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Old 08-03-2017, 05:55 PM   #1
palmic
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radar Real navigation - Perfectly controlled approach

With this, you should start to love real navigation target approaching because this turns real nav into real kingdom!

Aaaand... i know i am probably 1 millionth kaleun who started to use this so i really know that i haven't found out operation parkenshlag
Just believe me, its just about to repeating one or two simple equations all over again and its relevant to every situation in navy!

The reason for this is i became really lazy in years as i play TWOS, so i stopped to find out distance by target motion analysis and so even target speed, because i never used this to something more, than just to justify this really works in TWOS (and thus SH5 itself).
99% of targets will move between 6-8kts and for proper targeting you always have to analyse it via periscope anyway, so i stopped to get anything but course.
And from the books, i found out real kaleunen mostly used really simple rules by head..

There are just 2 requirements to have to use this:
1) You have to know target course +- 10 degrees
2) Target cannot change its course (as always in ww2 navy)
+ for the very newbies, please accept your targetting is not "map-position" relevant, its just relevant to your relationship to target, you could draw this situation to mediteranean as good as to north pole while you really are near south America, it will be always the same..

So lets start:
As i wrote before, you can calculate target future distance, where it will be before you with perpendicular Angle on bow (AoB) - 90° in advance.
While the target moves to you, its easy to calculate it.
It is just its current distance(d) * sine(current AoB).
So if it has current AoB=30°, it is current distance*0.5

Now let me tell what is approach about
Approach is of course to reach out our "sweet spot" for perfect firing position.
Lets just clarify, that perfect position for firing is directed to target where it will have perpendicular course to your's (90°AoB) with optimal distance to fire.
Optimal distance to fire would be depending on how defended the target is. ~700m it is for non defended target (yes the holy grail), 5km is for heavilly defended convoy (battleship..). And you could of course have different preference, this is just something like rule of thumb..
So, to be short, what we mean by approach is to get into proper point near of our target track and to turn our sub to heading which will be perpendicular to target track.
Thus our bearing will be its course - 90° if we will attack its starboard, or its course + 90° if we will attack its port side.

So , what we want is to know where our sweet spot is. How to find out just by current AoB and distance?
- By the rule of sine
To be simple, the rule of sine says that, if we will stop here, the target distance from us in the moment when it will have AoB90° will be its current distance * sine(current AoB).

So what this all is about is just to control 2 things from distance - current AoB and distance!.






Lets demontrate on example


1)
Your sub here is the point C
The target is the point B
Target is moving bofore you with course 70 and you are moving with course 347 into its track.
These two courses are your only input here, you can imagine this triangle, but thats not important, its just for you to have overview.
Everything what we need here, is to get its current distance and AoB, mission accomplished!

how to control the distance you know. (just dont be exact, if you can see the smoke, lets just say its about 10-15km, you'll have enough time to calibrate in periscope depth submerged...)
How to control current AoB? By the rule of triangle interior angles!

If you know our courses, we know angle A - here we will calculate it as 70(target course)+360-347(our course)=83.
Its always about subtracting two courses from each other, remember, if you are going to get into negatives, just add 360 to the first.. You are always turning in circle of 360
(if you are thinking this is just too complicated, just look to triangle and you will know how many degrees its between the courses..)

Angle C is simple, its just 347(our course)-293(bearing which we see our targets smoke at the horizon)=67.
And the 3rd angle? Always 180-two others - 180-67-83=30
So we now know the targets AoB and thats the key to everything..

Just go into the triangle example, drag angle C and move it closer to angle A to simulate your quick approach to firing position.
Can you see? The sum of inner angles is always 180 no matter what you wil do...
+ if you imagine yourself at tower of that ubote approaching to target track you can see here how the ship at the horizon will be moving to the left in your optic.

So right now, we know, that if we would stop, the target would be just its current distance * sine(current AoB) -> distance * sine(30) = distance*0.5!

2)
But this is just a beginning, now it will be just better for us, we know even that if we would get them to 6 AoB, their distance would be 1/10 when we would just wait for them here!!!

How to get them to AoB=6? By being so quick to move the target to see it at our bearing 269!!!
Why bearing 269? Because its 180-83-6=91 (83 is our current angle of tracks - angle A at image and 6 is our desired AoB) - if you will look by periscope or uzo to 360 (just before you) and move 91 degrees to the left, you will end at 269.
So you just could pick how many times closer you want them, check sine table to get angle and calculate where it will be at your bearing in relation to your course, thats really all.
If you want their AoB to be 1° smaller, you just have to move them 1° more to the side at the bearing you see them.


Can U see? Our position to target just moved and we was just waiting until we will see their smoke at 269, so we now know we are at position where they will move before us in 1/10 distance then they have now from us, because their current AoB is 6° and sine(6°)=0.1

What more we know?
We know even our perfect firing bearing is 340, because its their course-90°.

