Words from a sailor.

Well in any case the ships heading did change throughout the trip back.

Quote from: Shmeggley on April 09, 2013, 01:29:16 PM

Quote from: Roundy the Truthinessist on April 09, 2013, 12:31:31 PM

Quote from: rottingroom on April 09, 2013, 09:39:14 AM

This is common but it is actually well known and self-evident as a sailor that this is a much longer way to get across the Pacific Ocean than what is known as the Great Circle. Getting there through Hawaii is fairly close to a straight line

On a sphere, a great circle is a straight line.   

No, you're travelling in an arc. The straightest path on a sphere between two points would actually be a chord. However we're normally restricted to travelling on the surface of the sphere. So the path looks straight from one angle, looking at the circle from the edge, but looks curve from a different angle. Make sense?

What does the apparent path from different perspectives have to do with it?  When traveling along a great circle, a vessel is traveling in a straight line.  It is not turning left.  It is not turning right.  The only curving the vessel is doing is downwards.

Right, that shows why when you take these "straight line" paths from say a flight log, and plot them on a flat map, they appear curved, because the true path IS curved. If the actual path was really straight and flat to begin with, you wouldn't get that effect when plotted on a flat map.

Well in any case the ships heading did change throughout the trip back.

Of course.  Unless you're at the equator it would be impossible to travel a straight line eastward or westward without constantly changing heading.  But that doesn't mean you're not traveling along a straight path.  On a sphere, in the northern hemisphere, a vessel would have to start by traveling a bit northward, constantly change heading, and end by traveling a bit southward, in order to follow the path of a straight line.  The opposite is true in the southern hemisphere.  Traveling at a constant heading due east or west, one would have to constantly be turning, and therefore not traveling in a straight line... except at the equator, because the equator is itself a great circle.

Right, that shows why when you take these "straight line" paths from say a flight log, and plot them on a flat map, they appear curved, because the true path IS curved. If the actual path was really straight and flat to begin with, you wouldn't get that effect when plotted on a flat map.

Nobody was ever talking about what the trip would look like on a flat map.  Obviously if plotted on a flat map a great circle route would appear curved.  That doesn't mean it's following a curved route.  It doesn't change that the route itself is a straight line with no turning necessary.  Try to keep on topic please.

There is another part of my job that proves the earth is curved and this has to do with radar propagation. Along with oceanography my job includes meteorology and because of that we are vital to decisions that are made about radars because the weather has a direct impact on their performance. With radar propagation sometimes the radars perform better under certain conditions and in these cases we call it super refraction and sometimes they perform worse and we call this sub refraction. In both cases the radars propagation never goes around the earth forever but if the earth was flat it would. The reason why the propagation turns away from the earth is because of the curvature. We often make use graphs with an x and y axis to show what is happening. On the graphs the x axis is flat as if the earth was flat. As the distance (x axis) gets bigger the propagation (detection range) gets further from the surface and on the graph a curve is made.

It's also worth pointing out that Great Circles are also used in the southern hemisphere except they work in the opposite direction. This wouldn't work on a flat earth.

Quote from: rottingroom on April 09, 2013, 02:55:29 PM

Well in any case the ships heading did change throughout the trip back.

Of course.  Unless you're at the equator it would be impossible to travel a straight line eastward or westward without constantly changing heading.  But that doesn't mean you're not traveling along a straight path.  On a sphere, in the northern hemisphere, a vessel would have to start by traveling a bit northward, constantly change heading, and end by traveling a bit southward, in order to follow the path of a straight line.  The opposite is true in the southern hemisphere.  Traveling at a constant heading due east or west, one would have to constantly be turning, and therefore not traveling in a straight line... except at the equator, because the equator is itself a great circle.

Quote from: Shmeggley on April 09, 2013, 02:59:48 PM

Right, that shows why when you take these "straight line" paths from say a flight log, and plot them on a flat map, they appear curved, because the true path IS curved. If the actual path was really straight and flat to begin with, you wouldn't get that effect when plotted on a flat map.

Nobody was ever talking about what the trip would look like on a flat map.  Obviously if plotted on a flat map a great circle route would appear curved.  That doesn't mean it's following a curved route.  It doesn't change that the route itself is a straight line with no turning necessary.  Try to keep on topic please.

So you're saying that they took the longer route because according to your flat earth map he took a curved route which is not optimal.

Quote from: Roundy the Truthinessist on April 09, 2013, 03:08:36 PM

Quote from: rottingroom on April 09, 2013, 02:55:29 PM

Well in any case the ships heading did change throughout the trip back.

Of course.  Unless you're at the equator it would be impossible to travel a straight line eastward or westward without constantly changing heading.  But that doesn't mean you're not traveling along a straight path.  On a sphere, in the northern hemisphere, a vessel would have to start by traveling a bit northward, constantly change heading, and end by traveling a bit southward, in order to follow the path of a straight line.  The opposite is true in the southern hemisphere.  Traveling at a constant heading due east or west, one would have to constantly be turning, and therefore not traveling in a straight line... except at the equator, because the equator is itself a great circle.

Quote from: Shmeggley on April 09, 2013, 02:59:48 PM

Right, that shows why when you take these "straight line" paths from say a flight log, and plot them on a flat map, they appear curved, because the true path IS curved. If the actual path was really straight and flat to begin with, you wouldn't get that effect when plotted on a flat map.

Nobody was ever talking about what the trip would look like on a flat map.  Obviously if plotted on a flat map a great circle route would appear curved.  That doesn't mean it's following a curved route.  It doesn't change that the route itself is a straight line with no turning necessary.  Try to keep on topic please.

So you're saying that they took the longer route because according to your flat earth map he took a curved route which is not optimal.

Well, they didn't know any better.  After all they think the Earth is round.

Oh, my apologies.  This:

Quote from: rottingroom on April 09, 2013, 09:39:14 AM

we used the Great Circle which meant we traveled in a curve

is pure nonsense.  A great circle route does not curve.  Perhaps I should have read it more carefully than I did.  Whether he's really a sailor or not he has no idea what he's talking about.  Oh well, another potentially interesting debater bites the dust.

" I made careful observations about the direction the ship was going  (that is part of my job) and could even see the trail behind the ship throughout the trek that showed that the ship was in fact slightly turning the whole time."    Well, he's either a terrible observer, or a liar. I don't care which. The only "slight curving" the ship would take on the great circle route on a globe would be in a vertical direction. There would be no left-right, north-south curve as he claims.

I did look at all circles a boat could sail on a globe and they would require a turn since the boat is not perpendicular to the bisection (apologies earlier, I stupidly took bisection to always be equal parts being sectioned), but at a right angle to the surface. Wish I had a drawing program,  I might do it later by cutting a line in an apple ( necessity is the mother of bad analogies).

Well in any case the ships heading did change throughout the trip back.

Then it was not travelling on a great circle route...

It's also worth pointing out that Great Circles are also used in the southern hemisphere except they work in the opposite direction. This wouldn't work on a flat earth.

This part is actually correct.

Even if he is a sailor, he's not much of a helmsman. Even a big ship like a navy vessel is gonna have to be constantly adjusting for wave action. Of course it's always going to be turning.

Even if he is a sailor, he's not much of a helmsman. Even a big ship like a navy vessel is gonna have to be constantly adjusting for wave action. Of course it's always going to be turning.

right, im not a helmsman. Quartermasters do that. Why talk about something you know nothing about?

I said I'm a meteorologist and oceanographer. In the Navy this is called an Aerographers Mate, and yes we do adjust our course for high seas. In fact, it is someone who has a job like mine that forecasts where the large seas are in the ocean and recommends not steering the ship into them.