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Action and reaction , the ship is lighter from the discharged ballast- so it will float upwards with buoyancy. One assumes you are talking about submarines. Some surface ships have trim tanks to compensate for cargo compartments not being balanced- etc. but this is not a submergence device.

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Q: How does forcing air into the ballast tanks cause the ship to rise?
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What is the function of the ballast tanks on a submarine?

To change the buoyancy of the boat and allow it to rise and sink in the water.

How does a submarine change its density?

To be able to submerge in the water, the sub has to become heavier. Ballast tanks are utilzed for this purpose. Water is let into them, and the sub sinks. To rise, air is pumped into the ballast tanks, and the sub rises.

Why do submarine not sink?

As with all boats, a submarine does not weigh as much as the amount of water it displaces. To go under the water's surface, it pumps water into special tanks (ballast tanks), and to rise up again those pumps force the water out of the ballast tanks and back into the sea.Ans 2 - Submarines can go deep and rise again by using water ballast and air pressure, as planned by the captain. -Unfortunately, when things go wrong, submarines DO sink.

How do submarines travel below surface?

By reducing their bouyancy, through letting seawater into the ballast tanks then sinking to the desired level . When they want to stabilize or rise they use compressed air to blow this ballast water out.

How is a submersible made heavier to allow it to descend?

Some kinds of submarines use ballast tanks, they are tanks on the subamarine which the submarine fills with water to make it sink or filled with air to make it rise.

How does a submarine work?

A submarine has tanks that are called ballast tanks. When these tanks are flooded with sea water, the submarine sinks because the sub weighs more than the water it displaces. To rise again, the sub reduces its weight by pushing compressed air into the ballast tanks. The air forces the sea water out and sub returns to the surface. It maneuvers using its rudder and planes. A link is provided.

How do fluids help ballast chambers on a submarine?

A submarine actually controls its weight by allowing water to enter or exit hollow chambers in its hull. These chambers are called ballast tanks. Ballast is anything carried in a ship to give stability. When water is allowed to flood into a submarine's ballast tanks, the weight of the submarine increases. When this increased weight exceeds the submarine's buoyancy, the submarine will sink. To allow the submarine to rise, air is pumped into the ballast tanks. The air forces out the water, reducing the weight of the submarine. The submarine then becomes lighter, buoyancy increases, and it floats to the surface. A submarine can also be made to "float" underwater at any depth by adjusting the amount of water weight in its ballast tanks.

Why can a submarine sink and float in sea water?

A submarine has "ballast tanks" which can be filled with water to make the vessel heavier (total density greater) than water and dive to required depth. These ballast tanks can also be filled with air (compressed air is kept on board for this) to make the vessel lighter and rise to the surface

If a submarine is at depth of -300ft what must happen for it to reach sea level?

It must rise 300ft.Ans 2 - Water in the ballast tanks must be blown out with compressed air, and the planes set to rise as the sub makes headway forward.

How does a submarine change its buoyancy?

The ship floats because of its large volume which displaces an amount of water that is more than its weight. That creates an upward force called buoyant force which keeps the ship on the surface.

Why does a submarine rise?

Submarines have positioned along the outer hull, ballast tanks. These tanks are filled with sea water to cause the submarine to reach neutral displacement, and help the boat submerge. Additionally, at the bow are positioned moveable "wings" or bow planes. When the bow planes are pointed downward, and the screws (propellers) are turning, the force of the water against the planes pushes the bow downward, pulling the boat deeper into the water. The reverse is true as well. When the Captain wants to raise the boat, he orders the ballast tanks to be emptied, or blown for a fast rise in the event of emergencies. Pumps evacuate the water and compressed air is pumped into the tanks. This lowers the displacement. With the bow planes pointed upward, the screws push the boat upward, and it surfaces.

How do submarines float and then sink?

The majority if a submarine is not the space where the crew lives, but large tanks called ballast tanks. When the submarine wants to sink, water is pumped into the ballasts and the submarines average density gets higher than that of the surrounding water so it sinks. When this happens the air is compressed into smaller tanks, but when the submarine wants to rise the air is pumped back into the ballasts, forcing the water out, dropping the average density llower than the water so it floats. When it wants to remain neutral, halfway between the surface and the bottom, the amount of air and water in the ballasts is regulated until it is equal, so the submarine doesn't move. Hope this helps!