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Subject: Silicon Sea II: Leg 54
From: Dan Hogan (dhhogan@XXX.XXX)
Date: Tue Jun 01 1999 - 21:39:33 EDT
Chart(s): Plotting Sheet
Sight Reduction and
Dead-Reckoning problem Leg 54 060299 Test your knowledge!
---------------------- ------ ------ --------------------
TC 96.9d, speed 9.4 Kts, Var 17dE dev 2.0dW., Current Drift 10 Kts/day.
Set 175d. Our last FIX was(41d 59.9'S 178d 00.5'E) on 05/03/1999 @
07:30:00GMT. We are bound for Trans Ocean Point 1(49d 00.0'S 100d
00.0'W), to connect with the sailing route that will carry us across
the Southern Ocean toward Cape Horn.
1) What is the Compass Course(CC)/Course-to-Steer?
-- -----------------------------------------------
Winds are at to Force 6. We have a solid cloud overcast of cumulus
of bad weather. Wind has veered to 195d. Our speed is 10.3 Kts. We
sail under these conditions for 6 days. At 09:01:23GMT we are able
to take a quick sights of two bodies.
2) What is the DR position at 09:01:23GMT mark?
-- ---------------------------------------------
Var 25dE, Dev 2.5dW.
Body GMT Hs
Unknown 05:01:23 14d 53.0' 173.3d Steering Compass bearing
Body of low brightness.
Aldebaran 05:05:06 23d 17'
3) What is the unknown body?
-- -------------------------
4) What is the FIX position?
-- --------------------------
The wind backs to 180d, Force 4. Our Speed is 10.3 Kts. The Pilot Chart
of The South Pacific Ocean for March shows the line of the maximum
extent of Icebergs on our course at about (46d 00.0'S 135d 00.0'W). Var
25dE Dev 2.0dW, Current Drift 9.6 Kts/day, Set 85d.
5) What is our Estimated Time of Arrival(ETA) at this point
In GMT time and date?
In ZT time and date?
-- ---------------------------------------------------------
6) At the time of our position FIX, what is the distance to Trans
Ocean Point 1(49d 00.0'S 170d 00.00'W)?
-- --------------------------------------------------------------
7) At 10.3 Kts how many hours before we reach Trans Ocean Point 1?
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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 UTC/GMT,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- mobi@XXX.XXX
Jim Manzari - manzari@XXX.XXX
Dan Hogan - dhhogan@XXX.XXX
Dan Hogan
dhhogan@XXX.XXX
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