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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@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@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@XXX.XXX07; Nmi = SQRT HE@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@XXX.XXX
Ron Legere   - ronald.legere@XXX.XXX
Tony Severdia- anthonys@XXX.XXX
Wes Muffin   - wmurfin@XXX.XXX (Cartographer)
John Simmonds- mobi@XXX.XXX
Dan Hogan    - dhhogan@XXX.XXX

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@XXX.XXX
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```
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