How do big ass ships like aircraft carriers actually float on water while carrying the weight of aircraft, engines, controls, etc?
In: Engineering
Water is very heavy, most of those big ass things are still mostly air therefore the ship will float.
Buoyancy is what holds up a ship. A ship displaces a certain volume of water — the ship “makes a hole” in the water of a certain size. If the volume of the ship inside the hole is lighter in weight than the water would be, it floats.
Water is _heavy_, and the interior of a ship is mostly air, really.
A cubic foot of air weighs very little (like, .08 pounds). A cubic foot of seawater weighs 64 pounds.
It’s proportional, so the bigger the boat the more weight they can carry. Those aircraft carriers are ABSOLUTELY MASSIVE and the buoyancy grows accordingly. Also having a large volume displacing water maters. Use the same weight but as a pole and the pole would sink, the amount of water displaced is more than the weight of the ship. So the force of the water pushes the boat “up”.
Buoyancy.
This is the principle regarding whether things will float or sink. This compares the weight of the object you place in the water with the weight of the water that would take up the same space.
So if you put a 1cm cube of steel into water, 1cm³ of steel weights more than 1cm³ of water, and the steel sinks.
If you put a 1cm³ cube of polystyrene in the water however, the polystyrene will weigh less than 1cm³ of water, so the polystyrene isn’t heavy enough to push the water out of the way and it floats.
Ships like aircraft carriers are hugely heavy things, but they are also absolutely vast, but most importantly, they are also full of a lot of air and space – just think of all the space in corridors and rooms that is just air. So if you add up all of the weight of the steel and other heavy bits, that weight will be less than the weight of all the water it would take to fill up all the corridors and rooms inside.
So it seems mad when you consider that the big US carriers are approaching 100,000 tonnes, but they are so big that the water that would occupy the same space weighs even more than that.
As long as the amount of water it’s displacing (the area of the water from the water line and below) weighs more than the equipment/ship above the water line, then it will float.
Fluids exert an upward force on objects proportional to the fluid displaced by the object. If the force is greater than weight then the object (ship) floats. That’s why ships sink a little when it gets too heavy (to displace more water to increase the force)
* Two things can’t occupy the same space at the same time.
* So when the ship goes in the water, it takes up space.
* The water that used to be in that space gets pushed to the sides.
* But there was already water to the sides, so that water gets pushed up.
* So the weight of the boat is actually lifting the weight of the water that it pushed out of the way.
* As long as the weight of that water is heavier than the weight of the boat..it floats.
* Don’t forget that shape matters.
* IF the boat was super skinny, then it would only have to move a little bit of water out of the way.
* But boats are designed to take up enough space in the water to make the water it moves weight more than the boat.
By being big enough to displace a lot of water. The water they displace weighs even more than the ship’s weight, so it floats.
As long as what you’re putting in the water is buoyant enough, technically speaking, you can use or cram anything for / on said ship. Assuming your ocean is big enough and your ship buoyant enough, you could make a vessel the size of a city.
Water is actually really quite heavy. So there’s that. But even more important: steel ships, even aircraft carriers, aren’t one thick-ass solid hunk of steel— they’re hollow.
So this big honkin’ monster hollow steel bubble pushes SO much water out of its place, that if you weighed all of the water it pushes away, that water (which, remember, is actually really quite heavy) would weigh lots more than the ship. More, in fact, than the ship, the crew, all their crap and every boat and airplane stowed aboard.
However, the minute you put more weight aboard a floating object than the weight of the water it pushes away— guess what happens? It sinks.
This is how things float.
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