AOB question

[tjlegault]

Hi all,
I have a question about figuring the AOB.
Wouldn’t the AOB be the reciprocal of the bearing that your sonar operator gives you for the enemy contact? I read somewhere on the posts the AOB is the bearing (your sub) viewed from the enemy’s vessel. Is that correct? It seems to me that if it is correct then it would be the reciprocal of the bearing given to you by your sonar or radar or lookouts???

I have a problem with determining the AOB. I have watched and use WernerSobe’s fine tutorial and without it I wouldn’t be able to use manual targeting at all. I still seem to get the firing solution wrong a lot more than I would like, so I am looking for some help in that regard. Part of my problem is understanding the results of my firing solution when I check it on the attack map.
I need to figure out how to post a screenshot of my attack map on the forum and ask you seasoned vets out there to critique it for me.
Thanks for any help
TJL

[tomoose]

The AOB is the angle off the bow from the target ship back to your submarine, as you point out. As such, however, it is not the reciprocal of the sonar bearing as the reciprocal of that bearing doesn't take into account the orientation of the ship (i.e. a ship at bearing 110 degrees from the sub can be pointed in any direction of travel but still be 110 degrees from the sub!).
I don't have any graphics handy so I'll try and explain it best I can.

Take two pencils, place one (your sub) on a table in front of you lead pointing directly away from you, let's call that due north (0 degrees). Take the other pencil (a ship)and place it on the table a few inches in front of the first pencil at 90 degrees, lead pointing to the left, so you have a "T" shape formed by the pencils but with a bit of space between them. The ship pencil is at 0 degrees bearing from your sub, but the AOB from the ship pencil is 90 degrees port (the sub is seen at 90 degrees off the port bow of the ship). Now take the second, ship pencil and turn it slightly in place, say 45 degrees counterclockwise so you still have the "T" shape but now the top of the "T" is slanted "/" with the lead pointing down to the left. The bearing of the ship pencil is still 0 degrees from the sub but now the AOB is 45 degrees port (i.e. the sub is seen 45 degrees off the port bow of the ship). You can see how a reciprocal bearing doesn't work as it remains 180 in both cases.

That's probably a lame way of explaining it. I know one of the sub gurus here will dazzle you with a much better explanation or make fun of mine, LOL.

[tjlegault]

Thanks for the reply tomoose,
I figured it couldt be that simple! LOL!
Back to the trial and error (lots of error!) method.
Thanks again!
TJL

[Chock]

You probably know the easiest way to describe AOB is to imagine being on the bridge of the target ship and think what angle you'd have to turn your head to the side in order to see where you sub was. To work it out visually, you could try doing what quite a few sub skippers did in real life, which was to put a ship model on a rotating disk, have someone spin it, and then look at it from some distance through a pair of binoculars the wrong way around and try to guess the angle, after a bit of practice, they'd be pretty good at it. However, if you did this in your back garden, your neighbours would probably try and have you put in a rubber room :rotfl:

:D Chock

[Shyzar]

There is actually a great guide that has instructions on determinig the exact AOB. Here's a link:

http://www.subsim.com/radioroom/showthread.php?t=111998

[tjlegault]

Thanks to all for the replies. I now have plenty of reading material! LOL!
TJL

[jetthelooter]

the best way to get the correct AOB is to take a range and bearing with the scope. wait a bit the longer the better. then take another range and bearing, this plots two marks give a known distance and time between two known points. from those two points you can then use the speed calculation to get the speed of the target and the course. all that together gives the data you need to compute the AOB giving the final part for the PK.

the top dial of the PK represents the course of the target just swing the AOB dial on the right hand set of instruments and keep adjusting until the PK has the course of the target. dont forget to actually send the speed to the PK. then you can start the PK. after starting the PK re-send range and bearing then lower your scope and shoot.

if your sub is moving fast re-check to make sure the course of the target did not affect the PK target course/AOB. if it did just adjust and resend the PK data. the pk can be updated while it is running.

i always like to slow my boat to 1-2 knots or allstop to fire. this reduces the chance of my scope being spotted. whether the game takes this into effect or not i dont know.

the AOB is the last piece of data i put in to the PK. but it relies on accurate range plots. the only purpose of the AOB tool on the right hand side is to determine target course.

in a real plotting crew the captain would take a range and bearing the plot crew would place that mark and keep track of your own sub movement. then they would take a second range and bearing plot. from there they would get two marks they could determine course and speed from and all that would go into the TDC and the PK started. the only part that is kinda fuzzy and unreal is the lack of a plotting crew the game sims that by giving you a button that makes the calculations for you for course and speed. the captain would typically check his own speed estimate with the plotting crew.

the only thing i really dont care for is the fact i cant manually enter a range and bearing as seperate data.

[Keelbuster]

Angle on the Bow is kinda misleading - it took me a while to - it's actually _your_ angle on _their_ bow. When you think of it that way, it's a lot easier. It's basically an indicator of their course.

[howler93]

Although I'm now using Werner Sobe's method for AoB solutions, I was using a ISWAS banjo ? (manual AoB) spin-wheel calculator to determine AoB. Basically you would input your course, the target's course, and the bearing to the target and it would tell you the AoB. It was slightly tedious, but quite accurate and helpful. I don't have the link, but I know you could find it on these forums somewhere. Stick with it...you'll get the hang of it.

Regarding the attack map and checking your solution- I just try to have the sonar line match up with my solution plot, if that makes sense. What's REALLY effective is when you can pop up your periscope, view the target (so that it appears on your attack map), and THEN see if your solution matches. Adjust accordingly.

I don't know if any of this helped, but good luck, and

Good Hunting,
Howler :arrgh!: