Welcome to the NavList Message Boards.

NavList:

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

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    or...
       
    Reply
    Bowditch 1995 Table 18
    From: Bill B
    Date: 2005 Feb 2, 01:24 -0500

    Moving forward with "editors that do not know the subject matter"--or maybe
    it is just me--I would like to look at table 18, "Distance of an Object by
    Two Bearings."
    
    My premises:
    
    Bearing is the direction (cardinal angle) between the observer's north and
    the object, true or magnetic.  That being clockwise, 0 to 360 or 0 to
    359.xxx.
    
    Relative bearing is the angle between the bow end of the lubberline and the
    object, clockwise, 0 to 359,xxxd (or 0 to 360d, depending on your religion
    ;-)
    
    Bearing on the Bow is the angle between the bow end of the lubberline and
    the object, clockwise or counterclockwise, from 0-180d.
    
    The 1995 Bowditch, "Explanation of Navigation Tables" states for table 18:
    
    "To determine the distance of an object as a vessel on a steady course
    passes it, observe the difference between the course and two bearings of the
    object....Enter the table with the two differences..."
    
    My example, by the book:
    
    Course 2d true, object and shoreline to port
    First bearing 295d true, difference 293 d
    Second bearing, 245d true, difference 243d
    
    Now I go to the table.  Whoops!  No values greater than 160d for entering
    arguments.  I can understand that we want an reasonable difference in angles
    between two LOP's to obtain an useable running fix; but darn, here we have a
    system that only works on the starboard side of the boat!
    
    Q:
    
    Have I, as is most often the case, missed something?
    
    If not;
    
    A. How should the above sentences read?
    
    B. Given the errors already exposed in recent editions of "American
    Practical Navigator," how does the nautical community send a message to the
    editor/publisher that the lapses are unacceptable?
    
    Bill
    
    
    

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Join NavList

    Name:
    (please, no nicknames or handles)
    Email:
    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:

    Email Settings

    Posting Code:

    Custom Index

    Subject:
    Author:
    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