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Subject: Re: Silicon Sea: Leg 72 -NEW
From: Sam Chan (schan@XXX.XXX)
Date: Fri May 25 2001 - 01:47:47 EDT
Dan,
Please check the compass bearings to the unknown bodies. They may be in
error.
Sam
----- Original Message -----
From: "Dan Hogan" <dhhogan@XXX.XXX>
To: <NAVIGATION-L@XXX.XXX>
Sent: Wednesday, May 23, 2001 5:42 PM
Subject: Silicon Sea: Leg 72 -NEW
> This is a TOTAL and complete revision to Leg 72. You can delete the
previous
> issue.
>
> My apologies.
> *************************
> Chart(s): Plotting Sheet
>
> Sight Reduction and Revised
> Dead-Reckoning problem Leg 72 052301 Test your knowledge!
> ---------------------- ------ ------ --------------------
>
> Our Last position FIX was (13d 00.0'N 61d 30.1'W) at 08:50:10UT on
> 30/05/2001. We are bound for a point on chart INT 401 marked as Aruba Gap
> (13d 50.0'N 70d 00.0'W). Aruba Gap provides a favorable westerly current
of
> 1.5 Knts.
>
> We have had overcast skys and have missed some possible sights. The winds
> have been fluky and we have had to tack several times since our last FIX
> position.
>
> Tack 1: CC 333.0d - 04Hrs @XXX.XXX5 Kts - Var 12dW Dev 1dE
> Tack 2: CC 242.0d - 11Hrs @XXX.XXX5dE
> Tack 3: CC 262.0d - 08Hrs @XXX.XXX5dE
> Tack 4: CC 307.0d - 10Hrs @XXX.XXX0dE
>
> 1) What is the DR position at the end of the Tack 4?
> -- -------------------------------------------------
>
> 2) What is the DR position local Zone Time(ZT) and Date?
> What is the DR position GMT/UT time and Date?
> -- -----------------------------------------------------
>
> 3) From the DR position, what is the TC to Aruba Gap
> (13d 50.0'N 70d 00.0'W)?
> -- -------------------------------------------------
>
> Our speed is 8.5 Kts, Var 10dW Dev 1.0dE. Current Drift 0.7 Kts Set 265.0d
>
> 4) What is the Compass Course(CC)/Course-to-Steer for Aruba Gap
> from the DR position?
> -- ------------------------------------------------------------
>
> The following morning the navigator see stars through breaks in the
> clouds. He takes the following sights. Same data as for Q3 & Q4.
>
> Body ZT Hs
>
> UNKNOWN 05:39:00 13d 53.6' (Steering Compass Bearing
351.7d)
> Mars 05:39:11 18d 14.5'
> UNKNOWN 05:40:03 54d 58.9' (Steering Compass Bearing
329.3d)
> Vega 05:41:06 40d 10.3'
> Venus 05:43:33 35d 25.8'
>
> 5) What is the FIX position?
> -- -------------------------
>
> 6) What are the names of the two unknown bodies?
> -- ---------------------------------------------
>
> 7) What is the TC and Distance to the Aruba Gap (13d 50.0'N 70d 00.0'W)
> waypoint from our FIX?
> -- ---------------------------------------------------------------------
>
> 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(Ded-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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