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Silicon Sea: Leg 27 Answers
From: Dan Hogan
Date: 1997 May 11, 22:31 EDT
From: Dan Hogan
Date: 1997 May 11, 22:31 EDT
Because of the error in Leg 26 here is a revised correction to Leg 27. The answers are below the revised problem. The only change is marked by a"|". Dan Hogan Yacht GACHA West Covina, CA Catalina 27 dhhogan@XXX.XXX San Pedro, CA *************************************************** Chart(s): redsea6.gif Pilotage and Dead-Reckoning problem Leg 27 050297 Test your knowledge! ---------------------- ------ ------ -------------------- |On 15/06/1996 at 18:37:30 we plotted a course to Djibouti(11d 36.5'N 43d 07.5'E) from Bar el-Mandeb Island(12d 38.1'N 43d 27.5'E). On checking our chart we find that a large Ethiopian headland lies on our route. We need to re-plot our course. We want to stay offshore so we pick a point at (12d 00.0'N 43d 33.9'E). And make the voyage in 2 legs. Var0.0d, Dev4dE. Speed 9Kts. 1) What is the TC and Dist from Bar el-Mandeb to this point? -- --------------------------------------------------------- 2) What is the TC and Dist from the selected point to Djibouti? -- ------------------------------------------------------------ The wind is 270 at Force 4, current is 4Knt@XXX.XXX 3) What is the Compass Course for the first leg? What is the Compass Course for the second leg? -- ---------------------------------------------- 4) What is the total distance to Djibouti from Bar el-Mandeb? -- ---------------------------------------------------------- 5) Using the Speed Made Good(SMG) for each leg what is the Estimated Arrival Time(ETA) time and Date at Djoubiti? -- ----------------------------------------------------------------- As we approach Djibouti we have trouble locating the harbor due to poor visibility. The chart shows the Moucha Islands(11d 43.8'N 42d 14.2'E) North of a jetty(11d 38.4'N 43d 06.8'E) at the entrance to Djibouti Harbor. 6) What is the differeance between the two TC's? Is it practical to sail mid-way between the two TC's? -- ----------------------------------------------------- 7) What form of navigation is practiced as a result of your answer to the second part of Q6 on the second leg into Djibouti? -- --------------------------------------------------------------- 8) We are entering a foriegn country for the first time, as a coutresy what flags should we be flying? -- ---------------------------------------------------------- Note: Lat & Lo = XXd XX.X', Date=DD/MM/YY, HE 8 Feet, Index correction -.2', Time hh:mm:ss in UTC/GMT. Silicon Sea is a medium displacement sailing vessel, 40 Feet LOA. 38 Feet LWL; Cutter rigged. Looks a lot like a Mason. Can tack to 45d. Dist to Horizon: Nmi = SQRT HE@XXX.XXX07; Nmi = SQRT HE@ft x 1.17. Water Tank = 60 gal(Imp.). Fuel Tanks = 90 gal (Imp.). 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 Navgation List Working Group=- Peter Smith - psmith@XXX.XXX Ron Legere - ronald.legere@XXX.XXX Tony Severdia- anthonys@XXX.XXX Wes Muffin - wmurfin@XXX.XXX (Cartographer) John Simmonds- mobi@XXX.XXX Dan Hogan - dhhogan@XXX.XXX *****************************ANSWERS************************************ 1) TC= 170.6 Dist= 38.6 mi 2) TC= 227.9d Dist= 35.1 mi 3) CC First= 184.7d CC Second= 218.2d 4) Dist= 73.7 mi 5) ETA= 08:20:12 Date: 16/06/1996 6) Diff= 000.9' Practical= No 7) DR and Pilotage 8) Flags= "Q" Yellow, Pratique Flag and the Maritime Ensign of the country we are entering. Flown from the starboard spreader. Dan Hogan West Covina, CA dhhogan@XXX.XXX =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=--=-= =-= TO UNSUBSCRIBE, send this message to majordomo@XXX.XXX: =-= =-= navigation =-= =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=--=-=