Real navigation target motion analysis cheatsheet

[palmic]

Update 2023-12-21: please download this archive and find all mentioned documents there: https://drive.google.com/drive/folders/1oHufjmBAO7d5qg-nbayEpwpbPIPOCxtu


To those who likes real navigation mod in SH5 i can share my trigonometry cheatsheet (https://drive.google.com/file/d/0B9Rj7Hxxu0DYbmxQdDRvaWVPZXM/view?usp=sharing&resourcekey=0-STm0Rvc-vTdJMKJnEarClA).
You'll need also Sin/cosin + tan/cot tables to print! (https://docs.google.com/spreadsheets/d/15WupEn9q9Y5JuyYxuQRjzUHvryWe_aJCK50gvmZOtao/edit?usp=sharing) to conversion between angles and sin/cosin/tan/cot.

I always wanted to find how to calculate 4 bearings method by math, but always was too lazy to find out how :)
So i spent about a week by doing some research and found out many things about it.
The whole problematic is called bearings only target motion analysis (https://drive.google.com/file/d/0B9Rj7Hxxu0DYZXZpbHdUSk12ZE0/view?usp=sharing&resourcekey=0-B_mtuyuQ0HbKT9wP2Od_IQ).

While this document is very complex and you can find out how to detect target motion even if you are moving, i was focused only to replace tedious geometry work.
So i used just most simple equations from it.

Besides 4 bearings method i wanted to be able to solve any other situation while i was hunting some ship, so i found that everything between you and the target is triangle. So i started to learn old trigonometry again - you can find shortcuts how to calculate angles and sides of any triangle with some valid inputs also in that cheatsheet - its the law of sines and cosines.
With this you can find for example target distance in later stage of 4 bearings method, or which angle you should approach your target based on speeds.
Just try to write it again in geometry and see what triangle you have to solve.

Why you should want to use this?
Well if you are using geometry in silent hunter games, you should already know how tedious and often even inaccurate it is.
If you'll get used to this trigonometry work, you'll just write down a few equations which is much less work and its always 100% accurate no mater how rigorous you'll be.
And as an extra, you'll feel like ace :arrgh!:

How you can use it if you never tried it, but you know how to use 4 bearings method by geometry?
- i recommend you to begin by using your well-known geometry 4 bearings method in conjunction with this - just write your sollution into the map just like before and together with it start to calculate it in this formula.
This is just to start with it - to get orientation in what exactly you are counting
- if you will not understand to some variables or what exactly you are calculating, go find out here: bearings only target motion analysis document (https://drive.google.com/file/d/0B9Rj7Hxxu0DYZXZpbHdUSk12ZE0/view?usp=sharing&resourcekey=0-B_mtuyuQ0HbKT9wP2Od_IQ).
You'll find out many answers if you solve it by geometry and compare angles and so with trigonometry results..

What if you dont know even 4 bearings method by geometry?
just learn it here: video here (https://youtu.be/dD3aMoZxaLI)
and come back :)



EXAMPLE! :

Right now i had a convoy contact.
I measured all 3 bearings in constant timerange 10 minutes, so we dont have to calculate time ranges and we can use simplest equation:

My current course is Co (course own) = 255
B1 (bearing 1) - 71
B2 - 80
B3 - 87
(experienced wolves now already knows that the target is moving away of us for sure - thats the reason i would skip all targeting right now and let the target go, because i have different tasks)
You'll also realize how on your own when you started to use this technique, or geometry pretty soon..

Cot12 = (cotangent of angle between B1 & B2 which is 9) = 6.3138 (find it in the table from very beginning of this post)
Cot13 (cot of 16) = 3.4874

Sollution (from my cheatsheet):
1) Cot(DRM - B1) = 2*Cot13 - Cot12
2) Cot(DRM - B1) = 2*3.4874 - 6.3138
3) Cot(DRM - B1) = 6.9748 - 6.3138
4) Cot(DRM - B1) = 0.661
5) DRM - B1 = 56.4 degrees (here i got angle 56.4 from cotangent table - from that link at very beggining of this post - its cotanget 0.661 from 4) )
If you calculated negative cotangent value, go find angle in that table of the same absolute value and use the result angle as 90-angle+90.
This could be confusing from start, but if you look on linear scale of that values near to 90 degrees in cotangent table, it makes perfect sense. Contangent values dont finish by 90 degrees, but continues bellow zero behind 90 degrees!: video here (https://youtu.be/JPWVnpdfa0E)
And this little hack makes exactly that.
6) DRM - 71 = 56.4 degrees
7) DRM = 56.4 + 71
8) DRM = 127.4 degrees
(Direction of relative motion)

