Also...
That is one nice thing about attacking convoys-they are all on the same course and speed. If you get perpendicular to their course, since range doesn't matter, you can shoot multiple targets fairly easily.
:)

sharkbit,

that's exactly what I was doing (manual, AOB 90, dead stop). I didn't change range for second vessels and in both cases I missed.

----first_ship---------------second ship-----
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me

It was like this. First ship was hit when I aimed, second was missed. That happened with tankers and merchants. Next time I'm going to make separate entries of distance, one for every target. I'll see if that helps.

One thing I've noticed when attacking multiple ships at close range is the gyro angle is pretty big when firing at the trailing ship(I'm assuming your shots were fairly close together, time wise) which decreases your chances of a clean hit, plus the torpedo may have hit at too big of an angle and just bounced off the hull of the second.
I've tried to open the range a bit when trying multiple targets.

One thing I've done is generated a mission using the Mission Generator to practice engaging multiple targets without all those extra worries of night, escorts trying to kill you, and the like. I put a couple of ships in formation and set my sub up in good position and go from there. You can experiment with different approaches, angles, ranges, etc. at your leisure.

Hope all this helps. I'm by no means a manual targeting guru. I just started manual targeting a couple of months ago with a new career in the Med. I was an auto-targeter until then. I'm learning a lot as I go.
:)

If I can set everything in this mission editor (speed, course, distance between ships, wheather and time) your idea is certainly worth a try. Thanks for a tip!

Yes-all that and more.
Here is a link to bigboywooly's pdf tutorial on using the editor. Quite helpful and safe to download.

http://files.filefront.com/sh3+missi.../fileinfo.html

:)