Kreigsmarin Interface U Boat tutorial question

I'm goin' down · 01-31-11, 12:36 AM

I have read the tutorial. I understand how you use the AobF Wheel to calculate speed, range and Aob. But then Kasmaronov tries to explain intercepting the target and loses me.

I have copied the entire portion that I do not understand. The section dealing with the 180 Aob is particularly confusing. If someone can explian it, I would be very grateful.

Here it is. The pictures were deleted when I copied it.

I promised to show how to macth a course with a target. I’ll even throw a better one and show you how to intercept at specific angles fast. First you need to find the AOB. We’ve just found that our Bismark has an AOB of 110 right? He’s also doing 11 knots so we can overtake him easily. But where to turn to move along it’s course. We won’t use the map for this one, we’ll use the TDC. First, let’s input the AOB:
First, click on the TDC Autoupdate button so that it unlits. Then enter the AOB. In this image you can see I’ve entered an AOB of 109 degrees (the little small red 9 next to the green 1). Whatever, I’ll keep it as it is. Now click the TDC Autoupdate button so that it lights up again.

Now, as you move the periscope, keep looking at the AOB dial. Move it until it reaches 180. (Query: should this be 108 rather than 180?)The Bearing dial will also move with it. This means that your 108 bearing is actually pointing at the true course of the target.

Press the “Set Course to Bearing” Key ( ‘=’ default key).

Remember when I told you that our Bismark was going straight south? Now so are we. But what if we move alogside our Bismark, have overpassed it and want to intercept it at a specific intercept angle?

Let’s say that the target is at our 120 bearing. A quick math would say that the target’s AOB should be 60. But look:

Why is it 170? Simple: because the AOB dial doesn’t take into account YOUR course changes. Let’s fix that.
1. Point your Periscope at 000.
2. Set the AOB to 180 degrees. Why 180? Just imagine that since you’re going along a line parralel to the target, you’re actually right behind him. Of course you’ll be stearing at his proppelers, so the AOB will be 180.
Now if we move our periscope back on target we get what we wanted:

So just remember: Every time you set course to a specific X intercept angle (in our case it’s a 180 degree “interceptum ad infinitum”), move your scope to 000 and put the X for AOB. That way, as long as you keep the new course, when you’ll look at the target you’ll see a correct AOB. Now that we want to intercept at 90 degrees we again move the periscope until we see an aob of 90. Which should be around the bearing… uhmm… 90… It makes sense. But what’s nice is that this exact procedure applies to any situation. So to recap:
1. You spot a target closing and find an aob for it.
2. You enter the aob in the TDC
3. You move the scope until the AOB turns into the intercept angle you want X:
o If X is 180 then you’re matching course with the target
4. Without even looking at the compass or the nav map, you set the course for that bearing using the ‘=’ key.
5. After confirmation of the new course you move the periscope to 000 and reinput the X aob.
6. After you settle on your new course, as long as you and the target don’t change course, you’ll have a correct AOB already in the TDC. When the ship will pas right in front of you, it will have the X AOB that you were looking for. As the ship gets closer you can always adjust the AOB based on improved visibility and start again from step 1 to move again to the intercept course you wanted.
Now let me show you another nice trick. This works with ANY intercept angle and at ANY range as long as you shoot at 000 gyroangle. What is deadly important is that you calculate the speed and AOB very well. For this reason it’s good practice to use 90 degree intercept angles. Why? First of all, between 110 and 80 AOB it doesn’t really matter how big your error is. Second, as the target approaches, you’ll have a nice side view of it to calculate the speed. And third, the torpedoes have a smaller chance to dud. I usually calculate the speed when the target is at 45/315 degrees and, if she’s slow enough, again as she closes. So let’s take our Bismark again…

I’ve intercepted at 90 degrees but after a few minutes she decided to change course. I take a reading again and see it has a an AOB of 60, at a bearing of 40. I move the Periscope to a bearing of 000 and check the AOB. It’s at 100. So the ship will have an AOB of 100 degrees as it passes in front of me. That’s quite ok for impact pistols. I could adjust my course but nevermind. The ship is still going at 11 knots. So I’ll input the data in the TDC. Now let’s look at the Gyro.

