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Know matter how you put it, the original post related to basic navigation and the good practice of seamen, not the undoubted improvements and accuracy of gps over spherical trigonometry, - it’s still just one of many aids to navigation.

Until that’s understood, any examiner would give you another 6 months sea time – to think it over.
Ha! Indeed...
 

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In think your Ha! would raise that to 12 months.

But. What tests of competence concentrates on the safe navigation of a vessel carrying only that equipment demanded by SOLAS? Much noise is being made of the learning around ECDIS and its equipment specific training - seemingly not as effective as the world might like. But by SOLAS you have no sextant or chronometer. Perhaps it is difficult to blame ECDIS on the current problems (ships being exactly where they planned to be except that place being somewhere where they should not be) as that would have to be measured against how they would have erred given a proper chart, possibly onboard, possibly corrected, unlikely to have been on the chart table and even more unlikely to have a position plotted).

I wonder if it will take another of Sir Cloudesley's line to founder for the common good (if not that of Her Majesty's Navy) to return to an environment of professional seafaring (even if those taking it up would need to be teetotal eunuchs to enjoy the life now on offer).
 

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Professional seamen (navigators) would be suspicious and dispense with gobbledegook, sticking to ‘apples and oranges’, much simpler and easier to understand than talking about terrestrial spheroid’s etc. Once you understand the very old but basic principles of navigation everything that came later is just an aid to a subject that never was an exact science, as Sir Cloudesley and most of his fleet found to their misfortune, without the aid of a chronometer – it can be hit or miss, particularly if relying on DR positions. Anyhow, stick to the first principles irrespective of any aids to navigation and you’ll keep her off the rocks – and out of the courts.

Circa.1970’s - I forget the parameters when DP was used in cir***stances such as working close to rigs or with divers down, particularly when the weather turned inclement. No doubt it did a better job than I could manually, allowing me to relax with the ‘feet up’ and enjoy a cuppa and a wee puff on a ciggy. Earlier I remember the owners keeping in touch via satellite, the bridge ticker tape spewing out instructions and like most of my generation, thought it magic, invariably replying only, with one finger - ‘how now brown cow’ – as we didn’t appreciate the intrusions from owners and some charterers. But, as you say, things have changed. – indeed, whoever started this post, is clearly taking the piss.
 

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Well, I think we are on the same wavelength Harry T but that might be taken as suggesting Sir Cloudesely would have been a pussy had he had and used a chronometer.
 

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The call came in by radio one evening last September, at around 9 p.m. On the line was the master of a tanker, approaching the end of a monthlong journey from the Port of South Louisiana and carrying more than 5,000 metric tons of ethanol. The message was urgent: The ship’s GPS signal had suddenly disappeared—leaving the crew to navigate Cyprus’s shoreline in the dark.
On the other end of the line was the pilots’ office at the Vasiliko oil terminal, whose staff oversees shipping traffic at Vasiliko’s harbor on Cyprus’s arid, palm-fringed southern coast. Stelios Christoforou, the pilot on duty, recognized the gravity of the situation right away. In daylight, an experienced ship captain can maneuver using paper maps, markers, and the coastline as guides. But at night, GPS becomes a critical tool in unfamiliar waters—especially near Cyprus, where NATO and Russian warships roam. And any accident could spill the tanker’s cargo across miles of coastline.
What happened in the days when there was no GPS. The more we turn to digital modes, the more this type of situation is going to happen. Should we train sea going staff in the old ways again as well as all the modern.
Blair Lagerstedt
 

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A good morning to yourself Varley, it’s well recorded there wasn’t an accurate timepiece available to navigators in Cloudesely’s days hence the navigator’s reliance on DR’s (Dead Reckoning - guesswork) to calculate longitude. Resulting in far too many tragedy’s at sea. That was the worst with the loss of so many fine men and treasure from their battles. That incident galvanised parliament to put up the wherewithal to resolve the problem, hence the ships chronometer, as we know it today.
 

