Adjusting the contrast for the Stadimeter

[Munchausen]

Originally Posted by jazman

The key is 90-degree AoB.

Remembering that AoB is relative to the bow of your submarine. Not to the gyro (lead) angle of your fish.

[Platapus]

It really should be written Angle of the Bow

So you telling me that my AoB is not just the reciprocal of my bearing?

<ducking and hiding>

I actually did that when I started in sub sims. I can't remember which one first introduced AoB but I quickly found out the error is my ways

[Munchausen]

Originally Posted by Platapus

So you telling me that my AoB is not just the reciprocal of my bearing?

Actually, it's not AoB you need to worry about ... exactly. It's target track. With the O'Kane method, you want the target to cross your bow with an AoB of 90 degrees. The easiest way to do that is to position you sub perpendicular to the target's track (course line).

If you "pull lead" to optimise your gyro angle, you need to take care that you don't, at the same time, skew the AoB (check target heading on the TDC to be sure) . Whether you align your crosshairs with your bow or adjust them to lead the target, the target still needs to be at 90 AoB when it crosses your bow. (With a proper lead, you will fire prior to the target crossing your bow such that the torpedo impacts the target exactly as it crosses.)

[Nisgeis]

Originally Posted by Munchausen

Remembering that AoB is relative to the bow of your submarine. Not to the gyro (lead) angle of your fish.

AoB is a bit of a tough one to get your head around. I struggled for a while with it, mainly due to all the examples having a ship sailing directly towards or away from you, so the AoB doesn't change. AoB is relative to the bow of your target. If you were standing on the target ship, looking dead ahead at the bow, then however many degrees you would have to turn left or right to see your submarine is the AoB.

The reciprocal of your own bearing is the bearing from the target to you.

If you were sat stationary, pointing north and your target were directly ahead of you on a relative bearing of 000 and sailing NE, then the AoB would be 135 degrees to starboard. If the ship were due west of you and was sailing south, the relative bearing would be 270 and the AoB would be 90 degrees to port.

If you have two of the three pieces of info, target true bearing, target AobB and target course then you can work out the missing one.

[Rockin Robbins]

Angle on the bow is easy. It's a point of view problem, that's all. Just step off your submarine! You're just on the wrong boat.....ship.....vessel.....whatever.

Angle on the bow is your bearing from the target! The only thing different is that it is counted from zero at the bow to 180 on the stern and then starboard or port is attached, depending on which side the bearing is on.

[Munchausen]

Originally Posted by Munchausen

Remembering that AoB is relative to the bow of your submarine. Not to the gyro (lead) angle of your fish.

What I meant to say was, using the O'Kane attack method, your 90-degree AoB is relative to the bow of your sub. If you make an input to the TDC with your crosshairs offset from the sub's bow, make sure you also adjust AoB to compensate ... otherwise your 90-degree AoB will be relative to your offset bearing. And your attack geometry will be skewed.

[Fincuan]

Originally Posted by Munchausen

What I meant to say was, using the O'Kane attack method, your 90-degree AoB is relative to the bow of your sub. If you make an input to the TDC with your crosshairs offset from the sub's bow, make sure you also adjust AoB to compensate ... otherwise your 90-degree AoB will be relative to your offset bearing. And your attack geometry will be skewed.

Actually it's just your periscope that must point to where the targets AOB will be 90 degrees, but to simplify things(allowing you to pretty much ignore range among other things) players usually point the whole submarine towards that point. Skippers who are familiar with the "Fast 90" attack method know exactly what I mean. This method of targeting works exactly as advertised on the SH4 U-boat TDC, and can easily be adapted to the US TDC(the already mentioned Dick O'Kane method).

Wazoo's great "Fast 90" tutorial:
http://www.paulwasserman.net/SHIII/

[Munchausen]

Originally Posted by Fincuan

Actually it's just your periscope that must point to where the targets AOB will be 90 degrees....

:hmm: Yeah, I suppose you could do it that way. But, if you did, you'd need to set up the TDC so that "90 degrees AoB" was relative* to the crosshairs (and not to your sub). Doing it that way, though, would make it harder to lead the target (assuming you're setting up for an optimum torpedo run).

With the bow as a 90-degree reference point, you can use the crosshairs to adjust for lead. With the crosshairs as a reference point ... how do you lead the target?

Admittedly, I can see where your method would come in handy. For instance, a running surface attack on numerous targets. As soon as you judge yourself to be broadside of your current target, you take a bearing and shoot. As long as you've already set the AoB meter for 90 degrees (starboard or port, as required), any bearing sent to the TDC should give the torpedo a correct gyro angle.

* Again, not meaning to imply that AoB is, itself, relative to the sub.

[Platapus]

Rockin Robbins,

I have been using the 90 AoB targeting system that you described.

I still don't understand it
I still think it is magic
I still think that you are probably BSing me

But I AM putting holes in the floaty things without having to ID the ship or take a single range reading.

I don't know why it works and I probably don't have a need to know why it works

But it works, the floaty things have holes in them and I am having fun

This old dog at least learned to fake a new trick anyway

Thanks

[Rockin Robbins]

Originally Posted by Platapus

Rockin Robbins,

I have been using the 90 AoB targeting system that you described.

I still don't understand it
I still think it is magic
I still think that you are probably BSing me

But I AM putting holes in the floaty things without having to ID the ship or take a single range reading.

I don't know why it works and I probably don't have a need to know why it works

But it works, the floaty things have holes in them and I am having fun

This old dog at least learned to fake a new trick anyway

Thanks

:rotfl: :rotfl: :rotfl: :rotfl: :rotfl: :rotfl: :rotfl:

[jazman]

Here are a couple of images that document the math needed to understand. Part I shows the geometry, part II steps through the math. I can't help you if you don't understand Trigonometry, that requires a course.





You don't need the range X. It doesn't matter, if you have the speed of the ship correct and you really are at AoB of 90 degrees. And if your torpedo goes at the rated speed.

(In reality range does matter, because there is a curve in the torpedo's path, unless you have the sub pointed down the torpedo track.)