magnetic field

[cappy]

##read an article this morning which is stating the earths magnetic field is swinging at a very erratic way at this time ...the pull between canada and siberia being won by siberia ...and there is a pssibility that the poles may flip ...whether that is a good or bad scenario i dont know ..perhaps our navigators may through some light on it .....meanwhile back to my daily chores ....cappy

[j.sabourn]

All your charts you used at sea Cappy, and you will know yourself if scrutinised the charts you used when doing your boating for pleasure. Told you what the variation was on that area. They also told you however this error altered on a yearly basis. Variation to a Mariner was to all intents and purposes a fairly steady error. The earth is considered a large magnet with the magnetic lines of force running from the North magnetic pole to the South magnetic pole. Today they will have machines in the various parts of the world to measure this variation in the variation so to speak. Probably has been altering for centuries without anyone knowing , but modern technology enables these things today to become known. John in Oz”s compass adjuster could put more light on the subject. If one gets carried away with the subject one could even bring climate change into the topic. Making that subject even more speculative as would then bring into it the worlds tilt of its axis and its annual passage round the sun.all factual theories for the egg heads to suck their thumbs and say aaahhh but ! Anyone can make a magnet by just rubbing a bar of steel and agitating the molecules. Maybe Santa clause had Rudolph newly shod this year on his return home to the North Pole. Cheers JS

[Keith Tindell]

I am not a professional navigator, but when i was doing my yacht masters, we were taught the phrase, variation east, compass least _ variation west, compass best, so allowing for variation on the chart, made sure you added or subtracted same. I really enjoyed doing my night classes on navigation, and putting it into practice . too easy to just plug in a waypoint into the GPS, and not as much fun, kt

[j.sabourn]

Don’t decry a yacht masters cert. Keith you are as good a navigator as many others. As most know compass error is a combination of deviation and variation. With the compass course you applied the error to obtain the true course and vice versa. I use to remember it by TELC and CERT. True to compass easterly to the left, and Compass to true easterly to the right. If otherwise was the opposite. A simple aid to memory that one never forgets.when taking a compass error if the heavenly body ( apart from Jane Russel) was rising or setting it was called an amplitude. And was a simple working out of the formula Sine Amp = sin dec secant latitude. Some things one never forgets. . Like that fiver that was never paid back. Cheers JS

[Keith Tindell]

The practical side of that course was also very enjoyable, they put me down below on the chart table, switch off all aids , apart from the echo sounder, curtains drawn , so you had then to pick up a depth chart line, work out your height of water above chart datum, and navigate down the Solent, and in to the mouth of the Hamble river, giving course to the helmsman. In lots of ways i wish that i had taken up navigation at sea, but having said that, i did get out at the right time, 1964, kt

[j.sabourn]

There were similar questions in the chartwork paper for second mates , they were called a line of soundings , and had to work out your most probable position by same, most of this was done in the English Channel. Forget the chart number. The navigation papers apart from chartwork, were in all certificates of competency, unlike other subjects, navigation is a very broad subject and got more advanced with each cert. it was of course a failing paper. However it was only a small part of going to sea as compared to other duties of a different persuasion. JS

[Keith Tindell]

I wonder in Future how much will be dropped, with modern radar, gps etc etc ?, will the future seamen not bother with charts and rulers ?. I know for a fact that many small boat sailors, as time goes on, do not bother with navigation classes, reliant on chart plotters and Gps, crazy !!, but the RNLI must see many examples of this, kt

[thomas michael]

I wonder in Future how much will be dropped, with modern radar, gps etc etc ?, will the future seamen not bother with charts and rulers ?. I know for a fact that many small boat sailors, as time goes on, do not bother with navigation classes, reliant on chart plotters and Gps, crazy !!, but the RNLI must see many examples of this, kt

hi keith
like you im a small boat sailor, and I when sailing round the coast in good weather by( pilotage only),i would only put a gps fix on the chart every couple of hours. But a gps or any navigational aids are just that an ( AID ), and on a trip to the isle of man some years ago, I had my first gps so I was putting a gps fix and EP every hour along side just to compare the reliability of the gps, when a couple of miles off the isle of man a thunder bolt landing thirty feet or more took down every thing I had ie fixed radio etc, I was left with my fix on the chart taken half an hour earlier, I was then sailing into a bank of thick fog off the island , and after a while I could only make out a couple of feet off my bow.
using my hand held radio trying to raise douglas harbour master, Liverpool coastguard picked my signal up and they
gave me a fix into douglas harbour which coincided with my EP half an hour earlier, using that fix and the racon sound from douglas head which i knew if i kept it to my port side i would enter douglas bay safely, which i did.
so my answer would be that a paper chart is invaluable,
also did you know that the navigational aid for back up on the planned mars expedition is going to be a sextant.
tom

[Keith Tindell]

Hi Thomas, interesting post from yourself, i have had a similar experience in the Alderney race. I suspect us ex seamen small boat owners have a healthy respect for the sea in all its moods. I never owned a chart plotter, but i did have a gps, and like yourself, kept the chart on the table, and also a DR, as much as anything to keep what navigational skills i do have to practice. Alas , i no longer have a boat, at 68, moving about in a small boat would not be in my best interest, kt

[Doc Vernon]

Magnetic Fields relating to the Sea etc?? I have not a bleedin clue LOL
East is East and West is West
But the Sheilas of Southampton I found the best.

only magnetic field I ever knew was the one between Man and Woman!

But more to the point this is very interesting and I learn more as I grow old!
Thanks