You are ignoring the Curvature drop over 36 miles. Why? None of your diagrams include the curvature drop? Why?

Where is the curvature drop of 216' at 18 miles?

I clearly showed you where is the drop of 216 feet.

It is below the sea level.

**Between the sea level and the plane connecting the coast lines.**

EDIT: My mistake, and my apologies.

The drop is 216 feet, but from the local horizontal line at one coast.

The bulge is smaller.

The bulge is 53 feet high.

Several hours ago I corrected my mistake in this post above.

The distance of 18 miles has bulge of 53 ft.

The 216 ft is the drop on another side from the horizontal line from one side.

(Not even from the line of sight, unless your eyes are at sea level.)

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If there was no land, then the water would take its level in the shape of smooth ellipsoid.

Land submerged in that water is higher than that ellipsoid (the sea level) and the elevation is measured from that ellipsoid.

I already asked you what would be the values if you measured from Indian ocean?

By now you already understand why I asked that.

It is also sea level there.

But only local sea level is what counts,

not from 9 miles away from coastal line,

not from 615 miles away from Jamaica,

not from 1000 miles away from Galapagos.

From the level that would sea have

**right there**, if there was no land.