# NavList:

## A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

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Re: Bowditch 1995 Table 18
From: Doug Royer
Date: 2005 Feb 2, 16:43 -0800

```"... but is sometimes measured from 0? at the
heading either clockwise or counterclockwise through 180?, when it is
designated right or left."

Jim, I don't know where you got this.Relative bearings are ALWAYS taken from
the head in a counterclockwise(right to left,0 - 360)manner.
There is a reason for this.One ship takeing clockwise bearings and another
takeing c-clockwise bearings is a recipe for disaster.
RBs are always taken/given in the above prescribed format.

Here's a visual aid:

RB + MH = MB
RB + TH = TB

MB - MH = RB
TB - TH = RB

Example navigating a vessel and talking to another over the VHF;
vessel # 1
I'm in position approximate XYZ on a heading of 210 degrees true,14 kts.I
have you relative at 67 degrees,range 9 miles..
Now the 2nd vessel only has to take the recipical of that 67 * relative
bearing and that range and run the bearing line and range on the chart from
it's pos to plot vessel 1's pos.
Kind of dangerous takeing/giving relative bearings any other way due to
misunderstandings.

I worked your question this way:

Course = 002 T.
Bearing 1 = 295 T, so
RB = 293, or 067 to port.
Bearing 2 = 245 T, so
RB = 243, or 117 to port.

```
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