I assume the metal and materials the boats are made of are strong but surely not to withstand the pressure of being 12,000 feet underwater? At the end of the day it’s not like the engineers had to consider holding up to that much pressure in their design right?
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One system (submarine) has differential pressure, like a tire on a car.
The other system (titanic) has equal pressure on all sides, like a tire swing on a tree.
Going deep makes the pressure go up. In the closed system, this difference increases. It’s like adding weight to one side of a scale until it tips. The open system is like balancing a set of scales, so each time I add a weight to the left side, the same weight is added on the right and the difference never increases no matter how many weights I add.
One system (submarine) has differential pressure, like a tire on a car.
The other system (titanic) has equal pressure on all sides, like a tire swing on a tree.
Going deep makes the pressure go up. In the closed system, this difference increases. It’s like adding weight to one side of a scale until it tips. The open system is like balancing a set of scales, so each time I add a weight to the left side, the same weight is added on the right and the difference never increases no matter how many weights I add.
One system (submarine) has differential pressure, like a tire on a car.
The other system (titanic) has equal pressure on all sides, like a tire swing in a tree.
Going deep makes the pressure go up. In the closed system, this difference increases. It’s like adding weight to one side of a scale until it tips. The open system is like balancing a set of scales, so each time I add a weight to the left side, the same weight is added on the right and the difference never increases no matter how many weights I add.
Because the titanic doesn’t contain gases. Objects that are only composed of solids and liquids are almost unaffected by pressure.
They can be slightly affected if the pressure compresses some material more than other, but at the pressure of where the titanic is, the effect is negligible on any liquid or solid.
They can also be affected if a different crystal configuration is more stable at this pressure (like graphite to diamond), but they only happen at pressure a lot larger than that. Thousands of times larger for graphite to diamond, for example.
Also, all the posts you’ve seen about humans’ bodies being crushed at those depths are false. Humans would die if they were in water at those dephts because of the effects on gases in their lungs and blood, but their body will remain almost exactly the same as usual.
Because when they sink, they also flood. There’s water both inside *and* outside, so there’s no pressure differential. The force is equalized.
If pressure was only acting from the outside (like if a sub’s ballast tanks failed and it started sinking uncontrollably beyond its rated depth), it would eventually be crushed… but once the hull buckled and the interior was fully flooded, the pressure inside whatever was left would equalize and it wouldn’t *keep* being crushed.
**Practical demonstration:**
Pick up any flat object, like a board or a piece of paper, put a hand on either side and press your hands together. Not crushing anything, right?
Now pick up an egg and do the same thing (outside, please, and wearing clothes you don’t mind getting egg on). At some point, you exert enough pressure that the egg shell buckles and the whole thing implodes violently.
They don’t have to hold up to because they’re full of water, thus there’s no pressure differential acting upon them. This is different from a submarine which has to maintain a specific air pressure inside the passenger compartment whilst being at depths with extreme outside pressure acting on the submarine. If the pressures are equalised then there’s no pressure exerted on the ship because it’s being pushed equally by all sides.
Probably already got your answer, but if you want to see it in action, fill a balloon or a plastic bag with air and put it under water in your bathtub for example. That’s the submarine. Now fill it with water and do the same. That’s the ship. You will see the difference yourself.
The reason the Titanic isn’t crushed is because there is no air left in the ship. any air trapped in the ship was also considered open spaces where the water pressure was able to act on the pressurization of the air and compress it. The Titan is trying to maintain 1 atmosphere inside the capsule and to do this they have maintain an equil pressure from the inside as the water pressure from the outside. Any change in that equilibrium and you can have huge issue coming to the surface in the form of decompression sickness (aka the bends) or you can be crushed at depth.
FYI the pools on the Titanic (which was one of the few cruise ships to have pools), still have water in them. LOL
You need to think a bit about what “crushing under pressure” is, and why it happens.
The implication is that there’s some watertight structure maintaining sea level air pressure inside, with the external water pressure outside squeezing it. If the structure isn’t strong enough, it gets compressed, until either
1. the structure gains more strength due to deformation and now touching itself more internally,
2. the air pressure inside increases due to the compression and can support the water pressure, or
3. the structure loses its watertightness, water floods in, and *equalises the pressure* so there’s no more crushing
1 is what happens if you’re trying to squish, say, a carboard box. It folds in on itself, ridges etc form internally touching the other side, and it gets harder to squish.
2 is what happens if you blow up a balloon and then take it underwater – the water pressure will cause it to shrink, maintaining the balance of air and water pressure at increasing depths. (this is also happening to your lungs at the same time if you’re swimming down with the balloon!)
3 is what happens in most cases with rigid materials if you go deep enough, eg a shipwreck. There’s no air left anywhere in the ship once all air pockets have been crushed and broken by the pressure, so everything has water surrounding it so there’s no bulk crushing force any more. Sure each individual steel beam or whatever is being squished by water pressure, but solid metal is pretty strong stuff so the difference is barely measurable (I haven’t looked up the numbers, but probably a 1 meter steel beam is like 1 micrometer or something shorter at that depth)
And finally…
>but surely
It’s almost always a bad idea to preface your (quite possibly incorrect) suppositions with this
It imploded on the way down. So there’s no pressure acting on it because it is filled with water. https://youtu.be/FSGeskFzE0s
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