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Revised: 06/04/1999


                   THE CRUISE OF THE SILICON SEA

Is a series of navigation problems in the form of a circumnavigation.
         published by the NAVIGATION-L LIST

To join the list send a message with no subject and no signature to:
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The Archived Silicon Sea files and Navigation Programs may be
downloaded from http://nav.cnchost.com. There is NOT an ANONYMOUS FTP
access available at nav.cnchost.com.

The problems consist of voyage planning, Dead Reckoning(DR) and
Celestial Sight Reduction. The first problem is LEG 10, which starts at
Palma de Majorca, Spain. The cruise destination is Boston,
Massachusetts, USA via the Suez Canal, the Southern Ocean and Cape Horn.

Newbies, Oldbies, In-between-be's and anyone just plain interested,
join in. The only requirement is PARTICIPATE. If you don't know, ASK on
the Navigation-L list.

The problems require the Nautical Almanac for the year they were
posted, and a Sight Reduction method. There are several computer
shareware and freeware navigation programs available that will greatly
aid in learning and can be used instead of the Nautical Almanac.

All other information is lifted from the DMA Pilot Charts, Jimmy
Cornell's World Cruising Routes, and any documents and charts available
within the working group without incurring an added expense. This is a
navigation exercise, not a simulated voyage. There may be an occasional
errors in some of the problems, both intentional and accidental. They
are there to stimulate discussion by the list.

As of the above revision date the LEGS (problems) run from Leg 10 to
Leg 51. There is no Leg 45, it was a break in the sequence during a
hiatus by the author of the problems.

The problems are not copy righted. They may be used and modified as
desired. But credit to the Navigation-L list is appreciated.

NAVIGATION TOOLS:

A marine navigation reference book is recommded. Any government
published manual or general navigation text will suffice.

A Navigation Log Book, aka. Spiral Binder, to keep track of your
doings. Believe me it can't be done 100% on a computer.

The minimum tools you will need:

    1) A pencil and ERASER.
    2) Something to draw straight lines with.
    3) Something to layout angles with.
    4) Something to use as a plotting sheet.
    5) Something to calculate trig. formulas with.
    6) A current Nautical Almanac for sight reductions and sun problems.
    7) A pair of dividers.
    8) A Sight Reduction method. (229, 211, spreadsheet, etc. or...
    9) For us lazy souls, a Computer or Calculator Navigation Program
       of your choice.
   10) Plotting Sheets or a piece of paper to make a plotting sheet.

Below is Dan Hogan's QED plotting for the financially under-privliged.
Blatently stolen from Self Contained Celestial Navigation with H.O. 208,
John S. Letcher, 1977, International Marine, ISBN 0-87742-082-3.

****************

Use lined paper, college ruled, Turn the paper 90d, so the lines are
vertical. Ruled lines are used for longitude. Every sixth or twelfth
line is darkened to represent a whole degree of longitude. (depending
on the scale desired).

Lines of latitude are added by construction, starting with the lowest
latitude desired. Whole degrees are 60 miles.

From your lowest Latitude line, at the most R/H longitude line, draw a
line at an angle up from the Latitude of your lowest latitude line plus
a 0.5d(i.e.:28.5d). For ten miles to each vertical line use 6 lines;
for 5 miles to the line use 12 vertical lines. Where the angled line
crosses your 6th and/or 12th line swing an arc until it touches your
R/H vertical longitude line. This is the point of the next latitude
line. Draw a line perpendicular to the longitude across the page.
Repeat the process with each higher latitude (29.5d), etc.

The bottom angle line, where it crosses the the intermediate vertical
longitude lines, is the distance interval. 10 miles each line for 6
line spacing. 5 miles each line for 12 line spacing. This forms a handy
scale of miles or minutes of latitude.

The accuracy is within the tolerance of your #2 pencil point.


Dan Hogan
West Covina, CA
dhhogan@nav.cnchost.com
http://nav.cnchost.com

   

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