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Notice how broad and obvious the water surface is close to the periscope.
The water almost seems to be sloping downward toward the viewer.
But we all know that water doesn't do that.
What we are seeing is the effect of the telephoto lens.
It's even more dramatic with binocular view, which some periscopes have.
The farther away an object is, the more compressed in depth it gets (close to far).
The curvature of the earth is reproduced in the curvature of the surface of the sea.
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These images are under tremendous magnification by telescope.
The distance near-to-far is greatly compressed.
Therefore we can see the effect of the sea's curvature in the distance.
The view from left to right is not subject to the same effects of magnification.
This is because from the viewer to the target ship is several miles,
whereas from left to right is only a half mile.
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The lowest 10 feet of this target ship above the waterline is obscured by the curvature of the sea.
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This ship being torpedoed appears to be setting at the edge of the world.
There is utterly no water behind the ship and the lower pat of the hull is invisible.
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The massive IJN Shokaku aircraft carrier was sunk by the American
submarine USS Cavalla on June 19th, 1944.
845 feet in length, beam 85 feet, draught 29 feet and 25,675 tons in weight.
That's like 3 football fields of ship.
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With the huge expanse of water close to the periscope and height fading to nothing at the target range,
it is readily seen that it is the downward curve of the water surface over great distance
that explains why we see no water beyond the target ship.
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If the earth were "flat" we would see a lot more water in the distance
and the horizon line would be well up into the hull area of this sinking ship.
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But since the sea curves downward into the distance we don't see that at all.
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Topic: Why Do Periscope Views Hide the Lower Hull of Distant Ships? (Read 8656 times)