NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Silicon Sea II: Leg 52
From: Dan Hogan
Date: 1999 May 07, 11:37 EDT
From: Dan Hogan
Date: 1999 May 07, 11:37 EDT
Chart(s): Plotting Sheet(s) / Atlas
Passage Planning and
Dead-Reckoning problem Leg 52 050699 Test your knowledge!
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We arrived at Wellington New Zealand on the afternoon of 23/02/1999.
Our planned departure is for Saturday, March 6,1999. We use a departure
point out of Wellington of(41d 30.0'S 175d 00.0'E) for Cape Horn
(56d 04.0'S 67d 15.0'W).
1) What is the Great Circle route initial TC and Dist to Cape Horn?
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Using an increment of 600 mi for Great Circle planning.
2) What is the latitude of the GC vertex (the point closest to the
near
the pole)
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3) What is the Rhumbline TC and Distance to the Cape Horn point?
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A look at the March Pilot Chart of the South Pacific Ocean shows that
the
March iceberg line runs as high as 48dS. The probability of Gales below
50dS
reaches as high as 20 percent. The predominant wind is from a westerly
direction.
Cornell's, World Cruising Routes recommends heading SE east from New
Zealand until Westerly winds are encountered. Then turning for Cape
Horn, staying in the lower latitudes to avoid ice.
Ocean Passages for the World recommends that, from Cook Strait to Cape
Horn, we join the trans ocean route at 170dW. At this point the trans
ocean route lays between 48dS and 51dS and runs east to 100dW then
south west toward Cape Horn.
Taking the available information we plot the following waypoints.
Cook Strait(41d 30.0'S 175d 20.0'E)
Trans Ocean Route Point 1(49d 00.0'S 170d 00.0'W)
Trans Ocean Route Point 2(49d 00.0S 100d 00.0'W)
Cape Horn(56d 04.0'S 67d 15.0'W)
4) What is the TC and Dist. from Cook Strait to Trans Ocean Route
Point 1?
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5) What is the TC and Dist. from Trans Ocean Route Point 1 to
Point 2?
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6) What is the TC and Distance from Trans Ocean Route Point 2 to
Cape Horn?
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7) What is the total distance of this route to Cape Horn?
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8) Assuming an average speed of 9 Knots,how many days is it to
Cape horn?
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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.XXX07; 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@XXX.XXX
John Simmonds- mobi@XXX.XXX
Jim Manzari - manzari@XXX.XXX
Dan Hogan - dhhogan@XXX.XXX
Dan Hogan WA6PBY
dhhogan@XXX.XXX
Catalina 27 "GACHA"
