Yeah, I have experienced many times that I shot 4, 5 torps to a small ship and she'd still not sink. In my last patrol I ended up spending 10 torps to sink a pair of unguarded lone small tankers.

But it's likely that I kept hitting the same compartment and because of that they didn't easily sink. Probably this aspect is unrealistic since I guess I could have pentrated the other side of ship hull by the time 3rd torp exploded in the same position but that wouldn't happen in our game and it is the limitation of the original game. Modders are not the developer and there're many impossible-to-realise aspects. We should understand this and so cope with some compromises for better, bigger benefits.
As for uber DD, I *think* he fixed you
before you cut the engine.. Once they find you, they're very, very nasty now (a bit too much to my taste actually

) Because of that I'm no longer very enthusiastic on a convoy

and rather am excited on a lone ship for safe tagets.:rotfl:
Once I attacked a convoy in the middle of night. It was new moon so it was very dark. I was on the surface. The convoy was proteced by 4 DDs and leading DD on the front actively zigzagging. To get close as possible, I was going to cut the engine when I was very close but I didn't bother to calculate my ship's speed and I ended up getting
TOO close when the leading DD was going by. He was perpendicular to me. The NYGM manual says that "could be undetected as near as 800m." I was
490m to the DD on the surface when closed to my side but the DD did not detect me! (of course I was completely halt and dead silent at the moment). The DD just passed by... well, after 10 secounds he past right in front of me in the dark, he surely found me and rammed. So you
could get close undetected in some case. Well, after this experience, I now submerge even in a dark night if I wanted to get less than 2500 m to a target, though.
I haven't seen a ship sinking taking more than 9 hours with the mod, so I usually give up waiting about 10 hours. But in reality, it wasn't uncommon to take
days to a ship sink.
Also, with NYGM v2 prepare even 6 or 8 real hours to escape from DDs or even a DD. Not 30 minutes of fun thrilling escape. But if you think about reality, you could have been depth charged for over 2
days.
I don't use 'C' key for crash-dive any more for the hassle. I think "crash dive" doesn't make any faster than "ahead flank and 'D' for dive." So to avoid crash-dive problem not using 'C' is an easy solution. Then you can maintain the depth at 1 knot.
And lastly, I almost no longer make an attack in the light if there's an escort. I shadow a convoy for night and sometimes I
need to spend 2 days to get the position and ideal time. I used to shadow a convoy within my visual range (8km with the stock game, clear weather) but no longer. I space 20 km or even more to ensure that I would
never detected while establishing collision course. Attacking in a storm now is out of question. So, it's got much like the
real thing in ways of playing, and this is very frustrating, in fact. It's not game but much like a simulation, indeed.