Now whats DRM? in TMA document (https://drive.google.com/file/d/0B9Rj7Hxxu0DYZXZpbHdUSk12ZE0/view?usp=sharing&resourcekey=0-B_mtuyuQ0HbKT9wP2Od_IQ) on figure 11.1 you can see DRM is the angle between your heading and target ship course. It means that if we will add DRM to our current course (Co), which is 255 we should get target ship course:
Ct (course target) = Co + 127.4
Ct = 255 + 127.4 = 382.4 (-360=22.4! :rock:)

It may seem pretty difficult and tedious, but its really not since you're getting used to it. This was pretty slow because of full description of the process.
Buy some good old analog notebook, ink pen and you'll be solving targets like real ace in one week.
Your homework now is to try it on your own and to find how to solve the spiess line (solution is in cheat sheet and all the input for it we already got here).
Spiess line is the fourth virtual bearing for next time period which you are solving in 4 bearings method to find out target real position.
You can find all complex description here in the document (https://drive.google.com/file/d/0B9Rj7Hxxu0DYZXZpbHdUSk12ZE0/view?usp=sharing&resourcekey=0-B_mtuyuQ0HbKT9wP2Od_IQ).


Disclaimer: I found the TMA document at ricojansen.nl, i dont know who is author/owner.
If you know him, please let me know, ill gladly add his credits here :)


Gutte jagd Kaleunen! :salute:

[vdr1981]

Hardcore! Very useful thread! :up:

[Sjizzle]

Real navigation and hardcore till end of time :D
nice job m8 keep it up :up:

[siege00]

Wow... I love the chart work and using various tools like the attack disk, but may have to add this to my repertoire. Now where did I lose my high school trig book. ;)

Vielen Dank!

[WildBlueYonder]

This method is while being at full stop, correct? The problem is that even when I'm 0 kts I drift a few hundred meters, does it matter much?

[palmic]

This method is while being at full stop, correct? The problem is that even when I'm 0 kts I drift a few hundred meters, does it matter much?

Yes it's while you are stationary.
Few hundreds meters does not matter same like +-1 minute interval inaccuracy, since you are unable to calculate with 0.1 degrees bearings anyway.

To be honest, you can calculate cotangents just with one decimal accuracy at all, its enough :up:

You'll end up with 1-3 degrees target's course inaccuracy, which is ok i think, if you want real precise results, you should use longer period between bearings checks (20-30 minutes) and try to stay in around 100m from first bearing position..
Most of the time you dont need it, you can always confirm result next time around one hour after...
I always confirm it opticaly at firing position, where you need it accurate for your eels, but don't care much while i have it just for approach.
Since hydrophone can reach around 40km you cant lost contact if game dont despawn it..

[WildBlueYonder]

Yes it's while you are stationary.
Few hundreds meters does not matter same like +-1 minute interval inaccuracy, since you are unable to calculate with 0.1 degrees bearings anyway.

To be honest, you can calculate cotangents just with one decimal accuracy at all, its enough :up:

You'll end up with 1-3 degrees target's course inaccuracy, which is ok i think, if you want real precise results, you should use longer period between bearings checks (20-30 minutes) and try to stay in around 100m from first bearing position..
Most of the time you dont need it, you can always confirm result next time around one hour after...
I always confirm it opticaly at firing position, where you need it accurate for your eels, but don't care much while i have it just for approach.
Since hydrophone can reach around 40km you cant lost contact if game dont despawn it..

Thanks for the reply!

For the Spiess line, I've seen your PDF, but I'm a bit confused on its application, do you have an example?

[palmic]

Thanks for the reply!

For the Spiess line, I've seen your PDF, but I'm a bit confused on its application, do you have an example?

Ok let's calculate angle of spiess line from example from initial post.

So we have 3 bearings made with 10 minutes interval between
B1 - 71
B2 - 80
B3 - 87

What we get at example there is target course - 22 degrees. (its irrelevant here but just for clarification...)

--------

At my cheetsheet (https://drive.google.com/file/d/0B9Rj7Hxxu0DYbmxQdDRvaWVPZXM/view?usp=sharing) equation for spiess line is the second (Get 4 bearing method Spiess line)
So this is where we expect our sound contact sometimes at the future.

