By S.S. YOGA
The Star Lifestyle
THE Yellow Submarine is arguably the most famous submarine in the world even if it’s only a figment of the wonderful imagination of the Beatles (courtesy of the group’s 1968 animated feature film, soundtrack album and title song).
A real submarine is a vessel normally with a crew, operating independently below the surface of the water – at times, at great depth. They are often referred to as “boats”.
The English word “U-boat” for a German submarine (infamous during the two world wars) comes from the German word for submarine, U-Boot (an abbreviation of Unterseeboot, German for “undersea boat”).
Submarines can range from compact two-person vessels to monstrous ones like the Typhoon class from Russia.
Gargantuan: The humongous Russian Typhoon class submarine.
Their capability to remain underwater can stretch from a couple of hours to even six months (especially nuclear-powered ones).
Apart from nuclear power, subs can also run on an electric-diesel combination. Now there are even hybrids that use diesel and liquid oxygen or hydrogen fuel cells.
Modern submarines are best described as cigar-shaped or with a “teardrop hull” – the hull being the outer body of the sub.
The shape helps reduce hydrodynamic drag when submerged but increases drag when the vessel surfaces.
There is a vertical structure located off centre closer to the front of the sub (as opposed to the rear where the propeller, or pump jet, is).
Ninja turtle: The ‘Turtle’ submarine.
Americans call it the “sail”, while Europeans prefer “fin”.
It is beneath this structure that the periscope, electronic masts (radio, radar, etc) and the control room (or the Conn) are normally located.
As subs are designed for use at great depths, there is immense pressure on the vessel. Smaller subs have single hulls but the bigger ones have double hulls.
The inner hull (pressure hull) protects the crew and the vessel from the water pressure and insulates them from freezing temperatures.
The outer hull shapes the submarine’s body. The ballast tanks, which control the ship’s buoyancy, are located between the two hulls.
Submarines are a mix of metal (the hull), air and water (the ballast). Submarines have to sink or float and this works on the principle of displacement of water and buoyancy.
Air is compressed and water fills the ballast, making the vessel denser than the surrounding ocean water and so it sinks.
When it has reached the level it wants, a certain amount of air is pumped back in so that the submarine hovers at that level.
Row your boat: A painting depicting what is apparently the first working submarine, designed by Cornelius Drebbel, on London’s Thames River in 1623.
And when it needs to rise, more air is pumped in, forcing the water out and making it lighter.
It’s not only the crew that have to worry about their weight (they need to keep fit and healthy) but the submarine itself too.
Burning fuel and using supplies change the weight of the sub.
So it has to be kept “trim” and there are two tanks (called trim tanks, of course): one in the front and one at the back that allow water to be pumped in or out.
Two controls are used for steering: the rudder for side to side (or yaw) movements and diving planes for rise and descent (or pitch).
There are two sets of diving planes: the sail planes (at the sail) and the stern planes at the back (stern) of the boat where the rudder and propeller are.
And let’s not forget how a submarine locates other vessels in the area while remaining undetected – it uses sonar (sounds waves travelling through water that hit an object).
Passive sonar uses sound from other objects to detect them; active sonar has the sub releasing a burst of sound that gives off a “ping”.
When the sound wave hits an object, it is reflected back and shows on the sub’s screen as a blip. The danger is that the enemy vessel may also detect this “ping”.
Are you ready now for your voyage to the bottom of the sea?
Sourced mainly from www.yesmag.ca/how_work/submarine.html and www.globalsecurity.org.
The Star
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