How does a submarine go up and down in water?

Question

How does a submarine go up and down in water?

Answer 1

The 'Ballast' tanks are 'flooded' with either sea water, or 'blown' with compressed air, from reserve tanks. Once the submarine has achieved 'neutral bouyancy' (neither sinking nor rising) then the the forward motion of the sub forces water over the control surfaces (elavators to rise & fall) and rudder (Yaw). Thus the sub is 'flown' under water, in a similar fasion to an aircraft.

Answer 2

To go from the surface to submerged and back, the submarine floods water into, or blows water out of, tanks that surround the submarine - main ballast tanks.

While submerged, the submarine is almost always moving, and it uses planes (fins) attached to the "sail" - the part that sticks out in the middle. The planes tilt upward or downward to make the submarine go shallower or deeper as it moves through the water.

If the submarine ever stops, keeping depth is much tougher, because the planes no longer work - they need moving water to create the lifting or diving force. Then the submarine must hover by adding water (flooding a tank) or pumping water out of a tank.

Hovering is tough, especially when you are sinking, because pumping is very slow. You can blow a tank with air if needed, but that is bad because 1)you can over shoot and pop to the surface - very very bad, and 2) you make a lot of noise, also bad for a submarine.

Answer 3

The average density of a sub on the surface is less than water - obvious, its floating.. By filling the ballast tanks with water, the average density of the sub increases and, when greater than water, the sub sinks. The density of sea water increases with depth. When the sub decends to a depth where is't density is the same as the water around it, it 'hovers'

Answer 4

They have ballast tanks that air/water can be pumped in or out.
Water to submerge and air to surface.
The air is kept in compressed tanks in the submarine when not required to surface.

Answer 5

when it is travelling under water a sub uses the fins at the front. when they tilt upwards the sub will go up. when they tilt downward it will go down...when the sub is not moving it uses it ballast tanks. the tanks flood with water then it sinks .the sub pumps out the water from the tanks and fills them with air,then it floats.

Answer 6

To go down, it induces water into the ballast tanks; to surface it used air pressure to purge the ballast tanks and become buoyant.

Answer 7

Its got floatation tanks in it and they take water in when it wants to submerge and it blows the water out when it wants to surface

Answer 8

fills special tanks with air or water.

can also use a kind of sideways-pointing rudders to go up or down as it moves forward

Answer 9

they have pogo sticks. attatched to the underline...

Answer 10

Very well thank you.