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 ------------------------- ------ ------ -------------------- 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? -- ---------------------------------------------------------- If Silicon Sea's average speed is 7.5 Knots under sail. 2) How many days (to the nearest tenth) is it to Cristobal? -- -------------------------------------------------------- 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? -- ----------------------------------------------------------- 4) What is the Compass Course/Course-to-Steer for the Pass? -- -------------------------------------------------------- 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? -- ----------------------------------------------------------- 6) What is the TC from our departure point to MOP1(12d 30.0'N 70d 00.0'W)? What is the distance? -- --------------------------------------------------------------- Var 13dW, Dev 1.5dE. Current Set 270d, Drift 0.7 Kts. 7) What is the Compass Course(CC)/Course-to-Steer for MOP1? -- -------------------------------------------------------- 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