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!!!!



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.



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!!!!



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!!!!



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



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.



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.



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!!!!!



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

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

[Lanzfeld]

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

[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.

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... 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.

[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.

[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]

Originally Posted by 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)?

[geezerjo09]

Originally Posted by Monocell

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]

Originally Posted by geezerjo09

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.

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??

[don1reed]

Originally Posted by Monocell

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]

Originally Posted by don1reed

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.