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Harry T. Too much praise for Harrison (by implcation anyway). The docudrama made too much of the timepiece and not enough of Nevil Maskelyne (except to make him out to be the buffoon he was not). The chronometer was too much for many pockets and his (with his mentor and predecessor in post but one, Halley) lunar distance method held sway until the chronometer was less expensive.

(In the days when we were legitimately replacing those of the clockworkery kind with quartz (lcheap compared with the overhaul of precision engineering) I could have had one for nothing. Now it is GBP 1100 for the mediocrist model).

Troppo. Unfortunately the practice is something that cannot be maintained. Is anyone doing sights for a noon position daily? I suggest, without that, the fluency goes out of the window. We cannot expect the same dedication as those celestially navigating for the hydrographers (I have a lunching companion who was and he astonished me when saying they had their own personal 'errors') but without the fluency that practice instills it must remain a fall back. I think it would take some ionospheric catastrophy, forcing the majority back to Lagerstedt's 'old ways', before the general performance again became commercial/safe on the macro scale.
 

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Earlier posts – First Sextant
harry t.

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#18 Apr 4, 2019

In 1959, for £10 at Smithfield market in Belfast I bought, a Heath & Co. London SE9.- 1911, with an endless tangent screw and a “new automatic clamp”. It cost another £2.12s.06p to post it to the National Physical Laboratory in London to have it tested and checked for accuracy. A fat lot of good on my first trip 2nd mate, a rhumb line to the Azores thence a Great Circle to the Chesapeake on an old ‘empire’ ship on a ballast passage from Cork to Baltimore. DR positions only for the first 24 days, when we finally got a ‘blink’ of the sun, the lady was 200 miles to the south and 300 miles astern. The old man wasn’t too impressed.

harry t.
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#23 Apr 5, 2019 (Edited)

I flew into Manila looking to engage an experienced tug crew. Jesus, a Filipino tug Captain, in trouble with the authorities for breaking an employment contract whilst operating his tug in the Mekong River. Vietnam and Cambodia where dangerous places in the early seventies. His nerve cracked when the chicken wire he had rigged to catch and protect his wheelhouse from rockets fired by Vietcong wasn’t up to the job.

I talked him into bringing his whole crew of experienced tugboat men to join me. The main part of the two year deal we signed was that I teach him celestial navigation. As not one of them spoke a word of English a large part of the bridge wing deck was painted with blackboard paint and many balls of chalk used to communicate by numbers and stick men. Neither he nor his first mate had ever set eyes on Admiralty tables but with perseverance and patience I had them crossing a longitude by chronometer with a meridian altitude in six weeks. A running fix in months and star sights by the end of the year. They found using the instrument of double reflection on a bouncy wee tug the most difficult.

You’re wrong there old son. If you take the trouble to learn the 1st principals of a subject they will stick with you for all time, particularly if your wellbeing or life could depend on it - the good practice of seamen - you seem to have long forgotten.

Yes, GPS made us lazy but it was a wise man who “kept his hand in” and opened the sextant box now and again, as it was deemed good practice even though it might take a few minutes of revision.

My earlier remarks were left open ended as you clearly insist on having the last word.

I made my point, subject closed.
 

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GPS, the US Navstar system, is all rather old hat anyway. We should refer to it as GNSS now, which includes the Russian GLONASS and Chinese Beidou satellite constellations. Europe has had one on the drawing board for years, but is not quite there yet, therein lies a tale no doubt.

All modern GNSS receivers can process Russian, American and Chinese systems, so if one fails completely you still have two more which the receiver will use automatically. On DP ships of course, it will flag a warning, which is often weighed up as being non-critical because of the other available position reference systems, (and of course the GNSS still has redundancy).

I can remember when the old Transit navigation system came out. Huge great box on the bridge generating lots of heat giving a fix every 4 hours or so. The 3rd mate would rush up to the monkey island with his sextant and return triumphant declaring the satellite was out by 50 NM.
 
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