Manaual TDC - a new method

[geezerjo09]

p.s. (i know the ps dosent come here but this is just a warning)
Hello everybody, I was so happy with myself when I completed what your about to read. I posted on the ubisoft forums immediatly but didnt even get one response, either everybody already does this and i'm stupid in thinking I "invented" this, or nobody even understands what is written below. Anyways I hope at least one of you will find benifit it my hard work, and please ask questions if you want to understant but can't.

Ok here's a very theoretical way of doing your manual aiming. I havent even tried it yet put it should work, i hope it does :sadeyes: I think it can solve the few problems that happen when you use the map often. (We all know the map is not 100% precise and that often gets on my nerves) Two things are necessay for this method to work. 1) you have to be stationary 2) You have to assume that what your watchman tells you is precise (i mean when you ask him for nearest contact and he says "bearing 312, 3500 metres) I found him to be quite precise.
Thankfully i got pictures!!!!

http://img76.imageshack.us/img76/3776/tdcb1ue3.png (http://imageshack.us)

Ok, here's the situation. Your sub is the red dot on the bottom-centre of the screen.(remember you not moving during all of this operation) For the sake of this explanation, let us say that the blue line (although not perfectly aligned) represents true north, bearing 000. First off, your watch officer spot a merchant at bearing 339 and a distance of 14.6 km. The angle of 21o represents the reletive bearing from north. Later off, you ask you watchman for another reading of the same target. He says bearing 13, 29.3 km (i know that's impossible but it dosent really matter for this example)As you can see, I have not calculated anything yet, i have simply put in what the watchman told me.

http://img185.imageshack.us/img185/635/tdcb2xs5.png (http://imageshack.us)

What we are aiming to find out is the exact properties of the line that seperates the two dots that represent the two sightings og our prey, for now this is impossible. Lets take advantage of the magic the triangle can make!!!! Here i placed a fictional dot on the line that seperates me and the current position of the merchant. This dot is used to form 2 right angle triangles out of the old triangle. It allows us to calculate much needed information. First of all, since it is a right angle triangle, we can put 90o on the side opposite the hypotenuse (humm is that how its spelled?)this is the longest side of the triangle. Next, we add up the two angles we spotted the merchant on, 21+13=34, and add it on. Since the three angles of a triangle always add up to 180, we can do 180-(90+34)=56 and add it to the angle left. Hang in there, im not even started. As to now, almost no calculations were needed and certainly no estimation. NEXT!!!!

http://img71.imageshack.us/img71/5476/tdcb3ih1.png (http://imageshack.us)

Now comes the "hard" part. We are missing two bits of information on our triangle, the length of two sides. If you haven't done your high school you'll probably think this is impossible but it's not. Remember that sine, cosine thing? Well thats what we need. I can't really explain all of that since i have no buissness in doing that, ill simply tell you what to do with your calculator. To find the 8.2 cm value, you have to do (34*sin)*14.6 and to get the 12.1 cm value, you have to do (56*sin)*14.6. That's all. Simple no? Now do it without your calculator. HAHAHAHA. Ok enough with the jokes, NEXT!!!!

http://img185.imageshack.us/img185/7541/tdcb4eo9.png (http://imageshack.us)

This one is easy, now we have to solve the second right angle triangle. The 90o i added is a no brainer, do i even have to explain that one? 17.2cm is also easy. 29.3-12.1=17.2 Ok lets do this

http://img185.imageshack.us/img185/4751/tdcb5pu2.png (http://imageshack.us)

Now it gets rough. This is maybe the hardest part, so dont panic if you feel stupid. We have to use that sin and cosine thing again to get the two angles (64 and 26). Actually its the tangent we use this time, its probably written tan on your calculator. Oh wait, actually its the -tan we use, you were worried werent you? Ok heres the calculation. (8.2/17.2)*-tan you should get around 26 ( my picture is not 100% acurate) Then you can simply do like in the other triangle
180-(90+26)=64 to fill in the last angle.

http://img71.imageshack.us/img71/2994/tdcb6tf6.png (http://imageshack.us)

This one is pretty much like #3 but a bit different. Anyhow here's how you get the 19.1 value. 17.2/(64*sin)= 19.1. 19.1 represents the distance the merchant travelled between the first time you spotted him and the second. You can easily find speed of target if you took care to time this.

http://img184.imageshack.us/img184/1572/tdcb7ab7.png (http://imageshack.us)

Once you have the speed and course of your target, hes dead. Now that we have speed, lets get his course. Here, i continued both the lines that represent the angle at with i spotted the merchant last and his course. You can add the 26o because two lines that cross each other automatically have the same angle on opposit sides. Hey only one picture left!!!!!

