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
    Re: DR plotting techniques
    From: Jim Thompson
    Date: 2003 Oct 18, 07:30 -0300

    That's why I like waypoints connected by route lines.  On a longer crossing,
    I watch the tide, wind, compass heading and GPS chartplotter route line.  I
    estimate the heading I need to steer to correct for leeway and current, then
    follow that for a while.  If the GPS trackline starts to fall off the route
    line, then I correct the heading appropriately.  This method allows me to
    stay fairly close to the route line, without having to make large
    corrections.  I end up following a course that approximates the route line
    fairly well.
    
    See this page for some screenshots of the process I follow, which I think is
    a fairly efficient compromise.  In fact I doubt that I could do better if I
    tried to do the formal DR process, including calculating leeway and current
    vectors to derive headings.
    http://jimthompson.net/boating/Steering.htm
    
    Jim Thompson
    jim2{at}jimthompson.net
    www.jimthompson.net
    Outgoing mail scanned by Norton Antivirus
    -----------------------------------------
    
    > -----Original Message-----
    > From: Navigation Mailing List
    > [mailto:NAVIGATION-L{at}LISTSERV.WEBKAHUNA.COM]On Behalf Of George Huxtable
    
    > If the vessel was following a ground-track using GPS, waypoints would be
    > set at A and B, and a straight-line ground track drawn between them. The
    > helmsman would be commanded to steer West of South during the
    > first 6 hours
    > to keep to that track and counteract the tide, and then, later, East of
    > South, to do the same. In the case of a slow vessel, and a hot tide, the
    > attempt to keep to the straight track may even become impossible. But in
    > any case, those Eastings and Westings are quite counterproductive,
    > cancelling each other out, and are made at the expense of the Southing,
    > which in this case is all that matters. Sceptics may find that a simple
    > vector diagram will convince them, but are welcome to argue back if it
    > doesn't.
    
    
    

       
    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