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: Question about navigating......
    From: Nels Tomlinson
    Date: 2004 Mar 3, 10:45 -0900

    In general, you're right: you have to know three of the six sides or angles to solve a triangle.
    If we look at this from the perspective of one of the lighthouse keepers, 
    though, it looks different.  He can see the boat on the reciprocal bearing, 
    and draw on his chart a line through his known position and the boat.
    He can then call the keeper of the other lighthouse, get the bearing that 
    fellow observes, and draw a line through that lighthouse and the boat.  He 
    now knows where the boat is.
    If you have the chart on the boat, you can do the same thing, and know exactly 
    where you are.  There's no paradox here: the chart gives you the extra 
    information you needed.
    So, as the problem was stated, the answer you gave is certainly correct.  If 
    you have a chart which correctly shows the positions of the lighthouses (and 
    you've correctly identified them) you know your position.  Without the chart, 
    if you only know the distance between lighthouses, you're still at sea.
    ----- Original Message -----
    From: David Weilacher 
    Date: Wednesday, March 3, 2004 9:44 am
    Subject: Re: Question about navigating......
    > Except for two special cases I think not.
    > Those would be if you knew you formed a right angle from your boat
    > to one tower then the other.
    > ...or if you knew you were equi-distant from both of them.
    > -----Original Message-----
    > From: Rene Schmidt 
    > Sent: Mar 3, 2004 10:18 AM
    > Subject: Question about navigating......
    > Good Morning,
    > I am a new member to this list. Some sailing friends
    > of mine have a little bet that I am hoping some
    > super-navigator can help answer.
    > We are sailing and see two lighthouses in the
    > distance. The distance between the two are known (for
    > example 2 kilometers). We have a compass and we can
    > take a reading of the 2 lighthouses (for example 20
    > degrees off of magnetic north for one, and 50 degrees
    > off of magnetic north for the other).
    > This would be simple to plot to get a position on a
    > map. The question is: is this a mathematically
    > solveable problem?
    > If so, what is the formula?
    > Thanks in advance for your help!
    > Regards,
    > Rene Schmidt
    > __________________________________
    > Do you Yahoo!?
    > Yahoo! Search - Find what you?re looking for faster
    > http://search.yahoo.com
    > Dave Weilacher
    > .US Coast Guard licensed captain
    > .    #889968
    > .ASA instructor evaluator and celestial
    > .    navigation instructor #990800
    > .IBM AS400 RPG contract programmer

    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