Looking at this picture, the water appears to rise as it gets closer to the ship. To me it looks as if the boat is just on the other side of the crest of a wave ... which would explain why the bottom part of the ship is not visible.
If this were a photo from someone trying to deceive you, perhaps they would pick a shot with the crest of a wave in the way. But this is a photo taken by a submarine while attempting to record a GOOD IMAGE of a target ship. They wanted to get the most exposure of the target as possible, and if there were any rogue waves about they would have taken the shot while the target ship was on TOP of the crest with a trough in between the target and the periscope.
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Nobody is trying to fool you, and it's silly to presume you're being lied to. There are hundreds of movies showing periscope images, taken in calm seas, with no erratic waves making things unusual for cherry-picking.
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From the top edge of the water that's in front of the ship it's about 500 to 1000 feet back to the ship.
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What we see is the "hump" in the water's curvature.
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Look closely at the target ship. It has the appearance of a cardboard image.
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That's because telephotos do that to distant objects, which you would know if you had any experience with them.
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The moon appears to be flat as a pancake even with binoculars.
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People walking around at great distance appear to be paper dolls -- FLAT images, but they're MOVING!
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Why, also, is more of the ship's bow visible than the middle and stern? There appears to be a curvature of the water up towards the middle of the vessel. Perhaps the water is being displaced upwards further back as the bow of the ship is cutting through the water? See my point? If the bottom of the vessel were being hidden merely by the curvature of the earth, I would expect less of the bow to be visible as well.
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Perhaps you never built model WWII ships. The shape of the deck is typical, with a higher bow and stern and a lower midships.
Even the Queen Mary has such a curve in
all the decks, and it was built BEFORE WWII.
The curve you see is in the ship, not the water. Try a straightedge. The water makes a perfectly straight line from left to right.
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So I don't know. I'd want to see pictures and measurements taken scientifically where all the factors are known: distance between the observer and the target, height of the viewer above sea level, height of the target above sea level ... taking into account wave conditions.
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You ought to take a trip to a nautical museum and ask your questions. They have plenty of data you can sort through. Find a submarine captain (I've spoken to one) who can answer your questions. Try watching some WWII submarine movies with moving images of what the periscope showed. This isn't rocket science.
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But if you do speak to a sub captain, be prepared for some straight talk. They don't mince their words.
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If you tell a sub skipper that you think the earth is "flat" he might give you a real treat of Old Salt linguistics.
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