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Subject: Silicon Sea: Leg 62
From: Dan Hogan (dhhogan@XXX.XXX)
Date: Mon Apr 17 2000 - 08:34:06 EDT
Chart(s):Plotting Sheet
Sight Reduction and
Dead-Reckoning problem Leg 62 041700 Test your knowledge!
---------------------- ------ ------ --------------------
Our last fix was (25d 59.7'S 39d 00.3'W) on 04/05/2000 @XXX.XXX
We are headed for a Mid-Ocean Point 1(MOP1)(29d 00.0'S 34d 00.0'W)
where we will turn north toward the Equator. Var. 23dW Dev 2.0dE.
Current Drift 0.5Kts Set 170d. Speed 10Kts.
1) What is the TC and Dist to Mid-Ocean Waypoint MOP1
(29d 00.0'S 34d 00.0'W)?
-- --------------------------------------------------
2) What is the Compass Course(CC)/Course-to-Steer?
-- -----------------------------------------------
At 07:15:12UT the next morning, we take the following Sights:
Body Universal Time Hs
Antares 08:02:11 35d 57.4'
Deneb 08:03:00 16d 21.5'
Altair 08:03:45 51d 03.0'
Vega 08:04:10 17d 09.2'
Rigil Kentaurus 08:04:55 24d 50.0'
3) What is the Zone Time(ZT) of the start of Morning Nautical Twilight
(MNT) at the DR position for our Sights?
-- ------------------------------------------------------------------
4) What is the FIX position using the Time of the Antares sight?
-- -------------------------------------------------------------
5) What is the Dist to the turning point at(29d 00.0S 34d 00.0W)?
-- --------------------------------------------------------------
Being that we have a good FIX and the current seems favorable, we elect
to hard for the Equator and our second waypoint, Mid-Ocean Point 2(MOP2)
(00d 00.0'N 030d 00.0'W).
Speed 10Kts,Var 25dW Dev 0.0dW. Current Drift 0.5Kts Set 100d.
6) What is the TC and Dist to MOP2?
-- --------------------------------
7) What is the Compass Course(CC)/Course-to-Steer to MOP2?
-- -------------------------------------------------------
8) How many hours is it to MOP2, to the nearest minute?
-- ----------------------------------------------------
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=-
Peter Smith - PSmith@XXX.XXX
John Simmonds- johnsimmo@XXX.XXX
Jim Manzari - manzari@XXX.XXX
Dan Hogan - dhhogan@XXX.XXX
Dan Hogan
dhhogan@XXX.XXX
NAV-L Web Page: http://nav.cnchost.com
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