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    Silicon Sea: Leg 84
    From: Dan Hogan
    Date: 2002 Oct 2, 06:04 -0700

    Chart(s): Plotting Sheet, Chart INT 504
    
    *NOTE*  Year has been changed to 2002 to provide use of the current
    Nautical Almanac.
    
    Sight Reduction and
    Dead-Reckoning problem     Leg 84  100202   Test your knowledge!
    ----------------------     ------  ------   --------------------
    
    At 09:19:12ZT 16/07/2001 we were at our entry point for Hilo Hawaii
    (19d 44.0'N  155d 04.0'W).
    
    The plan is for a leisurely cruise north through the Hawaiian islands chain.
    A stop at Honolulu to re-supply and refit the boat. With our final
    destination
    being Hanalei Bay, on the island of Kauai. Hanalei Bay is where we will
    jump off for our voyage to San Pedro, CA.
    
    Sitting down with our charts we plot the following passage:
    
        1. Hilo Departure Point(19d 50.0'N  155d 01.0'W)
        2. Alenuihaha Channel Entrance(20d 15.0'N  155d 45.0'W)
        3. Off Maui(20d 30.0'N  156d 25.0'W)
        4. Pailolo Channel Entrance(20d 59.0'N  156d 55.0'W)
        5. Honolulu(21d 16.0'N  157d 53.0'W)
        6. Kaulakahi Channel(22d 15.0'N  159d 25.0'W)
        7. Hanalei Bay(22d 15.0'N  159d 31.0'W)
    
    We spend 5 days at Hilo(19d 50.0'N  155d 01.0'W) then depart. We get a
    departure FIX at 02:27:00Hrs after sunrise on the morning of 21/07/2002.
    
    1)  What is the Zone Time(ZT) of the departure FIX?
    --  -----------------------------------------------
    
    2)  What is the total plotted distance to Hanalei Bay?
    --  --------------------------------------------------
    
    3)  What is the calculated passage time at 9.3 Kts?
    --  -----------------------------------------------
    
    At a DR position of (20d 23.7'N  155d 26.9'W) we try for a Noon Sight.
    TC 324d.
        Sun LL Hs  89d 49.5'
    
    (See NOTE below for HE and IC)
    
    4)  What is the difficulty with this LAN?
    --  --------------------------------------
    
    From the Noon DR position(20d 23.7'N  155d 26.9'W) we change course toward
    the Pailolo Channel Entrance(20d 59.0'N  156d 55.0'W). Near evening Nautical
    Twilight(ENT) we take the following sights. Speed 10 Kts
    
        UT          Body            Hs
        05:30:02    Moon LL         23d 20.5'
        05:34:11    Vega            41d 39.7''
        05:40:00    Altair          21d 57.8'
        05:43:55    Polaris         20d 25.1'
        05:46:20    Regulus         16d 08.0'
    
    
    5)  What is our FIX position?
    --  -------------------------
    
    >All our plotting was to near the center of the channels and bodies of
    water. Speed 10Kts, Current set 275d, Drift 0.9 Kts. Var. 11dE, Dev 0.5dW.
    
    
    6)  What is the Compass Course(CC)/Course-to-Steer for the Pailolo
    >   Channel Entrance(20d 59.0'N  156d 55.0'W) from our FIX position?
    --  ----------------------------------------------------------------
    
    7)  What is the time enroute to the Pailolo Channel Entrance Point
        (20d 59.0'N  156d 55.0'W) from our FIX 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 - anthony.cappiello{at}baesystems.com
            Dan Hogan - dhhogan1{at}---.net
    
    
    Dan Hogan
    dhhogan1---.net
    
    
    

       
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