[REL] Radar Training for Nisgeis' 3D TDC and Radar Range Unit UPDATED: 7/31/10

[Roger Dodger]

Originally Posted by I'm goin' down

Are you saying the bearing displayed on the ceiling of the A scope is the true bearing? That appears to be what you mean to say.

If that is the true bearing, I wonder why the periscope view is referred to as the relative bearing. It seems that the periscope view is more accurate (i.e. true) than the true bearing you describe.

If I understand you, it is a good shortcut unless Nisgeis says you are crazy, or something like that.

Ship courses are given in True (Magnetic) bearings. The Periscope gives you the Relative (your bow = 0 degrees) bearings. Radar Bearings are also given in Relative bearings.

If the target bearing is 90 degrees (relative), then the target is 90 degrees to the right (off your bow) from your heading, no matter what your true course is.

When plotting the target's course, use the ruler with the compass open to get a True course. Start your line at your first mark, then continue through the rest. Read the true course right on the compass. You then plot the target's true course into the TDC which should give you the AOB. Your own gyro repeater (ship's compass) will auto update the TDC with your course (true).

If that isn't correct, then someone send me to the boatswain's locker for a pint of realative bearing grease.