Thanks! That's exactly what the problem was. I just scored my first manual targeting hit on a C2 (night surface attack at 2500m). The fish was aimed at bow of the ship but hit at the stern, but I assume that's my own fault for estimating something wrong.

Prior to this, I had assumed the periscope bearing was mechanically linked to the TDC at all times. Nope. Turns out you have to click that little unlabeled checkbox before you shoot.

Partially your assumption was right. It depends in what mode your TDC is. If the button in the TDC Screen (F6) is red, then the TDC is in Auto Mode and does only accept data entry from the note pad, but the bearing of the scope is automaticly locked to the TDC and needs no update.

If the button is green, you are in manual mode, you can enter data to the TDC by setting it manual via the TDC Sreen or through the notepad. In this case the scope is unlocked from the TDC and you have to update it before the shot.

Just check if the Schusswinkel/Firing Angle (FA) is somehow realistic. If the target passes from left to right the FA must be greater value than your bearing to target, if the target passes from right to left the FA must be of lower value. Just a rule of thumb.

Makes sense. Actually, that's a great tip and helps a lot.

Of course, on my second try, the target speed for a small merchant kept showing as 21 knots. By playing around with the bow angle and range, I was able to get speed down to 9 knots (which still seemed fast). Sure enough, the torp passed just barely in front of the target.

With the timing feature of the TDC I also mostly get strange speed results, so i stick to the method, plot the target on the map and calculate the speed from the distance between the plots. I once hat a tug running at 44 knots. Must have been some kind of uber-tug :rotfl:

Remember also that if your tube is not open, the torp will fire 3 seconds later then you planned, perhaps then lagging the target by that amount of time.

It is standard proceedure on a torpedo attack to open the tube(s) just before firing to have it ready to fire on command.