BTW, sorry about these pages, lots of gaps. So for a bearing of 000, we have an aob of 100 and a speed of 11 knots. The gyro is 336.5 (love the vernier right gyro dial  ). Now move the Periscope until the Gyro becomes 000.

In our case, that should be at bearing 020. Now, just for fun… Let’s play with the range dial:

Range=10.000 meters

Range= 300 meters.

To understand, the gyro has moved from 359.99 to 000.02.
So relax, you don’t need to calculate the range anymore. So, to recap:
1. Calculate the AOB and speed and enter them correctly in the TDC (do so while you’re locked on target).
2. Move the periscope at 000 to check that the AOB there is between 60 and 120. Othwerwise your torpedoes will bounce off.
3. Move the periscope untill you get a 000 Gyroangle.
4. Now either
- Wait there for the ship to pass and shoot when the juicy part is dead in the middle of the scope (altough you might miss the intended part because torpedoes take a few seconds to get to speed, so aim just before it)
- Turn the autotdc off an… nevermind, this is useless now….
- Lock on the ship and watch the gyro slowly going to 000. When it reaches zero, LOS!
So, as you see, there’s no need to keep a PERFECT 90 degree intercept course. If you’ve settled on a course and then, as the ship moves in, you realize that your aob estimate was off by up to 20 degrees, let it be so. You have the new AOB, you have the speed, just keep a 000 gyro and you’re fine. As a good practice, calculate the range if you have time. You might think that it’s useless but not only can you see when the torpedo will impact, you can also counteract the errors in speed and AOB calculations.

Good luck. I am totally lost on this explanation.

