Angle on the Bow

[sqk7744]

Here's a great real life way to do it via visual sighting:
http://www.subsim.com/radioroom/show...16&postcount=5

* I do enjoy plotting AOB with the protractor more thou

[joegrundman]

Forget that map contact updates nonsense. You are kidding yourself if you think that that is in some way a realistic option. Anyway once you get the hang of dealing with the problem properly you'll be amazed you ever even bothered with map contacts on.

Getting accurate AOB is not so hard, but there are many ways of doing it. Here are some that I use:

Method 1
Small AOBs (up to 20degrees) can be accurately observed visually. If you are looking at the ship head on you see something like this:

I___I___I

The two outer edges represent the port and starboard side, the middle line is the bow.

If the bow is in the middle, the AOB is 0

If it looks like this

I____I__I

Then you have AOB Starboard 10

If this
I_____I_I

You have starboard 15

An accuracy of to the nearest 5 degrees is perfectly enough.

Method 2

For AOBs between 15 and 60, you can use the aspect ratio method outlined by Hitman.

This takes advantage of knowing the ships length, which for some reason was not included in the SH4recog manual, but there are some mods that have restored it.

In this case the aspect ratio is the target ship's length divided by it's height. The observed aspect ratio divided by the known aspect ratio gives the sine of the AOB. This calculation is time consuming at first, but soon becomes easier. You can use a circular slide rule, like one that is on the back side of the Submarine ATtack Course Finder (SACF or ISWAS) to enormously spped up the calculation.

After a short while you get to know the Aspect ratios of many common targets too

Hitman has also produced an as yet unfinished circular whiz wheel that greatly speeds up this technique.

Method 3

Bearing and plot method outlined above. Works well, but is time consuming and has plenty of inaccuracies and requires a large number of peri observations to get a really accurate fix. By the way, building an ISWAS or SACF massively speeds up the process of obtaining AOB from target course and vice versa

Method 4

Constant bearing method. Again using the SACF for the calculation (see my guide in the sig), if you have knowledge of target speed you can calculate AOB and vice versa

Method 5

Matching course and speed will also give you AOB

Method 6

Sonar based target motion analysis can also give AOB

Conclusion

Just as in real life, there were many ways to skin this particluar cat, but they didn't have automatic map updates on.