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Subject: Silicon Sea: Leg 78
From: Dan Hogan (dhhogan@XXX.XXX)
Date: Wed Aug 29 2001 - 09:51:30 EDT
Is there anyone out there that is still interested in the Silicon Sea
navigation cruise. It seems that all the people that post answers/questions
on Silicon Sea are now members of the working group.
If there is no one willing to work/discuss it then there is not much point in
continuing the problems.
*********************Cut Here*********************************
Chart(s): Plotting Sheets
Sight Reduction and
Dead-Reckoning problem Leg 78 082901 Test your knowledge!
---------------------- ------ ------ --------------------
Our last FIX was (03d 20.7'N 080d 27.2'W) on 25/06/2001 @XXX.XXX The
electronic log on the Knotmeter was re-set to 000.0. We are bound for a
Mid-Ocean Point(MOP1) at (030d 00.0'N 110d 00.0'W). It is a turning point
that is recommended by most ocean passage Sailing Guides for a passage from
Panama to Hawaii.
There are high Mares Tails clouds moving in from the Northwest. The
Barometer has fallen slightly. The clouds are increasing. Speed 10.5 Kts, Var
0.0d Dev 1.5dE. Current Drift 0.6 Kts, Set 350d.
1) What is the TC we are on?
What is the Compass Course/Course-to-Steer?
-- -------------------------------------------
At a distance log reading of 116.5 Nmi since our last position FIX
(03d 20.7'N 080d 27.2'W) on 25/06/2001 @ 22:45:23UT we take the following
three sights through openings in the clouds.
Var 3dE Dev 1.5dE
Body UT/GMT Hs
Venus 10:51:10 36d 31.6'
Unknown 10:53:30 31d 53.8' Compass Bearing 276.5d
(Moderately bright)
Fomalhaut 10:57:11 55d 21.7'
2) What is the DR position at the time of the Venus sight?
-- --------------------------------------------------------
3) What is the FIX position?
-- -------------------------
4) What is the name of the unknown body?
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We expect to enter the South Equatorial Counter Current at about 03d 00.0'N
095d 00.0'W.
Var 3dE, Dev 1.5dE. Speed 10.0 Kts. Drift 0.6 Kts, Set 295d.
5) From our last FIX position with the log reading of 116.5 Nmi, what
is the distance the Knot Log should read at (03d 00.0'N 095d 00.0'W)? --
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6) What is the UT/GMT date and time of our Estimated Time of Arrival(ETA)
at the Counter Current Point?
-- ----------------------------------------------------------------------
7) What Compass Course(CC)/Course-to-Steer are we steering?
-- --------------------------------------------------------
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 - Smith_Peter@XXX.XXX
John Simmonds - johnsimmo@XXX.XXX
Tony Cappiello - cappiello@XXX.XXX
Frank Norris - NORRIS_FRANKLIN_H@XXX.XXX
Sam Chan - schan@XXX.XXX
Mike Wescott - wescott_mike@XXX.XXX
Dan Hogan - dhhogan@XXX.XXX
Dan Hogan
dhhogan@XXX.XXX
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