You have 2 options here - to calculate spiess line for moment of the same interval after (10 minutes here), or you can even calculate spiess line for other time, you just need to change the equation.
That's actually the reason for 2 equations in my cheetsheet (the first one is more simple, because you dont have to calculate different time interval than you used for getting first 3 bearings)
The second, allows you to calculate spiess line after 20 minutes, or 30 minutes here, its up to you how you plan your movement to get their real position.
(If you dont know what i am talking about, learn 4 bearings method (https://youtu.be/dD3aMoZxaLI) and you'll get it. - to get real position of target you need to move and cross 4.th bearing from another position with your calculated spiess line).

So - From my experience, 10 minutes is too short interval for moving to another position and get real 4th. bearing from there, you dont get far-enough from previous position, so lets calculate spiess line rather with 20 minutes interval.

What i mean here is we want to know, where we would hear our contact after 20 minutes from this position, while we will be already somewhere else to hear it from another position and by this situation we will actually create 2d raster to get real position of our target (spiess line is something like our ghost would stay at our previous position and get 4th. bearing from here, while we'll get it from another position and cross of this lines will give us real position of our target).
So lets do it!

Example to get bearing of spiess line after 20 minutes:

legend:
B4 - spiess line
t12 - time interval between B1 - B2 (first 2 bearings from first example in initial post) - 10 minutes = 10
t13 - time interval between B1 - B3 - 20 minutes = 20
t34 - time interval between B3 - B4(spiess line) - 20 minutes = 20 (yes, this is our decided time interval between B3 and spiess line)
t23 - time interval between B2 - B3 - 10
t24 - time interval between B2 - B4 - 10+20=30
t14 - time interval between B1 - B4 - 10+10+20=40
b12 - angle between B1 and B2 - 80-71=9
b13 - angle between B1 and B3 - 87-71=16

real calculation:
B4 = B1+arccot( ( t13*t24*cot(b13) - t12*t34*cot(b12) ) / t23*t14)
B4 = 71+arccot( ( 20*30*cot(16) - 10*20*cot(9) ) / 10*40)
B4 = 71+arccot( ( 2*3*cot(16) - 1*2*cot(9) ) / 1*4)
B4 = 71+arccot( ( 6*cot(16) - 2*cot(9) ) / 4)
B4 = 71+arccot( ( 6*3.5 - 2*6.3 ) / 4)
B4 = 71+arccot( ( 21 - 12.6 ) / 4)
B4 = 71+arccot( 2.1)
B4 = 71+25.4
B4 = 96.4

So after 20 minutes, we should here our contact from this position at bearing 96-97, we can move now and hear it from another position to get their distance as well...

[WildBlueYonder]

Ok let's calculate angle of spiess line from example from initial post.

So we have 3 bearings made with 10 minutes interval between
B1 - 71
B2 - 80
B3 - 87

What we get at example there is target course - 22 degrees. (its irrelevant here but just for clarification...)

--------

At my cheetsheet (https://drive.google.com/file/d/0B9Rj7Hxxu0DYbmxQdDRvaWVPZXM/view?usp=sharing) equation for spiess line is the second (Get 4 bearing method Spiess line)
So this is where we expect our sound contact sometimes at the future.

You have 2 options here - to calculate spiess line for moment of the same interval after (10 minutes here), or you can even calculate spiess line for other time, you just need to change the equation.
That's actually the reason for 2 equations in my cheetsheet (the first one is more simple, because you dont have to calculate different time interval than you used for getting first 3 bearings)
The second, allows you to calculate spiess line after 20 minutes, or 30 minutes here, its up to you how you plan your movement to get their real position.
(If you dont know what i am talking about, learn 4 bearings method (https://youtu.be/dD3aMoZxaLI) and you'll get it. - to get real position of target you need to move and cross 4.th bearing from another position with your calculated spiess line).

So - From my experience, 10 minutes is too short interval for moving to another position and get real 4th. bearing from there, you dont get far-enough from previous position, so lets calculate spiess line rather with 20 minutes interval.

What i mean here is we want to know, where we would hear our contact after 20 minutes from this position, while we will be already somewhere else to hear it from another position and by this situation we will actually create 2d raster to get real position of our target (spiess line is something like our ghost would stay at our previous position and get 4th. bearing from here, while we'll get it from another position and cross of this lines will give us real position of our target).
So lets do it!