01-31-11, 12:36 AM	#1
I'm goin' down Ocean Warrior Join Date: Sep 2008 Location: Notify command we have entered the Grass Sea Posts: 2,822 Downloads: 813 Uploads: 0	Kreigsmarin Interface U Boat tutorial question I have read the tutorial. I understand how you use the AobF Wheel to calculate speed, range and Aob. But then Kasmaronov tries to explain intercepting the target and loses me. I have copied the entire portion that I do not understand. The section dealing with the 180 Aob is particularly confusing. If someone can explian it, I would be very grateful. Here it is. The pictures were deleted when I copied it. I promised to show how to macth a course with a target. I’ll even throw a better one and show you how to intercept at specific angles fast. First you need to find the AOB. We’ve just found that our Bismark has an AOB of 110 right? He’s also doing 11 knots so we can overtake him easily. But where to turn to move along it’s course. We won’t use the map for this one, we’ll use the TDC. First, let’s input the AOB: First, click on the TDC Autoupdate button so that it unlits. Then enter the AOB. In this image you can see I’ve entered an AOB of 109 degrees (the little small red 9 next to the green 1). Whatever, I’ll keep it as it is. Now click the TDC Autoupdate button so that it lights up again. Now, as you move the periscope, keep looking at the AOB dial. Move it until it reaches 180. (Query: should this be 108 rather than 180?)The Bearing dial will also move with it. This means that your 108 bearing is actually pointing at the true course of the target. Press the “Set Course to Bearing” Key ( ‘=’ default key). Remember when I told you that our Bismark was going straight south? Now so are we. But what if we move alogside our Bismark, have overpassed it and want to intercept it at a specific intercept angle? Let’s say that the target is at our 120 bearing. A quick math would say that the target’s AOB should be 60. But look: Why is it 170? Simple: because the AOB dial doesn’t take into account YOUR course changes. Let’s fix that. 1. Point your Periscope at 000. 2. Set the AOB to 180 degrees. Why 180? Just imagine that since you’re going along a line parralel to the target, you’re actually right behind him. Of course you’ll be stearing at his proppelers, so the AOB will be 180. Now if we move our periscope back on target we get what we wanted: So just remember: Every time you set course to a specific X intercept angle (in our case it’s a 180 degree “interceptum ad infinitum”), move your scope to 000 and put the X for AOB. That way, as long as you keep the new course, when you’ll look at the target you’ll see a correct AOB. Now that we want to intercept at 90 degrees we again move the periscope until we see an aob of 90. Which should be around the bearing… uhmm… 90… It makes sense. But what’s nice is that this exact procedure applies to any situation. So to recap: 1. You spot a target closing and find an aob for it. 2. You enter the aob in the TDC 3. You move the scope until the AOB turns into the intercept angle you want X: o If X is 180 then you’re matching course with the target 4. Without even looking at the compass or the nav map, you set the course for that bearing using the ‘=’ key. 5. After confirmation of the new course you move the periscope to 000 and reinput the X aob. 6. After you settle on your new course, as long as you and the target don’t change course, you’ll have a correct AOB already in the TDC. When the ship will pas right in front of you, it will have the X AOB that you were looking for. As the ship gets closer you can always adjust the AOB based on improved visibility and start again from step 1 to move again to the intercept course you wanted. Now let me show you another nice trick. This works with ANY intercept angle and at ANY range as long as you shoot at 000 gyroangle. What is deadly important is that you calculate the speed and AOB very well. For this reason it’s good practice to use 90 degree intercept angles. Why? First of all, between 110 and 80 AOB it doesn’t really matter how big your error is. Second, as the target approaches, you’ll have a nice side view of it to calculate the speed. And third, the torpedoes have a smaller chance to dud. I usually calculate the speed when the target is at 45/315 degrees and, if she’s slow enough, again as she closes. So let’s take our Bismark again… I’ve intercepted at 90 degrees but after a few minutes she decided to change course. I take a reading again and see it has a an AOB of 60, at a bearing of 40. I move the Periscope to a bearing of 000 and check the AOB. It’s at 100. So the ship will have an AOB of 100 degrees as it passes in front of me. That’s quite ok for impact pistols. I could adjust my course but nevermind. The ship is still going at 11 knots. So I’ll input the data in the TDC. Now let’s look at the Gyro. BTW, sorry about these pages, lots of gaps. So for a bearing of 000, we have an aob of 100 and a speed of 11 knots. The gyro is 336.5 (love the vernier right gyro dial  ). Now move the Periscope until the Gyro becomes 000. In our case, that should be at bearing 020. Now, just for fun… Let’s play with the range dial: Range=10.000 meters Range= 300 meters. To understand, the gyro has moved from 359.99 to 000.02. So relax, you don’t need to calculate the range anymore. So, to recap: 1. Calculate the AOB and speed and enter them correctly in the TDC (do so while you’re locked on target). 2. Move the periscope at 000 to check that the AOB there is between 60 and 120. Othwerwise your torpedoes will bounce off. 3. Move the periscope untill you get a 000 Gyroangle. 4. Now either - Wait there for the ship to pass and shoot when the juicy part is dead in the middle of the scope (altough you might miss the intended part because torpedoes take a few seconds to get to speed, so aim just before it) - Turn the autotdc off an… nevermind, this is useless now…. - Lock on the ship and watch the gyro slowly going to 000. When it reaches zero, LOS! So, as you see, there’s no need to keep a PERFECT 90 degree intercept course. If you’ve settled on a course and then, as the ship moves in, you realize that your aob estimate was off by up to 20 degrees, let it be so. You have the new AOB, you have the speed, just keep a 000 gyro and you’re fine. As a good practice, calculate the range if you have time. You might think that it’s useless but not only can you see when the torpedo will impact, you can also counteract the errors in speed and AOB calculations. Good luck. I am totally lost on this explanation.