Determining target's true course

Leoz · 08-11-17, 09:35 PM

Occasionally when you spot a target for the first time and it is coming straight at you or 10 or 15 AOB there of, you can use an easy method to determine the target's true course.

If it is for example daytime and you may have to submerge soon or get spotted,...submerge and go to periscope depth.

Try to cross the path of the target to where you are visually seeing it at 0 angle on the bow (the bow pointed directly at you).

Then on the F5 map... plot that bearing. The opposite of that bearing is the targets true course.

Now, at your own time, without being rushed, you can go off to the side of that target track and get accurate position plots based on bearing alone and thus put a stopwatch against it and determine the target speed.

One author described this was how Lemp did the SS Athena.

I have used this many times in the game as it is low-workload and easy.

08-16-17, 08:52 AM

Could be useful against a convoy when approaching dead on. Erich Topp and many other U-boat commanders, apparently used to slip into the middle of a convoy on the surface at night and maneuver down the convoy lanes then fire their torpedoes at 90 degrees or less left and right at the passing ships. I imagine if one were to line up a ship first then travel down the lanes you could get its course that way. But then the thought occurs, it depends what technique your using, fast 90 that's useful, judging the AOB by sight maybe not at that point. I dunno? maybe i'll try it and see!

YellowFin · 08-17-17, 06:30 AM

It's called the 0-degree AOB method and is referenced as a SOP in the U.Kdt.Hdb, a tactical manual given to sub commanders by the Kriegsmarine. In fact they recommend it for every attack.

1. Intercept target
2. Get in front of target, keep taking bearings in regular intervalls, distance doesn't matter at this point
3. Cross in front of target. 0° AOB bearing -> true heading on map, and all the bearings now cross the true heading. If you've carefully taken bearings you will have a very exact speed estimate from the map.
4. Attack

I almost exclusively use this method, except when I surprise a target somehow I go for a "shot from the hip".

Check out my let's play where I demonstrate this method many times.

Greetings, and good hunting!

08-17-17, 07:23 AM

Thanks all will check this method out!

Leoz · 08-26-17, 11:21 PM

Quote:

Originally Posted by YellowFin

It's called the 0-degree AOB method and is referenced as a SOP in the U.Kdt.Hdb, a tactical manual given to sub commanders by the Kriegsmarine. In fact they recommend it for every attack.

1. Intercept target
2. Get in front of target, keep taking bearings in regular intervalls, distance doesn't matter at this point
3. Cross in front of target. 0° AOB bearing -> true heading on map, and all the bearings now cross the true heading. If you've carefully taken bearings you will have a very exact speed estimate from the map.
4. Attack

I almost exclusively use this method, except when I surprise a target somehow I go for a "shot from the hip".

Check out my let's play where I demonstrate this method many times.

Greetings, and good hunting!

Great info Yellowfin.

I did not know that.

Learn something new every day.

derstosstrupp · 09-20-17, 12:24 PM

All,

Absolutely correct on this one, very effective method and the basis of the tutorial in my sig! From what I can gather from reading German SOPs, I think these procedures closely reflect historical doctrine. Included in my tutorial is also an historical method of determining target speed by timing bearing change also referenced in German period documents. Please check it out and let me know your thoughts!

http://www.subsim.com/radioroom/showthread.php?t=229792

Pisces · 09-25-17, 11:15 AM

If the target is still far away you could also use this tool with periscope bearings recorded (and the differences between them calculated) to determine what the AOB was at the 1st bearing. Then calculate back that many degrees to the bearing where AOB would appear to be 0. Then 180 degrees from that would be the bearing indicating the target (relative) course. By adding your own course and reducing any multiples of 360 degrees you get the true course of the target.

[edit] It is important that your boat is not moving or turning while doing these bearing measurements at fixed intervals.

