Speed and AOB calculation
As Boris states target speed is the key to manual targeting.
I do not use the notepad method for determining target speed. Instead I plot the target's positon and course on the nav map while traveling to a good firing position.
Mark target's initial position on nav map and note the time.
Plot target's course.
Make additional marks for target's subsequent positions and note the time.
Measure distance from the first mark to subsequent marks and determine the time it took to travel between these marks.
Now, use this equation to determine estimated speed in knots:
Distance in kilometers x 32.5 divided by the time in minutes = speed in knots
(This is the same as the 3-minute 15-second method but can be used for any amount of time in minutes.)
If you do this a number of times, you'll have a good idea of estimated speed. Manually input this speed into the TDC on the attack map. By the way, speed can be in half knots so never round.
Simple and easy AOB method:
You already have an accurate plot of target's course.
Your u-boat should already be on an intercept course to target's course.
Using the angle tool, draw a line from the u-boat to the target's course along your zero bearing and then the second leg of triangle in direction of target's travel. Note the degrees. This is the AOB at course intercept point.
Go to the periscope or uzo screen and set at zero bearing. Go to the blank notepad, select AOB and set the degrees you've previously calculated and whether it is to port or to starboard. Don't forget to click the checkmarks on the notepad to send info to TDC.
Now you can rotate the scope or uzo and the TDC will always calculate the correct AOB at aiming point.
If target begins to zig-zag, do not change your AOB. Instead manually reduce target speed in the TDC by approximately 1/2 knot.
Don't worry about target distance, it has no affect in the TDC calculation of torpedo offset angle. However, I manually set it at 600 to 1000 meters because that's where I usually try to be at firing. Then the stopwatch is somewhat accurate.
Also, remember to open the outer torpedo doors.
This works, I've hit fast moving targets in excess of 5 kilometers. Must use slower torp speeds for the further torpedo runs. I don't like to shoot at this distance but sometimes you just can' get into a good firing position on a fast moving target.
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