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    Silicon Sea: Leg 73
    From: Dan Hogan
    Date: 2001 Jun 07, 7:23 AM

    Chart(s): Plotting Sheets
    Sight Reduction and
    Dead-Reckoning problem     Leg 73  060701   Test your knowledge!
    ----------------------     ------  ------   --------------------
    We are bound for a waypoint North of Aruba called Aruba Gap(13d 50.0'N
    70d 00.0'W).Our last position FIX was (13d 30.0'N 67d 00.0'W) 01/06/2001
    @ 09:39:00UT. Speed 9.5 Kts Var 10dW Dev 1dE. Current Drift 0.7 Kts,
    Set 275.0d.
    1)  What is the Compass Course/Course-to-Steer for Aruba Gap(13d 50.0'N
        70d 00.0'W)?
    --  -------------------------------------------------------------------
    At 14:30:22UT the same day. We take an Sight of the SUN LL. Hs 60d 54.0'.
    Speed 9.5 Kts, TC 276.5d.
    2)  What is the DR position at the time of the 14:30:22UT sight?
    --  ------------------------------------------------------------
    We continue sailing and prepare for a Noon sight which according to the
    Nautical Almanac occurs at 11:58:00LMT.
    3) What is the estimated Zone Time(ZT) of our Local Meridian Passage?
       Only required to the nearest whole minute.
    -- -------------------------------------------------------------------
    Ten minutes before LAN we are on deck and prepare for a Noon Sight.
    SUN LL Hs 81d 16.3'.
    4)  What is the Noon latitude?
    --  --------------------------
    Using the morning Sun sight at 09:30:22ZT and the Noon LAN work a
    RunningFIX(RFIX) to the Noon sight.
    5) What is the Running FIX(RFIX) position?
    -- ---------------------------------------
    Speed 9.5Kts, Var 9dW, Dev 1.0dE. Current Set 270.0d Drift 1.0Kts.
    6) What is the Estimated Zone Time of Arrival(ETA) at Aruba Gap
       (13d 50.0'N  70d 00.0'W):
       ZT time and date?
       UT time and date?
    -- ------------------------------------------------------------
    We will change our heading when the elapsed time and distance on the
    Knotmeter log indicate that we are at the Aruba Gap(13d 50.0'N 70d 00.0'W)
    7)  What is the TC, Compass Course(CC)/Course-to-Steer, and distance from
        the RFIX to Aruba Gap?
    --  ----------------------------------------------------------------------
    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@mtrs x 2.07; Nmi = SQRT HE@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     - Smith_Peter@EMC.COM
            John Simmonds   - johnsimmo@dingoblue.net.au
            David Weilacher - daveweilacher@earthlink.net
            Tony Cappiello  - cappiello@kearfott.com
            Frank Norris    - NORRIS_FRANKLIN_H@LILLY.COM
            Sam Chan        - schan@socal.rr.com
            Dan Hogan       - dhhogan@veriomail.com
    Dan Hogan WA6PBY
    C27 "Gacha"
    Nav-L Page: http://www.wa6pby.com
    Catalina 27 "GACHA"

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