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    Re: Silicon Sea: Leg 82
    From: Bill Allan
    Date: 2002 Jan 04, 5:33 AM

    -----Original Message-----
    From  Bill Allan [mailto:ballan{at}golden.net]
    Sent: Sunday, December 02, 2001 9:45 PM
    To: Bill Allan
    Subject: Fw: Silicon Sea: Leg 82
    
    
    > Sight Reduction and
    > Dead-Reckoning problem     Leg 82  120101   Test your knowledge!
    > ----------------------     ------  ------   --------------------
    > Our last position FIX was (11d 29.8'N  132d  29.5'W) 11/07/2001 {at}
    03:40:15UT.
    > We are bound for a landfall at Hawaii(19d 30.0'N  154d 45.0'W). Var 10.0dE
    > Dev 1.0dE; Current Drift 0.7 Kts Set 285d. Speed 9.7 Kts.
    >
    > 1)  What is the Compass Course(CC)/Course-to-Steer for our Hawaiian
    >     landfall point?
    
            CCTS is 280deg
    > --  ---------------------------------------------------------------
    >
    > 2)  Based on the available information, what is the anticipated
    >     Speed Made Good(SMG) to the Hawaii waypoint?
    
            SMG =10.2M
    > --  -----------------------------------------------------------
    >
    > The sky has been overcast for days. we have been unable to get a sight.
    > Var 10.0dE Dev 1.0dE. Speed 10.4 Kts.
    >
    > Since the last FIX(11d 29.8'N  132d 29.5'W) 11/07/2001 {at} 03:40:15UT,
    > navigating only on dead-reckoning having sailed a total of 1170.0 Nmi.
    > We take a SUN LL sight:
    >
    >     DATE          UT/GMT        Hs
    >
    >     15/07/2001    20:10:35      61d 20.6'
    >
    > 3)  What is the DR position?
            L = 18deg 10'
            LO = 151deg 20.4'
    > --  ------------------------
    >
    > 4)  What is the Speed Made Good(SMG) to this DR?
            SMG = 10.4 knots
    >     What is the Compass Course(CCMG) this DR?
            CCMG = 280deg
    > --  ---------------------------------------------------
    >
    > At 01:44:36UT that same day we take another SUN LL sight. Use your plotted
    > True Course(TC) and Speed 10.2 Kts:
    >
    >     Hs 40d 44.1'
    >
    > 5)  What is the Zn bearing of the SUN at the above sight?
            Zn = 282.6deg
    > --  -----------------------------------------------------
    >
    > 6)  What is the RFIX position?
    > --  -------------------------
    >
    > 7)  From our DR position, what is the Distance Off and True direction of
    >     the Running FIX?
    > --  --------------------------------------------------------------------
    >
    > 8)  What is the TC and Distance to the Hawaii landfall point at
    >     (19d 30.0'N  154d 45.0'W) from the FIX?:
    >
    >     You should try at least two of the methods.
    >
            I calculated from our departure fix, rather than the rfix.
    
    >     On a Great Circle?                TC = 293.2deg  Dist = 1371.8M
    >     On a Rhumb Line?
    >     On Mid-Latitude Sailing?  TC = 292.5deg  Dist = 1353.2M
    >     On Mercator Sailing?              TC = 290.4deg  Dist = 1380.1M
    > --  -----------------------------------------------------------
    >
    > 8a) As an aside try calculating from the RFIX to Sydney
    >     (33d 50.0'S  151d 20.0'E).
    > --  ---------------------------------------------------
    >
    > 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(Dead-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
    >         John Simmonds   - johnsimmo{at}dingoblue.net.au
    >         Tony Cappiello  - cappiello{at}kearfott.com
    >         Frank Norris    - NORRIS_FRANKLIN_H{at}LILLY.COM
    >         Sam Chan        - schan{at}socal.rr.com
    >         Mike Wescott    - wescott_mike{at}EMC.COM
    >         Dan Hogan       - dhhogan{at}veriomail.com
    >
    > *****************************ANSWERS LEG 82*******************************
    >
    > 1) CC= 279.7d
    >
    > 2) SMG= 10.4 Kts
    >
    > 3) DR= 18d 17.6'N  151d 17.8'W
    >
    > 4) SMG= 10.8 Kts
    >    CCMG= 280.3d
    >
    > 5) Zn= 282.5d
    >
    > 6) RFIX= 18d 37.2'N  152d 13.6'W
    >
    > 7) DistOff= .2 Nmi
    >    Direction= 187.7d
    >
    > 8) GC= Init.
    >         Course= 290.7d
    >         Dist= 152.5 Nmi
    >    RhumbLine
    >         Course= 290.1d
    >         Dist= 153.3 Nmi
    >    Mid-Latitude
    >         Course= 290.3d
    >         Dist= 152.5 Nmi
    >    Mercator
    >         Course= 290.1d
    >         Dist= 153.4 Nmi
    >
    >
    > Dan Hogan WA6PBY
    > C27 "Gacha"
    > dhhogan{at}verimail.com
    > Nav-L Page: http://www.wa6pby.com
    

       
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