The first reported submarine was designed as early as the year 1620 when a Dutchman named Cornelius van Drebbel experimented with a raw boat covered with waterproof leather skin. However, not much information is available regarding his experiment and the vessel that he created could probably be a ‘submersible’ rather than a ‘submarine’ when it comes to current terminology.
What is a ‘submarine’?
It is a ship designed to carry people through the harsh waters of deep seas with the ability to navigate either on top or underneath the ocean surface. Vessels that are created mainly to dive deep are given the term ‘submersible’ and these vessels appear rather small in comparison to a ‘submarine’.
What is the mechanism used by a submarine to ‘sink’, ‘float’ and ‘surface’?
When an object is denser than the surrounding water, it usually sinks while an object that is less dense will float. Similarly, when the object gains similar density to the surrounding water, it has the ability to float. The mechanism used by submarines to sink, float, and surface would be along this same principle.
The submarine body consists of two walls. The outer wall is strong and waterproofed while the inner wall is stronger and could resist immense pressures. The outer and inner walls of the submarines is also referred to as the ‘outer’ and ‘inner’ hulls while the much stronger ‘inner hull’ is also given the name, ‘pressure hull’. The space between the two hulls is called the ‘ballast tanks’ and it is the space which allows the submarine to move around through changing the overall density.
When the submarine needs to dive, the ballast tank will be partially filled with water and the air will be kept compressed and kept out from the tank. This mixture of less air and more water makes the submarine denser and therefore allows it to sink. Similarly, when the sub needs to surface, the water will be pumped out, and more air will be filling the ballast tank. The lessening of the density of the sub will allow it to rise. At the time of floating under the sea surface, the water and the air mixture within the tank will equal the density of the surrounding seawater and with the use of propellers; the submarine will be able to move.
How does a submarine generate its power?
In modern day submarines, nuclear generators mainly do the power generation while certain other submarines will depend on diesel electric generators. However, the engines driving the propellers do not get direct power from these generators and instead, an electric battery will store the generated energy and supply the propellers. Due to this, submarines can shut off its generators when the batteries are fully charged which makes it so silent when it floats through the seawater.
How do submarines generate water and oxygen?
Water and oxygen are essential for those who travel inside a submarine and modern day nuclear submarines can generate its own oxygen through splitting water molecules as well as prepare its own drinking water by removing salt from the seawater.
How does the submarine navigate through the waters?
As the deep seas are darker and do not allow the submarine crew to see, other modes of navigation such as radar, ultrasound, GPS…etc are being used to navigate through the waters.
Reference:
Office of naval research : Science and Technology Focus: http://www.onr.navy.mil/focus/blowballast/sub/default.htm
