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    Silicon Sea: Leg 27 Answers
    From: Dan Hogan
    Date: 1997 May 11, 22:31 EDT

    Because of the error in Leg 26 here is a revised correction to Leg 27. The
    answers are below the revised problem. The only change is marked by a"|".
    Dan Hogan 			Yacht GACHA
        West Covina, CA		Catalina 27
        dhhogan{at}XXX.XXX	San Pedro, CA
    ***************************************************
    Chart(s): redsea6.gif
    Pilotage and
    Dead-Reckoning problem     Leg 27  050297   Test your knowledge!
    ----------------------     ------  ------   --------------------
    |On 15/06/1996 at 18:37:30 we plotted a course to Djibouti(11d 36.5'N
    43d 07.5'E) from Bar el-Mandeb Island(12d 38.1'N  43d 27.5'E). On
    checking our chart we find that a large Ethiopian headland lies on
    our route. We need to re-plot our course. We want to stay offshore
    so we pick a point at (12d 00.0'N  43d 33.9'E). And make the voyage
    in 2 legs. Var0.0d, Dev4dE. Speed 9Kts.
    1)  What is the TC and Dist from Bar el-Mandeb to this point?
    --  ---------------------------------------------------------
    2)  What is the TC and Dist from the selected point to Djibouti?
    --  ------------------------------------------------------------
    The wind is 270 at Force 4, current is 4Knt{at}XXX.XXX
    3)  What is the Compass Course for the first leg?
        What is the Compass Course for the second leg?
    --  ----------------------------------------------
    4)  What is the total distance to Djibouti from Bar el-Mandeb?
    --  ----------------------------------------------------------
    5)  Using the Speed Made Good(SMG) for each leg what is the Estimated
         Arrival Time(ETA) time and Date at Djoubiti?
    --  -----------------------------------------------------------------
    As we approach Djibouti we have trouble locating the harbor due to
    poor visibility. The chart shows the Moucha Islands(11d 43.8'N
    42d 14.2'E) North of a jetty(11d 38.4'N 43d 06.8'E) at the entrance
    to Djibouti Harbor.
    6)  What is the differeance between the two TC's?
        Is it practical to sail mid-way between the two TC's?
    --  -----------------------------------------------------
    7)  What form of navigation is practiced as a result of your answer
        to the second part of Q6 on the second leg into Djibouti?
    --  ---------------------------------------------------------------
    8)  We are entering a foriegn country for the first time, as a
        coutresy what flags should we be flying?
    --  ----------------------------------------------------------
    Note:
    Lat & Lo = XXd XX.X', Date=DD/MM/YY, HE 8 Feet, Index correction -.2', Time
    hh:mm:ss in UTC/GMT. Silicon Sea is a medium displacement sailing vessel, 40
    Feet LOA. 38 Feet LWL; Cutter rigged. Looks a lot like a Mason. Can tack to
    45d. Dist to Horizon: Nmi = SQRT HE{at}XXX.XXX07; Nmi = SQRT HE{at}ft x
    1.17. Water Tank = 60 gal(Imp.). Fuel Tanks = 90 gal (Imp.).
    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 Navgation List Working Group=-
            Peter Smith  - psmith{at}XXX.XXX
            Ron Legere   - ronald.legere{at}XXX.XXX
            Tony Severdia- anthonys{at}XXX.XXX
            Wes Muffin   - wmurfin{at}XXX.XXX (Cartographer)
            John Simmonds- mobi{at}XXX.XXX
            Dan Hogan    - dhhogan{at}XXX.XXX
    
      *****************************ANSWERS************************************
    1) TC= 170.6
       Dist= 38.6 mi
    2) TC= 227.9d
       Dist= 35.1 mi
    3) CC First= 184.7d
       CC Second= 218.2d
    4) Dist= 73.7 mi
    5) ETA= 08:20:12
       Date: 16/06/1996
    6) Diff= 000.9'
       Practical= No
    
    7) DR and Pilotage
    8) Flags= "Q" Yellow, Pratique Flag and the Maritime Ensign of the
       country we are entering. Flown from the starboard spreader.
    Dan Hogan
        West Covina, CA
        dhhogan{at}XXX.XXX
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