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Subject: Re: Silicon Sea: Leg 71
From: Sam Chan (schan@XXX.XXX)
Date: Sat May 12 2001 - 00:33:31 EDT
Here is what I have.
Sam Chan
----- Original Message -----
From: "Dan Hogan" <dhhogan@XXX.XXX>
To: <NAVIGATION-L@XXX.XXX>
Sent: Wednesday, May 09, 2001 6:49 AM
Subject: Silicon Sea: Leg 71
> Chart(s): Plotting Sheets
>
> Sight Reduction and
> Dead-Reckoning problem Leg 71 050801 Test your knowledge!
> ---------------------- ------ ------ --------------------
>
> At 18:27:00ZT @XXX.XXX6'N
> 61d 30.1'W) as we passed between the Lessor Antilles islands of St, Lucia
and
> St. Vincent. We are bound for, Mid Ocean Point(MOP1)(12d 30.0'N 70d
00.0'W),
> in water of more than 1000 mtrs North of Aruba. This is to avoid
unfavorable
> currents along the coast.
> Dev 1.5dE, Var 12dW. Speed is 8.7 Kts, Current Drift 0.7Kts, Set 270.0d.
> TC 263.7d.
>
> 1) At the log reading of 89.6Nmi, what is the DR position?
> -- -------------------------------------------------------
Using Mercator sailing, DR is 13d 15.8'N 63d 08.0'W
>
> 2) At the DR position what is the celestial phenomena that is starting
> at this DR Zone Time(ZT)?
> -- -------------------------------------------------------------------
>
For 89.6 nm @XXX.XXX Starting at 291829Q May 2001,
we are at the DR in (1) at 300447Q May 2001. This is near the start of
nautical twlight.
> NOTE: Sextant Index correction is on the arc 1.5d.
>
> We then take the following sights:
>
> Body UT Hs
>
> Fomalhaut 08:50:10 40d 54.7'
> Polaris 08:50:55 13d 17.3'
> Deneb 08:51:05 56d 56.3'
> Mars 08:52:03 25d 35.0'
> Venus 08:53:22 28d 13.8'
> Vega 08:53:45 45d 55.6'
>
> 3) What is the FIX position?
> -- -------------------------
Fix is at 13d 01.4'N 61d 28.8'W.
>
> The navigator has been examining nautical chart INT 400. It shows an area
> labeled the Aruba Gap (13d 50.0'N 70d 00.0'W) with a favorable current of
> 1.15 Kts. He decides to make for this waypoint. Var 12dW, Dev 1dE.
> Current Set 275d Drift 0.8 Kts. Speed 9.3 Kts.
>
> 4) What is the TC and Dist from our FIX to the Aruba Gap
> (13d 50.0'N 70d 00.0'W)
> -- ------------------------------------------------------
Using Mercator sailing, TC = 275.6, D=502.6 NM
>
> 5) What is the Compass Course(CC)/Course-to-Steer for Aruba Gap?
> -- -------------------------------------------------------------
>
Course is 286.6C
> 6) What is the time enroute to Aruba Gap?
> -- --------------------------------------
@XXX.XXX3kts, time enroute is 54h 03m
>
> 7) What is the anticipated Speed Made Good(SMG) to Aruba Gap?
> -- ----------------------------------------------------------
Set of the current is very close to the TC. SMG is 10Kts.
>
> NOTE:
> Lat & Lo = XXd XX.X', Date=DD/MM/YY, HE 9 Feet, Index correction
> -1.5', 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@XXX.XXX
>
> 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@XXX.XXX
> John Simmonds- johnsimmo@XXX.XXX
> David Weilacher- daveweilacher@XXX.XXX
> Tony Cappiello- cappiello@XXX.XXX
> Frank Norris- NORRIS_FRANKLIN_H@XXX.XXX
> Dan Hogan - dhhogan@XXX.XXX
>
>
> Dan Hogan
> dhhogan@XXX.XXX
>
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