It depends upon whether I've intercepted a convoy, or if I've received a contact report, although they're both similar.
I strive very hard to avoid attacks in shallow (less than 100 meters) water. Sometimes that can't be helped, but I'm a lot more cautious in that instance. I also approach to within 1000 meters (400 during bad weather).
Basically I plot the convoy route as close as I can, manuevering my boat to be approximately 1 klick off to the side of the convoy path. Usually I use flank speed to position myself two hours ahead of the intercept, and place my boat (when possible) so that the sun or moon is in front of me (to backlight the ships) and/or so that the wind is behind me (to avoid having rain or wavespray in my scope face).
Until radar becomes popular I'll wait on the surface, deck awash, until I make visual contact with the approaching convoy, making range and bearing checks and plotting them on the map to verify their approach (I don't use map updates; my realism is full except for manual TDC entry), making minor corrections to my position if needed to maintain my 60-90 degree, 1 klick position off the convoy track. Once they are within 6 klicks (normally that's the lead escort) I submerge.
Once radar starts appearing on the scene I wait submerged, day or night, a minimum of two hours advanced whenever possible. The escorts normally don't start getting 'frisky', nor does the convoy excessively zig-zag, unless they have a reason to do so, and picking up an unknown radar contact sort of ranks right up there with a 'good reason'.
I track using the hydrophone (manually from the sonar room, as well as asking for reports every so often) and by periodically popping up the scope. I try not to leave the scope up for longer than a minute or two at a time at long and medium ranges. When the weather is rough I don't use the scope, as I'll linger at 15 - 18 meters depth, to avoid possibly broaching. Nothing sucks quite as much as having your conning tower pop up in heavy swells with an escort 800 meters away.
As long as I stay above 20 meters it's
very difficult for escorts to passively sound detect me, especially if I run only 1 - 2 knots, and I've actually manuevered by destroyers within 500 meters of me, threading my way and sliding just past them and through behind to the convoy (on patrols as late as late '43, too; not sure how easy that might be in early '45, as I've never played that late yet. I also run SHIII modded with GW 1.1). I keep running very slow (mostly for depth-keeping stability) as the escort keeps chugging past and away and the convoy comes closer. If I've set everything up just right, by the time I'm flushing tubes I'm sitting about in the middle of the convoy, columns fore and aft of me, with between 2 -6 ships within 1 - 2 klick range. I don't fire unless I can visually identify ship flags, or unless I have very good target solutions.
(Which makes me wonder, and ask, just how were the ladder-seeking torps used? It sounds as if you fired them several klicks from the target and, if so, how the heck did you identify nationality at that range? Or was it a case of, by then,
everyone was fair game?)
Now, depending on the situation and circumstances (types/numbers of escorts, weather, ship types, distance to ports, etc.) I either target to kill or cripple (especially with the damage mod incorporated in GW :p ). If I want a definite kill at range I'll salvo two tubes, or try targeting the fuel bunker with a single torp. If I want to try and maximize the number of kills, I'll go for crippling shots, firing impact-pistolled torps at mid-depth settings (depending on the draft) and specifically targetting either the engine rooms or the steering/rudder/propulsion areas at their sterns.
Either way, after firing I almost always just go silent running until at 18 meters, then set my speed at 1 knot and just twiddle my thumbs and wait. I very rarely get detected by escorts, even though I clearly can hear them approach and swan around looking for me. It helps that they're trying to pick up a virtually silent boat at a depth their hydrophones don't work well at, whilst surrounded by the churning sounds of lumbering merchants.
I also immediately mark-notate my position at time of firing (you'll see why in a bit)
On those occassions that an esort
does detect me (when they start active pinging that's never a good sign) I immediately 'crash-dive' while setting the rudder at around 20 degrees, port or starboard, then set the depth (seafloor permitting) to 160 meters. (As escort-evading is something else I'll just leave it here about that)
Once the closest escort is at long range I'll begin a slow ascent to periscope depth, while coming off of silent running, manning the torpedo rooms and reloading the tubes (if I have internal reloads available, of course). I also set a course that takes me in a wide looping arc back to my firing position, which I'd earlier marked on the map. Trust me, there is nothing more gratifying than to reach your firing position and pop the scope up, and to see three dead-in-the-water big-ass cargo ships bobbing motionless. I just wait until all the tubes are reloaded, and until at least an hour has passed since losing the last escort, then leisurely finish off the cripples.
Albrecht von Hesse