NavList:
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Silicon Sea: Leg 70
From: Dan Hogan
Date: 2001 Apr 21, 10:22 AM
From: Dan Hogan
Date: 2001 Apr 21, 10:22 AM
Chart(s): Plotting Sheets
Dead-Reckoning & Planning Leg 70 052001 Test your knowledge! problem
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We cleared Customs at Bridgetown, Barbados on 21/05/2001. The Trade winds are
|begining to die down. We start our provisioning and refit of Silicon Sea.
The Skipper begins the navigation planning for the trip to Panama and home.
Direct Passage Plan Waypoints:
Bridgetown 13d 05.5'N 59d 47.4'W
ST Lucia/St Vincent Pass 13d 30.0'N 61d 10.0'W
MOP1(N of Aruba) 12d 30.0'N 70d 00.0'W
Cristobal, Panama 09d 23.0'N 79d 55.0'W
1) What is the total distance in nautical miles to Cristobal?
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If Silicon Sea's average speed is 7.5 Knots under sail.
2) How many days (to the nearest tenth) is it to Cristobal?
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We are headed for our home port of San Pedro, CA. Because going up the
coast of Mexico to California From Panama is a brutal slog into the current
and wind, so we elect go via Hawaii. The best time to cross from
Panama to Hawaii is,from March to May. And the Pacific storms start in
June, we are cutting our time close for the best weather.
The boat is stocked, the compass repaired and swung. All fuel, water and
supplies are topped off (See NOTE Below). After our final checks, we
depart Bridgetown at |Sunrise(SR) 29/5/2001. Speed 8.1 Kts, Var 13dW, Dev
2dW. Current Set 270, Drift 0.7 Kts.
Bridgetown Departure 13d 05.5'N 59d 47.4'W
St. Lucia Is./St. Vincent Is. Pass 13d 30.0'N 61d 10.0'W
3) What is our Zone Time(ZT) ETA at the St. Lucia/St. Vincent
Pass waypoint?
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4) What is the Compass Course/Course-to-Steer for the Pass?
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The navigation is pilotage as we can see several of the Lessor Antilles
islands. The islands highest points are, St. Lucia 959 mtrs(13d 50.1'N
64d 04.0'W); |St. Vincent 1219 mtrs(13d 15.7'N 61d 10.0'W). Var 13dW,
Speed 8.0 Kts. Using a handbearing compass at 18:27:00ZT we take the
following bearings, :
St. Lucia 292.2d
St. Vincent 129.7d
5) What is our Departure point position to the nearest minute?
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6) What is the TC from our departure point to MOP1(12d 30.0'N 70d
00.0'W)?
What is the distance?
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Var 13dW, Dev 1.5dE. Current Set 270d, Drift 0.7 Kts.
7) What is the Compass Course(CC)/Course-to-Steer for MOP1?
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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 - Smith_Peter@EMC.COM
John Simmonds- johnsimmo@dingoblue.net.au
David Weilacher- daveweilacher@earthlink.net
Tony Cappiello- cappiello@kearfott.com
Frank Norris- NORRIS_FRANKLIN_H@LILLY.COM
Dan Hogan - dhhogan@veriomail.com
Dan Hogan WA6PBY
Catalina 27 "GACHA"
dhhogan@verimail.com
Navigation-L List Owner
http://www.wa6pby.com
