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Cont: The Sinking of MS Estonia: Case Reopened Part V

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Vixen said:
No. When a ship or any item is submerged beneath water the laws of gravity do not remain the same (buoyancy)
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Haha. No. The laws of gravity are the same under the sea as they are above the sea. As they are the same on the moon, or on the top of Mount Everest, or at the bottom of the ocean, or in deep space.

You fail basic physics.
 
JesseCuster said:
Haha. No. The laws of gravity are the same under the sea as they are above the sea. As they are the same on the moon, or on the top of Mount Everest, or at the bottom of the ocean, or in deep space.

You fail basic physics.
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Oh my. Vixen actuallly wrote that, didn't she! I never before realized that ships float because of different effects of gravity. Naval architecture musr be a world unto itself.
 
Steve said:
Oh my. Vixen actuallly wrote that, didn't she! I never before realized that ships float because of different effects of gravity. Naval architecture musr be a world unto itself.
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A universe unto itself indeed if it has different Physical Constants.
 
Vixen said:
No. When a ship or any item is submerged beneath water the laws of gravity do not remain the same (buoyancy) and nor do doors swing open and shut, due to water pressure. So imagine a surge of seawater enters the car deck. How then would the open car ramp now swing shut 'a few times'?
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I could be wrong, but with my simple background in marine geology, buoyancy is about floating, or the inability to float, and or sinking. Either way, gravity is main feature. I point to the fact that, as of yet, no ship has ever floated into the sky, and drifted out of the atmosphere after taking on water.

I'm not an engineer or a physicist, so I can't address the many factors of ship-design, and the sinking thereof. But I can tell you about what happens at the bottom of the ocean. Rock formations undergo erosion undersea the way they do in mountains and deserts. While the process is different, subject to water-flow from deep sea currents, normal, and storm-driven. The results are similar. When a large foreign object from the surface is introduced into a deep sea (benthic) environment, this object is subjected to those deep sea forces.

The Estonia isn't in deep water, which means it's subject to a variety of currents. These have been logged, thanks to the latest investigation where they planted sensors to chart current flow, speed, direction, and duration (really cool marine science). Since the wreck has not been monitored regularly no one can say for certain what has gone on with the bow ramp over the years, but it is wide open now. The ship is slowly rolling as it has come to rest at the edge of a steep slope, crested with a rocky outcrop. This rolling is what caused the hull plates to split open, The rolling is caused by a combination of currents, structural failure from rust and water pressure, and...*drum roll*...gravity.

*I apologize about the 45-degree thing. Should be 90.*

Either way, the issue is closed, Estonia sank from heavy seas it was never designed to sail through in the first place. And with the new evidence pointing to design flaws, the ship should not have put to sea at all in that weather.
 
JesseCuster said:
Haha. No. The laws of gravity are the same under the sea as they are above the sea. As they are the same on the moon, or on the top of Mount Everest, or at the bottom of the ocean, or in deep space.

You fail basic physics.
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Scotty: "Ye cannae change the laws of physics, Cap'n!"
Kirk: "Take her underwater, Scotty."
Scotty: *slaps forehead* "Och aye! Of course! Brilliant, Cap'n! Takin' her under water!"
 
Steve said:
Oh my. Vixen actuallly wrote that, didn't she!
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Yes. Yes, she did. Her abject ignorance of physics in this thread is the stuff of legend, despite her claim that she can somehow know that the crackpot Anders Björkman is correct on the subject of ship stability and therefore we should all take him seriously.

On that subject, she found a YouTube video that discusses how schooner-type hulls right themselves after heeling—up to a certain angle (i.e., the G-Z method of establishing metacentric height, an important parameter in transverse stability). But when she tried to restate that model in her own words, she hopelessly confused basic concepts like lines and points. It was pure, amusing gibberish. The model is correct and useful, but Vixen doesn't understand a word of it.

And that model has two important limitations. First, it's intended for an "intact hull," meaning that neither the center of gravity reckoning or the center of buoyancy reckoning in that model accounts for flooding, which—when it occurs—changes both. When asked whether she could adapt the model to including flooding, she was silent. It can be adapted, but she can't do it. And until she can, the model doesn't apply to MS Estonia.

The reason it's useful is that schooners (or rather, ships with sails) must be handled with very careful attention paid to roll moments induced by such things as heeling under "by" points of sail, as opposed to "large" points of sail that tend to induce pitch moments instead. For powered vessels, metacentric height is considered mostly in the case of turn radius for a given speed. It's not as important as for sail, and it's mostly irrelevant when a ship is listing because it is flooding.