http://img184.imageshack.us/img184/2743/tdcb8xl0.png (http://imageshack.us)

The last blue line I added is actually bearing 000 and parallel to the first blue line. This is a 3d application thingy and it tries to be 3d-ish, so it points true north, trust me. Wow, before i finish this thing, lets take a moment to admire that last picture, isn't nice? I truely surpassed myself.God i'm good. Ok so this last number, 13o, can be added because of a known carateristic of lines. Something like "two parallel lines create the same angle when crossed by another line" Basicaly, its the same angle you see the merchant at. Course of merchant =13+26=39. Ok i'm done. Youppi! I hope you understood cause i realized i didnt explain enough, im not even sure anyone is gonna read this so why should I? If people ARE interested ill try to answer any question i can. Next week ill try to come up with the same method but then on the move. OWWWWW! thats gonna be hard. Stop.

[Cpt. Stewker]

Just wanna say welcome before I read your post!! It looks interesting from what I see so far.

I'll post ther rest of my comments after I read it.

EDIT: I have heard of this before in regards to targeting so no I don't think you are the first mate, but nevertheless you did a great job of explaining it! You could also do this while submerged while looking through the scope (which of course, is ideal :) ). Just will take a few more steps. You will be able to find the range and the bearing through that, just like the watcheman, but will have to do manually.

[_Seth_]

Welcome, mate...PS: Ease up on the coffee...:rotfl: No seriously, it lookes good!

[melnibonian]

Welcome mate:up:

Since I love maths and I make my living from them I have to say that I liked the post. I haven't read it all and in great detail as I'm at work now but it looks really good. Keep them comming:yep: :yep:

[Lanzfeld]

Looks good but your sub should never be sitting still. More tru if you are at periscope depth but good work!:up:

[Ole]

nice post, you ever heard of dynamic geometry software like euklid dyna geo?
thats great to edit this stuff dynamic, so you can use it by entering variables and the constructed "rest" is moving on its own. try it, you´ll like it!

[Lovro]

The only problem is the fact that WW2 subs cant stand perfectly still. :damn:

Concernig the sub movement- it sways, banks and dances around a lot more in RL than in SH3. I read an interwiew with a yugoslavian diesel submarine captain (though his sub was much more advanced than your avarege U-boot) and he said that when they fired a torpedo all avalible men were rushed stern to keep the sub balanced until the water tanks kicked in (a topedo weighed around a tone). Something simillar was happening in storms when the sub could sway down in a 45° dive and sink 30m or 40m until they leveled her and in adriatic sea which is just 50m deep such menuvers were...:arrgh!: Anyway an interesting guy- he also talked about how it was to be under water for 60 days with no shower, barely breathable air and so on (todays nukes are much more comfortable)- nice read for submaniacs.

[AVGWarhawk]

Isn't this basically the "is-was" the British used?

[geezerjo09]

Isn't this basically the "is-was" the British used?


Hummm, are you telling me I managed to find the exact method the brits used during ww2? That would be a great honour, although i'd rather find out how the Germans did it, they proved their method to be quite .... efficient.

[Monocell]

Certainly a valid method, but I belive some people (including me) dont like to use a calculator in a WW2 sim. Perhaps I should see if I can go and buy a slide rule for quick calculations. :)

[geezerjo09]

Certainly a valid method, but I belive some people (including me) dont like to use a calculator in a WW2 sim. Perhaps I should see if I can go and buy a slide rule for quick calculations. :)


I'm not sure if it's because you don't likle the anachronism "feel" to using a calculator or if it's only because you don't like calculators, but im quite sure calculators did exist during ww2 (Can someone confirm/disprove this?). Anyways, the only thing youd have to use it for is Sine, cosine and tangent, THAT has been along for centuries. I don't know why the clever german captains should not take advantage of it.




p.s. I'm working on a way to use this method on the move. Maybe some of you could help me, I looking for an online calculator that would allow me to solve a function. Something like (A+B=x, B+C=y+2, C+D=2x-y ....) Anybody know of something i could use to solve that?

[Monocell]

I'm not sure if it's because you don't likle the anachronism "feel" to using a calculator or if it's only because you don't like calculators, but im quite sure calculators did exist during ww2 (Can someone confirm/disprove this?). Anyways, the only thing youd have to use it for is Sine, cosine and tangent, THAT has been along for centuries. I don't know why the clever german captains should not take advantage of it.

