HOW DOES A SUBMARINE WORK?!

[Dream's land]

How Does a Submarine Work?




Submarines are ships that can operate both under and on top of the water. One of the first submersible vessels was built around 1620 by a Dutchman named Cornelius van Drebbel.

We don't know that much about Drebbel's vessel, but diaries and books written at the time tell us his sub was really just a rowboat covered with a waterproof leather skin. Apparently 12 people with oars moved the vessel through the water. It could submerge to about 4.5 metres and go up to 8 kilometres before it needed to surface. It must have had some type of portholes to let in the light because one passenger wrote that people could see well enough underwater to read.

Submarines have changed a lot since Drebbel's day. Today some submarines are two football fields long (200 m) and carry a crew of over 150! Nuclear powered submarines can stay underwater for months at a time.

How It Works

Submarines are designed for use at great depths. Their rigid, double-walled hulls allow the crew to live and work normally underwater for as long as air and power supplies last. Submarines are steered by turning a rudder left and right. A propeller moves the sub through the water, pushing water backward so that the submarine moves forward.

The crucial problem for a submarine is that it must either sink or float on command. Most things either sink or float, but can’t do both. Why? When an object is placed into water, it either sinks or floats according to its density. Objects denser than water (like metal) sink, while objects less dense than water (like air-filled balloons) float. What about a submarine?
Submarine cross section



Submarines are a mixture of metal (the hull), air, and water (the “ballast”). The secret of a submarine’s ability to either sink or float lies in a special property of air. Unlike water or metal, air can be squashed into a tiny space. While the submarine is sinking, its air is compressed. Water fills the compartments called the ballast tanks. The combination of water and metal, with just a little bit of air in the centre for the crew to breathe, is more dense than the surrounding ocean water, and so the submarine sinks.

Once the submarine is underwater, air is pumped into the ballast tanks. The new combination of metal, water, and air is just as dense as the surrounding water, so the submarine hovers, neither sinking nor rising. This is called “neutral buoyancy”, and allows the sub to maneuver underwater.

When it’s time to rise, even more air is pushed into the ballast tanks. This pushes water out, resulting in a mixture of air, metal, and water that is now less dense than the water surrounding the sub. Under these conditions, the sub rises to the surface.



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http://www.funonthenet.in/forums/index.php?topic=125490.0

[***ShIvAm***]

 
nice info dear
 

[Dream's land]

THANKS LOADS SHIVAM DEAR...FOR YOUR NICE VISIT...
WHICH MADE ME SO HAPPY.

[Pŕąvźŷ]

 

[$bindass dame$]

GR8 INFO

[ђยzєє]

  nice post sarah a k added for posting first time here 

[hvpurs]

Thanks Sarah for explaining the working of a Submarine in Layman's language.

 

HVP Urs