Sailing on a straight path, what's the greatest sailing distance possible between one coast to another?

Question

By "straight line", I mean on a great circle on the seas of Earth, so that the ship travels steady dead straight ahead at all times. How far can a ship go without making landfall? Let's assume that the ship is self-powered and has adequate fuel.

No, the answer is not "an endless circle" about Anarctica, because in fact the ship would have to be constantly turning, however minor. It would not be a great circle.

You almost have to get a string and use a real globe of the earth to make sure that the path you have is really a great circle.

For the mathematically inclined: Any great circle path greater than 12,500 miles has to pass through the equator.

The Great Sailing Ship Contest is on! The one with the greatest distance will get 10 whole points! I will first verify best answer on a globe!

Folks! Once again, sailing along a latitude is NOT a great circle path.

Zanti, your proposed route makes landfall in Europe, limiting its distance to less than 12,000 miles. Dr D, you did well in estimating distances of your paths, and as you know, so far morningfoxnorth seems to be the leader with about 17,000 miles, which I've verified. Can anyone beat 17,000 miles?

Dr D, I checked your "Pamana Canal" route, and while it does seem to beat morningfoxworth's 17,000 mile route, it does not seem to exceed 18,000 miles. But unfortunately, the Panama Canal actually runs almost PERPENDICULAR to your great circle route. Alas!

For those deprived of a world globe, here's a helpful link:

http://www.acscdg.com/

Now go see if you can beat 17,000 miles or even 18,000 miles.

Here's another great circle route: Start about where Juneau, Alaska is, go SW towards Australia but just miss it, continue towards Antarctica, but just miss it, then upwards towards the Altantic Ocean and just miss the west coast of Africa, and finally northward towards Canada near the entrance to Hudson Bay. The total distance is over 19,000 miles.

Answer 1

I believe it the the Great Circle starting on the coast of Pakistan, heading south-west between Africa and Madagascar, then around the tip of South America, then northwards toward the Kamchatka peninsula; for a total sea distance of over 17,000 nautical miles, or about 31,500 kilometers. (Assuming that no stray islands get in the way.)

Answer 2

Oh damn I don't have a globe with me. This is impossible with paper maps.

OK here's what I found on google earth (am I allowed to say google here?). There is a vast array of ocean travelling from Acupulco, Mexico SW through the Pacific ending up at the South of Yemen or Oman. This path takes you south of Australia and New Zealand and north of Antartica into the Indian Ocean travelling NW toward the Arabian Sea.

This distance is approximately 15000 miles. And the good thing about this route is that there are not too many islands nearby. If you could sneak it through the Panama canal, then you could end up near Jamaica, adding a few hundred miles to the journey. But it still won't come anywhere near morningfoxnorth's answer.

There is also a good one from Japan to Ghana/Nigeria. It passes through the Pacific, between South America and Antartica, on to Western Africa. Approximately 16000 miles.

*EDIT*
OK I found one that might be a real long shot. I don't even think it will work, but you can check it in your globe. Start in SE India. Travel SE just pass Sri Lanka, just missing the SW tip of Australia, passing north of Antartica, heading toward Central America. IF you could manage to go through hte Panama Canal and squeeze in between Cuba and Hispaniola, you could keep going until you hit NW Norway. That would be over 20000 miles. But I don't think it would work. Nevertheless this was one of the most fun questions I've done in a while.

Answer 3

Looking at a globe, it appears there MIGHT be a longitudinal line you can follow from the north pole all the way to Antarctica. If it works, the longitudinal line takes you through the Bering Strait between Alaska and Siberia, skirts a few islands off the coast of Alaska, slides between the Aleutian Islands, and then manages to avoid a few isolated islands in the South Pacific. You won't hit land until you get to the Ross Ice Shelf on Antarctica at around 80° S latitude.

Answer 4

Here's a good one: the great circle containing the easternmost point in Brazil and the easternmost point in the Falkland Islands. Not necessarily the greatest, but a good lower bound on the maximal great circle.
Or perhaps the great circle containing the easternmost point in Brazil and the northernmost point in Antarctica's Enderby Land.

Answer 5

Why don't you just tilt the planet and get it over with.
Can you really sail "steady and dead straight ahead at all times" (as you put it) on the ocean?
I miss your fun questions.