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

08-11-17, 09:35 PM	#1
Leoz Officer Join Date: Apr 2016 Location: Near The Rockalls Bank Posts: 247 Downloads: 261 Uploads: 0	Determining target's true course Occasionally when you spot a target for the first time and it is coming straight at you or 10 or 15 AOB there of, you can use an easy method to determine the target's true course. If it is for example daytime and you may have to submerge soon or get spotted,...submerge and go to periscope depth. Try to cross the path of the target to where you are visually seeing it at 0 angle on the bow (the bow pointed directly at you). Then on the F5 map... plot that bearing. The opposite of that bearing is the targets true course. Now, at your own time, without being rushed, you can go off to the side of that target track and get accurate position plots based on bearing alone and thus put a stopwatch against it and determine the target speed. One author described this was how Lemp did the SS Athena. I have used this many times in the game as it is low-workload and easy. __________________ Leoz "Auf gefechtsstationen!" NYGM

08-16-17, 08:52 AM	#2
kickswitch Stowaway Posts: n/a Downloads: Uploads:	Interesting Could be useful against a convoy when approaching dead on. Erich Topp and many other U-boat commanders, apparently used to slip into the middle of a convoy on the surface at night and maneuver down the convoy lanes then fire their torpedoes at 90 degrees or less left and right at the passing ships. I imagine if one were to line up a ship first then travel down the lanes you could get its course that way. But then the thought occurs, it depends what technique your using, fast 90 that's useful, judging the AOB by sight maybe not at that point. I dunno? maybe i'll try it and see!

08-17-17, 07:23 AM	#4
kickswitch Stowaway Posts: n/a Downloads: Uploads:	Cool Thanks all will check this method out!

09-20-17, 12:24 PM	#6
derstosstrupp Grey Wolf Join Date: Aug 2008 Posts: 914 Downloads: 490 Uploads: 0	All, Absolutely correct on this one, very effective method and the basis of the tutorial in my sig! From what I can gather from reading German SOPs, I think these procedures closely reflect historical doctrine. Included in my tutorial is also an historical method of determining target speed by timing bearing change also referenced in German period documents. Please check it out and let me know your thoughts! http://www.subsim.com/radioroom/showthread.php?t=229792 __________________ Ask me anything about the Type VII or IX! One-Stop Targeting Shop: https://drive.google.com/drive/folde...WwBt-1vjW28JbO My YT Channel: https://www.youtube.com/channel/UCIJ...9FXbD3S2kgwdPQ Last edited by derstosstrupp; 09-20-17 at 01:02 PM.

09-25-17, 11:15 AM	#7
Pisces Silent Hunter Join Date: Dec 2004 Location: AN9771 Posts: 4,904 Downloads: 304 Uploads: 0	If the target is still far away you could also use this tool with periscope bearings recorded (and the differences between them calculated) to determine what the AOB was at the 1st bearing. Then calculate back that many degrees to the bearing where AOB would appear to be 0. Then 180 degrees from that would be the bearing indicating the target (relative) course. By adding your own course and reducing any multiples of 360 degrees you get the true course of the target. [edit] It is important that your boat is not moving or turning while doing these bearing measurements at fixed intervals. http://www.subsim.com/radioroom/showthread.php?t=147719 Last edited by Pisces; 09-25-17 at 11:28 AM.

08-17-17, 06:30 AM	#3
YellowFin Engineer Join Date: Mar 2017 Posts: 208 Downloads: 56 Uploads: 0	It's called the 0-degree AOB method and is referenced as a SOP in the U.Kdt.Hdb, a tactical manual given to sub commanders by the Kriegsmarine. In fact they recommend it for every attack. 1. Intercept target 2. Get in front of target, keep taking bearings in regular intervalls, distance doesn't matter at this point 3. Cross in front of target. 0° AOB bearing -> true heading on map, and all the bearings now cross the true heading. If you've carefully taken bearings you will have a very exact speed estimate from the map. 4. Attack I almost exclusively use this method, except when I surprise a target somehow I go for a "shot from the hip". Check out my let's play where I demonstrate this method many times. Greetings, and good hunting!