NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Silicon Sea SAMPLE Problem
From: Dan Hogan
Date: 2001 Mar 24, 12:22 PM
From: Dan Hogan
Date: 2001 Mar 24, 12:22 PM
There have been several requests asking what the Silicon Sea navigation problems are like. Below is a previous lesson, with the answers. Please post inquires about Silicon Sea to the list. You Oldbe Silicon Sea crewmen please respond with your thoughts. Cheers -Dan- ========================================================================= Chart(s): Plotting Sheet Sight Reduction and Dead-Reckoning problem Leg 59 |112299 Test your knowledge! ---------------------- ------ ------ -------------------- Our Last DR position was (49d 40.7'S 62d 20.0'W) on 29/03/1999 @ 1800ZT. We have been traveling under a solid overcast for days. TC 29.6d, Speed 10.3Kts, Current 0.8Kts Set 20.0d. Var 19dW Dev 1dW. Log distance is 1648 mi. We are bound for a waypoint at Rio de Janerio, Brazil (30d 00.0'S 48d 00.0'W). 1) What is the DR position? -- ------------------------ 2) Based on the provided information, what is the Compass Course we are steering? -- -------------------------------------------------------------------- The GMT/UT is 1300. 3) What is the Zone Time(ZT) -- ------------------------- 4) What is the Date? -- ----------------- That evening we manage a round of sights. Body GMT Hs Venus 21:30:00 14d 43.7' Rigil kentaurus 21:33:04 13d 31.1' Achernar 21:35:11 21d 55.4' Hadar 21:37:02 17d 55.4' 5) What is the FIX position? -- ------------------------- 6) What is the distance to the Rio waypoint? -- ----------------------------------------- The current, according to the Pilot Chart, Set is 23d, Drift is 0.8Kts. Speed 10.3Kts. Var 21dW, Dev 1dW. 7) What is the Compass Course(CC)/Course-to-Steer? -- ----------------------------------------------- 8) To the nearest minute, based on Q7 data, how many hours are we from the Rio waypoint? -- ------------------------------------------------------------------- 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=- (On Hold Pending Acknowledgement) ********************ANSWERS Leg 59 (112299)************** 1) DR= 25d 39.3'S 45d 18.2'W 2) CC= 49.0d |3) ZT= 1000Hrs. 4) Date= 04/04/1999 5) FIX= 24d 21.5'S 42d 55.3'W 6) Dist= 434.5 mi 7) CC= 239.6d 8) Hours= 45h35m54s