A SUBMARINE (or simply SUB) is a watercraft capable of independent operation underwater. It differs from a submersible , which has more limited underwater capability. The term most commonly refers to a large, crewed vessel. It is also sometimes used historically or colloquially to refer to remotely operated vehicles and robots , as well as medium-sized or smaller vessels, such as the midget submarine and the wet sub . The noun submarine evolved as a shortened form of submarine boat; by naval tradition , submarines are usually referred to as "boats " rather than as "ships ", regardless of their size (boat is usually reserved for seagoing vessels of relatively small size).
Although experimental submarines had been built before, submarine design took off during the 19th century, and they were adopted by several navies. Submarines were first widely used during World War I (1914–1918), and now figure in many navies large and small. Military uses include attacking enemy surface ships (merchant and military), attacking other submarines, aircraft carrier protection, blockade running, ballistic missile submarines as part of a nuclear strike force, reconnaissance , conventional land attack (for example using a cruise missile ), and covert insertion of special forces . Civilian uses for submarines include marine science , salvage, exploration and facility inspection and maintenance. Submarines can also be modified to perform more specialized functions such as search-and-rescue missions or undersea cable repair. Submarines are also used in tourism, and for undersea archaeology .
Most large submarines consist of a cylindrical body with hemispherical (or conical) ends and a vertical structure, usually located amidships, which houses communications and sensing devices as well as periscopes . In modern submarines, this structure is the "sail " in American usage, and "fin" in European usage. A "conning tower " was a feature of earlier designs: a separate pressure hull above the main body of the boat that allowed the use of shorter periscopes. There is a propeller (or pump jet) at the rear, and various hydrodynamic control fins. Smaller, deep-diving and specialty submarines may deviate significantly from this traditional layout. Submarines use diving planes and also change the amount of water and air in ballast tanks to change buoyancy for submerging and surfacing.
Submarines have one of the widest ranges of types and capabilities of any vessel. They range from small autonomous examples and one- or two-person vessels that operate for a few hours, to vessels that can remain submerged for six months—such as the Russian Typhoon class , the biggest submarines ever built. Submarines can work at greater depths than are survivable or practical for human divers . Modern deep-diving submarines derive from the bathyscaphe , which in turn evolved from the diving bell .
* 1 History
* 1.1 Early submersibles * 1.2 18th century submarines
* 1.3 19th century submarines
* 1.3.1 Mechanical power
* 1.4 20th century submarines
* 1.5 21st century submarines
* 2 Usage
* 2.1 Military * 2.2 Civilian * 2.3 Polar operations
* 3 Technology
* 3.1 Submersion and trimming
* 3.2 Hull
* 3.2.1 Overview
* 3.2.2 Single and double hulls
* 3.3 Propulsion
* 3.3.1 Electric
* 18.104.22.168 Diesel-electric
* 3.3.2 Air-independent propulsion * 3.3.3 Nuclear power * 3.3.4 Alternative propulsion
* 3.4 Armament * 3.5 Sensors * 3.6 Navigation * 3.7 Communication * 3.8 Life support systems
* 4 Crew
* 4.1 Women * 4.2 Abandoning the vessel
* 5 See also
* 5.1 By country
* 6 References * 7 Bibliography * 8 External links
History of submarines
Drebbel , an early submersible craft, propelled by oars
According to a report in Opusculum Taisnieri published in 1562:
Two Greeks submerged and surfaced in the river
In 1578, the English mathematician William Bourne recorded in his
book Inventions or Devises one of the first plans for an underwater
navigation vehicle. A few years later the Scottish mathematician and
The first submersible of whose construction there exists reliable
information was designed and built in 1620 by
18TH CENTURY SUBMARINES
By the mid-18th century, over a dozen patents for
submarines/submersible boats had been granted in England. In 1747,
Nathaniel Symons patented and built the first known working example of
the use of a ballast tank for submersion. His design used leather bags
that could fill with water to submerge the craft. A mechanism was used
to twist the water out of the bags and cause the boat to resurface. In
1749, the Gentlemen\'s Magazine reported that a similar design had
initially been proposed by
The first military submarine was the Turtle (1775), a hand-powered
acorn-shaped device designed by the American
19TH CENTURY SUBMARINES
1806 illustration by
In 1800, France built a human-powered submarine designed by American
In 1864, late in the
American Civil War
In 1866, the
Sub Marine Explorer
The first submarine not relying on human power for propulsion was the
French Plongeur (Diver), launched in 1863, which used compressed air
at 180 psi (1241 kPa ). The first air–independent and combustion
–powered submarine was
The submarine became a potentially viable weapon with the development
Discussions between the English clergyman and inventor George Garrett and the Swedish industrialist Thorsten Nordenfelt led to the first practical steam-powered submarines, armed with torpedoes and ready for military use. The first was Nordenfelt I, a 56-tonne, 19.5-metre (64 ft) vessel similar to Garrett's ill-fated Resurgam (1879), with a range of 240 kilometres (130 nmi; 150 mi), armed with a single torpedo , in 1885.
