Please read ENaG.
* Thork takes a bow, waves to the crowd and walks off to rapturous applause. A veteran performance.
Rowbotham's explanation of perspective at sea is flawed, something he would have seen if his desire to have the world flat didn't overirde his common sense.
Yes, the swell can certainly make it appear that the lower part of the boat has disappeared. However the swell is something continually changing. If the swell on any given day of experiment, was sufficient at times to obscure the hull, it would do so on and off, not continuously. So if you were to take several measurements over the course of several minutes, you could expect that at some times the hull will be obscured at other times not. The level of the swell changes minute to minute.
Recently I visited the seaside and took some photos of ships in Moreton Bay. I took a series of photos, some taken at sea level, some taken from atop a cliff face, coincidentally about the height of a crows nest - 10m. In all cases the sea level photos showed an obscured hull, and the cliff top photos showed an unobscured hull. The camera used to take the photos had affixed a 250mm lens on a 3/4 frame sensor (equivalent to 380mm).
It was quite a hot day, and there was reflection on the surface of the water nearest the ships (by line of sight). This makes it look at first glance like the horizon is lower than it actually is. I have drawn lines through the middle of the reflection to show where the horizon actually lies. This reflection disappears once you gain some height. It can be seen that, if the earth were flat, the waterline of the ships would be at the mid point of the reflection, yet once you climb to 10 metres, the ships waterline is suddenly much lower.
It's quite clear from these photos that the ship appears to be sitting ON the horizon while at sea level, yet at 10m, you can see clearly that the Horizon is beyond the ship. All the images, including versions without the reflection line drawn on, can also be viewed here:
My Location was -27.32519, 153.08607, corner of Swan and Shorncliffe Parades, Shorncliffe.
Ships 1 2 and 3 where located at approximately -27.2314, 153.334, 25km from my position.
The Gantry and Berthed ship where located at approximately -27.3617, 153.180, 10km from my position.
Each ship is displayed in the order the photos were taken.
Ship 1 (distance approx 25km):10 metres:
Ships below the Horizon by
max_wedge, on Flickr
Ships below the Horizon by
max_wedge, on Flickr
sea level
Ships below the Horizon by
max_wedge, on Flickr
Ships below the Horizon by
max_wedge, on Flickr
Ships below the Horizon by
max_wedge, on Flickr
Ships below the Horizon by
max_wedge, on Flickr
10 metres:
Ships below the Horizon by
max_wedge, on Flickr
Sea Level
Ships below the Horizon by
max_wedge, on Flickr
10 metres:
Ships below the Horizon by
max_wedge, on Flickr
Ship 2 (distance approx 25km):sea level:
Ships below the Horizon by
max_wedge, on Flickr
10 metres:
Ships below the Horizon by
max_wedge, on Flickr
sea level:
Ships below the Horizon by
max_wedge, on Flickr
20 metres:
Ships below the Horizon by
max_wedge, on Flickr
Ship 3 (distance approx 25km):sea level:
Ships below the Horizon by
max_wedge, on Flickr
10 metres:
Ships below the Horizon by
max_wedge, on Flickr
sea level:
Ships below the Horizon by
max_wedge, on Flickr
Berthed Ship (distance approx 25km):
sea level:
Ships below the Horizon by
max_wedge, on Flickr
20 metre:
Ships below the Horizon by
max_wedge, on Flickr
Gantry (distance 25km):
sea level:
Ships below the Horizon by
max_wedge, on Flickr
20 metres:
Ships below the Horizon by
max_wedge, on Flickr
My location:
Ships below the Horizon by
max_wedge, on Flickr
20110828-002 by
max_wedge, on Flickr