On what principle , a submarine runs under water?

Question

On what principle , a submarine runs under water?

Answer 1

Control of buoyancy and of course a system of propulsion and air supply and other provisions if manned..

Answer 2

Neutral bouyancy.  There is a balance between the weight that's causing it to sink and the air that's causing it to rise.

Answer 3

Archimedes principle (EUREKA!) ? (buoyancy and all that-displacement of an equal mass of volume allows the object to float).

Answer 4

Archimedes principle (EUREKA!) ?  (buoyancy and all that-displacement of an equal mass of volume allows the object to float)

Answer 5

Subs run under the water because they take on water to make their weight equal to or slightly less than they weight of water they displace.

A ship in water floats because the sides of the vessel remain above the water when the vessel pushes down into the water as a result of it's weight. An amount of water is pushed aside when the vessel is put into the water. The weight of the water pushed away by the hull is equal to the total weight of the vessel. AS long as the sides of the vessel are high enough so that no more water enters the inside of the vessel it will float.

A submarine can allow water to enter special tanks (Ballast) The weight of this water is added to the weight of the submarine. The submarine looses "Bouyancy" that is it is heavier than the weight of the water it displaces and it sinks.

Now - whether on the surface, with dry ballast tanks and riding light, or under water, submarines are driven by engines or better - electric motors (Deisel-electrics) or steam turbines (Nuclear). These motors, engines or turbines turn propellor shafts to which propellors are attached. Turning the propellors (Screws) will push the sub through the water.

You can see how a sub gets underwater by taking a common drinking glass and putting  it into a tub of water. Put enough water in the glass so it floats upright. The glass floats because it's weight plus the water you added (Ballast) is exactly equal to the weight of the water the glass pushed away when you put it in the tub. You will see that with just some water in the bottom, the glass will float. Now when you add water, the glass will get heavier - loosing bouyancy. It will be lower in the water - like a sub filling the ballast tanks. Add too much weater and the edge of the glass will sink below the surface of the water in the tub. The glass sinks uncontrollably to the bottom of the tub. In a sub, they do the same thing. But they admit only enough water into the ballast tanks to let the sub sink a bit. The diving planes - like big wings, are tilted a bit and as the sub moves through the water, they literally drive the boat deeper - or, when they are way down, up toward the surface. The depth of the sub underwater is controlled by a delicate balance between the angle on the diving planes and the amount of sea water in the ballast tanks

There are books on this subject. These have diagrams and much more detailed explanations but I think you get the general idea.

Answer 6

good question never thought of it...