A reliable means of propulsion for the submerged vessel was only made
possible in the 1880s with the advent of the necessary electric
battery technology. The first electrically powered boats were built by
Isaac Peral y Caballero in
20TH CENTURY SUBMARINES
Submarines were not put into service for any widespread or routine
use by navies until the early 1900s. This era marked a pivotal time in
submarine development, and several important technologies appeared. A
number of nations built and used submarines. Diesel electric
propulsion became the dominant power system and equipment such as the
periscope became standardized. Countries conducted many experiments on
effective tactics and weapons for submarines, which led to their large
World War I
The Irish inventor
John Philip Holland built a model submarine in
1876 and a full-scale version in 1878, which were followed by a number
of unsuccessful ones. In 1896 he designed the Holland Type VI
submarine, which used internal combustion engine power on the surface
and electric battery power underwater. Launched on 17 May 1897 at Navy
Lt. Lewis Nixon 's
Commissioned in June 1900, the French steam and electric Narval employed the now typical double-hull design, with a pressure hull inside the outer shell. These 200-ton ships had a range of over 100 miles (161 km) underwater. The French submarine Aigrette in 1904 further improved the concept by using a diesel rather than a gasoline engine for surface power. Large numbers of these submarines were built, with seventy-six completed before 1914.
These types of submarines were first used during the Russo-Japanese
War of 1904–05. Due to the blockade at Port Arthur , the Russians
sent their submarines to
World War I
The German submarine SM U-9 , which sank three British cruisers in less than an hour in September 1914
Military submarines first made a significant impact in
World War I
At the outbreak of war
The U-boats' ability to function as practical war machines relied on
new tactics, their numbers, and submarine technologies such as
combination diesel-electric power system developed in the preceding
years. More submersibles than true submarines, U-boats operated
primarily on the surface using regular engines, submerging
occasionally to attack under battery power. They were roughly
triangular in cross-section, with a distinct keel to control rolling
while surfaced, and a distinct bow. During
World War I
World War II
List of submarines of World War II The Imperial
World War II
The Imperial Japanese
The submarine force was the most effective anti-ship weapon in the
American arsenal. Submarines, though only about 2 percent of the U.S.
Navy, destroyed over 30 percent of the Japanese Navy, including 8
aircraft carriers, 1 battleship and 11 cruisers. US submarines also
destroyed over 60 percent of the Japanese merchant fleet, crippling
Japan's ability to supply its military forces and industrial war
Allied submarines in the Pacific War
During World War II, 314 submarines served in the US Navy, of which nearly 260 were deployed to the Pacific. When the Japanese attacked Hawaii in December 1941, 111 boats were in commission; 203 submarines from the Gato , Balao , and Tench classes were commissioned during the war. During the war, 52 US submarines were lost to all causes, with 48 directly due to hostilities. US submarines sank 1,560 enemy vessels, a total tonnage of 5.3 million tons (55% of the total sunk).
Cold-War Military Models
HMAS Rankin , a Collins-class submarine at periscope depth
The first launch of a cruise missile (
In 1959–1960, the first ballistic missile submarines were put into
service by both the
During the Cold War, the US and the Soviet Union maintained large
submarine fleets that engaged in cat-and-mouse games. The Soviet Union
lost at least four submarines during this period: K-129 was lost in
1968 (a part of which the
Indo-Pakistani War of 1971
21ST CENTURY SUBMARINES
THIS SECTION NEEDS EXPANSION. You can help by adding to it . (June 2016)
Before and during
World War II
Mine -laying submarines were developed in the early part of the 20th
century. The facility was used in both World Wars. Submarines were
also used for inserting and removing covert agents and military
forces, for intelligence gathering, and to rescue aircrew during air
attacks on islands, where the airmen would be told of safe places to
crash-land so the submarines could rescue them. Submarines could carry
cargo through hostile waters or act as supply vessels for other
submarines. Retractable 7.5 cm submarine gun produced by the
Submarines could usually locate and attack other submarines only on the surface, although HMS Venturer managed to sink U-864 with a four torpedo spread while both were submerged. The British developed a specialized anti-submarine submarine in WWI, the R class . After WWII, with the development of the homing torpedo, better sonar systems, and nuclear propulsion , submarines also became able to hunt each other effectively.
The development of submarine-launched ballistic missile and submarine-launched cruise missiles gave submarines a substantial and long-ranged ability to attack both land and sea targets with a variety of weapons ranging from cluster bombs to nuclear weapons .
The primary defense of a submarine lies in its ability to remain concealed in the depths of the ocean. Early submarines could be detected by the sound they made. Water is an excellent conductor of sound (much better than air), and submarines can detect and track comparatively noisy surface ships from long distances. Modern submarines are built with an emphasis on stealth. Advanced propeller designs, extensive sound-reducing insulation, and special machinery help a submarine remain as quiet as ambient ocean noise, making them difficult to detect. It takes specialized technology to find and attack modern submarines.
