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    Re: Leg 83
    From: Dan Hogan
    Date: 2002 Sep 24, 06:27 -0700

    On 22 Sep 2002, at 13:52, Peter Fogg wrote:
    
    >  Q1)          navigator (9ft) to horizon      3.51nm
    > Mauna Loa (4169m) to horizon         +133.66 nm
    >       navigator to top ML on horizon    137.2 nm
    OK
    >
    > Q2) First calculate TC along rhumb line from (N18d 37'.2  W152d 13'.6)
    > to (N19d 30'.0  W155d 36'.0)
    >        by MP&MD  285.3d
    >            MP           285.3
    >        PS (ML)        285.4
    >        by plot          285d
    >
    > Then, by plotting, with fast speed and weak contrary current,  I get CMG
    > 286d and SMG 9.3k,
    >        thus TC to steer  284d
    > combined error     E   -11d
    > CC to steer                273d
    RIGHT!
    >
    > Q3) Time Zone at (W150d +/- 7.5d) is West 10 hours, 10 hours behind UT.
    OK
    
    >
    > Q4) traverse from N18d 37'.2   W152d 13'.6    at 290d  for 140 nm.
    >        MP&MD       N19d 25'.3   W154d 32'.5
    >         ML              N19d 25'.1   W154d 32'.0
    >         plot              N19d 24'      W154d 31'.5
    >
    >     elapsed time is 140 nm / SMG 9.3k = 15h 03m 14s
    OK
    
    >
    > Q5) Am a little unsure what is meant to be done here, assume what is
    > needed is the CC to steer from
    >     calculated DR (N19d 25'.3  W154d 32'.5) to DO point (N19d 30'.0
    > W154d 41'.6).
    >     First calculate TC along rhumb line   (distance
    >           MP&MD 298.6d                           9.8 nm
    >             MP       298.5                             9.8
    >          PS(ML)   298.7                             9.8
    >             plot      299.0d                          12.0 nm - from
    > plotted DR)
    >
    >     Then another vector diagram, this time with current setting to the
    > west. TC to steer 300d
    >
    > combined error     E   -11d
    >
    > CC to steer                289d
    >     elapsed time is 9.8 nm / SMG 10.5k = 00h 56m 00s
    Poor structure of question on my part. Desired is the CC to steer for the
    DISTANCE OFF(D.O.) of Cape Kumukahi.
    >
    > Q6) rhumbline calculation for distance from (N19d 30'.0  W154d 41'.6)
    > to (N19d44'.0  W155d 04'.0)
    >     by MP&MD  25.3 nm
    >          MP          25.4
    >          PS (ML)  25.3
    >              plot     25.8
    > There is no information on current for this leg so shall assume speed is
    > 10k.
    > elapsed time is 25.3nm / 10k = 02h 31m 48s
    OK
    
    >
    >
    > Q7)     For the ETA at Hilo add the time for each leg to   01:44:36 UT
    > on 16/07/2001
    >
    > + 15:03:14
    >
    > + 00:56:00
    >
    > + 02:31:48
    >
    > = 20:15:38 UT on 16/07/2001
    >
    > = 10:15:38 ZT on 16/07/2001
    Hmmm. One of us is off. I'll have to recheck mine.
    
    > Notes:
    > MP&MD     Meridional Parts and Meridional Distances
    > MP             Meridional Parts
    > PS (ML)      Plane Sailing (Middle Latitude)
    > As all the distances involved in these rhumb line and traverse
    > calculations are fairly short ones in low latitudes there is little
    > difference between the different calculations.
    
    
    
    Cheers
    -Dan-
    
    
    

       
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