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 89 ver. 1.2
    From: Dan Hogan
    Date: 2004 Mar 15, 07:47 -0800

    Leg 89: Ver.1.2
    Ok I think I got it. I also think I forgot how to set up the problems :^(
    Q3- Errr..re-defined(?) the question, and changed the info and Log Distance.
        Corrected Almanac Data for SR.
    Q6- Corrected Date and Time.
    Chart(s): Plotting Sheets
    Sight Reduction and
    Dead-Reckoning problem     Leg 89  XXXXXX   Test your knowledge!
    ----------------------     ------  ------   --------------------
    On 11/09/2002 at 05:10:21UT we had a Running FIX(RFIX) (39d 43.5'N  151d
    Due to movement of the Pacific High. With the resulting wind change we have
    altered our course toward Mid-Ocean Point 3(MOP3) at (37d 00.0'N  130d
    Var 17dE, Dev 2.0dW. Current Drift 0.4 Kts, Set 145d. Speed 10.3 Kts.
    1)  What is the TC and Distance to MOP3(37d 00.0'N  130d 00.0'N)?
    --  ------------------------------------------------------------
    2)  What is the Compass Course(CC)/Course-to-Steer to MOP3?
    --  -------------------------------------------------------
    Due to overcast skys and intermittent rain we are unable to get a FIX for 3
    |until a Log reading of 724.4 Nmi since the Running FIX(RFIX) on 11/09/2002.
    05:10:21UT (39d 43.5'N  151d 59.1'W).
        Var 17dE, Dev 2.0dW. Speed 10.3 Kts, Set 175.0d, Drift 0.4 Kts
    3)   What is the Dead Reckoning(DR) position for the Sight Reduction?
         Use the time of the first SR.
    --   ----------------------------------------------------------------
    |Then we manage to get the following round of morning sights on UT
            UT                              Body                    Hs
            03:30:31        Moon LL                 25d 59.3'
            03:31:00                Polaris                 36d 40.2'
        03:31:12            Vega                    83d 07.8'
            03:31:21                Deneb           59d 28.3'
            03:31:55                Altair                  52d 57.0'
            03:32:55                Antares                 22d 51.9'
    Almanac Data
    |       03:30:31  Moon           GHA = 126d 29.5' Dec = 25d 23.2'S
    |       03:31:00  Polaris        GHA = 007d 46.3' Dec = 89d 16.5'N
        03:31:12  Vega               GHA = 127d 28.3' Dec = 38d 47.4'N
            03:31:21  Deneb          GHA = 096d 22.9' Dec = 15d 17.5'N
            03:31:55  Altair         GHA = 109d 10.8' Dec = 08d 52.5'N
            03:32:15  Antares        GHA = 159d 46.3' Dec = 26d 26.3'S
    4)   What is the FIX position?
    --   -------------------------
    Examining our charts at the time of the FIX, we select a MOP4 off of Point
    Conception, California near the entrance to the Santa Barbara Channel at
    (34d 20.0'N 120d 33.0'W).
    Speed 10.0 Kts. Current Drift 0.6 Kts, Set 170d. Var 15dE, Dev 2.0dW.
    5)  What is the Compass Course(CC)/Course-to-Steer?
    --  -----------------------------------------------
    Speed 10.0 Kts. Current Drift 0.6 Kts, Set 170d. Var 15dE, Dev 2.0dW.
    6)  What is our Estimated Time of Arrival(ETA), Time and Date at MOP4 near
        Santa Barbara Channel MOP4 (34d 20.0'N  120d 33.0'W), UT & ZT?
    --  --------------------------------------------------------------------------
    As we completed plotting our FIX position, the weather picks up and the cloud
    cover increases again. We also run into contrary winds,rain and swells that
    heading our course.
    Var 15dE, Dev 2.0dW.
    We make the following traverses against the wind.
            Compass Course                  Distance
            86.6d                                   45 Nmi
            45.0d                                   55 Nmi
            80.0d                                   75 Nmi
    7)  What is the DR position at the end of the last Tack?
    --  ----------------------------------------------------
    8)  What is the TC and Distance to the entrance to the Santa Barbara Channel
        waypoint(34d 20.0'N  120d 33.0'W) from the last DR position?
    --  ------------------------------------------------------------------------
    Lat & Lo = XXd XX.X', Date=DD/MM/YYYY, 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
            Federico  Rossi - fedeastro.rossi@libero.it
            Dan Hogan - dhhogan1@earthlink.net
    *****************************ANSWERS LEG 89*******************************
    1) TC= 98.9d
       Dist= 1051.2 Nmi
    2) CC= 82.3d
    |3) Date= 14/09/2002
       Time= 03:30:21UT
       DR FIX= 37d 49.8'N  136d 31.7'W
    4) Celestial FIX= 37d 00.0'N  135d 59.9'W
    5) CC= 85.8d
    |6) ETA UT= 07:13:49UT @ 18/09/2002
           ZT= 23:13:48ZTZT @ 17/09/2002
    7) Tack DR= 37d 44.8'N  134d 08.7'W
    8) MOP4 TC= 112.0d
            Dist= 637.9 Nmi

    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