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    Re: Wartime (WW2) navigation
    From: Gary LaPook
    Date: 2010 Feb 01, 02:39 -0800

    This is interesting. The first waypoint, 38° South, 150° West is nowhere 
    near the great circle from Curvier Light to Los Santos which would cross 
    150° West at 32° 34.1' South which is 325.8 NM north of the first 
    waypoint! The great circle crosses 130° West at 25° 18.3' South, 401.7 
    NM north of the second waypoint. The initial great circle course is 
    92.4° and the great circle distance is 6352.1 NM. Using just these two 
    correct waypoints and sailing rhumb lines between the departure, the 
    waypoints and the destination results in a total distance of 6365.4 NM, 
    making this approximation of the great circle course just 13.3 NM 
    longer. The rhumb line course is 65.9° and the rhumb line distance is 
    6447.0 NM, 94.9 NM longer than the great circle and 81.6 NM longer than 
    the approximation of the great circle.
    The great circle course from Curvier Light to the given first waypoint 
    at 38° South, 150° West is 103.8 and the distance is 1628.7 NM. The 
    rhumb line between these two points is  93.3° and 1637.7 NM. The great 
    circle from this waypoint to Los Santos is 71.5° and 4753.9 NM making a 
    total distance of 6382.6 NM, only 30.5 NM longer than the proper great 
    circle course. ( This stands for the proposition that on long voyages 
    you can deviate significantly off to one side without amassing a large 
    penalty.) This great circle from the given waypoint to Los Santos 
    crosses 130° West at 30° 29.9 South, 90.1 NM north of the given second 
    waypoint. The length of this leg is 1088.0 NM and the course is 65.6°. 
     From there to Los Santos is another 3673.8 NM for a total distance of 
    6390.5 NM
     From the first given waypoint to the second given waypoint the great 
    circle is 75.9° and 1044.2 NM and the rhumb line is 69.9° and 1046 NM.  
     From there to Los Santos the great circle is 59.4° and 3712.9 NM and 
    the rhumb lline is 50.4° 3720 NM making the total distance, sailing 
    rhumb lines between all points,  Curvier Light - WP1 - WP2- Los Santos 
    is 6403.7 NM only 38.3 NM longer than sailing rhumb lines approximating 
    the correct great circle track.
    Trevor Bell wrote:
    > Ooooops - it should have been 150d 00m W - thanks George.
    > Trevor Bell
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