Calculate AOB

[kanolsen]

I need some more help in how I manually calculate AOB by using relative and true bearing and such.

I have read what I can find about the topic, but when I do it in praxis, I doesn't make sense.

Kanolsen

[Abd_von_Mumit]

Have you read Wazzo's manual? It can be found here: http://www.paulwasserman.net/SHIII/
I doubt anyone could make the issue more clear than Wazoo did (thanks Wazoo, you taught me my very valuable lesson!).

[Corsair]

Once you have plotted the target course, use the protractor to measure the AOB. One leg on target course, second leg from target to you sub. The angle is there.

[kanolsen]

I have read it until my eye got sore and red. But still when I calculate it I get it wrong.
To be more specific:
When calculating aob the formula is:
AOB=Target true bearing - target course +- 180 degrees.
To find target true bearing=relative bearing - own bearing.

But What is relative bearing? how do I measure it?
what is the difference between target course and relative bearing, how do I measure them?

thanks for any answer

Kanolsen

[Corsair]

Own bearing is your heading, i.e. the direction you're travelling.

Relative bearing is the position of the target relative to your sub. You get it directly from periscope/UZO/Binos.
TGT in front of you : 0° behind : 180° left : 270° right : 90°
As a help you find these on the inner wheel of the compass and on the bearing overlay at high zoom levels.

Target course is the heading of the target (the direction it travels). You get it by plotting on your map several positions and drawing a line through these successive positions.

If you want to have the speed as well, you plot these positions every 3 mn 15". The distance between 2 plots give the speed. For instance 0.5 km = 5 Knots, 0.6 km = 6 knots and so on... If you use "map contact updates" these will be precise. If not, take more plots to average errors in measuring.

As said above, rather than calculating you can use the protractor tool to read the angle directly.

Hope this helps ;)

[von Zelda]

Once you have plotted the target course, use the protractor to measure the AOB. One leg on target course, second leg from target to you sub. The angle is there.

I find it very difficult to use the angle tool to measure AOB and then go to either the UZO/Periscope view or directly to the Target Data Computer to input AOB. By the time you do this it has changed.

Therefore, the easy way:
1. You should be on an intercept course with target course.
2. On Nav map plot the target course.
3. Go to UZO/Periscope view and put on zero degrees bearing.
4. Then use the angle tool. First point is placed on your course. Second point is placed on the intercept point. Third point is placed on the target course in the direction of its travel.
5. Read the angle, this is the AOB at your intercept point. As long as your course and the target course does not change, this will always be the AOB at the intercept of the two courses. Thus, you have the time to go to the UZO/Periscope view and input the exact angle into the AOB section. Make sure you x out all other information first and don't forget to doubleclick so it is sent to the TDC.
6. Now you can rotate the UZO or Periscope and the exact AOB will automaticaly be updated.

It is also my assumption that as long as the target course remains the same, you can even make minor course changes and these will be reflected automatically by the TDC.

If the target begins to zig-zag, do not change your computed AOB. Change (lower) the target speed. The target may well be traveling at the original computed speed but his relative speed from point A to Point B will be slower. Compute this by time and distance traveled.

Hope this is helpful.

[Corsair]

I find that if I am submerged 2 knots it doesn't have time to change much and anyway don't need to have a 1° precision if you shoot at a normal 500 / 1000 m distance.
Whenever possible, I try to shoot a 90, so I don't even take a measure of the AOB 90% of the time.
In my game also I have sliding TDC dials on the map screen so don't need to change view to enter data. I never use the notepad.

[von Zelda]

I find that if I am submerged 2 knots it doesn't have time to change much and anyway don't need to have a 1° precision if you shoot at a normal 500 / 1000 m distance.
Whenever possible, I try to shoot a 90, so I don't even take a measure of the AOB 90% of the time.

With the method I described above, I've routinely hit fast merchants and warships in excess of 6km with torpedo runs of over 7 minutes. I beg to differ, precision and accuracy does matter.

[Corsair]

I find that if I am submerged 2 knots it doesn't have time to change much and anyway don't need to have a 1° precision if you shoot at a normal 500 / 1000 m distance.
Whenever possible, I try to shoot a 90, so I don't even take a measure of the AOB 90% of the time.
With the method I described above, I've routinely hit fast merchants and warships in excess of 6km with torpedo runs of over 7 minutes. I beg to differ, precision and accuracy does matter.

You're allowed to differ...:D
Now if you're using manual targeting, no WO help and no map contact update, you must be pretty good to measure a precise distance at 6000m (specially if the sea is choppy)... anything above 2000 I am usually off the mark, this is why I shoot close.