Intercepting

[Robert Fulton]

Originally Posted by Pisces

To get a target's course based on (hydro) 'bearings only' look at the following from a guy named Redwine. Because of his language (I think he's from argentina) it may be difficult to follow, but the formula works.

http://rotteufel.iespana.es/htdc_tut...ualtdc_009.htm

...

Thanks. This is very useful. Despite knowing hardly any Spanish, I was able to work my way through this with a little help from a dictionary and also found this site with Spanish nautical terms: http://bahiaredonda.com/dictionary/dictionary.php.

Given how important accurate bearing readings are to this calculation, who has tips for accomplishing this? I find that if a target is at between 20km and 30km, I must go to the hydorphone myself. And so far my skill level is not all that precise (maybe I need better headphones ).

As an aside, this forum has immensely increased my enjoyment of SH3. I am a novice still in my 1st career with the stock game.

[Pisces]

Longer time intervals inbetween taking the bearings makes the AOB error reduce alot. But this has the disadvantage of possibly putting you well behind his 90 AOB when you are done. And you also don't know how long he is going to stay in your hydrophone range.

So it's best to start with the smallest amount of bearing drift for the initial interval (for the tool I provide a download link to: take a time until b2-b1 becomes 5 degrees) to have a rough estimate on AOB. Compute how many degrees this rough AOB can grow until it reaches 90 degrees (assuming it is not allready past it). Take that as the bearing change for 2 intervals (B3-B1), and look how many degrees that would be for the 1st one interval (B2-B1), leaving the marker set on the rough AOB. Deduct one or two degrees for good measure from this (B2-B1). And repeat the 3 bearing method by waiting until the bearing has drifted this new (B2-B1) since the very first bearing taken.

Apart from that you can get a slightly better resolution out of your hydrophone. If you listen to the sides where the sounds are barely audible, and average those, you get the bearing to the target. This works alot better than finding the maximum volume. If one of those sides is an even number and the other is an odd number the true bearing is somewhere close to xxx.5. Allways take that halve decimal when you can get it!!!

Originally Posted by Robert Fulton

...(maybe I need better headphones )

The hydro station has a volume knob built-in aswell.


Thirdly, make sure your rudder is amidships, even if you think you have no speed! You don't want to have very slow turning screw up the bearings.

[Robert Fulton]

Originally Posted by Pisces

...
Apart from that you can get a slightly better resolution out of your hydrophone. If you listen to the sides where the sounds are barely audible, and average those, you get the bearing to the target. This works alot better than finding the maximum volume. If one of those sides is an even number and the other is an odd number the true bearing is somewhere close to xxx.5. Allways take that halve decimal when you can get it!!!

The hydro station has a volume knob built-in aswell.

...

Pisces, you provide a treasure trove of valuable information. I had tried the averaging from the outer limits method, but only with modest success. My difficulty is picking up on the precise locations where I lose all contact. I had looked for a volume knob at the hydro station, but did not find it. I am now eager to do so. Is it there in the stock version? (I am away from home for a while, and cannot recheck for myself.)

[Weiss Pinguin]

Yup, there should be a knob on the lower-right corner of the hydrophone station. Click on the top of it to increase the ambient volume.

[FIREWALL]

Three things I've found you have to get good at to really get the gut tightening immersion from this sim.

Manual targeting, the hydrophones and plotting courses and not necessarily in that order.

When you master those your a Kaluen.

Then the bottom line is tonnage.

[Robert Fulton]

Thanks, guys. I shall look for that volume control upon getting home before even taking my hat off.

On the way to immersion, too. I have course plotting down pretty well; I am working on the hydrophone; manual targeting is next.

I already get pleasure from the increased contacts I am getting with my current hydrophone skill. The last two patrols I have been taking it down to 25 meters; all stop; listen for a couple of 360s; then I turn 45 degress at ahead 1/3 and repeat to pick up anything in the blind spots. I estimate I am getting several contacts per patrol that I had been missing by relying solely on my highly qualified and decorated radioman. After all, the area of a 30km circle is more than double that of a 20km circle.

[FIREWALL]

Originally Posted by Robert Fulton

Thanks, guys. I shall look for that volume control upon getting home before even taking my hat off.

On the way to immersion, too. I have course plotting down pretty well; I am working on the hydrophone; manual targeting is next.

