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    Silicon Sea II: Leg 57
    From: Dan Hogan
    Date: 1999 Aug 05, 11:17 AM

    OK, here's Leg 57 warts and all.
    Chart(s): Plotting Sheet
    Sight Reduction and
    Dead-Reckoning problem     Leg 57  080599   Test your knowledge!
    ----------------------     ------  ------   --------------------
    The last FIX position was (51d 30.0'S  80d 59.5'W) 24/03/1999 {at}
    00:10:23UT, TC 119.3d, Var 18dE, Dev 2.5dW. Speed 10.3 Kts. Current
    Drift 1.0 Kts Set 115d. The weather has moderated, we have broken
    clouds, and a clear horizon. We are bound for Cape Horn (56d 04.0'S
    67d 15.0'W). We are now using chart INT 20 and the Pilot Chart of The
    South Atlantic, NVPUB 105.
    The following evening after our last FIX we take the following sights:
        Body                UT          Hs
        Moon LL             23:40:01    15d 04.9'
        Rigil Kentaurus     23:41:56    35d 14.8'
        Acrux               23:42:06    48d 40.2'
        Aldebaran           23:43:12    13d 51.6'
        Peacock             23:45:22    22d 24.8'
    1)  What is the DR position at the time of the first sight?
    --  -------------------------------------------------------
    2)  What is the FIX position?
    --  -------------------------
    3)  What was the Speed Made Good(SMG) between fixes?
    --  ------------------------------------------------
    Var 19dE, Dev 2.5dW. Speed 10.3Kts, Current 0.8 Kts, Set 115.0d.
    4)  What is the Zone Time(ZT) and Date Expected Time of Arrival(ETA)
        to abeam of Cape Horn?
    --  --------------------------------------------------------------
    5)  What is the distance to Cape Horn from our FIX?
    --  -----------------------------------------------
    6)  What is the Compass Course(CC)/Course-to-Steer for Cape Horn?
    --  -------------------------------------------------------------
    After sighting a dark low gray non-descript island abeam, Cape Horn.
    We break out a bottle of Champagne and celebrate.
    We set a course for a waypoint at(55d 30.0'S  63d.00.0'W). At which time
    we must decide to either turn north up the South Atlantic Ocean west of
    the Falkland Islands or go around outside to the east of them. The
    weather will make our choice at the time. Speed 10.3 Kts, Var 14dE,
    Dev 2.0dW, Current Set 45d, Drift 0.8 Kts/day.
    7)  What is the TC and distance to the decision waypoint?
    --  -----------------------------------------------------
    8)  What is the Compass course(CC)/Course-to-Steer to the waypoint?
    --  ---------------------------------------------------------------
    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 WA6PBY
    Catalina 27 "GACHA"

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