NavList:

Byron: I have been experimenting with magnetic compass fixes, with some luck
and have used the sextant to best get a good fix. What do you think?
I will also put this on you tube. I am sure someone has used this before?
At sea can be an enjoyable experience and pastime.
Navigation and getting fixes should be fun and part of the sailors, life at sea.
Being good at navigation makes for the complete sailor or skipper.
Most large boats and ships carry on board a magnetic compass and sextant and the skipper
has had training either at a school or from the many books on navigation.
Many skippers have tried to get good magnetic compass fixes only to find poor
and confusion results on the chart. After additional tries the magnetic bearing compass is stored away
the attempted fixing is put on hold, maybe permanently.
If the skipper got what he believes a good fix, he would feel good about the idea and would continue to
navigate and learn more and will demonstrate his ability to his/her friends. This success will carry the skipper on to more navigation goals and success.
Why should one skipper get bad fixes and another get good fixes?
Much is in the incomplete teaching of Navigation by schools and text.
In 1950’s I was an instructor of Navigation at a Navy School at Newport RI.
The classroom students were taught how to taking bearings and plot them for a pin point fix.
The instructor demonstrated in the standard way, by class notes and blackboard.
This simple idea of, taking bearings and plotting, would be understood by the student. But! When they went to sea on training boats with bad compasses, the pin point fixes turned into large triangles. The results were a turnoff to the students.
The novice Navigator or skipper must experience early good results to continue and enjoy navigation.
The magnetic compass can be used with the sextant to get that good fix in an easy technique.
Easy Technique background: “compass to sextant fixes.”
The Magnetic compass has 3 errors, 1.Variation, 2. Deviation (they are compass systematic error.) and 3. Random, (random is an unknown error that causes bad fixes.) If the random error is eliminated or reduced leaving systematic, good fixes will be the results.
The sextant can give the systematic Lines of Position {LOP}
Procedure:
1. Take one magnetic bearing LOP from the closes Navigation Aid correct the compass error for variation and deviation leaving a true bearing.
2. Take a sextant angle between the close navaid & another Navaid and apply the angle to the closes magnetic corrected bearing LOP.
3. Work each sextant angle off each LOP, for 3 or4 LOP’S
4.Plot each LOP for the fix.
Example: The magnetic bearing of the charted War College is 343 corrected “variation” -15W=LOP 328T. See Charted Blue LOP’S Newport RI. chart
Sextant angle “War College and Rose Island LT (RI): 66 degrees/328-66=LOP, RI. 262T
Sextant angle “Rose Island and Fort Adams (FA): 46 degrees/262-46=LOP 216T
The Magnetic Compass and correction plotted in this example was a good fix, the sextant prove useful.
There will be times that the magnetic plus corrections will still leave some doubt, resulting in a triangle.

Doubt resulting in a triangle.
The next example will use a 10 degree error instead of the known
15W. This will introduce a known 5 degree error. The Franklin plotting Technique will be use to find and correct this known error.
Example: The magnetic bearing War College 343 corrected -10W= (WC) LOP 333T. Pink LOP’S
Sextant angle “War College and Rose Island LT: 66 degrees/333-66= (RI) LOP 267T.
Sextant angle “Rose Island and Fort Adams: 46 degrees/267-46= (FA) LOP 221T.
This example left a triangle, the selected fix is the intersection of the two closer Navaids WC&RI.
Place yourself on the fix facing the far Navaid (FA). The far Navaid LOP runs to the left of the fix, and is a west error, correction is a minus. Reminder READ= Right East ADD/Left West subtract.
A bearing of the far Navaid from the fix has a bearing of 216T.
the difference between the far fort Adams original bearing of 221 and 216 is 5 degree.
Subtract 5 degrees to correct each LOP’S will give a great fix and compass error of 15W.
These simple rules can motivate the experience and the novice to enjoy navigation,
and want to learn more. See chart. Green is 1st example & red is 2nd example.

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