So! We just need to have as high enough speed to see, they are moving at our bearing to the left and just wait until they will be at 269.
.. And then just turn to course 340, stop the engine and submerge to periscope depth, no guessing, you are pretty set to have them at your 360 with perfect 90° AoB - sweeeet!!!!
Just wait until you will be able to confirm perfect firing solution to TDC optically


Please set TDC more preciselly by optical input from closer range, this is really just for perfect approach, not to set TDC!


Final recapitulation to show you how easy this whole process is:
1) get course of target from distance by 4 bearing method or different way
2) set your course to cross target's track in way you profit most (i recommend you for most of situations angle of track 30-60° - see 3) )
3) subtract your courses to get angle between them (angle of track)
4) calculate angle between your course and bearing to target
5) subtract them both from 180 to get angle on bow
7) alter AoB of your target by moving forward the way you want (if you want to have AoB of target 26° smaller, just move forward to see target 26° more to the side of you)
- This is very simple and comfortable way how to control your relationship to target! If you calculate 0° AoB you are directly in its track! Thats all. No more guessing ever!
8) change your course to your firing course (course of your target -/+90) and wait for him here.
..Repeat over and over again, because its so boringly simple, you will lost any mistery behind navigation


This pattern is most comfortable i found in years of playing TWOS, its pretty satisfying and easy to repeat over and over again.

And this all you can very easily calculate in head. (+i can confirm this very quickly recover your skills which were lost by using smartphones )

And as always kaleunen Gutte Jagd

Last edited by palmic; 09-21-2017 at 12:49 PM.
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Old 08-04-2017, 08:10 AM   #2
vdr1981
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Awesome job mate! Thank you very much!
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Old 08-04-2017, 10:56 AM   #3
palmic
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Old 08-06-2017, 12:41 PM   #4
JughedJones
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Thanks a lot for the detailed explanation, but I'm math dumb. It just makes my brain hurt.

Is there a good video out there of someone using this info to make a good approach? I'd love to see it in action, when they submerge, how far to stay away, etc.

Thanks!
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Old 10-15-2017, 11:02 AM   #5
Xall
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Palmic,
Thank you for your post, I been reading this and trying to figure it out.

Can you healp me with my situation?

So my case is the following:

I got a contact report, that a convoy is heading SW, so true course 225.
I made visual contact while on course 210,
and using the Raofb I estimated the distance to the target to be around 11,000 meters (11Km.)
The targets bearing is 274.

Using your formula:

Step 1.
225 (Targets Course) - 210 (Our Course) = 15 [Angle A]

And here is where I am getting issues:

Step 2.
----------- Our course 210 - target bearing 274 = -64 [Angle B] -----------

If i continue your method with this negative -64 I get:

Step 3.
180 - 15 [Angle A] - 64 [Angle B] = 101 [Angle C]

But this is incorrect since it does not check out.
Using the Attack Disk to determine the True course of the Convoy,
I entered the AOB we plotted, and the course does Not check out to 225

I get Course 203 instead.

Setting the Attack disk to the true course of the target (225) I get an AOB of 79.

So in Step 3 I should get an AOB of 79, but I believe I am doing something wrong in Step 2.


If I do 210 (Our Course) PLUS 360 MINUS 274 (Target Bearing)
I get = 296

If I do Step 3 then:
180 - 15 - 296 = -131

Something is off and I need help with it.

Hopefully you know where I am going wrong



Edit:
Is it possible that in step 2. I need to have my course (210) then add 360, and then subtract the targets bearing (274) = 296 and convert this into degrees by doing 360 - 296 ?= 64
Because then it makes sense, 180 - 15 - 64= 101.

I just don't understand why the attack disc does not add up to course 255 if i use 101 as the aob... Maybe I am doing something wrong on the attack disc, but can anyone confirm that I am doing step 2 correcty?
Basically I am getting lost when my course is a smaller value when subtracking a larger bearing value, what do I do then? Add 360 before subtraction like in step 1 (Angle A)?

Please reply...

Last edited by Xall; 10-19-2017 at 05:35 AM.
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Old 11-07-2017, 05:34 PM   #6
palmic
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Default Real navigation - Perfectly controlled approach

Quote:
Originally Posted by Xall View Post
Palmic,
Thank you for your post, I been reading this and trying to figure it out.

Can you healp me with my situation?

So my case is the following:

I got a contact report, that a convoy is heading SW, so true course 225.
I made visual contact while on course 210,
and using the Raofb I estimated the distance to the target to be around 11,000 meters (11Km.)
The targets bearing is 274.

