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## A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

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Silicon Sea SAMPLE Problem
From: Dan Hogan
Date: 2001 Mar 24, 12:22 PM

```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

Cheers
-Dan-
=========================================================================
Chart(s): Plotting Sheet

Sight Reduction and
----------------------     ------  ------   --------------------

Our Last DR position was (49d 40.7'S 62d 20.0'W) on 29/03/1999 @ 1800ZT.
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?
-- --------------------------------------------------------------------

The GMT/UT is 1300.

3)  What is the Zone Time(ZT)
--  -------------------------

4)  What is the Date?
--  -----------------

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'

5)  What is the FIX position?
--  -------------------------

6)  What is the distance to the Rio waypoint?
--  -----------------------------------------

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?
--  -----------------------------------------------

8)  To the nearest minute, based on Q7 data, how many hours are we from
the Rio waypoint?
--  -------------------------------------------------------------------

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.

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!

(On Hold Pending Acknowledgement)

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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