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Subject: Re: Silicon Sea: Leg 74
From: Michael Wescott (wescott_mike@XXX.XXX)
Date: Sat Jun 16 2001 - 17:01:42 EDT
> Our last Running FIX(13d 37.8'N 68d 10.5'W) 16:30:29UT @XXX.XXX
> We were headed for Aruba Gap(13d 50.0'N 70d 00.0'W).
> On 02/06/2001 @XXX.XXX7 Nmi from our RFIX we made a course
> change at the Aruba Gap (13d 50.0'N 70d 00.0'W) waypoint. Our destination is
> Cristobal, Panama(09d 23.0'N 79d 55.0'W). We are anticipating a transit of the
> Panama Canal.
> Var 8.0dW, Dev 1.0dE . Current Set 275.0d Drift 1.5 Kts. Speed 10.4Kts.
> 1) What is the the TC and Distance from Aruba Gap(13d 50.0'N 70d 00.0'W)
> to Cristobal, Panama(09d 23.0'N 79d 55.0'W)?
> -- ---------------------------------------------------------------------
dLat = 9d23.0' - 13d50.0' = -4d27.0' = -267.0
dLo = -(79d55.0 - 70d00.0') = -9d55.0' = -595'
dep = -595 * cos 12 = 582.0
TC = 270.0 - atan(267/582) = 245.4
> 2) What is the Compass Course(CC)/Course-to-Steer?
> -- -----------------------------------------------
CC = 245.4 + 8.0 - 1.0 = 252.4
Correcting for current (on plotting sheet) gives
course 242.5T or 249.5C
> Since our turn at Aruba Gap(13d 50.0'N 70d 00.0'W)We have been sailing in a
> steady wind and clear skys.
> At 05:16:28ZT @XXX.XXX
> Speed 10.4 Kts, TC 245.5d.
> 3) What is the 05:16:28ZT DR position?
> -- -----------------------------------
We're in the GMT-5 zone centered at 75d W
04-06-2001 10:16:28UT
-02-06-2001 06:46:28UT
======================
2 days 03:30:00 = 51.5 hr
D = 51.5 * 10.4 = 535.6
dLat = 535.6 * cos 245.5 = -222.1 = -3d42.1'
Lat = 13d 50.0'N - 3d 42.1' = 10d 07.9'N
dep = 535.6 * sin 245.5 = -487.4
dLo = -487.4/cos 12 = 498.3' = -8d 18.3'
Lon = 70d 00.0'W + 8d 18.3' = 78d 18.3'W
DR: 10d 07.9'N 78d 18.3'W
> We take the following sights:
> Body UT/GMT Hs
> Fomalhaut 10:17:22 47d 14.7'
> Deneb 10:17:56 51d 52.0'
> Altair 10:18:00 59d 18.2'
Wow! only 4 seconds between sights. :-)
> Vega 10:18:46 37d 34.3'
> Venus 10:19:33 33d 20.0'
> 4) What is the position FIX?
> -- -------------------------
Using NAO sight reduction table and plotting sheet
about
10d 29.0 N 78d 30.5W
> Speed 10.0 Kts. Var 5dW, Dev 1.5dE. Current Set 100.0d Drift 0.7 Kts.
> 5) What is the TC and Distance to Cristobal(09d 23.0'N 79d 55.0'W)
> from the FIX position?
> -- ----------------------------------------------------------------
Using plotting sheet TC = 232 D = 106
> 6) What is the ZT and Date of our ETA at the Cristobal waypoint
> (09d 23.0'N 079d 55.0'W)?
> -- ------------------------------------------------------------
Allowing for current, SOG is about 9.5 which is about
11:03 sailing time. That's 21:21 UT or 16:21 ZT same day
4-Jun-2001
--
Mike Wescott
Wescott_Mike@XXX.XXX
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