Using your formula:

Step 1.
225 (Targets Course) - 210 (Our Course) = 15 [Angle A]

And here is where I am getting issues:

Step 2.
----------- Our course 210 - target bearing 274 = -64 [Angle B] -----------

If i continue your method with this negative -64 I get:

Step 3.
180 - 15 [Angle A] - 64 [Angle B] = 101 [Angle C]

But this is incorrect since it does not check out.
Using the Attack Disk to determine the True course of the Convoy,
I entered the AOB we plotted, and the course does Not check out to 225

I get Course 203 instead.

Setting the Attack disk to the true course of the target (225) I get an AOB of 79.

So in Step 3 I should get an AOB of 79, but I believe I am doing something wrong in Step 2.


If I do 210 (Our Course) PLUS 360 MINUS 274 (Target Bearing)
I get = 296

If I do Step 3 then:
180 - 15 - 296 = -131

Something is off and I need help with it.

Hopefully you know where I am going wrong



Edit:
Is it possible that in step 2. I need to have my course (210) then add 360, and then subtract the targets bearing (274) = 296 and convert this into degrees by doing 360 - 296 ?= 64
Because then it makes sense, 180 - 15 - 64= 101.

I just don't understand why the attack disc does not add up to course 255 if i use 101 as the aob... Maybe I am doing something wrong on the attack disc, but can anyone confirm that I am doing step 2 correcty?
Basically I am getting lost when my course is a smaller value when subtracking a larger bearing value, what do I do then? Add 360 before subtraction like in step 1 (Angle A)?

Please reply...


Hi Xall, sorry for my delay, i noticed today....

You are very close, but you are making mistakes, because you have no experiece with this, thats ok, this way of conversation is not very good for this teaching, but as i wrote, you are very close....

Just to clarify - what you are doing in step 2 is getting angle in triangle whose angles are crosses of your tracks (angle A - or angle of tracks - that you have right from step 1) and the second angle - at your current position, which you are calculating in step 2 from your course - 210 and target bearing 274 - thats just half right.
The third angle is obviously at position of your target.
That means no negative angles are possible here (no triangle has any negative angle, they are just differences - use always absolute value from subtraction.
That being said, we can continue:

Your mistake is you are using your relative bearing to target (274), thats wrong, its absolute bearing to target (your course + relative bearing), because when you look on that equation, your course is absolute value at map and your target course also. You cannot mix into equation relative bearing...
You just have to imagine that triangle at map, maybe draw it to sh5 map, youll get what you are doing wrong...

===
So Your input data for step 2 is your course 210 and absolute bearing to target.
Absolute bearing => 210+274=484 (-360=124)
210-124=86 => thats your second angle. (Honestly i do this in few seconds in my head - just look at your bearing scale - its your 360 - bearing 274 = 86.
(270 is 90 to the left from 360 yes its so simple! :-) )
Always keep this 4 bearing in head and train it with experience - 90,180,270,360, this way youll get much better situation awarnes just like that in your mind and youll start to calculate this not like 360-274, but like 4 degrees from 270, which is your relative "west" - 90 degrees on left..

Third angle (AoB) => 180-86-15=79.

Youre done sir


Bottom line:
I know it looks dificult at the begining, but its realy most simple and quick way how to get this. 99% of that post is just to clarify the facts which you have to absorb by 3-10. successful solutions.
This everything is just repeating of few little rules. Just keep it simple and dont try to be digitaly exact. It is realy not needed.
Most important things:
- if you and your target dont change your course, and you are quick enough to move them (or simply just their smoke 1 degree behind at your horizon, you've just managed to change their AoB by 1 degree - 1:1)
All inner angles of triangle are always 180 - ever. So just keep in mind triangle is always angle a+b+c and its always 180.
So if you can get difference of your courses (like you did) and you know where they are at your bearing, you have even the 3rd. - 180 - both of them.
- Their distance from you at 90AoB if they dont change their course will always be their current distance * sin(current Aob).

And my golden rule: Most of the times i always have my target about 10km away. Ideal firing distance is about 1/10 - 1km away.
So I would like to get my target into situation, where i submerge into periscope depth and wait for them to be about 1 km away before me.
1/10 is always sin(6), so i know i ALWAYS want to get before them into 6 degrees AoB.
And that ALWAYS means bearing where i want to see their smoke/hull is always 180-6-angleOfTrack (angle between our courses).

So from your example it would be 180-6-15=159 on your port.
159 on your port is your 360-159=201 (simply 159 degrees to the left from your 360).

So if youll manage to get them into your 201, submerge and turn your sub into course 225-90=135 (because its their course - right angle) youll have absolutelly perfect firing position.
Theyll be their current distance / 10 and they will be right before you just perpendicular to you - perfect 90 AoB.

This is something which youll master very quickly by your own experience, just go step by step, example by example, just finish your first and second example next time, i swear youll get into this by your own experience very quickly. Again - This seams to be complex, but its not, its just repeating of very simple triangle equations from elementary school which we forgot...

Last edited by palmic; 11-08-2017 at 05:56 AM.
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