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Subject: Re: Silicon Sea problem solving
From: Dan Hogan (dhhogan@XXX.XXX)
Date: Tue Apr 11 2000 - 21:37:18 EDT
Patrick:
If you are going to use the Concise Sight Reduction tables in the Almanac
you can work all the Sight Reduction problems. But you will need something
to work the Dead-Reckoning problems. Either a calculator, a computer
program or "OLD" fashioned Traverse Tables/Trig. Tables
Go to the NAV-L web site and use the menu to get to the download files
there are several Freeware and Shareware computer navigation programs
there. Download 4mulas.zip, it has much good navigation information.
And below for any members interested is the Silicon Sea intro message:
THE CRUISE OF THE SILICON SEA
First problem scheduled for February 3, 1999. The tentative schedule of posts will be
the first and third wednesday of the month.
This portion of the Silicon Sea cruise will start with Leg 46 at Sydney Harbor. It
is scheduled as a preparation leg for the trip to Boston via New Zealand.
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. That's why
we are doing this.
Obviously those doing their navigation the old fashioned way, working for it, will
need a current Nautical Almanac Sight Reduction method. The dates for the problems
will be concurrent with the current (1999) Nautical Almanac. All other information
will be lifted from the DMA Pilot Charts, Jimmy Cornell's World Cruising Routes, and
any documents and charts available within the working group without incurring expense.
This is a navigation exercise, not a simulated voyage.
THE ANTICIPATED ROUTE:
Sydney Harbor, Australia(our current layover point)- Wellington, New Zealand-Cape Horn
-Barbados-Boston(home port). Be aware this is the planned route, STUFF Happens.
NAVIGATION TOOLS:
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.
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.
Anyone who thinks of something I missed post it to the navigation.
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 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@XXX.XXX
Nav-L Web Site: http://nav.cnchost.com
On 11 Apr 2000, at 16:35, Patrick McVey wrote:
> Can I solve the SS nav problems by using ONLY the Nautical Almanac,
> Year 2000? Or do I need to have other books? Because, Mrs.
> One-who-must-be-obeyed watches over my M/C charges at Celestaire
> real close. I got me Cornell's World Cruising Routes earlier this
> year. It helps me understand some why & wherefors about SS's route.
> Thx
> Patrick
>
Dan Hogan
dhhogan@XXX.XXX
NAV-L Web Page: http://nav.cnchost.com
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