Nautical miles and kilometres.

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[dharl]

How odd,  How odd the Prime Meridian was at Greenwich when i last visited a few years ago!   And when i was studying for my Master Mariners it was never mentioned about it moving either... 

Though the actually equipment for the observatory has moved, the building and the prime merdian are still there as agreed in 1884.

See http://en.wikipedia.org/wiki/Prime_Meridian for further details.

cheers and happy sailing 

[mvsmith]

Had you read my post with comprehension, you would have seen that I did not say that the Prime Meridian had moved.

[dharl]

In which case i apoliugise and stand corrected.   Though the physical building of the Greenwich Observatory, with the prime merdian, is still in situ.  I can see it from my office window.   I agree that the tasks carried out by the Greenwich Observatory have been moved out of London, but the names havnt changed.... as far as i knoe anyway! 

[Traddles]

Hello mvsmith,
Sorry you don't know when your leg is being pulled!! I do not, in fact cannot, dispute what you say,but if I divide ten million by 5,400 I get 1,851.8518 French thingys. Which is not equal to 1,852 thingys. If I multiply 1,852 thingys by 5400 it comes out as 10,000,800. O hell, now I'm 800 thingys out! . My point, which I will stress, is that Jolly Jack is not a scientist, the name Jolly Jack coming from Jack of all Trades, (ie not being the master of anything,  but being pretty good at most.) Whereas you as an oceanographer have to be precise, we bumble along quite happily and still get to our destination OK. When I started at sea navigation needed a sextant, a fancy clock, (Invented in UK) a set of Nautical tables and the Nautical Almanac. Of course added to that was an exercise book and a pencil. There was no satellite navigator or even a gyro compass and auto pilot. BUT it was GREAT!!! The strange thing is that I spent some twenty years using my kind of nautical miles and never went wrong once, nor did many many other seafarers. We are a differing breed from landlubbers, and to go all French again, "Vive la differance". One point though, can you explain how heading alters things, it never did when I was at sea!

[Traddles]

To quote another "weird Britishism" I get the feeling I have set the cat among the pigeons here, Or to quote a weird Americanism, I've opened a real can of worms!!!

[dharl]

There is nothing quite as satisfying as arriving at the port you planned to arrive at!   I must admit that as a modern navigator there are plenty of toys to help you along, but the basics on costal navigation and ocean navigation hasnt changed for hundreds of years! (or even longer!!!)   

[Traddles]

When I was studying for my tickets I had to get a mark of 100% on the navigation paper. I was told it's no good getting half way there, you must arrive!!!

[dharl]

Hi Traddles,

it was the same when i was sitting my 2nd mates and mates/masters.  You either passed or failed!   At sea theres not much room for error, you either get it right or you look for a seat on a lifeboat..

[mvsmith]

Sorry you don't know when your leg is being pulled!!

Traddles,
You were pulling on me peg, which was under the bed at the time, so I didn’t notice.
Of course I was yanking yours with the semantic quibble about the Greenwich Observatory having been moved. The building was, in fact, still there on the hill on my last visit.
Dharl, no apology is necessary. Often these discussions can become quite murky.
Regards,
Marty

[Stuart2007]

Well, I must say this really is fascinating!   

Did anyone ever see a film about a light aircraft getting lost over the sea (Mercy mission: The rescue of flight 771) - it starred Scott Bakula?

Basically, the pilot lost his position and had to use the time difference between the sun setting at his location and that of a commercial jet (position known) to work out his relative location.

How they worked out his position of latitude I can't remember. I know it's aircraft, but the navigation principle is the same.

Stu