I already get pleasure from the increased contacts I am getting with my current hydrophone skill. The last two patrols I have been taking it down to 25 meters; all stop; listen for a couple of 360s; then I turn 45 degress at ahead 1/3 and repeat to pick up anything in the blind spots. I estimate I am getting several contacts per patrol that I had been missing by relying solely on my highly qualified and decorated radioman. After all, the area of a 30km circle is more than double that of a 20km circle.

Doesn't sound like you need any help.

[UberTorpedo]

Robert Fulton

Here's some other hydrophone hunting tutorials you might find interesting.

http://forums.ubi.com/eve/forums/a/t...7821098535/p/1
and
http://www.subsim.com/radioroom/showthread.php?t=110619

The video (U42HydroHunt.exe) for both posts has also been uploaded to my Filefront. See link under my sig

cheers

[Sandman_28054]

Originally Posted by ddiplock

With it being Mid 1943 now in my campaign, and Allied forces using Radar in earnest now, its very difficult to move into an attack position on the surface without being detected. The problem therein also lies in the ability to know the course of the ships in question, in order to get into an attack position.

Is there a way, when your forced to dive after detecting radar signals, that you can use the hydrophones to plot the course of the target if its the case of a convoy or a task force who's radar you've detected?

I've come across several task forces and convoys, but i've missed out on each because I don't know which direction they are heading while i'm submerged, and can't plot an intercept course. Why just earlier, I thought I was heading in the right direction to intercept a Task Force after picking up their radar, only to discover I was infact heading the wrong way.

Any help guys?

Cheers

Perhaps its just me, but what I have done in those situations is to dive as soon as I get the warning of "detecting radar."

I dive to periscope depth, and raise my periscope. Using the "pencil" I will "mark" their position. As somebody said, you need at least two visual observations. When you have these two marks, its easy to plot their course and an intercept.

[FIREWALL]

A simple way is get them on your hydro and turn into them till your at 0 degrees and see if they go port or starboard or right at ya.

[Pisces]

Originally Posted by UberTorpedo

Robert Fulton

Here's some other hydrophone hunting tutorials you might find interesting.

http://forums.ubi.com/eve/forums/a/t...7821098535/p/1
and
http://www.subsim.com/radioroom/showthread.php?t=110619

The video (U42HydroHunt.exe) for both posts has also been uploaded to my Filefront. See link under my sig

cheers

Indeed, the 2nd image in the 2nd link... or to be less confusing ... this one:



... shows what is missing with the 3-bearing sliderule post (figuring out range and speed). Project an imaginary future 4th bearing line on the map (by drawing the target track at an arbitrary range, and copying the distance between bearing intersections with a circle) and sprinting away from the listening location for the duration of the interval as fast as possible. A real 4th hydrophone bearingline (the 5th in the image) taken from the new position should intersect the imaginary 4th bearing at the real location of the target at that time. From that also speed can be figure out. (once the target track is re-drawn through the 4th bearing position fix.)

I really should be making a complete walkthrough of this oneday. Ugh, so often I promised to do.

[XLjedi]

Originally Posted by Pisces

Indeed, the 2nd image in the 2nd link... or to be less confusing ... this one:



... shows what is missing with the 3-bearing sliderule post (figuring out range and speed). Project an imaginary future 4th bearing line on the map (by drawing the target track at an arbitrary range, and copying the distance between bearing intersections with a circle) and sprinting away from the listening location for the duration of the interval as fast as possible. A real 4th hydrophone bearingline (the 5th in the image) taken from the new position should intersect the imaginary 4th bearing at the real location of the target at that time. From that also speed can be figure out. (once the target track is re-drawn through the 4th bearing position fix.)

I really should be making a complete walkthrough of this oneday. Ugh, so often I promised to do.

This picture represents exactly what the TMA tool in MoBo was built to do... In fact, you can also add vectors to negate your own subs movement to get an accurate true course if taking the bearings while moving.

Anyone ever try it?

[Robert Fulton]

Ubertorp, Pisces, Firewall: You guys are awesome. This forum is awesome.

Thanks to Mittelwaechter, too. I am sooooo eager to get back to my hydrophones and become proficient with these methods and tools (currently 2,100 km away from my boat ).