Right. I am on my first patrol, and I came across a Jap Freighter, which I sunk.
A Fubuki? Destroyer came after me, but missed with DC's, and after spending some time hiding, I came up to PD and am now about 1,200 yards from her. It is about 22:30, and she is doing 0 knots - just sitting there sucking her thumb...
Now, as this is my first patrol, and have no experience in sinking ships, I saved the game before I fired, so I can load again if I miss. Cheating I know, but I want to get the hang of this

(it is a trial career).
I fire 4 torps set to 15ft (draft if 11.5) depth, high speed, and mag-detonate... miss, miss, miss, miss. WTF!
Re-load the game... changed the settings, trying different combinations of depth, detonate type etc - but not a single torp hits.
I have tried depth ranges from 5-15 with different detonation types.
As I am 1,200 yards away, and she is doing 0 knots - my TDC data is spot on as far as I can tell. I have just spent and hour loading the game, firing, loading, firing... what is going on?
I am running stock 1.5 (apart from some cosmetic changes to the game).
Am I really that crap?