[CapnScurvy]

The trick to firing an accurate torpedo, without using the periscope, is in inputting the relative bearing of the target. If you have the Speed, AoB (which provides the target track or its expected traveled path), and Range, the only part that's missing is inputting the target Bearing.

In the game, the targets relative bearing is inputted along with the range figure when you take a stadimeter reading and "Send" the range to the TDC/Position Keeper. The fact that the periscope is positioned onto the target just to take a stadimeter reading allowed the developers to think "we can put the two inputs together". That's one reason the manual states you should "lock" onto a target before taking a stadimeter reading. Locking onto a target "centers" the periscope on the ship and makes the bearing of the periscope compass the one inputted along with the Range when sent.

Looking at the Position Keeper dials will show you the firing solution as it stands. Judging from them and comparing their setup to any other information you may be using (nav map, radar, sonar) you can make a fairly good guess as to how accurate your firing solution will be.

The sonar will input the target bearing if you specifically "send" it to the TDC/Position Keeper. Use the toggle switch on the far right of the sonar unit to send the bearing. That small notepad at the top left corner is only for the German sonar display. A leftover from the SHIII combining of the two games. Don't use it to send the bearing if you are playing the American side. It doesn't send the bearing to the TDC/Position Keeper for the American side of play. Only the toggle switch that's below the sonar bearing dial does.

But, we all know that making a sonar ping and receiving the data alerts any escorts that may be about to your presence. So, how do you input a bearing without using sonar while being submerged, unable to lock onto the target using the periscope? Go to the periscope station and raise the scope just enough to read the compass bearing. When the scope is retracted the view is black, hiding the relative compass bearing. Raising it up just a bit allows the compass bearing to be visible. Turn the periscope to the desired bearing you choose and "send" the Range/Bearing both at the same time. The proper gyro angle will be shown on the lower sub dial of the PK.

There's only one catch with the above procedure. You'll need to have the Range set as well before sending the input. If you input the correct estimated bearing without knowing a good range figure, the solution will be incorrect. Unless you have the Range dial modded to allow for inputting a figure you choose, or have a separate range dial that allows doing the same thing, just sending an accurate bearing won't be enough. Accurate range is important too. Knowing both are "sent" at the same time requires you to have them modded to allow for manual input when trying to fire a torpedo without the use of the periscope viewing the target, and using the stadimeter for inputing range.