Example to get bearing of spiess line after 20 minutes:

legend:
B4 - spiess line
t12 - time interval between B1 - B2 (first 2 bearings from first example in initial post) - 10 minutes = 10
t13 - time interval between B1 - B3 - 20 minutes = 20
t34 - time interval between B3 - B4(spiess line) - 20 minutes = 20 (yes, this is our decided time interval between B3 and spiess line)
t23 - time interval between B2 - B3 - 10
t24 - time interval between B2 - B4 - 10+20=30
t14 - time interval between B1 - B4 - 10+10+20=40
b12 - angle between B1 and B2 - 80-71=9
b13 - angle between B1 and B3 - 87-71=16

real calculation:
B4 = B1+arccot( ( t13*t24*cot(b13) - t12*t34*cot(b12) ) / t23*t14)
B4 = 71+arccot( ( 20*30*cot(16) - 10*20*cot(9) ) / 10*40)
B4 = 71+arccot( ( 2*3*cot(16) - 1*2*cot(9) ) / 1*4)
B4 = 71+arccot( ( 6*cot(16) - 2*cot(9) ) / 4)
B4 = 71+arccot( ( 6*3.5 - 2*6.3 ) / 4)
B4 = 71+arccot( ( 21 - 12.6 ) / 4)
B4 = 71+arccot( 2.1)
B4 = 71+25.4
B4 = 96.4

So after 20 minutes, we should here our contact from this position at bearing 96-97, we can move now and hear it from another position to get their distance as well...

Thanks for the explanation, I'm working on a mathematical proof to see if this is always applicable, it should though!

I still have a few questions if you don't mind:
1) What is distance float? And the "Get spiess line distance" part allows us to calculate how many meters the contact has moved during the measurements? So that dividing by time we get speed?
2) What does the "Target distance float" part accomplish?
3) Are A and B input variables or things which need to be calculated? I'm a bit confused. Yes, I know how to apply Carnot's theorem or the sine one, it's just that I don't understand what A and B refer to, I've read it to no avail.

[palmic]

Thanks for the explanation, I'm working on a mathematical proof to see if this is always applicable, it should though!

I still have a few questions if you don't mind:
1) What is distance float? And the "Get spiess line distance" part allows us to calculate how many meters the contact has moved during the measurements? So that dividing by time we get speed?
2) What does the "Target distance float" part accomplish?
3) Are A and B input variables or things which need to be calculated? I'm a bit confused. Yes, I know how to apply Carnot's theorem or the sine one, it's just that I don't understand what A and B refer to, I've read it to no avail.

With "distance float" i mean distance you float from position of first 3 bearings to new position to get 4th. bearing from there.
Relatively distance target float is the same in relevance to target.

The other quetstions are pure simple trigonometry, just draw the bearings, target course and even your course to new position to map, 4th. bearing from there and try to understand what side or angle of triangle you need to solve.

The law of sine is ultimate solution for every sides and angles in that triangles..

[WildBlueYonder]

With "distance float" i mean distance you float from position of first 3 bearings to new position to get 4th. bearing from there.
Relatively distance target float is the same in relevance to target.

The other quetstions are pure simple trigonometry, just draw the bearings, target course and even your course to new position to map, 4th. bearing from there and try to understand what side or angle of triangle you need to solve.

The law of sine is ultimate solution for every sides and angles in that triangles..

So after I calculate the 4 bearings, I have do draw them on the map? Yes, I know how to solve it, but my question is, to get angle A and B, do I get them from the map or calculate them with a formula?

[palmic]

It's up to you, you can get it from map.
I prefer calculation.

Just draw it if you need to imagine the triangles, then solve them mathematically.
It's more simple and geometry is not as accurate as math


Sent from phone

[hauangua]

I not understand that so step

"5) DRM - B1 = 56.4 degrees (here i got angle 56.4 from cotangent table - from that link at very beggining of this post - its cotanget 0.661 from 4) )"

how to get 56.4?....

[palmic]

I not understand that so step

"5) DRM - B1 = 56.4 degrees (here i got angle 56.4 from cotangent table - from that link at very beggining of this post - its cotanget 0.661 from 4) )"

how to get 56.4?....

In 4) you can see:
4) Cot(DRM - B1) = 0.661

0.661 is cotangent of angle 56.4 degrees
Download sin/cosin tangent/cotanget tables from beginning of this thread and print it ;)

[hauangua]

In 4) you can see:
4) Cot(DRM - B1) = 0.661

0.661 is cotangent of angle 56.4 degrees
Download sin/cosin tangent/cotanget tables from beginning of this thread and print it ;)

I download your tables... but no see 0.661 ...Ctg of 56.4...!!
this I no understand

[palmic]

Read legend at those tables carefully.
Tangent values are from left top, contangent values are from bottom right to top left (in opaque way).

