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The basic working of a submarine will be discussed in this post.
A submarine is a type of vessel which can travel both on the surface of water and below the surface of water. Most submarine hulls are cigar shaped, designed to offer less drag when travelling below the surface. A submarine has a conning tower which houses periscopes, syphon and communication and radar antennas.
Working of a submarine
Following basics about the operation of a submarine will be covered in this article:-
Propulsion
First of all, we will see how a submarine travels on surface and below the surface. What is the source of it's propulsion, what fuel it uses.
Based on the propulsion system, submarines are typically classified into two types.
As the working of the two above mentioned types is different, so they will be discussed separately.
Conventional submarines
Conventional submarines incorporate diesel-electric propulsion system. This type of submarine incorporates two types of power sources. The diesel engine and batteries.
The diesel engines are used for surface propulsion as they need air for combustion and produce toxic fumes.
Thus, diesel engines cannot be used when the submarine is submerged. When the submarine is dives, the diesel engine is shut down and the batteries are utilized for propulsion . The batteries run the submarine for only a limited amount of time (around one week in case of modern naval subs) before they have to be recharged. The batteries are recharged when the submarine surfaces and starts it's diesel engines, which recharge the batteries with the help of a generator. Submarines also incorporate snorkels, which means that to recharge the batteries and replenish the oxygen supply, total surfacing is not necessary.
Diesel-electric system (Number of cylinders and cells may varry)
The batteries are also the source of power of various instruments, equipments and lights.
Some modern submarines are fitted with AIP (Air independent propulsion) systems. In AIP capable submarines, diesel engines are used for surface propulsion and AIP system for underwater propulsion. The AIP system has an increased underwater endurance as compared to conventional batteries. AIP fitted subs can stay submerged for much longer time periods(upto 3 weeks) as compared to conventional submarines.
Nuclear Submarines
As opposed to the hybrid propulsion system(diesel engine+batteries) of conventional submarine, nuclear submarine uses only a nuclear plant for propulsion on both the surface and below the surface.
Nuclear fuel is used to boil the water to produce steam, which in turn drives the propellers. Batteries aren't used in propulsion. Thus nuclear submarines can stay underwater for indefinite time period and only needs to surface when it has to get supplies. Moreover, nuclear fuel has much greater energy value as compared to diesel or electric batteries thus as a result, a nuclear submarine has far greater range and speed than a conventional or AIP submarine.
More importantly, a nuclear submarine has unlimited range at top speed. This allows it to travel from its operating base to the combat zone in a much shorter time and makes it a far more difficult target for most anti-submarine weapons. Nuclear-powered submarines have a relatively small battery and diesel engine/generator powerplant for emergency use if the reactors must be shut down.
Nuclear submarines are larger and costlier than conventional submarines. They can travel around the world with ease. Conventional and AIP submarines have a stealth advantage over nuclear subs.
Diving
A submarine or a surface vessel floats because it is in a positive buoyant condition i-e it weighs less than the volume of water it displaces. To submerge, a submarine must enter a negative buoyant condition that is, it must weigh more than the volume of water it displace.
So to dive (achieve negative buoyancy) a submarine has ballast tanks(usually 2, forward and aft) which can hold varrying amounts of water and air. Ballast tanks are filled with desired volume of water to increase submarine's weight.
For more precise and quick control of depth, submarines use smaller Depth Control Tanks, or DCTs.
For trimming purposes and to increase/decrease the speed of diving, a submarine has forward and aft trim tanks. Pumps can move water between these and hence a submarine could be made point upwards or downwards.
A submarine's control surfaces include a rudder for changing direction, stern planes located near the propeller control the trim(same as trim tanks) and bow planes(which are not present on some submarines) control the depth with less effect on trim.
Due to hull limitations, a submarine can only reach deapths around it's rated depths, which vary for different classes of submarines.
Navigation
Modern submarines use GPS for navigation when on the surface while it can't be used when the sub is submerged. When below the surface, a submarine uses internal navigation system (INS).
INS is a navigation aid that uses a computer, motion sensors (accelerometers) and rotation sensors (gyroscopes) to continuously calculate via dead reckoning the position, orientation, and velocity (direction and speed of movement) of a moving object without the need for external references.
Communication
Military submarines use several systems to communicate with distant command centers or other ships. One is VLF (Very Low Frequency) radio, which can reach a submarine either on the surface or submerged to a fairly shallow depth, usually less than 250 feet (76 m). ELF (Extremely Low Frequency) can reach a submarine at much greater depths, but has a very low bandwidth and are generally used to call a submerged sub to a shallower depth where VLF signals can reach. A submarine also has the option of floating a long, buoyant wire antenna to a shallower depth, allowing VLF transmissions by a deeply submerged boat.
By extending a radio mast, a submarine can also use a "burst transmission" technique. A burst transmission takes only a fraction of a second, minimizing a submarine's risk of detection.
To communicate with other submarines, a system known as Gertrude is used. Gertrude is basically a sonar telephone. Voice communication from one submarine is transmitted by low power speakers into the water, where it is detected by passive sonars on the receiving submarine. The range of this system is probably very short, and using it radiates sound into the water, which can be heard by the enemy.
Civilian submarines can use similar, albeit less powerful systems to communicate with support ships or other submersibles in the area.
Life
In submerged older vessels, with the passage of time, oxygen would deplete and concentration of carbon dioxide would increase due to breathing. In modern submarines, for breathing, submarines are equipped with oxygen generators which generate oxygen by electrolysis of water. Carbon dioxide is absorbed by scrubbers installed in a submarine. Most submarines have systems available to distill sea water for drinking and other uses.
For more,
www.warfactsandtactics.blogspot.com
A submarine is a type of vessel which can travel both on the surface of water and below the surface of water. Most submarine hulls are cigar shaped, designed to offer less drag when travelling below the surface. A submarine has a conning tower which houses periscopes, syphon and communication and radar antennas.
