Need assistance with the four bearing method as described by Makman

[Mar01]

I'm having a heck of a time trying to get this to work. I really hope I can because I like being able to get the course from well outside of enemy detection range. Or is that my problem?

I'm here to ask you folks if I need to be closer than "long range" to make this work, or if I need to have the bearing lines cross eachother, or if I'm just doing everything upside down, etc.

It is never described what to do if the bearings do not cross, and I think this is my problem. So far I've tried this method on three different contacts and only on one of the occasions did my bearing lines cross, but just barely. Even then I got the same wrong course as I've got here, pictures to follow.

http://img850.imageshack.us/img850/3968/sh3img1812201118615346.png

http://img855.imageshack.us/img855/8397/sh3img18122011185657148.png

I got the red line by doing the same thing Makman did in his video here: http://www.youtube.com/watch?v=4RWDWd62q4w
and, as you can see, got just about the opposite course of the real one.

:help:

[postalbyke]

Think about target motion and drawing lines...
If you want the lines to cross, go the opposite way you think he's going.
If he's moving to the left, go right!
If he's moving to the right, go left!

Wait one while I watch the vid.

edit: I didn't find the video helpful cause I'm a diagnosed hearing/doing learner, so I found the manual here:

http://www.subsim.com/radioroom/showthread.php?t=179137&page=2

Looks easier already! :D
p.s. disregard the first part of this post unless it really does help :P

edit edit:

WELCOME ABOARD, TEAMMATE!
I'm personally glad to see more people joining up and playing an older game (or any combination thereof!) I look forward to your questions and contributions to this great website!

[Mar01]

The welcome is absolutely appreciated. I started playing a few years ago but wasn't able to get into it then, but recently I got the itch to play something with a nice relaxing atmosphere, where stealth and planning is the key to success. I've already spent many hours packed into my chair modding the game and learning various hunt techniques. There's just something about sitting and waiting in the blue, and then watching as the enemy ships cry out "WHAT JUST HAPPENED?!?" I guess you could say that I'm a hunter by nature.:arrgh!:


Anyway, I just got through tracking another one, and this time the target's course bearing was dead on and displaced by only 150 meters. I did have to get the bearings crossed, so perhaps this method can only be done from in front of the target and heading roughly the opposite direction? From now on I'll do as you said, wait to see which direction the bearings will change, and make my course the opposite.

Now I'm wondering if this can be done accurately enough if I make my speed one knot...

[Pisces]

It looks like the bearing differences are quite small, like 3 to 4 degrees between b1, b2 and b3. I think you should allow more time between the bearings. This drawing method doesn't work well if lines are close to parallel. Try with a minimum of 5 degrees, or 10 w hile you are trying to get the routine down. Then as you get more experienced go for shorter periods.

BTW, where the 3 bearing lines cross does not really matter. It really depends on how the target is moving compared to you. And you simply can't tell that beforehand. You just need to make sure the lines diverge as much as possible within reasonable time periods. Not too short to mess up accuracy. Not too long to risk him getting out of detection range. It's a gamble how long this should actually be. Sometimes you win, sometimes you loose.

Postalbyke was correct in suggesting that if the sounds drift left, you turn to the right of it. And vice versa. This does get you behind the target, but makes for more accurate course/position info. The alternative is to go at full speed or flank in the other direction. This keeps you in a forward position, but makes the bearing drift slower. Trade-offs as allways.

[Pisces]

If you move at 1 knot then you are practically motionless. For that the video by Nefelodam works better.:

http://www.subsim.com/radioroom/showthread.php?t=154461

direct link to video:

http://blip.tv/nefelodamon/hydrophone-interception-tutorial-part-1-2462628

[makman94]

.....
It is never described what to do if the bearings do not cross, and I think this is my problem...