Trigonometric functions yes, but then most commonly in the form of look up tables as far as I know. Unfortunatly I have trouble as it is to keep the plotting speedy enough to be usefull, so thats certainly not for me. :)

[geezerjo09]

Trigonometric functions yes, but then most commonly in the form of look up tables as far as I know. Unfortunatly I have trouble as it is to keep the plotting speedy enough to be usefull, so thats certainly not for me. :)


But that's the beauty of it all, you don't have to plot anything (usually i love to plot but i have been frustrated by near misses so often that i gave it up). Of course if your really visual you have to plot, but not if you can pictrure yourself the situation. I havent tried it yet, but this method is probably great for late war-submerged attack ( with the sonar replacing the watchman)

[Ole]

calculators did not exist as we´ve got them today. they had small tables you could move sideways against each other, works pretty good and if you got enough practice it is fast enough.
i build a small html to show you what i meant with the dynamic geometry. scroll down to select the range etc.
its not very exact in html-modus. the version edited in the programm is already pretty good.
http://mitglied.lycos.de/myphpspace/sh3/euklid/course1.html
sorry, it needs a java applet, i hope it works on your pcs.
here is a screen too:
http://mitglied.lycos.de/myphpspace/sh3/euklid/euklid.jpg

[Jimbuna]

I'm afraid I'm mathematically retentive :oops:

Welcome aboard matey :arrgh!:

[geezerjo09]

Hummmmm, I can't blame you guys for being over-polite and i'm happy you are, but you seem to be more happy to wish me luck aboard than to discuss this new method, that would make me happy(i worked really hard on this). Have any of you guys tried it? Anyone having problems with it? Simply can't understand it? Or do you have Suggestions to make it easier/more accurate? Or, do most of you use automatic tdc?

I loved making this thing and im currently working on a way to use it while on the move, but if theres no interst in it and your not even thinking about using it, i wont go through all the work. I'm not complainning here i'm just wondering if your posting here cause your so used to watching the forums and posting that its like a reflex, or if you actually read whats written. Anyways i'm on board, might as well give my two cents.

Pray God, but keep swimming.

[melnibonian]

Your method seems fine. I haven't tried it but I will give it a shot at some point and come back to you. As far as your explanations it doesn't seem too complex, although I can understand people getting a bit scared about the trigonometry (not that it's difficult but people are affraid of numbers and functions).

Most people do play on auto targeting as it's faster and simple. There are some who play with manual but I don't know how many they are.

Anyhow welcome and enjoy your stay:up:

[_Seth_]

Hummmmm, I can't blame you guys for being over-polite and i'm happy you are, but you seem to be more happy to wish me luck aboard than to discuss this new method, that would make me happy(i worked really hard on this). Have any of you guys tried it? Anyone having problems with it? Simply can't understand it? Or do you have Suggestions to make it easier/more accurate? Or, do most of you use automatic tdc?

I loved making this thing and im currently working on a way to use it while on the move, but if theres no interst in it and your not even thinking about using it, i wont go through all the work. I'm not complainning here i'm just wondering if your posting here cause your so used to watching the forums and posting that its like a reflex, or if you actually read whats written. Anyways i'm on board, might as well give my two cents.

Pray God, but keep swimming.

Im sure this is an excellent method, but im not very good in such mathematics...:nope:

[melnibonian]

Im sure this is an excellent method, but im not very good in such mathematics...:nope:
You're not the only one Seth. I'm sure most of my students will find it 'overwhelming' and it's really simple:nope: :nope: :nope:

[don1reed]

Welcome aboard, geezerjo09. Great work on your method; however, check out the "Sticky" above re Newbie guide. See Wazoo's manual charting and Dantenoc's how to.

The concept of manual targeting is the KISS formula. Although your method eventually solves the course and speed problems the Newbie guide will explain how to do it faster and simpler.

All the best,

[Monocell]

The concept of manual targeting is the KISS formula. Although your method eventually solves the course and speed problems the Newbie guide will explain how to do it faster and simpler.
I belive the point of it wasn't speed but accuracy. If you dont have to rely on a graphical solution you can potentially get greater accuracy.

@geezerjo09: If you want do discuss:

Wouldn't it be easier to skip the calculation of the uneccessary part of the second triangle. (ie the 64degree angle on your image) and instead calculate the targets traveled distance with 8.2/sin(26)?

[geezerjo09]

The concept of manual targeting is the KISS formula. Although your method eventually solves the course and speed problems the Newbie guide will explain how to do it faster and simpler.
I belive the point of it wasn't speed but accuracy. If you dont have to rely on a graphical solution you can potentially get greater accuracy.

@geezerjo09: If you want do discuss:

Wouldn't it be easier to skip the calculation of the uneccessary part of the second triangle. (ie the 64degree angle on your image) and instead calculate the targets traveled distance with 8.2/sin(26)?

