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Chart(s): Plotting Sheet

Sight Reduction and
Dead-Reckoning problem     Leg 90  033104   Test your knowledge!
--------------------------     -------   --------   --------------------

At a DR position of (38d 18.8'N  132d 44.2'W), @ 22:57:11UT 15/09/2002 a
shift
in wind permits us to break off of the tack we are on and set a course for
MOP4(34d 20.0'N  120d 33.0'W) the entrance to the Santa Barbara Channel in
Southern California.

Current Drift 0.6 Kts, Set 170d. Var 15dE, Dev 2.0dW. Speed 10.5 Kts.

1)  What is the CC/Course-to-Steer and the Distance to MOP4
 (34d 20.0'N  120d 33.0')?
--  --------------------------------------------------------

At 15:22:55UT @ 16/09/2002 at DR position (37d 13.7'N  129d 19.3W)) we
manage
a SUN sight.

 SUN LL
    Hs= 11d 32.4'
 GHA = 52d 01.2'  Dec = 02d 32.8'

2)  What is the Azimuth of the SUN?
--  -------------------------------

At 02:11:20UT @ 17/09/2002 we take a sight, of the only body visible through
the clouds:

TC 112.0d, Speed 10.5 Kts, Var 15dE, Dev 2dW.

 MOON LL
    Hs: 15d 38.5'
 GHA = 81d 34.8'  Dec = 23d 07.7'S

3)  What is the DR Position for the MOON sight?
--  -------------------------------------------

4)  What is the Running FIX(RFIX) at the time of the MOON Sight Reduction?
--  ----------------------------------------------------------------------

5)  What is the reliability error of this RFIX? Small or OK.
--  --------------------------------------------------------

Var 14dE, Dev 2.0dW. Current Set 185d, Drift 0.3 Kts. Speed 10 Kts.


6)  What is the CC and Dist to MOP4 (34d 20.0'N  120d 33.0')?
--  ---------------------------------------------------------

As we approach the coast line the weather turns hazy. We are on the look
out for
Mt. Tranquillon, 658 mtrs in height, it is the highest peak near the
entrance to
the Santa Barbara Channel near Pt. Conception.

7)  At what distance should Mt. Tranquillon be visible, weather permitting,
    above the horizon?
--  -----------------------------------------------------------------------


NOTE:
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@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

   

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