Working of a submarine
Following basics about the operation of a submarine will be covered in this article:-
- Propulsion
- Diving
- Navigation
- Communication
- Life
Propulsion
First of all, we will see how a submarine travels on surface and below the surface. What is the source of it's propulsion, what fuel it uses.
Based on the propulsion system, submarines are typically classified into two types.
- Conventional submarines.
- Nuclear submarines.
As the working of the two above mentioned types is different, so they will be discussed separately.
Conventional submarines
Conventional submarines incorporate diesel-electric propulsion system. This type of submarine incorporates two types of power sources. The diesel engine and batteries.
The diesel engines are used for surface propulsion as they need air for combustion and produce toxic fumes.
Thus, diesel engines cannot be used when the submarine is submerged. When the submarine is dives, the diesel engine is shut down and the batteries are utilized for propulsion . The batteries run the submarine for only a limited amount of time (around one week in case of modern naval subs) before they have to be recharged. The batteries are recharged when the submarine surfaces and starts it's diesel engines, which recharge the batteries with the help of a generator. Submarines also incorporate snorkels, which means that to recharge the batteries and replenish the oxygen supply, total surfacing is not necessary.
Diesel-electric system (Number of cylinders and cells may varry)
The batteries are also the source of power of various instruments, equipments and lights.
Some modern submarines are fitted with AIP (Air independent propulsion) systems. In AIP capable submarines, diesel engines are used for surface propulsion and AIP system for underwater propulsion. The AIP system has an increased underwater endurance as compared to conventional batteries. AIP fitted subs can stay submerged for much longer time periods(upto 3 weeks) as compared to conventional submarines.
Nuclear Submarines
As opposed to the hybrid propulsion system(diesel engine+batteries) of conventional submarine, nuclear submarine uses only a nuclear plant for propulsion on both the surface and below the surface.
Nuclear fuel is used to boil the water to produce steam, which in turn drives the propellers. Batteries aren't used in propulsion. Thus nuclear submarines can stay underwater for indefinite time period and only needs to surface when it has to get supplies. Moreover, nuclear fuel has much greater energy value as compared to diesel or electric batteries thus as a result, a nuclear submarine has far greater range and speed than a conventional or AIP submarine.
More importantly, a nuclear submarine has unlimited range at top speed. This allows it to travel from its operating base to the combat zone in a much shorter time and makes it a far more difficult target for most anti-submarine weapons. Nuclear-powered submarines have a relatively small battery and diesel engine/generator powerplant for emergency use if the reactors must be shut down.
Nuclear submarines are larger and costlier than conventional submarines. They can travel around the world with ease. Conventional and AIP submarines have a stealth advantage over nuclear subs.
Diving
A submarine or a surface vessel floats because it is in a positive buoyant condition i-e it weighs less than the volume of water it displaces. To submerge, a submarine must enter a negative buoyant condition that is, it must weigh more than the volume of water it displace.
So to dive (achieve negative buoyancy) a submarine has ballast tanks(usually 2, forward and aft) which can hold varrying amounts of water and air. Ballast tanks are filled with desired volume of water to increase submarine's weight.
For more precise and quick control of depth, submarines use smaller Depth Control Tanks, or DCTs.
For trimming purposes and to increase/decrease the speed of diving, a submarine has forward and aft trim tanks. Pumps can move water between these and hence a submarine could be made point upwards or downwards.
A submarine's control surfaces include a rudder for changing direction, stern planes located near the propeller control the trim(same as trim tanks) and bow planes(which are not present on some submarines) control the depth with less effect on trim.
Due to hull limitations, a submarine can only reach deapths around it's rated depths, which vary for different classes of submarines.
Navigation
Modern submarines use GPS for navigation when on the surface while it can't be used when the sub is submerged. When below the surface, a submarine uses internal navigation system (INS).
INS is a navigation aid that uses a computer, motion sensors (accelerometers) and rotation sensors (gyroscopes) to continuously calculate via dead reckoning the position, orientation, and velocity (direction and speed of movement) of a moving object without the need for external references.
Communication
Military submarines use several systems to communicate with distant command centers or other ships. One is VLF (Very Low Frequency) radio, which can reach a submarine either on the surface or submerged to a fairly shallow depth, usually less than 250 feet (76 m). ELF (Extremely Low Frequency) can reach a submarine at much greater depths, but has a very low bandwidth and are generally used to call a submerged sub to a shallower depth where VLF signals can reach. A submarine also has the option of floating a long, buoyant wire antenna to a shallower depth, allowing VLF transmissions by a deeply submerged boat.
By extending a radio mast, a submarine can also use a "burst transmission" technique. A burst transmission takes only a fraction of a second, minimizing a submarine's risk of detection.
To communicate with other submarines, a system known as Gertrude is used. Gertrude is basically a sonar telephone. Voice communication from one submarine is transmitted by low power speakers into the water, where it is detected by passive sonars on the receiving submarine. The range of this system is probably very short, and using it radiates sound into the water, which can be heard by the enemy.
Civilian submarines can use similar, albeit less powerful systems to communicate with support ships or other submersibles in the area.
Life
In submerged older vessels, with the passage of time, oxygen would deplete and concentration of carbon dioxide would increase due to breathing. In modern submarines, for breathing, submarines are equipped with oxygen generators which generate oxygen by electrolysis of water. Carbon dioxide is absorbed by scrubbers installed in a submarine. Most submarines have systems available to distill sea water for drinking and other uses.
For more,
www.warfactsandtactics.blogspot.com
Last edited:
! I was RNoAF Search and Rescue.
Just given the info , so people may feel curious and go on to read for that .
what i remember from college times
