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    Silicon Sea: Leg 86
    From: Dan Hogan
    Date: 2002 Nov 14, 06:23 -0800

    Chart(s): Plotting Sheets
    
    Sight Reduction and
    Dead-Reckoning problem     Leg 86  111402   Test your knowledge!
    ----------------------     ------  ------   --------------------
    
    We took a departure from Hanalei Bay, Kauai, Hawaii(22d 18.0'N  159W 30.0'W)
    at 22:36:40UT 05/09/2002. We are bound for San Pedro, CA. Our course has
    been planned to take us North, above the Pacific High and then turn East
    until we can make for the Southern California coast.
    
    Wind 035d Force 5, Current Set 195d Drift 0.3 Kts. TC 012.3d, Speed 10.3 Kts.
    Var 11dE, Dev 0.5dW. Wave height is 12 feet from the NE period 18 secs.
    
    Our planned Mid-Ocean waypoint 1(MOP1) is 1086.7 Nmi from Hanalei Bay
    (22d 18.0'N  159W 30.0'W).
    
    1)  What is the DR position of our Mid-Ocean Waypoint 1(MOP1)?
    --  ----------------------------------------------------------
    
    We are taking a pounding and getting green water over the bow. So at
    04:00:00UT we alter our 000.0d Compass Course(CC) 20d to port to ease the
    motion.
    
    2)  What is the DR position at 04:00:00UT?
    --  --------------------------------------
    
    3)  What is the new True Course?
    --  ----------------------------
    
    In broken cloud cover on the next morning we take the following sights,
    Procyon is the first sight:
    
        Body            GMT/UT          Hs
    
        Procyon         15:34:00        33d 16.9'
        Betelgeuse      15:35:03        57d 06.8'
        Capella         15:36:01        63d 25.5'
        Polaris         15:37:33        25d 17.8'
        Jupiter         15:38:10        25d 24.2'
        Sirius          15:40:22        32d 55.3'
    
    
    4)  What is the FIX position at 15:34:00UT?
    --  ---------------------------------------
    
    In a solid overcast we continue our True Course(TC) until 07/09/2002
    {at} 20:20:30UT.
    
    5)  What is the DR position  at this time?
    --  --------------------------------------
    
    6)  How many miles have we traveled since our last FIX on 06/09/2002
        (24d 30.1'N  160d 00.0'W)?
    --  ----------------------------------------------------------------
    
    The current and wind have veered to our port quarter. It appears that we
    are north of the Pacific High. So we alter course for our original
    Mid-Ocean Point 1(MOP1).
    
    7)  What is the TC and Distance to MOP1 from our current DR position?
    --  -----------------------------------------------------------------
    
    NOTE:
    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 -  Smith_Peter{at}emc.com
            Mike Wescott - wescott_mike{at}emc.com
            Dave Weilacher - daveweilacher---.net
            Tony Capiello - cappiello_ar---.net
            Richard Berkowitz - richdberko---.com
            Dan Hogan - dhhogan1---.net
    
    
    

       
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