Four bearings...

[Shkval]

Well, I'm playing SH3 again after a long time, with GWX3.0 gold an MaGui mods... and I have a few questions, first, this situation in picture, contact is moving away and when I try to copy first bearing on a symmetrical point it does not intersect with last bearing... what does it means and what should I do?

Second question is does anybody knows some good tutorial about these tools in MaGui mode, attack disc, this second "brown" disc that has something to do with AOB,...and this third disc attached to periscope?

I got this Angriffsscheibe_Handbuch_3 pdf for attack disc but it's pretty different from this one in MaGui, and off course two "main" tutorials about hydro-hunting... I need more...

I'm practicing the four bearings method because I like this "mathematical" approach of aiming torpedoes and because I intend to survive the war . I'm not a total beginner but for the first time I'm playing with "map turned off" feature... and it's bloody difficult... yesterday I did mine first "blind" hit at 4,5 km .

[Mittelwaechter]

Just two comments:

- remember your bearings are cones - resulting in unavoidable inaccurate drawings. Our SH3 map tools were not designed for this task. Still good enough for a fire solution at 'short' distances but the further you shoot the more luck you'll need. Hits over 4500 meters are possible but you'll be frustrated by the work you invest versus the score you get.

- don't go for targets sailing away. ^
Get into better position or let them go.

[Pisces]

One of the circular wheels you describe is probably my 3-bearing AOB calculator. If doesn't calculate speed or range. But it could help to verify the correctnes of your drawing up to this point.

The 3 bearing AOB calculator is based on my design:

http://www.subsim.com/radioroom/showthread.php?t=147719

The MaGUI mod should have the explanation how to use it somewhere in the documentation files. But the above link explains it perfectly. (I hope) Align the differences between the specific bearings and read out the AOB at the first bearing. Then add the difference between bearing 1 and bearing 3 to the AOB in the window, to get the AOB at bearing 3.

The shown AOB is correct insofar you adhered to the equal time-interval requirement and not turning during the procedure.

[Shkval]

Ok, guys I got it, at least how AOB finder works... and how to get true course of a target with attack disc, my following question is: is it possible to get range from AOB and true course... without moving the sub? without triangulation?

[makman94]

Here you are Shkval ,
you must place the red marked point to the green marked point (look at pic)...etc



for the tool that pisces is talking you about ,''there really is no reason to'' use it once you ''know how'' to do your drawings on navmap .
the tool is not there for ''helping you to verify the correctnes of your drawing up to this point'' , navmap drawings are as much accurate as accurate your bearing readings are .
so, in case you are wondering why the tool is there then ,the answer is : alternative playing styles ...nothing more and nothing less than this,you choose what suits best for you.

[ETsd4]

Originally Posted by Shkval

my following question is: is it possible to get range from AOB and true course... without moving the sub? without triangulation?

True course, yes, true range no.


You have to understand what the soundman is telling you and what your drawings tell you:
(1)soundman rounds the bearing:
True 359.5° = 000° for the soundman
and
True 000.4° = 000° for the soundman.

(2)The arcs in the drawings are rounded:
True 359°30' arc = 000° arc in your drawing
True 000°29' arc = 000° arc in your drawing
etc.

With these 2 facts in mind the laws of probability says you have a 0.0000000007715 % possibility to get all your 4 bearings and all 4 arc drawings at once error-free on you nautical chart ...

See also http://www.subsim.com/radioroom/show...light=bearings

[Shkval]

So I have 0.0000000007715 % chance to hit him with single torpedo ? Well guys you really know how to cheer up somebody... is there a cure for sonar guy? Some mod? More precise drawing tools?

@ETsd4... how did you get this 0.75 precision, and I was thinking about some "AOB+Bearing= Range" magic formula/drawing in my question...

@makman94 ... I can see the mistake now... nice tutorials btw

Lately I constantly have some error in projected course of a target I don't know how much but it's not bigger than 7-8 degrees (I think...) when a target approaches on it's course sonar guy doesn't reads out "constant distance" as it should... but "closing" until about 35-40 degrees on my scope, then suddenly he changes to "moving away" . This happens no matter what way of tracking I use... moving... stationary... is this result of cumulative "round up" bearing errors? I'm off-course on the 90 degrees approach to projected course of a target.

[Mittelwaechter]

Your chance to hit something is way better, because you try to shoot at short distances (!) and your target is 150 to 200 meters long. It takes some time for the ships hull to pass along that imaginary hit point your calculations may reveal.
Within this intervall your torpedo has time to reach the target.

The 0.000..75% chance is for the exact 0.44 cm width of the top of the torpedo impact pistol hitting that certain spot directly next to the spill hole under the foremast. There is plenty of hull area to hit instead.

Range is negligible for a 90° attack. AOB is tolerant up to a certain degree. Really important is target speed.

Edit: the change from 'closing' to 'moving away' is a bug. Simply take it as 'constant distance' instead.
Your hydrophone operator reveals a lot of information. Think about it.

[ETsd4]

Originally Posted by Shkval

More precise drawing tools?

