A navigation question.

[Captain Kong]

I was lying awake most of the night, had a bit of pain, so to while away the hours I got thinking of a problem with navigation. I havent navigated for17years so a little rusty.
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I am on a ship say in Fanning Island, on the International Date Line, 180` Eor W.
I am sailing to London on the Greenwich Meridian .
There is No land or Ice so, I am sailing North over the Pole and down to London. So up the Longitude of 180` and down the Longitude of 000`.
So the Course is OOO` to the Pole then it will be 180` to London.
What happens when I arrive at the Pole. ?
At the Pole I alter course to 180` and does the ship go back on a reciprical course to Fanning Island, to London or down any other Longitude South. ??
I cannot have a drink now as I have to go back to Hospital for treatment in a few minutes. or I would have solved it with a few Tots.
Cheers Brian.

[John Arton]

Tricky that one Brian
Question
Are you steering using magnetic compass or gyro compass as each one should give you a different answer
rgds
JA

[Captain Kong]

I know it is a only a queston that could not be,
If I was on auto,[ Iron Mike.] what happens at the Pole,
If I was on Magnetic then Compass errors would had to be taken very regular as the Magnetic pole would eventually be in a different direction and moving as I get past it and ..... its no wonder I had no sleep. all night, trying to figure out what happens at the Pole, assuming there is No Ice, just clear ocean all the way on passage.
Just off to the hospital, I will ask one of the Nurses ,
Cheers
Brian

[Ivan Cloherty]

I know it is a only a queston--Cheers
Brian

Tell her to take your pole in one hand and walk round it, she may come up with a solution

[Chris Allman]

There certainly could be a solution in that case Ivan but of a different kind to the mental one

[j.sabourn]

#6... Lost again Brian,? If you want to baffle someone with science re navigation, after asking them the Haversine Formula, say what is a haversine, if they finally reach the conclusion it is half a versine, ask them what is a versine then, if they get stumped here, you can come out very bombastically it is 1 minus Cos Theta. If he is generally a proper navigator I would have to crawl off somewhere and frantically look up books I dont possess anymore. All my nautical publications apart from Nories disappeared many moons ago. Regarding your query best look for a polar bear they reckon they know what they are doing. Your gyro as usual would be pointing to a fixed point in space, your magnetic compass if someone hasnt already taken the spirits out of it, drink it, they say it gets quite chiilly at the pole, one good point though you wouldnt be moving at the 600 knots you would be at the equator. Hope your hospital apointment goes well. Was at the doctors today and asked him to look at 2 nodules on neck and shoulder and one in the groin, asked him to burn them off, he reckoned the 2 on upper body were skin cancer and the one in groin was not, he burned them off, I told him to be very careful of the one in the groin and make sure he got the right one, as have high hopes of the use of the other one some day. Cheers just think of all the nurses tomorrow JS

[Captain Kong]

Thanks for all that, also hope your nodules get OK had a few of those in the past. got to be carefull if he gets the wrong Nodule. It will make your eyes water.,
,
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Regarding the question, it is not a trick question I have the answer for.
I just lay awake all night trying to figure it out. What direction do you steer at the Pole after coming up from the south and then heading south on the same Meridian over the North Pole with no land and no Ice just ocean.
No GPS or aids. just a compass and sextant.
Cheers
Brian
For curiosity I just wondered if anyone knew the answer.

[Don Rafferty]

If you're on a magnetic compass you'll be heading North for the first part of the trip to the pole, and then South for the second part as you pass the pole. There'll be no course change on the vessel, just a 180' on the compass card.

As the compass will be going loopy as you pass the pole, you'd better make it a niight passage so you have the stars to guide you

[j.sabourn]

Suppose in theory your magnetic compass would just be spinning continuously if sitting on top of the magnetic pole. The magnets of the compass would have no directive force. Although the magnetism of the ship may have some directice consequences. All your correctors Flinders bar, lord Kelvins balls, and other corrective magnets would have no use, As soon as moved away from the magnetic pole would have to start recorrections when far enough away. Dont think the magnetic compass would be much use in high latitudes. The gyro compas as you know is a fast spinning wheel where the axle points to a fixed point in space so to go south would be the reverse of where it was pointing. Sounds daft to me as well. Just keep the pole star at your back and go man. Cheers JS

[Captain Kong]

Thanks for all that.
I had a vision of steering North 360` to the Pole then alter course to South, 180` and find myself on a reciprical course back to Fanning Island or to anywhere else to the South of the North Pole . if you can get my drift.. All directions from the Pole are South ,180`................... I think.
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Very strange what the mind thinks up when you cannot sleep.
Dont know where I am going tonight. let you know.
Cheers
Brian.