NavList:

   

Reply

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.

gl




Trevor Bell wrote:
>
> Ooooops - it should have been 150d 00m W - thanks George.
>
> Trevor Bell
>
> ----------------------------------------------------------------
> 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
> ----------------------------------------------------------------
>

   

Reply