Second, most powered vessels have vastly different hull cross-sections than a schooner. As such, they have more than two nodes of stability. Björkman (and, consequently, Vixen) wrongly applies the G-Z model, and as such comes up with only two stable nodes: righted and turtled. Many modern squarish hull designs have another node of stability on their beam ends, such as with the Herald of Free Enterprise, which floated stably on her beam ends before settling to the bottom on her side. I asked Vixen if she could compute whether Estonia had such a stable node. Again she was silent.

No, the "laws of gravity" do not change underwater. Yes, the final dynamic state of an object is a combination of gravity and the effects of any fluids that may also be present, such as air or water. But gravity doesn't behave any different simply because we're now underwater. The law of gravity is in full force.

No, Vixen, you don't know what you're talking about, as usual. And as usual, you're trying to teach from a position of abject, fully-evidenced ignorance. Just stop.
 
JesseCuster said:
Haha. No. The laws of gravity are the same under the sea as they are above the sea. As they are the same on the moon, or on the top of Mount Everest, or at the bottom of the ocean, or in deep space.

You fail basic physics.
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Indeed close to my exact thoughts when I read that post. Particularly when the buoyancy of any object is directly proportional to the acceleration of gravity (as well as the volume of the medium displaced, and that medium's density).
 
Vixen said:
When a ship or any item is submerged beneath water the laws of gravity do not remain the same
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Here comes the physics masterclass once again...... :D


(ETA: should've realised I'd be ninja'd comprehensively on this one!)
 
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Axxman300 said:
I could be wrong, but with my simple background in marine geology, buoyancy is about floating, or the inability to float, and or sinking. Either way, gravity is main feature. I point to the fact that, as of yet, no ship has ever floated into the sky, and drifted out of the atmosphere after taking on water.

I'm not an engineer or a physicist, so I can't address the many factors of ship-design, and the sinking thereof. But I can tell you about what happens at the bottom of the ocean. Rock formations undergo erosion undersea the way they do in mountains and deserts. While the process is different, subject to water-flow from deep sea currents, normal, and storm-driven. The results are similar. When a large foreign object from the surface is introduced into a deep sea (benthic) environment, this object is subjected to those deep sea forces.

The Estonia isn't in deep water, which means it's subject to a variety of currents. These have been logged, thanks to the latest investigation where they planted sensors to chart current flow, speed, direction, and duration (really cool marine science). Since the wreck has not been monitored regularly no one can say for certain what has gone on with the bow ramp over the years, but it is wide open now. The ship is slowly rolling as it has come to rest at the edge of a steep slope, crested with a rocky outcrop. This rolling is what caused the hull plates to split open, The rolling is caused by a combination of currents, structural failure from rust and water pressure, and...*drum roll*...gravity.

*I apologize about the 45-degree thing. Should be 90.*

Either way, the issue is closed, Estonia sank from heavy seas it was never designed to sail through in the first place. And with the new evidence pointing to design flaws, the ship should not have put to sea at all in that weather.
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You would be factually wrong. The issue is not closed as the Swedish government is investing in salvaging the car ramp door.

Compare and contrast with the 'facts' surrounding the Titanic. Most people believed it was an established fact that the Titanic hit an iceberg. The thinking person knew all along that this theory was just someone's 'best guess'. This is the difference between true sceptics and those who accept unproven theories at face value. Which camp do you fall into?

Now that there has been an extremely detailed three-dimensional imaging of the wreck hitherto not technically possible, we can now say it is an established fact it hit an iceberg, although this is not 100% definitive.

But the new images confirm that the Titanic has clearly hit an iceberg and then went down into the ocean. However, it may not have hit the ship’s starboard, as shown in the Leonardo DiCaprio movie.
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Spieltimes

Is the issue of the Estonia closed as you claim?

Estonia's bow visor was already salvaged in 1994, not long after the disaster occurred. But the bow ramp, which was behind the visor, remains at the bottom of the Baltic Sea.

Discussions have been held as to whether the bow ramp should also be salvaged as it is considered an important piece of the puzzle in the sequence of events in the sinking. And now the government has added 25 million kroner following a request from the National Accident Commission to carry out the work.

Damage to the ramp
The dives are being procured, says Jonas Bäckstrand, and the idea is that they will take place during the early summer.

There is some damage to the ramp that they want to examine, among other things they have been able to see marks in the ramp in the shape of a triangle in photographs that correspond well with how it hit the front car deck.
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aftonbladet
 
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MBDK said:
Indeed close to my exact thoughts when I read that post. Particularly when the buoyancy of any object is directly proportional to the acceleration of gravity (as well as the volume of the medium displaced, and that medium's density).
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It is your prerogative to believe that the car deck door/ramp swung open and shut like a barn door on a windy day whilst it sank. Perhaps ask yourself this question. How come people who accidently drive into a river or get swept away by sudden floods - as happens in US hurricanes or Japanese tsunamis - don't just simply open their car door and escape?

I'll leave it to you to find your own answer.
 
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