Torpedo Attacks

[Faideeeeeee21]

Hey everyone, i have been playing this game for a while now and "I´ve figured out" most thing (navigation, how to give orders, when to go evasive and escape ASW ships....) , but thers something that im not too good at ,I just can´t wrap my head arround: torpedo attacks.
I have my game running at 86% realism and i like it like that, but I just don´t know how to topedo a ship, even if it is a still target and the sea is calm.

I´m running these mods:
-Grey Wolves Expansion
-Sh3 Commander
-Thomsen's Sound Pack V3.2cg
-Rbs1_SH4_Effects_GWX_30_71
-M.E.P v6
-TKSS18 German U-Boats Compilation No Eagle
-German U-Boats Compilation 2 (only VIIB & VIIC models by WISE)
-FixAllSubGWX
-ARB WideGui 1920x1080 V3
-M.E.P v6- VisualSensors for GWX3
-H.sie Hard-coded fixes.

I "mostly" now how to set up the shoot;identify the target, do the rangefinding,check the speed,and find the angle on bow...
But i must be doing something wrong, as my torpedoes always miss.
If you can give me some advice or point me towards a video I would be very thankfull.

But anyway, thanks for reading and any help is apreciated