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
    Re: Advance LOP of High Speed Vessel
    From: Greg Rudzinski
    Date: 2012 Nov 8, 18:35 -0800


    There are two ways which I use to advance lines of position.

    1. Advance the assumed position along the vessel heading using time, speed and distance tables or a pocket calculator. From the advance A.P. plot the azimuth and intercept.

    2. Advance the line of position from the course track intersection along the track line to the desired DR position.

    Greg Rudzinski

    [NavList] Advance LOP of High Speed Vessel
    From: Bruce J. Pennino
    Date: 8 Nov 2012 21:12

    I've followed the Trans-Atlantic postings closely. Thank you Kevin and all those working on the CN/ sight data. I realize I don't understand the most correct technique to advance the first LOP on a Universal Plotting Sheet based on DR.

    For example, for a vessel at 17 knots with the first LOP @ about 49 Deg N, and 3 hours between sights, the first LOP must be advanced in parallel fashion 51 NM . If vessel is going true N or S, LOP moves N or S 51 minutes of arc.

    If going true E or W, we know 51 NM is about 77 minutes of arc (at 49 N there is about 39.5 NM/degree of longitude). For DR we plot the new DR ---

    For all other courses, change x and y scales to NM and use vectors? Linear or trig approximation? I just don't seem to find the answer exactly in any of my three CN books. The proper technique is probably there, but I'm not seeing it!

    Thanks in advance.

    NavList message boards and member settings: www.fer3.com/NavList
    Members may optionally receive posts by email.
    To cancel email delivery, send a message to NoMail[at]fer3.com

    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