Well the calculation for the 64 degree IS useless in a way, but 180-(90+26)=64 is not what I would cal a difficult calculation.

[Monocell]

Well the calculation for the 64 degree IS useless in a way, but 180-(90+26)=64 is not what I would cal a difficult calculation.

Agreed, but that was the only thing I could find to nitpick on. ;)

I belive the 56 degree angle is useless in the same way.

[Kiwi Commandant]

I feel this is like "The Emperor's New Clothes" but maybe I'm completely missing the point. So you determine the target's course - but then what do you do with that info. I reckon I'm getting better at manual targeting (in fact, pretty darn good), using my own modified version of what's in the Wiki and Wazoo's method - but how do you use the info that comes from this approach??

[Monocell]

You determine both speed and course, wich is the same things you determine if you use Wazoo's manual I belive?


Like I said before, I prefer to plot, but this method is certainly valid as well.

[Kiwi Commandant]

You determine both speed and course, wich is the same things you determine if you use Wazoo's manual I belive?


Like I said before, I prefer to plot, but this method is certainly valid as well.

Well - it's late in the evening here, so I'll have another glass of vin and retire to ponder on this.

[don1reed]

The concept of manual targeting is the KISS formula. Although your method eventually solves the course and speed problems the Newbie guide will explain how to do it faster and simpler.
I belive the point of it wasn't speed but accuracy. If you dont have to rely on a graphical solution you can potentially get greater accuracy.

@geezerjo09: If you want do discuss:

Wouldn't it be easier to skip the calculation of the uneccessary part of the second triangle. (ie the 64degree angle on your image) and instead calculate the targets traveled distance with 8.2/sin(26)?

@Monocell:

Actually, the point is both speed and accuracy.
Manual targeting has been around for a very long time. The military KISS formula is: Keep It Simple, Stupid. We don't have to get wrapped around the axel over this, and, it isn't necessary to re-invent the wheel. The skippers of the time period used a quick and simple representation of a maneuvering board of one design or another to take into account both vessels moving. Submerged submarines of the period continue to move to keep from sinking (that neutral buoyancy thing), so, even though this "NEW" method is interesting, skippers of the period didn't have benefit of a pause-button while doing the math.

...that said, as subsim players, we all enjoy any method that works and helps us sink ships, including the time honored, traditional methods as well as the "new".

All the best,

[Monocell]

Actually, the point is both speed and accuracy.
Manual targeting has been around for a very long time. The military KISS formula is: Keep It Simple, Stupid. We don't have to get wrapped around the axel over this, and, it isn't necessary to re-invent the wheel. The skippers of the time period used a quick and simple representation of a maneuvering board of one design or another to take into account both vessels moving. Submerged submarines of the period continue to move to keep from sinking (that neutral buoyancy thing), so, even though this "NEW" method is interesting, skippers of the period didn't have benefit of a pause-button while doing the math.

You are preaching to the choir friend. For me plotting the normal way seems superior for numerous reasons. However, if you want to find a reason for doing it this way then the added accuracy of not relying on graphics would be one.

[don1reed]

Well, its kind of like the eternal battle of which is more accurate, Geometry or Trig? :D

[don1reed]

@ geezerjo09:

Here's a mathematical method of determining course and speed with both vessels moving.

http://img254.imageshack.us/img254/4483/movinguboatwm9.th.jpg (http://img254.imageshack.us/my.php?image=movinguboatwm9.jpg)

[geezerjo09]

@ geezerjo09:

Here's a mathematical method of determining course and speed with both vessels moving.

http://img204.imageshack.us/img204/3553/movinguboatrz2.th.jpg (http://img204.imageshack.us/my.php?image=movinguboatrz2.jpg)


BRAVO!!!!! I must admit, you are better than me. I'm only a novice at this. I thought sine and cosine could only be used with right angle triangles :damn: Would you give me copyright to explain this method as I did with the stationary one?

[don1reed]

No copyright necessary, geezer. There's no pride in authorship here in the forum, you're free to use this at will.

All that is required is to research solving Oblique Plane Triangles. Just Google it and you're in business.

One other thing, I'm not better than you...we're all equals here...but, I'm a lot older than you are :D

I'm not sure if you want me to explain how it works..(?)

...just in case you do...here goes:

1) We're at periscope depth (PD) and on course 269° (True) @ 3kn., when we spot the tgt. BR 068° (Relative) at Range 3800m. Start the stopwatch.

2) Rule of Three (using yards=3 min., using metric 3min 15sec) We're using metric so 3:15 it is. When time elapses, we take 2nd bearing on tgt., which is now BR 064° @ 3200m. (note 4° difference).

