all SHs so far, & I'm struggling with 5 as well, don't feel bad. so far, hunting for targets isn't easy.
I play custom difficulty, 88% realism. everything ticked except map contacts. gotta have some sort of point of reference, the best thing about it is using it to plot a contact's course, for the purpose of intercept.
currently on patrol, have to sink 100k with a whopping 11 fish. I will say that @ the beginning, using impact detonators with more success. magnetics are prematurely detonating ... often.
as far as rudimentary tidbits the manual simply doesn't discuss,
this helps:
http://steamcommunity.com/sharedfile.../?id=201108789
only had the game a few nights now, the stadiometer is still a pain in the stern, especially in rough water.
thinking of foregoing it altogether.
good luck!