Wish I had a fast enough rig to do movies, but so far no luck. There are four pieces of information that the TDC needs to hit your target. Pop up the periscope and ID the target. This tells your TDC the height of the tallest mast.
Usually the first thing you get is the speed. It most likely won't change if you remain undetected. Here's what you'll do. Have the stopwatch handy. Pop up the periscope and lock onto the target so it is plotted on your nav map. Change to the nav map, type ctrl-x to bring up the stopwatch, with the pencil tool make an x where the target is and start the stopwatch. Down scope.
About two minutes and 45 seconds on the stopwatch (you might need to do it at 2:30 at first until you get coordinated) raise the scope and lock on target. Switch to nav map and press the "x" key to bring up the stopwatch. Grab the pencil and exactly at three minutes x the position of the target. Down scope.
Now the distance between the two positions in hundreds of yards is the speed of the target in knots. 750 yards is 7.5 knots. Plug that into the TDC and press send speed. That's piece of information #1.
Next, we need Angle of the Bow (AoB)/course of the target. Go back to the nav map and use the ruler tool (open the compass first to give you tool help) to connect the two positions you have plotted and extend the line in the direction of target movement. You can use the compass rose on the ruler tool to find the target's course.
To find the AoB, use your protractor tool. You'll click on the target's course ahead of the target, then click again on the middle of the target and a third time on the middle of your submarine. You'll read the angle right beside the target. That's the AoB. Now, which side of the target are you looking at, starboard or port? That tells you whether the AoB is starboard or port. Enter that into the TDC and press the send AoB button. Once we get the position keeper on we'll update that before we shoot. That's piece of information #2.
It's stadimeter time! (Yuck) When you use the stadimeter in the conventional (yuck) manner you are really sending two pieces of information to the TDC, the bearing and the range. So use the stadimeter to put the waterline of one part the split image on the top of the mast of the other and left-click. Then press the send bearing/range button.
Immediately start the position keeper after you enter the range/bearing. You're in the ballpark. Switch to the attack map and you'll see an x marking the torpedo impact point. It should be on top of your target and moving with it. If it is moving in a slightly different direction your AoB needs refining. If it is moving too fast or too slow your speed needs adjustment. And if it is not on top of the target, the range or bearing is off.
If the range is wrong but a line from your sub to the impact point crosses the target, you can shoot anyway because the torpedo will hit the ship on its way to where it thinks the target is. If you're not too far off in range but the line is gaining or losing ground on the target, rather than screw with the stadimeter, I usually just tweak the speed to make it work and shoot. The stadimeter drives me crazy.
I hope this is clear enough. I really wish I could do movies to demonstrate this stuff, because it's really fun once you have a unified picture of the whole process in your head.
OK, I know it's not fun yet, you'll have to just trust me.