I got the red line by doing the same thing Makman did in his video here: http://www.youtube.com/watch?v=4RWDWd62q4w
....

hi Mar01,

first of all ,the ''four bearings method'' belongs to the great mind of Kuikueg . i just made some videos for showing ingame Kuikueg's brilliant method.

about your question:
at the comments of the youtube video someone had asked the same thing with you and i replied:

When two bearing lines (b1 and b2) happens to be parallel (extremely unsual to happen though) means that you are on a collision course with target (pay attention: this DOESN'T mean that you are moving parallel with him).

don't wait for the third bearing in this case becuase you allready have a critical info for target : that he and you are on a collision course.

to 'lock' his exact course ...do this:

1. mark on map the point that YOUR boat would be after X time (X=time between b1 and b2) if you continue to move forward and draw from this point a line parallel to b1 and b2

2. repeat the step 1 one more time ...so now you have two theoritical bearings (lets call them b3 and b4)

3. CHANGE COURSE and speed and after exactly X time take a bearing to target and find where this bearing is intercepting b3 (call this mark ..as 'mark1')

4. after exactly X time (again) take a bearing to target and find where this bearing is intercepting b4 (call this mark ..as 'mark2')

5. mark1 and mark2 are two true positions of target so by connecting them ...you have the true course of target


in all other situations (non parallel bearing lines) you will have the needed 'triangle' that Kuikueg describes at his notes (exept in one extremely-again-situation that the three bearing lines intercepts at the same point which means that target is moving parallel to your own course) and it is a pure geometrically solution that always works .
in game ,you need to be very accurate at your drawings to see it 'happening'.the more accurate you are at drawings...the more 'close' to true target's data will be (yes, in cases that bearings lines are close to parallel, drawings getting much much harder but this has to do with the way that navmap station is designed in sh series...it is just torturing the player).

as Pisces told you, the chasing targets with hydro definetely containes a little (or much much more if you switch off the hydro lines) ....'gambling' and ...'guessing' in order not to lose contact to target and you have to make manouvers in order to secure this(thats the beauty of this method: you don't wait to see what will happen.you are moving and at the same time you are always 'studing' the behaviour of hydro lines,changing freely own course and speed untill you got two 'good' bearing lines and then you go for the third one.if third is good too you proceed to the rest of procedure ...if not you start manuevers again and so on) . only expierience and many hours of exersice are your 'friends' here and it is exactly what makes the difference between captains and real good captains ! i am guessing that losing contact to target was something that also happened in reality back then.

anyway, speaking about reality , a big question that i always have in my mind is this :
left aside the game ....does the captains of cargo ships(targets) were (are) travelling at a constant speed and constant course in reality ? especially during war times and even especially at 'dangerous waters' ...this seems totally like a ....suiside ! don't you think so ?

[Mar01]

you are moving and at the same time you are always 'studing' the behaviour of hydro lines,changing freely own course and speed untill you got two 'good' bearing lines and then you go for the third one.if third is good too you proceed to the rest of procedure ...if not you start manuevers again and so on)

Duh! Sheesh, it seems I'm just too impatient, I never thought of that.

A couple more questions:

Does it matter which direction you change course for the fourth bearing? What I would prefer to do is turn 135 degrees from my current heading away from the target so I don't get too close, and that leads to the next question,

If I am running at full speed at "long range" from the nearest destroyer, would he be able to detect me? Assuming the destroyer has an "elite" crew. If not then there will be no need for making just one knot.:)

anyway, speaking about reality , a big question that i always have in my mind is this :
left aside the game ....does the captains of cargo ships(targets) were (are) traveling at a constant speed and constant course in reality ? especially during war times and even especially at 'dangerous waters' ...this seems totally like a ....suicide ! don't you think so ?

Well if I was a cargo ship captain sailing in WWII I'd be making completely random zigzag patterns and changing speed every so often. Of course I'd be yelled at by the company I'm working for for wasting fuel and taking too long to reach destination, but better safe than sorry. However this makes for a nightmarish experience for a gamer trying to sink em., so I prefer them going straight and steady. :DL