Welcome to the NavList Message Boards.


A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Add Images & Files
    Silicon Sea: Leg 68
    From: Dan Hogan
    Date: 2000 Aug 07, 10:00 EDT

    Chart(s): Plotting Sheets
    Sight Reduction and
    Dead-Reckoning problem     Leg 68  080700   Test your knowledge!
    ----------------------     ------  ------   --------------------
    Our last position FIX was at (3d 00.0'N  30d 59,9'W @ 12/05/2000 at
    20:30:00UTC). Our last DR position was at a Walker Log reading of 614.4 mi
    (15/05/2000 at 05:30:00ZT @XXX.XXX We are heading for the
    island of Barbados(13d 10.0'N  59d 20.0'W). Speed 10.5Kts, Current
    Set 280.0d, Drift 0.7Kts. Var 19dW. Dev 1.5dE.
    The weather is deteriorating. Mares Tails clouds have changed to Cirrus
    clouds which have been thickening and lowering. The wind is increasing and
    is slowly backing.
    At a Walker Log (which reads a maximum of 999.9) reading of 919.1 mi we
    manage a quick sight of the Sun through a short break in the clouds.
       Body                 UT                              Hs
       Sun LL               10:31:12                66d 10.2'
    Later that evening at a Log reading of 004.2 mi we manage a quick sight of
    an unknown moderately bright Star through a quick break in the clouds.
            Body            Zone Time(ZT)   Hs            Steering Compass Bearing
            Unknown         18:31:12        48d 29.0'     316.0d
    1)  What is the Running FIX(RFIX) position?
    --  ---------------------------------------
    Var 19dW, Dev 1dE. Speed 10.7Kts. Current Set 280d, Drift 0.7Kts.
    2)  What is the Compass Course(CC)/Course-to-Steer for Barbados
        (13d 10.0'N  59d 20.0'W)
    --  ------------------------------------------------------------
    3)  What is the distance to Barbados from our RFIX?
    --  -----------------------------------------------
    The weather has been, scattered showers and a solid overcast. The wind has
    been shifting and un-predictable. We have sailed the following courses
    since our Running FIX. Speed 10.7 Kts.
            TC       DIST       TIME ON COURSE
        333.0d   213.6 mi   20:13:00Hrs
            248.0d   263.9 mi   24:40:00Hrs
            288.0d   192.6 mi   18:00:00Hrs
    4)  What is the DR position at the end of this run?
    --  -----------------------------------------------
    5)  What is the TC and Distance to Barbados(13d 10.0'N  59d 20.0'W)
        from this DR position?
    --  ---------------------------------------------------------------
    6)  What is the UT date at the DR position?
    --  ---------------------------------------
    The highest point on Barbados is Mt. Hillaby 1104 meters.
    |7)  What should the Walker Log read when we are be at the distance
         that the Navigator expects to be able to sight Mt. Hillaby on the
    --  ------------------------------------------------------------------
    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@XXX.XXX
    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  - PSmith@XXX.XXX
            John Simmonds- johnsimmo@XXX.XXX
            Jim Manzari  - manzari@XXX.XXX
            Dan Hogan    - dhhogan@XXX.XXX
    Dan Hogan
    NAV-L Web Page: http://nav.cnchost.com

    Browse Files

    Drop Files


    What is NavList?

    Join NavList

    (please, no nicknames or handles)
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.

    Email Settings

    Posting Code:

    Custom Index

    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site