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Buck & All:

Here is the intro for the Silicon Sea Navigation Cruise.


Dan Hogan WA6PBY
"Gacha" Catalina 27
dhhogan@concentric.net

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

Silicon Sea is an armchair(computer?) circumnavigation excersize.
This version started at Palma de Mallorca, Spain. West about via the
Indian Ocean to Boston. If I live that long ;^)

Below are the original announcements for the cruise. Each problem is
complete in it self, no need to have worked the previous.

The following files are available. Due to roninhouse.com problems
with the FTP site. I can provide them on reqyest, but be patient;
dhhogan@concentric.net


 ALMANAC.ZIP - freeware Nautical Almanac by John Simmonds
 POSPLOT.ZIP - freeware plotting sheet program by Wes Murfin
 SSCHARTS.ZIP - freeware chartletts for the Silicon Sea excersizes.
 SSNAVCRUZ.ZIP - the Silicon Sea navigation excersizes with answers
 				in a separate text file.

 The total set is about 718 Kb.


******************
ANN-1

The Cruise of the Silicon Sea

If you want to join us, do. The only requirement is enthusiasm and
participating in the discussions.

The response for the resumption of the Silicon Sea cruise is
overwhelming! The first problem is just about completed. The plan is
to post it next week or would it be better to wait until after the
Spring Break?

Got caught on my first post. Obviously those doing their navigation
the old fashioned way, working for it, will need an Almanac. This
makes the essential tools, Almanac, Plotting tools, plotting sheet,
and a Sight Reduction method. The dates for the problems will be
concurrent with the Nautical Almanac. All other information will be
lifted from charts and documents available to the working group.

In order to save some time, and make it easier on me, the cruise
will pick up where the old one left off, at Palma de Mallorca in the
Mediterranean. The route is consistent with Pilot Charts for the
time of year (although mine date from 1978).

The Route:

Palma de Mallorca-Isle Horadada Light(departure point)-a point at
the entrance to the Strait of Sicily-Port Said-Transit the Suez
Canal-Transit the Red Sea-Adan(planned stop)-Cape Lueewin-Bass
Strait-Sydney, Australia(planned stop)-Cape
Horn-Barbados-Boston(home port).

Be aware this is the planned route, STUFF Happens.

I have kept the posts sent from those joining the cruise. If I don't
see your participation you will be asked to WALK around Cape Horn.

******************
Ok, time is running out Leg 10 the *FIRST* problem in the cruise of
ronin.com's SV Silicon Sea will be out on 10/05/96.

Newbies, Oldbies, In-between-be's and anyone just plane interested,
join in. The only requirement is PARTICIPATE. If you don't know,
ASK. That's why we are doing this.

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

Again the required tools:

    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) Nautical Almanac for sight reductions and sun problems.
    7) A pair of dividers.
    8) For us lazy souls, a Computer Navigation Program of your
   	   choice.

Anyone who thinks of something I missed post it to the list.
*********************
ANN-2

Below is Dan Hogan's QED plotting for the financially
under-privileged. Blatantly 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 lie 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
0.5d(ie.: 28.5d). For ten miles to the vertical line use 6 lines;
for 5 miles to the line use 12 vertical lines. Where the angled line
crosses your 6th 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 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.
*********************************


The programs are currently unavailable from FTP roninhouse.com. If
you use an ftp program or some other web browser you may need a
program to view and print gif coded files. Freeware viewer programs
for Windows are available at http://www.winfile.com. Contact
dhhogan@concentric.net for Email copies that will be ZIPPED and
UUENCODED to you. But be patient.

CHARTLETTS
There are30 Silicon Sea chart files. They cover harbors, headlands
and coasts included in the problems. They cover the Mediterranean
Sea, Malta to Port Said. The Red Sea, Port Said to Djibouti. The
Indian Ocean Djuboiti,Maldive Islands,Cape Leeuwin to Sydney.


These are minimal charts with not much more than a coast
outline and a lat-long grid.  They are all derived from the Map
Viewer program at Xerox PARC, http://pubweb.parc.xerox.map, with
place names from assorted atlases and encyclopedias.  I don't have
any access to the detailed information usually found in navigation
charts and these might better be called "chartlettes".  They are
still useful for providing some geographic orientation for the
Silicon Sea cruise and if printed can be used as plotting sheets.

PLOTTING
For plotting you will need a course plotter or some device
for measuring angles.  Each chart has part of the latitude scale
graduated for measuring distance.  You need to construct a scale for
measuring longitude but this is easy to do using the method outlined
in Bowditch in the emergency navigation section.  You can probably
get an accuracy of about 2 nautical miles.

There is also a Windows program to generate and print position
plotting sheets, posplot.zip at ftp://ftp.ronin.com/incoming.
These sheets include a compass rose and are specific for each
latitude. Even with the occasional jagged line of computer graphics
they should allow an accuracy equivalent to universal plotting
sheets.






Dan Hogan
dhhogan@concentric.net
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