[palmic]

I download your tables... but no see 0.661 ...Ctg of 56.4...!!
this I no understand

http://image.prntscr.com/image/83ba4a3220d64f78adb3ca00c44830a7.png

[hauangua]

http://image.prntscr.com/image/83ba4a3220d64f78adb3ca00c44830a7.png

Thanks...
me and mathematic...no good feeling

[palmic]

You're welcome, try it and you'll not be regret it ;)

BTW. you could be pretty comfortable to use 0.7 here, dont be very hard for yourself in this calculations as you cant get even those hydrophone bearing so precised..
And dont even push yourself to measure it in too perfect time, just feel free to have 2. bearing after 9:30 and third after 11 it doesnt matter so much.... (just dont mess it by 30% or so...)

In the end you always have to get more precise information optically from periscope anyway.
This is rather for decide good approach strategy and to know which bearing to have roughly before fire to not to have to turn ubote later..

[Unkki]

Thanks for the videos!

I see in the video you can move an earlier made line by clicking it. I can't do this? Do I need to press a button or something?

Thanks !:Kaleun_Cheers:

[Xall]

Hey palmic, I been trying to understand your methods, I been reading this one and trying to understand it, and I get stuck on one point, I am hoping you can help me with it.

So I will recap and show you how far I get.

First we have our course of 255 and our 3 bearings,

b1 = 71
b2 = 80
b3 = 87

each timed at 10 minutes in this case, while we are stationary.

Next we use your cheatsheet to find the cotangents,

cotan for b1 to b2 is 9 so we get = 6.3138 from your sheet,
and
cotan for b1 to b3 is 16 so we get 3.4874

so far so good.

next we have the formula

and this is where I cannot find out what the DRM is, direction of relative motion, is that not the angle beween our course and the target course? If so, how do we find the target course?

How do we find this?



----------------------------------------------------------------------------------------------------------------------



EDIT: I just read the conversation between you and hauangua, seems like he ran into the same confussion,

So what I understand is that, once you do the formula,
Cot(DRM -B1) = 2* Cot13 -Cot12 = 0.661

Then we Search in the cheatsheet for the closest value?
So in the Cheatsheet the closest value in this case is = 0.6644?

So 0.661 becomes 0.6644 which is = 56?

Am I understanding this correctly?

[Cyborg322]

HI Palmic

I overlooked your Tables they are very good , Odd description "Cheatsheet" its definitely not a cheat its just good Maths was this method Actually used by the Kriegsmarine ? Would be interested to know.

THX Best Regards Simon

WOLVES OF STEEL MEGAMOD

[palmic]

Hey palmic, I been trying to understand your methods, I been reading this one and trying to understand it, and I get stuck on one point, I am hoping you can help me with it.

So I will recap and show you how far I get.

First we have our course of 255 and our 3 bearings,

b1 = 71
b2 = 80
b3 = 87

each timed at 10 minutes in this case, while we are stationary.

Next we use your cheatsheet to find the cotangents,

cotan for b1 to b2 is 9 so we get = 6.3138 from your sheet,
and
cotan for b1 to b3 is 16 so we get 3.4874

so far so good.

next we have the formula

and this is where I cannot find out what the DRM is, direction of relative motion, is that not the angle beween our course and the target course? If so, how do we find the target course?

How do we find this?



----------------------------------------------------------------------------------------------------------------------



EDIT: I just read the conversation between you and hauangua, seems like he ran into the same confussion,

So what I understand is that, once you do the formula,
Cot(DRM -B1) = 2* Cot13 -Cot12 = 0.661

Then we Search in the cheatsheet for the closest value?
So in the Cheatsheet the closest value in this case is = 0.6644?

So 0.661 becomes 0.6644 which is = 56?

Am I understanding this correctly?

Hi Xall!
Sorry for my delay, i noticed right now.

Yes you have it right. Your targets DRM is 56.
Now you just have to subtract, or add it to first ABSOLUTE bearing.
Since your course in that time was 255 and the first bearing was 71, absolute bearing was 255+71=326.
Since bearings went up, you have to add, you would subtract otherwise.
So course of your target is 326+56=382=22!

For educative details about DRM please read the document (https://drive.google.com/file/d/0B9Rj7Hxxu0DYZXZpbHdUSk12ZE0/view) from my initial post.

