How do you determine the target's heading with passive sonar?

[Silver_Silence]

In the late war, it is hard to get close enough to a convoy before the escorts are on top of you. I believe it is important to find out the target's heading at a much farther range with passive sonar.

I looked up the topic and decided not to use raduz technique (doesn't seems to be historically accurate) There is one link I found in the forum that lead me to a page with explanation on how it can be done, except the page is not in English. But I do see a few sins equation going about. Looks pretty interesting.

I wonder if there is some site similar that give passive sonar tutorial in English.

[kenijaru]

maybe if you post the link, someone literate on both languages will be able to help you :know:

[Pisces]

Most people, I think, just chase the bearing line and hope for the best. But there are smarter ways to get into visual range. My post in the following link might help. It a sort of a sliderule that needs 3 bearings taken at equal intervals. And this takes atleast halve an hour in time total. I wait until 5 or 6 degrees change has occured and take the 3rd bearing an exact interval later. If you are stationary you will get the target's AOB [Oops, not course] at the 1st bearing after correctly aligning the slideruler, ... BUT with a reasonably large error. And you'll loose a possible advantagous position ahead of him. If you are moving, ... then it's not so simple. As the 'course' will be skewed by your speed and is actually the direction of relative motion. And that is to complex to explain further here.

http://www.subsim.com/radioroom/showthread.php?p=875260#post875260

But there is also a graphical way to determine this course from these 3 bearings. I've been thinking of writing a tutorial on this, but that will need some preparation before it is done. As a placeholder for now I would suggest downloading The Radar Navigation and Maneuvering Board Manual (http://www.nga.mil/portal/site/maritime/?epi_menuItemID=22707e6ae3d0c1b25b2a7fbd3227a759&epi_menuID=35ad5b8aabcefa1a0fc133443927a759&epi_baseMenuID=e106a3b5e50edce1fec24fd73927a759). (I can only download the big package, individual chapters through the pulldown list don't seem to work) Find example 25 in chapter 6 (p 298) to learn how to do it. It also explains how to correct if you are moving in between taking the bearings.

There is also a thread with video with another graphical method, made by Mittelweachter on this forum but I cannot find a link to it in my bookmarks. You may have to search the forum for that.

[urmama]

why not use babel fish translator.
http://au.babelfish.yahoo.com/translate_txt
you just put the url of the page you want translated and select the languages you want.

[Mittelwaechter]

Here is a link to the Ubi thread for my graphical solution to determine a contact course using only hydrophone. You even get a torpedo solution for manual TDC input to sink the contact without visual support.
The link for the video tutorial is up to date.

http://forums.ubi.com/eve/forums/a/tpc/f/857101043/m/7821098535?r=7821098535#7821098535

Have fun!

[Puster Bill]

It's not quite historical, but you could make a bearing rate computer. It's a circular slide rule that was used in the 1950's-1980's to do the calculations.

Here is the inner wheel:

http://img225.imageshack.us/img225/1273/brcinnerwh5.jpg

And here is the outer wheel:

http://img207.imageshack.us/img207/3040/brcouterhs2.jpg

The parts where it looks messed up are the parts where I had to erase the "cursor" on the illustration (I pulled it from a navy manual online somewhere). You can clean it up if you want, but it works fine as-is.

Obviously, you print them out and then make a cursor for them, then pin it all together in the center.

I don't have the instructions handy, but if you google "bearing rate computer" you should find it. The procedure does work, but I don't do it anymore because it isn't historical (at least, not WWII German historical).

[Pisces]

Oops, made a mistake in my 1st paragraph, it calculates AOB at 1st bearing instead of course.