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: Finding Howland Island
    From: Gary LaPook
    Date: 2010 Feb 06, 01:53 -0800

    I'm not sure what eight degree difference you are talking about.
    Clarence Williams was hired by Earhart to do some of the planning for 
    the world flight. Since the original plan was to travel westward he 
    calculated the leg from Howland to Lae with an initial great circle 
    course of 257.3° True. He then applied the variation of 9° East 
    resulting in a Magnetic Course of 248.3°. When they reversed the route 
    they simply subtracted 180° from the prior computations making the 
    inbound course to Howland 68.3°° M, 77.3 T.  My calculations came up 
    with 77.6° T, rounded to 78° T essentially the same result as Williams. 
    The distance is 2222.6 NM, 2556.0  SM, the same as Williams' calculated 
    distance. See attached Williams' documents.
    He used 6° 47' S, 147° 00' E for the location of Lae and 0° 49' N, 176° 
    43' W for Howland. The coordinates for Lae, based on the official 1935 
    Australian chart (New Guinea was administered by Australia at the time) 
    are 6° 48' S, 147° 02' E an insignificant difference from the 
    coordinates used by Williams. See attached chart.
    Williams used 0° 49' N, 176° 43' W for Howland, about 5 nm west of the 
    actual location given in the 1938 Bowditch as 0° 48' N, 176° 38' W. This 
    is what gave rise to the theory that Noonan was aiming for the wrong 
    coordinates, causing him to miss the island. But Williams did his 
    calculations early and the correct location of Howland was determined by 
    the Itasca after Williams had completed his work but well before Earhart 
    departed on the second, eastbound, attempt so these correct coordinates 
    may have been available to Noonan for his approach to Howland. Either 
    way, the error was not great enough to cause them to miss the island.
    I have checked Williams' work and the points that I calculated for the 
    great circle are within two nautical miles of the ones listed by him. My 
    calculations show that the initial GC course from Lae was 79.5° T and 
    the final course was 77.6°  T, a change of less than two degrees. The 
    numbers shown on Williams chart show a greater change of five degrees 
    but his are magnetic courses and the variation changed by about three 
    degrees from Lae to Howland accounting for this difference, see the 
    charts at:
    I have attached a place mark file to take you to Howland on Google Earth.
    The rhumb line course from Lae to Howland is 78.2°  T and the rhumb line 
    distance is 2222.7 NM, only one-tenth of a mile longer than the great 
    circle since the route was along the equator.
    Ted Campbell wrote:
    > On William's Nav guide for this flight he had a course of 68 degrees 
    > from Lae to Howland. How would this 8 degree difference effect your 
    > analysis if AE and FN followed this line?
    > Ted Campbell
    > ----------------------------------------------------------------
    > 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