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    Silicon Sea: Leg 70
    From: Dan Hogan
    Date: 2001 Apr 21, 10:22 AM

    Chart(s): Plotting Sheets
    Dead-Reckoning & Planning     Leg 70  052001   Test your knowledge! problem
    -------------------------     ------  ------   --------------------
    We cleared Customs at Bridgetown, Barbados on 21/05/2001. The Trade winds are
    |begining to die down.  We start our provisioning and refit of Silicon Sea.
    The Skipper begins the navigation planning for the trip to Panama and home.
    Direct Passage Plan Waypoints:
        Bridgetown                  13d 05.5'N  59d 47.4'W
        ST Lucia/St Vincent Pass    13d 30.0'N  61d 10.0'W
        MOP1(N of Aruba)            12d 30.0'N  70d 00.0'W
        Cristobal, Panama           09d 23.0'N  79d 55.0'W
    1)  What is the total distance in nautical miles to Cristobal?
    --  ----------------------------------------------------------
    If Silicon Sea's average speed is 7.5 Knots under sail.
    2)  How many days (to the nearest tenth) is it to Cristobal?
    --  --------------------------------------------------------
    We are headed for our home port of San Pedro, CA. Because going up the
    coast of Mexico to California From Panama is a brutal slog into the current
    and wind, so we elect go via Hawaii. The best time to cross from
    Panama to Hawaii is,from March to May. And the Pacific storms start in
    June, we are cutting our time close for the best weather.
    The boat is stocked, the compass repaired and swung. All fuel, water and
    supplies are topped off (See NOTE Below). After our final checks, we
    depart Bridgetown at |Sunrise(SR) 29/5/2001. Speed 8.1 Kts, Var 13dW, Dev
    2dW. Current Set 270, Drift 0.7 Kts.
        Bridgetown Departure                    13d 05.5'N  59d 47.4'W
        St. Lucia Is./St. Vincent Is. Pass      13d 30.0'N  61d 10.0'W
    3)  What is our Zone Time(ZT) ETA at the St. Lucia/St. Vincent
        Pass waypoint?
    --  -----------------------------------------------------------
    4)  What is the Compass Course/Course-to-Steer for the Pass?
    --  --------------------------------------------------------
    The navigation is pilotage as we can see several of the Lessor Antilles
    islands. The islands highest points are, St. Lucia 959 mtrs(13d 50.1'N
    64d 04.0'W); |St. Vincent 1219 mtrs(13d 15.7'N  61d 10.0'W). Var 13dW,
    Speed 8.0 Kts. Using a handbearing compass at 18:27:00ZT we take the
    following bearings, :
        St. Lucia    292.2d
        St. Vincent  129.7d
    5)  What is our Departure point position to the nearest minute?
    --  -----------------------------------------------------------
    6)  What is the TC from our departure point to MOP1(12d 30.0'N 70d
        What is the distance?
    --  ---------------------------------------------------------------
    Var 13dW, Dev 1.5dE. Current Set 270d, Drift 0.7 Kts.
    7)  What is the Compass Course(CC)/Course-to-Steer for MOP1?
    --  --------------------------------------------------------
    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
            Dan Hogan    -   dhhogan@veriomail.com
    Dan Hogan WA6PBY
    Catalina 27 "GACHA"
    Navigation-L List Owner

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