More precision with drawing-arc (tenths of arc), distances (meters) and range/bearings lines can be copied, shifted etc.:
Paint.Net (without map), free
GeoGebra (without map), free
MoBo (with maps), free
Chart Navigator Pro (with maps)


0.0000000007715 % is the probability that your 4 bearings drawing on your map is exact that what has happened on the sea.
10% probability for ONE bearing that the soundman is error-free with his shouting.
1.6% probability for ONE arc-drawing that the arc is error-free with your SH5-arc-drawing tools.
After 4 bearings and 4 arc-drawings you got a 0.0000000007715 % that everything is error-free.

[Shkval]

Are these mods compatible with GWX gold and MAGui?

[Mittelwaechter]

These are no mods but standalone programs.
Alt-Tab out of the game and draw your stuff, then Alt-Tab back and act accordingly.

[Shkval]

Well...we are not playing Sub Command here aren't we that is a little bit unfair to poor unsuspecting merchants isn't it? Is there any cure for my sonar guy or I had to put the barrel of my Luger against his forehead and tell him "now... listen veeery carefully"? Or maybe I'm not listening correctly? How can you know when bearing is 345.7 and he says it's 346? Or there is no way to know such things?
Anyway thanks a lot guys it was very educating and now this game has a whole new meaning.

Little update, latest attempt is a clear hit at 5,2 km, tracking - while - moving, medium speed torpedo, contact fuse... you were wright Mittelwaechter speed of a target is most important element in solution.
I think I'm ready... for long range salvo attacks on convoys with LuT torpedos, invisible for radar, equipped with snorkel in late '43... maybe I even survive...

[Mittelwaechter]

Your sonar guy is one of your best men. Try to get his spot on bearings yourself and you'll realize how well trained he is. Keep your Luger beneath your pillow, Herr Kaleun.

The FAT/LUT are fun in combination with hydro data only. Remember to check the settings twice - or learn it the hard way.

Good luck in '43 Herr Kaleun, keep an eye at the flyboys while snorkeling. They tend to be nasty.

[Pisces]

Originally Posted by Shkval

So I have 0.0000000007715 % chance to hit him with single torpedo ? Well guys you really know how to cheer up somebody... is there a cure for sonar guy? Some mod? More precise drawing tools?

@ETsd4... how did you get this 0.75 precision, and I was thinking about some "AOB+Bearing= Range" magic formula/drawing in my question...

Nope, sorry. A stationary listening or viewing point will never provide range information from bearings only. It doesn't matter how many bearing lines you provide, or how accurate they are. It just isn't there in the math formula. Range can only be found with a (4th) bearing from a different point of view.

Lately I constantly have some error in projected course of a target I don't know how much but it's not bigger than 7-8 degrees (I think...) when a target approaches on it's course sonar guy doesn't reads out "constant distance" as it should... but "closing" until about 35-40 degrees on my scope, then suddenly he changes to "moving away" . This happens no matter what way of tracking I use... moving... stationary... is this result of cumulative "round up" bearing errors? I'm off-course on the 90 degrees approach to projected course of a target.

7 or 8 degrees deviation in projected course is reasonably good or normal. At least good enough to know the general direction it is going, and to parallel course or chase after it. The accuracy of the projected course depends on the length of the time-periods, and the divergence of the bearing-differences. The bearings are reported in steps of 1 degree, so the divergence in the differences needs to be larger than that. More time allows the bearing-differences to encompass more degrees. For example, compare:

bearing set "a":
B1a=0,
B2a=6,
B3a=13
Bdiff 1-2=6
Bdiff 2-3=7


to

bearing set "b":

B1b=0,
B2b=11,
B3b=25,
Bdiff 1-2 = 11,
Bdiff 2-3 = 14.

Each set ("a" and "b") has the same AOB at bearing 1, namely 49 degrees.

In set "a" the bearing drift accelerated 1 degree during the second interval. This is just as large as the bearing inaccuracy. So useless to rely on.

In set "b" the bearing drift accelerated 3 degrees during the second interval (about twice as long as intervals at "a"). This is clearly bigger than the 1 degree measurement accuracy. And so results in a more accurate AOB.

Patience pays in accuracy. But there comes a time when the target is lost. So don't stay there once you know where the target is going to. Go at the same course to get the different point of view for the 4th bearing. With minimal risk of collision/detection.

[Pisces]

I really should know better than to respond to this...

Originally Posted by makman94

...

for the tool that pisces is talking you about ,''there really is no reason to'' use it once you ''know how'' to do your drawings on navmap .
the tool is not there for ''helping you to verify the correctnes of your drawing up to this point'' , navmap drawings are as much accurate as accurate your bearing readings are .
so, in case you are wondering why the tool is there then ,the answer is : alternative playing styles ...nothing more and nothing less than this,you choose what suits best for you.

I suggested he used this tool because he suspected, or almost knew for certain, that he made a mistake in his drawing! So there IS a reason to verify the angles in the drawing! At the time of posting I couldn't provide detailed instructions how to correct his drawing because of time constraints and lack of editing ability. Otherwise I would have helped more. I just gave him another tool for finding the correct values. (based on same geometry and math) If they didn't match then the drawing was likely at fault. Wether Shkval would have been able to trace the error from it is another matter. But that's where follow-up posts are for. But he seems to have solved it allready. Case closed.

You may have had multiple reasons (or playing-styles in mind) for adding my wheel to your mod, but I had my own reasons for making it in the first place. One of it was infact verifying my drawings for errors and projecting the 4th bearing.