Welcome to the NavList Message Boards.


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

Compose Your Message

Add Images & Files
    Relative bearings
    From: Bill B
    Date: 2015 Apr 14, 14:34 -0700

    Recently viewed a page at the URL below and it struck me as vague and misleading regarding "relative bearing" and pelorus use:


    I've always regarded relative bearing (RB) as a 0-360d measurement with the bow-end of the lubber line being O. The above article seems to suggest it is always measured 0-180 CW on the starboard side and 0-180 CCW on the starboard side. Also that a pelorus card is always set to 0.

    I consider RB starboard and RB port to be a subset of RB. Borrowing from submariner terminology it makes communications/notations easier for me to use "Angle of the bow" or "AOB" noting port or starboard when necessary.

    My calculations use the following (True bearing = TB, compass = C)

    AOB or RB starboard = RB

    AOB or RB port = 360 - RB

    RB = TB + C

    TB = RB-C

    C = RB - TB

    Add or subtract 360 if less than 0 or greater than 360 respectively.

    Any opinions on standard usage of RB and AOB?

    Browse Files

    Drop Files


    What is NavList?

    Join NavList

    (please, no nicknames or handles)
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.

    Email Settings

    Posting Code:

    Custom Index

    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site