Just one more thing, you are unnecessarily too exact, round just to 1 decimal, your bearings from hydrophone and timing is the same unexact anyway and youll be surprised how exactly youll calculate even with one dec, its just way more quicker..

Happy hunting!

[palmic]

HI Palmic

I overlooked your Tables they are very good , Odd description "Cheatsheet" its definitely not a cheat its just good Maths was this method Actually used by the Kriegsmarine ? Would be interested to know.

THX Best Regards Simon

WOLVES OF STEEL MEGAMOD

Hi Cyborg322, its like cheatsheat in school because it keeps my shortcuts for getting the sollution :)

I would bet they've used this, but they used just very rounded way how to getting these informations and they did just easier math in head i think..
They just remembered cotangents of most common angles rounded to 1 decimal point, thats enough even here to get good enough solution. I use it like this.

[McDonnel]

I am sorry to resurrect this old thread, but I would really like some help here with the target course determination.

Let me use my example, encountered in the game - "stationary" 4-bearings method, readings taken at the same time interval of 10 minutes:

Co = 287° (my u-boot course)
b1 = 48°
b2 = 59°
b3 = 70°

So, if I start calculation using the easiest formula:
1) Cot(DRM - B1) = 2*Cot (22) - Cot(11)
2) Cot(DRM - B1) = 2*2,4751 - 5,1446
3) Cot(DRM - B1) = 4,9502 - 5,1446
4) Cot(DRM - B1) = -0,1944 (this is negative, so I take absolute value, determine angle of 79 from the tables provided and put it further as (90-79+90 = 101) according to your instructions)
5) DRM - B1 = 101 degrees
6) DRM = 149 degrees (correct? or do I use here the true bearing of b1t = 335° (= Co + b1 = 287+48) already, which gives different DRM = 436 (-360?) = 76 degrees?)

How do I get from here to the target course?
Ct = Co + DRM according to your instructions, but no matter if I use 149 or 76, (resulting in either Ct = 287+149 (-360) = 76° (??) or Ct = 287 + 76 (-360) = 3°

For the Poseidon´s beard, I am unable to get to that correct target course of cca 91°, which I get with graphic resolution.

Thank you very much for any help.

Btw: Spiess line formula comes out to 80,24°, which is pretty close to expected 81° (and later verified 82° from graphic solution).

[palmic]

Hi McDonnel,
Your target course is 76.

Funny thing is how i shortened the calculation in your example:
Since angles between your 3 bearings (b1,b2,b3) are both the same (11), you can just pick the middle bearing, recalculate it to absolute bearing by adding your course (Co) and add 90 degrees, which is 436 (-360 = 76) :Kaleun_Wink:
If your angles are the same, course is logically perpendicular.

Don't forget that if the target would be moving to the left, you would be subtracting.

[Rosco74]

Very interesting thanks

[Xall]

Hey Palmic, I went to revisit this method, but the links to your cheat sheets are down, would you be so kind and upload them again? : )

[saintkas]

I fell in love with the idea of the Submarine Attack Course Finder (Is-Was) 40 some years ago after reading and watching the movie Run Silent Run Deep. As you can see I come from the pre-computer generation which is also the generations around WW I and WW II, the Silent Hunter 3 and 4 game timeframe. I spent 23 years in the Navy and am a submariner, dolphins and all. I remember when the Squadron Admin Dept. got so excited about the new typing machine they had gotten that stored what you typed electronically and you could edit without using an eraser and correction fluid.


In ROTC I had to take a course in Navigation in which we learned the use of the paper and ruler maneuvering board, yes the one with all the circles. The maneuvering board was a great advance because you could graphically solve trig problems and not have to use trig tables and logarithms. The next step forward in the targeting solution problem was the Is-Was which then became the TDC.


Even in the Silent Hunter 4 game the TDC is much more powerful than I have seen it used on the various youtube videos and "Let's Play" videos. What I have usually seen is that people use the TDC as if they are aiming a gun.



Take a look at the Sublant and Subpac doctrine manuals and the OP-1442 & OP-1442A Torpedo Data Computer Mark 4 Ordnance Pamphlets which describe in detail how to use all the power of the TDC.

[palmic]

Hey Palmic, I went to revisit this method, but the links to your cheat sheets are down, would you be so kind and upload them again? : )

Hi Xall!
sorry for huge delay, here you go, please download all the files (link at top right) as I cannot guarantee how long it will be available.
Merry Christmas :salute:

https://drive.google.com/drive/folders/1oHufjmBAO7d5qg-nbayEpwpbPIPOCxtu?usp=sharing