Angle on Bow guide
 

I've put together a quick guide for understanding AOB.

Angle tracking misunderstanding.
 

Hi!

Nice guide, but I think people got trouble with the A.O.B and the angle tracking device.

I use two ways to set the A.O.B :

• With angle Tracking OFF :
  the bearing is at 0, so you can enter the angle between your course and the target course (alpha in the image). Then you turn on angle tracking and the AOB will update based on the periscope or uzo direction.

• With angle tracking ON (or bearing entered manually) :
  Use the angle between the target and the sub (beta in the image).

Most of the time, I use the first one. Correct me if I'm wrong but I have good result so far.

Well, I think people that are getting into this kind of business as a newby do not immediately have a feel for what course the target they encounter has. That would require plotting it first. Not many seem to want to get into that routine. Looking at the way the bow is oriented to their sight of it is more natural. But if you do know the course of the target, and the angle between it and your course, then the direction-feed selector to Off is the easiest way. But you better make sure that number is still valid and the target has not changed course. (due to detection or something else)

This isn't exactly right. Someone on Discord posted a guide to calculating (estimating) AOB for a ship at a known distance and with known length by measuring its apparent length.

That’s very true, you can use aspect ratio to compute it. Divide the target’s length by its height - call it A. Then count horizontal marks and vertical marks in the scope, dividing horizontal by vertical, call it B. Then take the sine of B/A and that’s the AOB. The attached picture is from Hitman’s optics in SH3 and is a visualization of this, great if you can visualize the % of the target showing and mentally turn that reference image in your head to match, reading off AOB on the bottom scale.

Only downside here in WP is regarding height in scope. The real graticle (forget Das Boot) was in mils for the vertical marks, allowing for a finer measurement. With the degrees in ours, there is a large margin for error at longer ranges. May be better to measure range based on apparent length as well in WP (while estimating AOB). I’ve added this calc to my excel file in my sig.:up:

That's true but I am trying to reach people who are puzzled by AOB.

I can see the logic of that, but personally I think it's the wrong end to start at. I don't even bother trying to eyeball AOB myself, I consider it next to impossible to do with any amount of accuracy. If you know (approximate) range, you can determine position and course easily, and once you have the course and position you also have the AOB. Taking into account that range calculation (estimation) is relatively straightforward once you have identified a ship I think it's more newbie-friendly to go that route. There is not much point in having the AOB unless you also manage to get the range, anyway.

Most newcomers I've seen do think that AOB is what the periscope bearing shows when they look at a target. So they think it is what we call relative bearing as seen from own ship. Neal tried to correct that with his document. No matter if you get the target course from the map-plot, or take a visual snapshot of it, you still need to know the correct meaning of the dial. If you don't set the needle to the proper angle concept, then garbage comes out. So Neals intent is very valid. How you use it is another matter.

That, I agree with. I just don't agree that it's best (or even correct) to say, "You have to eyeball AOB". I'd rather emphasize the relation between course and AOB.

Otherwise, good guide!