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    Silicon Sea: Leg 62
    From: Dan Hogan
    Date: 2000 Apr 17, 6:34 AM

    Chart(s):Plotting Sheet
    Sight Reduction and
    Dead-Reckoning problem     Leg 62  041700   Test your knowledge!
    ----------------------     ------  ------   --------------------
    Our last fix was (25d 59.7'S  39d 00.3'W) on 04/05/2000 {at} 08:13:11UT.
    We are headed for a Mid-Ocean Point 1(MOP1)(29d 00.0'S 34d 00.0'W)
    where we will turn north toward the Equator. Var. 23dW Dev 2.0dE.
    Current Drift 0.5Kts Set 170d. Speed 10Kts.
    1)  What is the TC and Dist to Mid-Ocean Waypoint MOP1
        (29d 00.0'S 34d 00.0'W)?
    --  --------------------------------------------------
    2)  What is the Compass Course(CC)/Course-to-Steer?
    --  -----------------------------------------------
    At 07:15:12UT the next morning, we take the following Sights:
        Body             Universal Time       Hs
        Antares          08:02:11             35d 57.4'
        Deneb            08:03:00             16d 21.5'
        Altair           08:03:45             51d 03.0'
        Vega             08:04:10             17d 09.2'
        Rigil Kentaurus  08:04:55             24d 50.0'
    3)  What is the Zone Time(ZT) of the start of Morning Nautical Twilight
        (MNT) at the DR position for our Sights?
    --  ------------------------------------------------------------------
    4)  What is the FIX position using the Time of the Antares sight?
    --  -------------------------------------------------------------
    5)  What is the Dist to the turning point at(29d 00.0S 34d 00.0W)?
    --  --------------------------------------------------------------
    Being that we have a good FIX and the current seems favorable, we elect
    to hard for the Equator and our second waypoint, Mid-Ocean Point 2(MOP2)
    (00d 00.0'N 030d 00.0'W).
    Speed 10Kts,Var 25dW Dev 0.0dW. Current Drift 0.5Kts Set 100d.
    6)  What is the TC and Dist to MOP2?
    --  --------------------------------
    7)  What is the Compass Course(CC)/Course-to-Steer to MOP2?
    --  -------------------------------------------------------
    8)  How many hours is it to MOP2, to the nearest minute?
    --  ----------------------------------------------------
    Lat & Lo = XXd XX.X', Date=DD/MM/YY, HE 9 Feet, Index correction
    -2.5', Time hh:mm:ss in UT,unless otherwise stated. Silicon
    Sea II is a 34,000 lb(15.40t) displacement sailing vessel, 48' 3"
    (14.70m) LOA. 39' (12.00m) LWL; Cutter rigged. Can tack to 45d.
    Water Tanks = 220 gal(1000 ltrs). Fuel Tanks = 155 gal(700 ltrs).
    Fuel consumption .675 gal/Hr at 8.5 Kts. DR(Ded-Reckoning)=position
    by sailings, EP(Estimated Position)=DR+current affect. Dist to
    Horizon: Nmi = SQRT HE{at}mtrs x 2.07; Nmi = SQRT HE{at}ft x 1.17.
    PLEASE respond with your results and thinking on these exercises to
    the NAVIGATION list at large. If you have questions or problems, A
    lot of folks on the list are knowledgeable and willing to help. Any
    questions or doubtful areas will be responded to promptly. Let us
    hear from you soon!
    Good Navigating!
       -=The Navigation List Working Group=-
            Peter Smith  - PSmith{at}IMPS0014.US.DG.COM
            John Simmonds- johnsimmo---.com
            Jim Manzari  - manzari{at}bluewin.ch
            Dan Hogan    - dhhogan{at}nav.cnchost.com
    Dan Hogan
    NAV-L Web Page: http://nav.cnchost.com

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