NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Silicon Sea: Leg 65
From: Dan Hogan
Date: 2000 Jun 01, 2:26 PM
From: Dan Hogan
Date: 2000 Jun 01, 2:26 PM
Chart(s): Plotting Sheet
Sight Reduction and
Dead-Reckoning problem Leg 65 060100 Test your knowledge!
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On 09/05/2000 @ 14:05:13UT, with a Noon Sight(LAN), we had an Estimated
Position of (13d 10.9'S 32d 12.7'W). We are headed for our Mid-Ocean
Waypoint 2(MOP2) (00.00dN 30d 00.0'W) to cross the Equator. TC 009.5d,
Speed 10.5Kts. Var 21dW, Dev 0.0dW. We have logged 504 mi since our Noon
Sight.
1) What is the DR position?
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2) What is the UT Date and Time of our DR at the 504 mi?
What is the Zone Time(ZT)?
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3) What is the celestial event that occurs at about 17:57:00ZT?
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4) What is our DR position at the time of this celestial event?
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Body UT Hs
Moon LL 20:20:05 68d 01.5'
| UNKNOWN 20:21:10 46d 07.5'
Arcturus 20:22:45 18d 02.2'
Spica 20:23:30 33d 43.4'
Miaplacidus 20:24:10 24d 15.2'
Dubhe 20:25:30 22d 28.9'
5) One of the above bodies is unsuitable for a sight. Which
body and Why?
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6) What is the name of the UNKNOWN bright Star half way up from the
horizon bearing 270.0d by the steering compass?
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7) What is our FIX position at the time of the first Sight Reduction?
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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@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 - PSmith@IMPS0014.US.DG.COM
John Simmonds- johnsimmo@bigpond.com
Jim Manzari - manzari@bluewin.ch
Dan Hogan - dhhogan@nav.cnchost.com
Dan Hogan
dhhogan@nav.cnchost.com
NAV-L Web Page: http://nav.cnchost.com
