Leg 29 -- Departure from Djibouti.


  Cheers,
-- Dan --
*********************************************

Chart(s): redsea6.gif & 51d Lat plotting Sheet

Sight Reduction and 
Dead-Reckoning problem     Leg 29  XXXXXX   Test your knowledge!
----------------------     ------  ------   --------------------

After our loading is completed we swing the compass and find that dev has
changed to 2dW. Var0.0d. On 25/06/1996 at SunRise(SR) we depart Djibouti
(11d 36.5'N  43d 07.5'E) our destination is a Point N of Cape Guardifuai
(12d 10.0'N 50d 45.0'E). This clears us from Cape Guardifuai's lee.
Current 10 Kts, set 32d. Speed 8.5 Kts. The sky is slightly overcast with
Cirro Cumulus. Wind Force 4 @ 130d. 


1)  What is the Zone Time(ZT) of SunRise(SR) on our departure date?
    What is the Zone Description(ZD) we are in?
--  ---------------------------------------------------------------

2)  What is the TC and Dist to Point N Cape Guardifuai(12d 10.0'N
     50d 45.0'E)?
    What is the Compass Course(CC) and Speed Made Good(SMG)?
--  -------------------------------------------------------------

3)  According to our SMG what is our ETA at Point N of Cape Guardifuai
     (12d 10.0'N 50d 45.0'E)?
--  ------------------------------------------------------------------

4)  What is the approximate time of SunSet(SS),+/-5 min, on our course?
--  -------------------------------------------------------------------


5)  What is the expected DR position at the time of SunSet(SS)?
--  -----------------------------------------------------------

Because of the increasing cloud cover and we are in sailing parallel
to land north of Cape Guardifuai we can take only two sights. Use the SS DR.

     GMT             Body            Hs            Zn
     19:10:23        Vega          50d 28.6'      41.0d
     19:13:11        Moon LL       39d 22.0'      248.6d

6)  What is the FIX position of our two body sight?
    What does the main difference between the DR and the Fix suggest?
--  -----------------------------------------------------------------

7)  What is the Compass Course(CC) and SMG from Djibouti to FIX(19:10:23)
    What was the elapsed time?
--  ---------------------------------------------------------------------

8)  What is the TC and Dist from FIX to Point N of Cape Guardifuai
     (12d 10.0'N 50d 45.0'E)?
--  --------------------------------------------------------------

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@mtrs x 2.07; Nmi = SQRT HE@ft x
1.17. Water Tank = 60 gal(Imp.). Fuel Tanks = 90 gal (Imp.). Fuel
consumption .450 gal/Hr at 8.3 Kts.

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@wellspring.us.dg.com
        Ron Legere   - ronald.legere@yale.edu
        Tony Severdia- anthonys@ix.netcom.com
        Wes Muffin   - wmurfin@onslowonline.net (Cartographer)
        John Simmonds- mobi@netconnect.com.au
        Dan Hogan    - dhhogan@lightside.com
        
