NavList:
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Re: Silicon Sea: Leg 82
From: Bill Allan
Date: 2002 Jan 04, 5:33 AM
From: Bill Allan
Date: 2002 Jan 04, 5:33 AM
-----Original Message----- From Bill Allan [mailto:ballan@golden.net] Sent: Sunday, December 02, 2001 9:45 PM To: Bill Allan Subject: Fw: Silicon Sea: Leg 82 > Sight Reduction and > Dead-Reckoning problem Leg 82 120101 Test your knowledge! > ---------------------- ------ ------ -------------------- > Our last position FIX was (11d 29.8'N 132d 29.5'W) 11/07/2001 @ 03:40:15UT. > We are bound for a landfall at Hawaii(19d 30.0'N 154d 45.0'W). Var 10.0dE > Dev 1.0dE; Current Drift 0.7 Kts Set 285d. Speed 9.7 Kts. > > 1) What is the Compass Course(CC)/Course-to-Steer for our Hawaiian > landfall point? CCTS is 280deg > -- --------------------------------------------------------------- > > 2) Based on the available information, what is the anticipated > Speed Made Good(SMG) to the Hawaii waypoint? SMG =10.2M > -- ----------------------------------------------------------- > > The sky has been overcast for days. we have been unable to get a sight. > Var 10.0dE Dev 1.0dE. Speed 10.4 Kts. > > Since the last FIX(11d 29.8'N 132d 29.5'W) 11/07/2001 @ 03:40:15UT, > navigating only on dead-reckoning having sailed a total of 1170.0 Nmi. > We take a SUN LL sight: > > DATE UT/GMT Hs > > 15/07/2001 20:10:35 61d 20.6' > > 3) What is the DR position? L = 18deg 10' LO = 151deg 20.4' > -- ------------------------ > > 4) What is the Speed Made Good(SMG) to this DR? SMG = 10.4 knots > What is the Compass Course(CCMG) this DR? CCMG = 280deg > -- --------------------------------------------------- > > At 01:44:36UT that same day we take another SUN LL sight. Use your plotted > True Course(TC) and Speed 10.2 Kts: > > Hs 40d 44.1' > > 5) What is the Zn bearing of the SUN at the above sight? Zn = 282.6deg > -- ----------------------------------------------------- > > 6) What is the RFIX position? > -- ------------------------- > > 7) From our DR position, what is the Distance Off and True direction of > the Running FIX? > -- -------------------------------------------------------------------- > > 8) What is the TC and Distance to the Hawaii landfall point at > (19d 30.0'N 154d 45.0'W) from the FIX?: > > You should try at least two of the methods. > I calculated from our departure fix, rather than the rfix. > On a Great Circle? TC = 293.2deg Dist = 1371.8M > On a Rhumb Line? > On Mid-Latitude Sailing? TC = 292.5deg Dist = 1353.2M > On Mercator Sailing? TC = 290.4deg Dist = 1380.1M > -- ----------------------------------------------------------- > > 8a) As an aside try calculating from the RFIX to Sydney > (33d 50.0'S 151d 20.0'E). > -- --------------------------------------------------- > > 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(Dead-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 > Tony Cappiello - cappiello@kearfott.com > Frank Norris - NORRIS_FRANKLIN_H@LILLY.COM > Sam Chan - schan@socal.rr.com > Mike Wescott - wescott_mike@EMC.COM > Dan Hogan - dhhogan@veriomail.com > > *****************************ANSWERS LEG 82******************************* > > 1) CC= 279.7d > > 2) SMG= 10.4 Kts > > 3) DR= 18d 17.6'N 151d 17.8'W > > 4) SMG= 10.8 Kts > CCMG= 280.3d > > 5) Zn= 282.5d > > 6) RFIX= 18d 37.2'N 152d 13.6'W > > 7) DistOff= .2 Nmi > Direction= 187.7d > > 8) GC= Init. > Course= 290.7d > Dist= 152.5 Nmi > RhumbLine > Course= 290.1d > Dist= 153.3 Nmi > Mid-Latitude > Course= 290.3d > Dist= 152.5 Nmi > Mercator > Course= 290.1d > Dist= 153.4 Nmi > > > Dan Hogan WA6PBY > C27 "Gacha" > dhhogan@verimail.com > Nav-L Page: http://www.wa6pby.com