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Thread: Interesting for the navigators

  1. #21
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    Default Re: Interesting for the navigators

    In the late fifties,I signed on with Counties Ship Management as third mate.None of their ships had radar and we had no problems navigating. When we were awarded a contract to take stores to the Dewline early warning station at Frobisher Bay on Baffin Island ,we were obliged to rent radar equipment which was a big help in spotting ice bergs at night and in fog.There can be no substitute for proper old fashioned navigation.
    Jim Domleo
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    Default Re: Interesting for the navigators

    The original link given was faulty.

    https://www.bbc.co.uk/news/uk-politics-57440787

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  5. #23
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    Default Re: Interesting for the navigators

    Thanks for rectifying that Mike, kt
    R689823

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    Default Re: Interesting for the navigators

    I have only just opened this post by Lord West whoever he is. And found it quite enlightening as to the suspected knowledge of today’s navigators. Although persons of my generation had to live with both the old and the newmost of us never forgot the old , but that generation is fast disappearing .e.g. how many today know the definition of a meridional part . How many know what a Haversine is, how many even know the definition of the 3 horizons. These were just the basics of stellar navigation . To be competent to the same as former navigators level it is probably back to the drawing board for most and this is not a 5 minute job. The best of British luck. It took a mininum of 6 years at sea to achieve competency and many years after that to achieve the experience to be trustworthy in the subject. I have always said this , the easy solution is not always the best, in the event of war and all the toys being made useless , then will come the time of truth. JS.
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    Default Re: Interesting for the navigators

    John, so many changes over the years.
    But now with GPS and other such equipment I would suggest many of the modern day mariners would not be concerned about that.
    Juist enter the in formation into the computer and sit back.

    But sadly as we know computers are only as good as the information entered there in, many a slip between cup and lip!!

    Then when it goes belly up they will say the computer is faulty.
    Happy daze John in Oz.

    Life is too short to blend in.

    John Strange R737787
    World Traveller

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  10. #26
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    Default Re: Interesting for the navigators

    Quote Originally Posted by j.sabourn View Post

    I have only just opened this post by Lord West whoever he is.


    . how many today know the definition of a meridional part . How many know what a Haversine is, how many even know the definition of the 3 horizons. These were just the basics of stellar navigation . To be competent to the same as former navigators level it is probably back to the drawing board for most and this is not a 5 minute job. The best of British luck. It took a mininum of 6 years at sea to achieve competency and many years after that to achieve the experience to be trustworthy in the subject. I have always said this , the easy solution is not always the best, in the event of war and all the toys being made useless , then will come the time of truth. JS.
    Admiral West, a nice man and a great supporter of our MN,had the pleasure of meeting and talking to him at a reception in the House of Commons in 2008 (how time flys!). He later became Admiral of the Fleet.

    The definitions , Reminds me of a line from the song Galway Bay ' For the strangers came and tried to teach us their ways' yes John if the electrics fail, they'll find out that celestial navigation isn't a five minute job

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    Default Re: Interesting for the navigators

    #27 yes Ivan only 3 little examples of many others , but 3 which one used all the time. Better explain for those who don’t know what I’m tarking aboot.
    Meridian parts .... for a terrestrial spheroid are the number of minutes of longitude contained in an arc of longitude between the equator and that latitude.
    Visible hoizon. The sea horizon one sees looking at , its distance is 1.17 x the square root of the ht/eye in feet.
    Sensible horizon .. the arc of a Small circle, but going straight out at right angles to the observers zenith.
    Rational horizon..similar to a small circle but a great circle but whose plane passes through the centre of the earth.
    Haversine = half a versine and a versine = 1 - cosine theta.
    The sextants in the chart room with the chronometer , anyone can go and find out where we are ??!! As long as they can remember all the other myriad formulaes and know how to read a sextant and allow all the errors etc.etc. Maybe 6 years is cutting it too fine. Cheers JS
    Last edited by j.sabourn; 8th August 2021 at 05:06 AM.
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    Default Re: Interesting for the navigators

    #26... John the problem will be if war conditions ever occur in the present world as it stands today , your GPS will not exist anymore your computer apart from adding and subtracting numbers is immaterial to the working out of sights which is all celestial geometry and not plane geometry which you may or may not have learned at school. Without appearing to boast I could still do it , as we of earlier years were taught by professionals and it was cemented in , we also used in our time the GPS systems and these made us lazy. But the old ways still exist with some of us. The problems however are almost with us now, and that is there will be shortly no one left to teach anyone anymore , the same as there is no square rigged old windjammer masters left. I have also in my varied career sailed with RN navigators and putting them in competition with merchant seamen they would come second best. They may exceed in the likes of signals but not in navigation by what I saw that is the old ways I am referring to. Celestial navigation should still be in the old syllabus and a failing paper as it always was . Cheers JS
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    Default Re: Interesting for the navigators

    Quote Originally Posted by j.sabourn View Post
    #27 yes Ivan only 3 little examples of many others , but 3 which one used all the time. Better explain for those who don’t know what I’m tarking aboot.
    Meridian parts .... for a terrestrial spheroid are the number of minutes of longitude contained in an arc of longitude between the equator and that latitude.
    Visible hoizon. The sea horizon one sees looking at , its distance is 1.17 x the square root of the ht/eye in feet.
    Sensible horizon .. the arc of a Small circle, but going straight out at right angles to the observers zenith.
    Rational horizon..similar to a small circle but a great circle but whose plane passes through the centre of the earth.
    Haversine = half a versine and a versine = 1 - cosine theta.
    The sextants in the chart room with the chronometer , anyone can go and find out where we are ??!! As long as they can remember all the other myriad formulaes and know how to read a sextant and allow all the errors etc.etc. Maybe 6 years is cutting it too fine. Cheers JS
    Not the full monty but this gives the basics of celestial navigation as taught to marine students studying for an O.O.W STCW ticket.
    Rgds
    J.A.
    https://www.oceantraining.com/acatal...ation-106.html

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  16. #30
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    Default Re: Interesting for the navigators

    Thanks John, all sounds very plausible. I have seen the same method of teaching supplied to naval officers . One ex Dartmouth cadet asked me crossing the Bay of Biscay and out of the Decca navigator system if he could come on bridge in the morning and take star sights with me I said of course you can . He was on the bridge at 0500 and wanted his printed sheets which told him what to do move by move , I said we don’t use them we just use the Haversine formula which he could not remember , this man actually taught navigation at Dartmouth . I can still recite that formula today off the top of my head Hav ZX = Hav LHA cos. Lat. cos Dec + hav ( L diff D) he went off the bridge and couldn’t do without the paperwork to tell him what to do.To me that is not a navigator. If you cant retain important facts in your memory you are no navigator. Navigation is not a Do it yourself job, just follow the written instructions , it’s an art you can do in the dark by flashlight if necessary and no written instructions. Cheers JS.
    Last edited by j.sabourn; 9th August 2021 at 01:08 AM.
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