Chart(s): Plotting Sheets

Sight Reduction and
Dead-Reckoning problem     Leg 81  101701   Test your knowledge!
----------------------     ------  ------   --------------------

At 13:10:12UT @ 06/07/2001 our DR position was (07d 50.2'N  121d 39.8'W).
We are headed for a Hawaii landfall point at (19d 30.0'N  154d 45.0'W).

The sky has been overcast. Wind has been increasing and we are under a
reefed main. The seas are building and at 13:08:00UT @ 08/07/2001 WWV radio
reports a large storm with gale force winds at (120d 30.0'N  019d 45.0'W)
moving Northwest at 0.5 Kts.

At 14:00:00UT @ 08/07/2001, by log meter, we have traveled a distance of
439.5 Nmi since our last DR position. True Course(TC) 289.9d.

1)  What is the current DR position?
--  --------------------------------

2)  What is the approximate distance and direction to the storm
    (019d 45.0'W  120d 30.0'N) from our DR position at 14:00:00UT @
    08/07/2001?
--  ----------------------------------------------------------------

During the storm, from the time of our DR at 14:00:00UT @ 08/07/2001 we
sail as follows until the end of the storm:

    TIME        TC          SPEED

    6 Hrs       289.9d      9.5Kts
    12 Hrs      278.0d      6.2Kts
    5.5 Hrs     275.0d      4.5Kts
    36 Hrs      270.0d      Hove-To fore reaching at 1.3Kts

3)  What is the DR position at the end of this time?
--  ------------------------------------------------

4)  What is the UT/GMT date and Time?
    What is the Zone Time(ZT) and day?
--  ----------------------------------

5)  What is the TC & Distance from the DR to our Hawaii landfall point at
    (19d 30.0'N  154d 45.0'W)
--  ---------------------------------------------------------------------

From the DR position after the storm we pick up our TC, Speed 10.2Kts.
Var 9.0dE Dev 1.0dE. That same evening we manage the following sights:

    BODY        UT/GMT          Hs

    Mars        03:39:20        33d 51.2'
    Unknown     03:40:15        24d 43.7' 42.0d Compass Bearing. Bright
    Antares     03:46:09        39d 40.0'
    Regulus     03:46:59        30d 15.1'
    Dubhe       03:47:45        29d 20.8'
    Rasalhague  03:48:11        41d 11.3'

6)  What is the unknown body?
--  -------------------------

7)  What is the FIX position at the time of the unknown body?
--  ---------------------------------------------------------

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@mtrs x 2.07; Nmi = SQRT HE@ft x 1.17.

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@EMC.COM
        John Simmonds   - johnsimmo@dingoblue.net.au
        Tony Cappiello  - cappiello@kearfott.com
        Frank Norris    - NORRIS_FRANKLIN_H@LILLY.COM
        Sam Chan        - schan@socal.rr.com
        Mike Wescott    - wescott_mike@EMC.COM
        Dan Hogan       - dhhogan1@earthlink.net


