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FW: Silicon Sea: Leg 79
From: Russell Sher
Date: 2001 Sep 19, 12:26 AM
From: Russell Sher
Date: 2001 Sep 19, 12:26 AM
Here are some answer attempts - any verifications?? My intercepts for Q3 seemed a bit long for some of the sights. Chart(s): Plotting Sheets Sight Reduction and Dead-Reckoning problem Leg 79 091701 Test your knowledge! ---------------------- ------ ------ -------------------- Our last FIX position was (03d 00.00'N 082d 00.0'W) @ 10:51:11UT @ 26/06/2001. We are sailing toward MOP1(03d 00.0'N 110d 00.0'W) where we will turn and head for Hawaii. At a Log distance traveled of 710.5 Nmi from the FIX position. TC 270.0d, Speed 10.0 Kts, we determine that we have entered the Equatorial Counter Current. 1) What is the DR position on entering the Equatorial Counter Current? departure = 710.5 nm, since D lat. = 0. Diff. Long in minutes = 710.5 *cos (3)), so D Long = 11 deg 49.5', so DR long = 093 deg 49'W DR latitude unchanged: so... DR = 03 deg 00'N, 093 deg 49.5'W. -- ------------------------------------------------------------------- On the morning of 30/06/2001 we manage the following sights: Body UT/GMT Hs Fomalhaut 11:53:00 54d 01.8' Deneb 11:55:10 30d 03.8' Altair 11:57:20 27d 35.1' Saturn 11:59:05 23d 17.4' Venus 12:04:11 38d 50.8' 2) What is the DR position at the time of the Fomalhaut sight? -- ----------------------------------------------------------- distance travelled = 10 knots * 97.3 hours = 973.08 nmiles = departure (due west) Diff. long in minutes = 973.08 * cos (3)=971.74' from DR 26/06/2001 D Long = 15 deg 50.3', so DR long = 082 deg 00'W + 16 deg 11.7' = 098 deg 11.7' W DR latitude unchanged: DR = 03 deg 00'N, 098 deg 09'W. 3) What is the position FIX? -- ------------------------- using Navigator Light: Lat: 03�32.2'N Lon: 097�30.5'W Intercepts/Az For each LOP as follows: Fomalhaut: 37.6' Away/Zn = 202 deg Deneb : 4.6 To / Zn = 322 deg Altair : 29.2' Away / Zn = 278 deg Saturn : 50.2' To / Zn = 069 deg Venus : 51.4' To / Zn = 072 deg ----------------------- ********************************************************************** Notice: The information contained in this e-mail (including any attachments) may contain commercially sensitive or confidential information which may be legally privileged and is for the sole use of the intended recipient(s). If you are not, or believe you may not be, the intended recipient, you are hereby notified that any use, dissemination, copying, review, disclosure or action taken in reliance of this e-mail is prohibited and may be unlawful. If you have received this message in error, please notify the sender immediately by reply e-mail and delete all copies of the message. Any views expressed in this message are those of the individual sender unless expressly stated by the sender to be given on behalf of Tellumat (Pty) Ltd. Tellumat (Pty) Ltd disclaims liability for any unauthorised opinion or representation made by the sender on behalf of Tellumat (Pty) Ltd. No warranty is given by Tellumat (Pty) Ltd that the integrity or security of this e-mail (including any attachments) has been maintained through transmission, nor that the communication is free of virus, interception or interference. **********************************************************************