Equations for course and torpedo gyro

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I found these in some notebooks.
To determine ship course:
1. Determine range
2. Determine AOB
3. Find reciprocal to BRG
> if BRG is 0-180 degrees, add 180
> if BRG is 180-360 degrees, subtract 180
4. Add or subtract reciprocal BRG to AOB
> if contact is port, add reciprocal BRG to AOB
> if contact is starboard, subtract reciprocal BRG to AOB
5. Determine Course
> if number from #4 is between 0-360 degrees, this is target course
> if number is > 360 degrees, subtract 360 to get course
> if number is < 0 degrees, add 360 to get course

Torpedo gyro angle:
1. a=sin-1(sin b * Vt/Vs)
where a= offset snapshot bearing
b= AOB
Vt= target speed
Vs= torpdeo speed

sin-1 = arcsine. I cant figure out how to type this but its sine to the negative 1 power.
with that in mind and a little algebra you should be able to determine AOB...

a negative answer would be a port target track and a positive answer would be a stbd track

2. b= sin-1( sin a * Vs/Vt)
it should theoretically work, but how do you determine the offset snapshot bearing?

There has to be another equation to determine AOB.

I think the easiest way right now is to do this....
hold on be right back...

edit: here it is:
http://www.subsim.com/radioroom/showthread.php?t=115512

here is an AOB equation:
http://www.subsim.com/radioroom/showthread.php?t=115547