[Graf Paper]

I may be wrong about this... [EDIT] -Okay, I'm not wrong. Thanks for confirming this, privateer. My brains are a little faulty today.

I recall many discussions like this in the past. It seemed the general consensus was that you get no credit for torpedoing a ship that later sinks if you are out of contact range with that ship.

I believe the limit is you have to be within visual or hydrophone range of the ship or else the AI of your crew won't "know" the ship is sinking. That makes sense. How would you know indeed if a ship goes down unless you have some proof? Without confirmation, you get no credit, just like in the actual war (mostly).

So your crew either needs to see her going down or listening on the hydrophone for the distinct sounds of bulkheads collapsing.

Unfortuantely, this means you need to stick around and possibly find your boat in the path of a destroyer's ASDIC, as they're running to investigate the scene. You'll have to use another eel to make her sink faster if you're in a hurry or just want to vacate the area before those pesky ASW blighters show up.

One other thing to keep in mind...

In bad weather/rough seas, sometimes you will not get credit for a ship that sinks after you torpedo her because it was actually the waves swamping the ship that caused the sinking and not the torpedo damage.