3) We now have a large narrow oblique triangle ABC with apex angle A = 4°; angle B = 64° since it is a vertical angle created by the sub's track as part of triangle BEF; angle C = 112° the supplementary to straight line ACD (180-68=112).

4) We solve triangle ABC using the law of sines giving us the lengths of AB and AC.

5) AB + BE = 7665m; AC + CD = 7187m.

6) Line DF = the tgt's. track. Line segment DE = distance tgt travelled in 3:15, which is solved using the Law of Cosines. In my example it = 684m, according to the rule of three = 6.84 kn. ~ 7 kn.

Course:

269° T (Own course)
+064° R (Tgt Bearing)
333°
-180° (reciprical)
153°
+054 (Add Port AOB, Subtract Starboard AOB)
207° T (Target's course)


All the best,

[geezerjo09]

How can you know your older than me? Or are you talking about forum-wise age?

[AVGWarhawk]

Fun with math......I thought that was just a myth!

[melnibonian]

Fun with math......I thought that was just a myth!
Oh yes mathematics is the one and only true form of art in this word. And they can be fun. Trust me I spent my life learning them and using them in every and not so everyday problems;)

[don1reed]

...geezer if you were born in '38, then you're older :rock:

[AVGWarhawk]

...geezer if you were born in '38, then you're older :rock:

lets do the math..............:rotfl:

[geezerjo09]

...geezer if you were born in '38, then you're older :rock:


Ohhhhhh, you are a "SEASONED" skipper.

Allow me to ask you. What exactly is it you do for a living, or for a hobby (i wouldnt blame you for being retired).

[Jimbuna]

Check his last post 'Seasoned Skipper' :D

[don1reed]

Click on my name on the left side and check out my profile...:arrgh!:

I'm whats referred to as an OUA (old ugly arse) aka curmudgeon aka old fart...:smug:

heck, I'll answer to anything, as long as it's for payday or chow!!

cheers,

[AVGWarhawk]

Click on my name on the left side and check out my profile...:arrgh!:

I'm whats referred to as an OUA (old ugly arse) aka curmudgeon aka old fart...:smug:

heck, I'll answer to anything, as long as it's for payday or chow!!

cheers,

That's right call me what you want but not late for dinner:up:

[don1reed]

o.t.

I'm Homer Simpson of the Borg. Prepare to be assim... doh...cookies!

[despat]

No copyright necessary, geezer. There's no pride in authorship here in the forum, you're free to use this at will.

All that is required is to research solving Oblique Plane Triangles. Just Google it and you're in business.

One other thing, I'm not better than you...we're all equals here...but, I'm a lot older than you are :D

I'm not sure if you want me to explain how it works..(?)

...just in case you do...here goes:

1) We're at periscope depth (PD) and on course 269° (True) @ 3kn., when we spot the tgt. BR 068° (Relative) at Range 3800m. Start the stopwatch.

2) Rule of Three (using yards=3 min., using metric 3min 15sec) We're using metric so 3:15 it is. When time elapses, we take 2nd bearing on tgt., which is now BR 064° @ 3200m. (note 4° difference).

3) We now have a large narrow oblique triangle ABC with apex angle A = 4°; angle B = 64° since it is a vertical angle created by the sub's track as part of triangle BEF; angle C = 112° the supplementary to straight line ACD (180-68=112).

4) We solve triangle ABC using the law of sines giving us the lengths of AB and AC.

5) AB + BE = 7665m; AC + CD = 7187m.

6) Line DF = the tgt's. track. Line segment DE = distance tgt travelled in 3:15, which is solved using the Law of Cosines. In my example it = 684m, according to the rule of three = 6.84 kn. ~ 7 kn.

Course:

269° T (Own course)
+064° R (Tgt Bearing)
333°
-180° (reciprical)
153°
+054 (Add Port AOB, Subtract Starboard AOB)
207° T (Target's course)


All the best,

I just came across this and thought I'd try to understand it. If it's ok, I'll be emailing for help (if I get stuck)?

Thanks

[Bubblehead729]

Not to put a damper on your enthusiasm or anything, but you do realize this thread is six years old, right?
:hmmm:

[don1reed]

Hello All.

Still lurking the forum(s). Would it help if I posted a graphic of the solution? A pic is worth 1k words.

Cheers.

[sublynx]

Hello All.

Still lurking the forum(s). Would it help if I posted a graphic of the solution? A pic is worth 1k words.

Cheers.

I'm sure most of us U-boat fanatics are always salivating for new ways of stalking our prey :D

If you have the time it would be great to see a pic that tells it all in one view AND a series of pics telling what to do pic by pic...