course relative to bearing help ?

[geosub1978]

Originally Posted by flag4

hi hunters

could someone please explain 'course relative to bearing'

if a ship is spotted at 301 degrees, what is the bearing relative to me ?

im watching olc's tutorial and trying to understand the bit where he is plotting the course of the ship, and, he says its 59 degrees relative to his course.

ive treid to work this out on my own and it doesnt add up, coz i know something happens when a ship is moving away from, like, subtracting the 301 from 360 which gives 59. and yet this doent always seem to work.

ive tried it with numerous different courses and i can not get the maths to work - and i have to say its driving me nuts: is there a formula for this ?

ie; when a ship is coming to me and when a ship is moving away.
im very confused...

thanks

OK! Let's make something clear.

It depents on how you BEGIN counting the bearing of the target.

A circle has 360 degrees.

The NORTH direction is always at 000 degrees. TRUE bearings and TRUE coarses are always counted from NORTH. So if target's TRUE bearing is 301, this means that the direction of the target is 301 degrees (counting right) from NORTH. This is indepentend from submarines coarse.

However, if you want to measure the direction of the target relative to your BOW, then you have to regard as 000 the direction your bow points! So if a target's RELATIVE bearing is 301, this means that the direction of the target is 301 degrees (counting right again) from SUBMARINE'S BOW!

So! 301 degrees relative bearing is 301 degrees RIGHT from you coarse.

Your bow can be regarded as the begining of a circle (000 degrees) OR the end of a circle (360 degrees).

If you regard you bow the end of the circle, then if you substruct 301 degrees from the end (360-301=59) you have target's RELATIVE bearing 59 degrees LEFT from your bow!

That's all!