This has been discussed ad nauseum on this site.
And it has been answered again and again and again.
We agree that when you have a body of water, it bulges in the middle. It does this for the following reason. Pressure. But that does not mean the world is round. A curve on a localised surface does not mean you can extrapolate a circle.
Barometric pressure is measured in millibar, that's 0.001 bar.
You could also measure it with a column of water, a 10m high water column gives 1 bar. Or a water column of (1000cm*0.001) 1cm gives 1 millibar.
So to get a bulge with hight 10cm in the middle of the measured stretch by barometric pressure, the pressure difference between the middle of the observed stretch compared to the pressure at the coast/beach has to be 10 millibar.
The observed distances are something (beach to mid point) less than 10 nautical miles.
10 millibar over a distance of 10 nautical miles?
The general observation at moderate latitudes is: 5 millibar pressure difference over a distance of 100 (one hundred) nautical miles results in gale force winds.
Your
"It does this for the following reason. Pressure" just swirled away in a fierce tornado.