Hydrophone Hunting (tutorial)

[Alcibiades]

Originally Posted by Pisces

Why wouldn't it? The bearings show where the target is (and was). In step 4 Alcibiades has just drawn a line in a random direction (well, from bearing 1 over to and across bearing 3). Look at step 5 to 8. Using the circle and line parallel to bearing 1 he corrected the NW line to the correct course. It doesn't matter where he comes from or it's actual course being totally different. The circle and parallel line will show if it is a wrong guess, and what the right course is.

Yes.

The line in step 4 is just a random line (guess) to allow use of geometry to get the real heading.


Also, since you were sitting still and not moving from when you took bearing 1 until when you took bearing 3 - then you know that the target is moving towards the west. And you guess he's coming towards you.

If the target is E or N of you when you first pick him up, follow the same procedure, but just "guess" his route and assume he is 'slanting' towards you.



additional note: you can also tell he is coming towards you based on how much larger the angle is between bearing line 2 and 3. The larger that angle, the sharper angle the target is heading towards you. if the big angle is between lines 1 and 2 (and a small angle between bearing lines 2 and 3) then hes moving away!


Hope the PDF's help!

word of caution again: be careful if trying to use it against a convoy!!! if you record a different ship each time you listen (likely), then your estimates will be off. usually close enough to plot a rough intercept course, but that's probably about all