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Subject: Silicon Sea SAMPLE Problem
From: Dan Hogan (dhhogan@XXX.XXX)
Date: Sat Mar 24 2001 - 14:22:07 EST
There have been several requests asking what the Silicon Sea navigation
problems are like. Below is a previous lesson, with the answers.
Please post inquires about Silicon Sea to the list. You Oldbe Silicon Sea
crewmen please respond with your thoughts.
Cheers
-Dan-
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Chart(s): Plotting Sheet
Sight Reduction and
Dead-Reckoning problem Leg 59 |112299 Test your knowledge!
---------------------- ------ ------ --------------------
Our Last DR position was (49d 40.7'S 62d 20.0'W) on 29/03/1999 @XXX.XXX
We have been traveling under a solid overcast for days. TC 29.6d, Speed
10.3Kts, Current 0.8Kts Set 20.0d. Var 19dW Dev 1dW. Log distance is 1648
mi. We are bound for a waypoint at Rio de Janerio, Brazil (30d 00.0'S 48d
00.0'W).
1) What is the DR position?
-- ------------------------
2) Based on the provided information, what is the Compass Course we are
steering?
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The GMT/UT is 1300.
3) What is the Zone Time(ZT)
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4) What is the Date?
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That evening we manage a round of sights.
Body GMT Hs
Venus 21:30:00 14d 43.7'
Rigil kentaurus 21:33:04 13d 31.1'
Achernar 21:35:11 21d 55.4'
Hadar 21:37:02 17d 55.4'
5) What is the FIX position?
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6) What is the distance to the Rio waypoint?
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The current, according to the Pilot Chart, Set is 23d, Drift is 0.8Kts.
Speed 10.3Kts. Var 21dW, Dev 1dW.
7) What is the Compass Course(CC)/Course-to-Steer?
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8) To the nearest minute, based on Q7 data, how many hours are we from
the Rio waypoint?
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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@XXX.XXX
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=-
(On Hold Pending Acknowledgement)
********************ANSWERS Leg 59 (112299)**************
1) DR= 25d 39.3'S 45d 18.2'W
2) CC= 49.0d
|3) ZT= 1000Hrs.
4) Date= 04/04/1999
5) FIX= 24d 21.5'S 42d 55.3'W
6) Dist= 434.5 mi
7) CC= 239.6d
8) Hours= 45h35m54s
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