I was talking to a friend to is a keen sailor - I told him about my recent fascination about the Flat Earth Society.
He was telling me how often you can see lighthouse light bouncing off clouds before you can see the light itself.
Then as you get closer and when the curve permits you can then see the light.
This is an example of the "heads I win, tails you lose" argument Flat Earthers resort to.
Rowbotham claimed that the dark hull of a ship can merge into the sea, so it only appears to be sinking behind the horizon and the hull can be restored with magnification.
That can be true in some cases if the ship gets far enough away it can be hard to distinguish from the sea.
But at some point it will sink behind the curve of the earth and when you post photos of video of that they just say "waves".
This video has been posted before.
Are they seriously claiming that is caused by waves? He shows where the different shots were taken from, looking at the times when he shows the GPS readings it looks like the same afternoon and the weather doesn't seem significantly different. While the channel does connect with the ocean, you can see that the water is pretty calm in all the shots as you would expect in a fairly narrow channel like this. It's not the open ocean. If waves were a factor you would expect the amount of the building you can see to vary significantly as the swell comes and goes, but you can't.