NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Silicon Sea II: Leg 46
From: Dan Hogan
Date: 1999 Feb 17, 9:46 PM
From: Dan Hogan
Date: 1999 Feb 17, 9:46 PM
Chart(s): Plotting Sheet Route Planning and Dead-Reckoning problem Leg 47 021799 Test your knowledge! ---------------------- ------ ------ -------------------- It is 0830 ZT(Zone Time) on 17/02/1999. We left our mooring just after Sunrise and departed Sydney. We exit the entrance to Port Jackson and take a pair of departure bearings that give a position of (33d 51.2'S 151d 10.2'E). There is a high solid overcast sky. Speed is 8.4Kts. Wind is Force 4 from 175d. Current Set is 185d, Drift is 1.4Kts/Hr. Variation 12dE, Our destination is (40d 50.0'S 174d 00.0'E), a point north of Stephens Island at Cook Strait, New Zealand. 1) Our compass deviation is 2.5dE, what is the Compass Course(CC)/ Course to Steer to our waypoint? -- -------------------------------------------------------------- We maintain our course through out the day. Slowly we begin adjusting to the ships motion and the rolling seas. Two of the crew are seasick. After noon the clouds begin to break up. By that evening the cloud cover is scattered. At 1930ZT we see enough stars to take sights. 2) What is the DR at 1930ZT? -- ------------------------- We take the following sights (as customary use the time of the first sight for plotting): TimeZT Body Hs 19:32:20 Procyon 40d 58.9' 19:33:13 Elnath 27d 28.7' 19:34:10 Miaplacidus 43d 53.6' 3) What is the GMT whole hour and date? -- ------------------------------------ 4) What is our fix position? -- ------------------------- Examine your distance off. Should we make a course correction? If yes/no: 5) What is the new TC to our destination at (40d 50.0'S 174d 00.0'E) -- ------------------------------------------------------------------ 6) What is this NEW Compass Course(CC)/Course to Steer? -- --------------------------------------------------- 7) What should the Speed Made Good(SMG) be on this leg? -- --------------------------------------------------- The wind has picked up and has backed to about 150d. The knotmeter is indicating 9.2 Kts. We estimate that there is approximately 9 Hrs and 22 min between Morning Nautical Twilight(MNT) and the End of Civil Twilight(ECT). 7) What should our DR be at the start of Morning Nautical Twilight(MNT) on 18/02/1998? -- ------------------------------------------------------------------- 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. 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 - psmith@wellspring.us.dg.com John Simmonds- mobi@netconnect.com.au Jim Manzari - manzari@bluewin.ch Dan Hogan - dhhogan@concentric.net Dan Hogan WA6PBY dhhogan@concentric.net Catalina 27 "GACHA" =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=--=-= =-= TO UNSUBSCRIBE, send this message to majordomo@roninhouse.com: =-= =-= navigation =-= =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=--=-=