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Subject: Re: Silicon Sea: Leg 74
From: Dan Hogan (dhhogan@XXX.XXX)
Date: Sun Jun 17 2001 - 09:54:14 EDT
On 16 Jun 2001, at 17:01, Michael Wescott wrote:
> > 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
OK
> > 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
OK
>
> > 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. :-)
Thanks for commenting ;^)
>
> > 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
OK.
>
> > 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
OK
> > 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
OK
> --
> Mike Wescott
> Wescott_Mike@XXX.XXX
Dan Hogan
dhhogan@XXX.XXX
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