How does a submarine doesn't sink to the bottom of the sea bed?

Answer 1

Buoyancy. In simple terms, there are both floats and weights as part of the ship which keep the submarine either submerged or afloat at the level it wishes to be.

Answer 2

On the surface, a submarine has several tanks in the forward (front) and aft (back) ends of the ship full of air. These tanks are called Main Ballast Tanks, and they provide the extra buoyancy to keep the ship afloat. When the submarine submerges, vents open to let the air out, and this extra buoyancy is lost. The goal is to make the ship neutrally buoyant after the main ballast tanks are full of water. This way, the submarine neither sinks nor floats back to the surface. There are additional tanks inside the submarine called variable ballast tanks that can have water added or pumped out. By adjusting the level in these tanks, the sub is kept as close to neutrally buoyant as possible.

Note that when moving, the stern planes (horizontal fins in the back) and either bow planes (horizontal planes in the front of the ship) or fairwater planes (horizontal planes on the sail) can be used to provide lift. The faster the ship is moving, the more lift these planes generate. A submarine can hold a lot of extra weight and still not sink due to the operation of the planes.

Now, if a submarine were to loose all propulsion and come to a stop, it would most likely not be exactly neutrally buoyant. If it was a little too heavy (and no one did anything about it), it would start to sink. The increased sea pressure would compress the hull slightly. This would reduce the buoyancy, and it would then start to sink faster. This would continue until the sub hit the bottom, or broke up from the pressure (and then would hit the bottom in pieces). If the ship was a little light, it would start to rise. The reduction in sea pressure would cause the hull to expand, and buoyancy would go up. It would then rise faster until it reached the surface.

Answer 3

Submarines have air tanks that they can pump water in and out of in order to vary their depth, or to surface they pump all the water out.

Of course if the hull of a submarine is breached, and it fills with water, then it will sink.

Answer 4

The earth farts, whenever large heavy metallic tubes grow near. This causes the submarine crew to hear what they perceive as enemy presence. They then rise to the surface, as cowardice is the reason uniforms and brass cover their quivering chests.

This natural phenomenon explains the foam that is found on most shorelines, worldwide.

Answer 5

Air

A sub uses compressed air and water as ballast. That keeps them from going too deep.