Active sonar uses the reflection of sound emitted from the search equipment to detect submarines. It has been used since WWII by surface ships, submarines and aircraft (via dropped buoys and helicopter "dipping" arrays), but it reveals the emitter's position, and is susceptible to counter-measures.
A concealed military submarine is a real threat, and because of its
stealth, can force an enemy navy to waste resources searching large
areas of ocean and protecting ships against attack. This advantage was
vividly demonstrated in the 1982
Auguste Piccard (model pictured), built by
Although the majority of the world's submarines are military, there are some civilian submarines, which are used for tourism, exploration, oil and gas platform inspections, and pipeline surveys. Some are also used in illegal activities.
Submarine Voyage ride opened at
In a typical operation a surface vessel carries passengers to an offshore operating area and loads them into the submarine. The submarine then visits underwater points of interest such as natural or artificial reef structures. To surface safely without danger of collision the location of the submarine is marked with an air release and movement to the surface is coordinated by an observer in a support craft.
A recent development is the deployment of so-called narco submarines
by South American drug smugglers to evade law enforcement detection.
Although they occasionally deploy true submarines , most are
self-propelled semi-submersibles , where a portion of the craft
remains above water at all times. In September 2011, Colombian
authorities seized a 16-meter-long submersible that could hold a crew
of 5, costing about $2 million. The vessel belonged to
* 1903 –
Simon Lake submarine Protector surfaced through ice off
Newport, Rhode Island .
* 1930 – USS O-12 operated under ice near
See also: Timeline of underwater technology
SUBMERSION AND TRIMMING
An illustration showing submarine controls USS Seawolf
All surface ships, as well as surfaced submarines, are in a positively buoyant condition, weighing less than the volume of water they would displace if fully submerged. To submerge hydrostatically, a ship must have negative buoyancy, either by increasing its own weight or decreasing its displacement of water. To control their displacement, submarines have ballast tanks , which can hold varying amounts of water and air.
For general submersion or surfacing, submarines use the forward and aft tanks, called Main Ballast Tanks (MBT), which are filled with water to submerge or with air to surface. Submerged, MBTs generally remain flooded, which simplifies their design, and on many submarines these tanks are a section of interhull space. For more precise and quick control of depth, submarines use smaller Depth Control Tanks (DCT) – also called hard tanks (due to their ability to withstand higher pressure), or trim tanks. The amount of water in depth control tanks can be controlled to change depth or to maintain a constant depth as outside conditions (chiefly water density) change. Depth control tanks may be located either near the submarine's center of gravity , or separated along the submarine body to prevent affecting trim .
When submerged, the water pressure on a submarine's hull can reach 4 MPa (580 psi ) for steel submarines and up to 10 MPa (1,500 psi) for titanium submarines like K-278 Komsomolets , while interior pressure remains relatively unchanged. This difference results in hull compression, which decreases displacement. Water density also marginally increases with depth, as the salinity and pressure are higher. This change in density incompletely compensates for hull compression, so buoyancy decreases as depth increases. A submerged submarine is in an unstable equilibrium, having a tendency to either sink or float to the surface. Keeping a constant depth requires continual operation of either the depth control tanks or control surfaces.
Submarines in a neutral buoyancy condition are not intrinsically trim-stable. To maintain desired trim, submarines use forward and aft trim tanks. Pumps can move water between the tanks, changing weight distribution and pointing the sub up or down. A similar system is sometimes used to maintain stability. Sail of the French nuclear submarine Casabianca ; note the diving planes, camouflaged masts, periscope, electronic warfare masts, hatch, and deadlight.
The hydrostatic effect of variable ballast tanks is not the only way to control the submarine underwater. Hydrodynamic maneuvering is done by several surfaces, which can be moved to create hydrodynamic forces when a submarine moves at sufficient speed. The stern planes, located near the propeller and normally horizontal, serve the same purpose as the trim tanks, controlling the trim, and are commonly used, while other control surfaces may not be present on all submarines. The fairwater planes on the sail and/or bow planes on the main body, both also horizontal, are closer to the center of gravity, and are used to control depth with less effect on the trim.
When a submarine performs an emergency surfacing, all depth and trim methods are used simultaneously, together with propelling the boat upwards. Such surfacing is very quick, so the sub may even partially jump out of the water, potentially damaging submarine systems.
Main article: Submarine hull
Modern submarines are cigar-shaped. This design, visible in early submarines is sometimes called a "teardrop hull ". It reduces the hydrodynamic drag when submerged, but decreases the sea-keeping capabilities and increases drag while surfaced. Since the limitations of the propulsion systems of early submarines forced them to operate surfaced most of the time, their hull designs were a compromise. Because of the slow submerged speeds of those subs, usually well below 10 kt (18 km/h), the increased drag for underwater travel was acceptable. Late in World War II, when technology allowed faster and longer submerged operation and increased aircraft surveillance forced submarines to stay submerged, hull designs became teardrop shaped again to reduce drag and noise. USS Albacore (AGSS-569) was a unique research submarine that pioneered the American version of the teardrop hull form (sometimes referred to as an "Albacore hull") of modern submarines. On modern military submarines the outer hull is covered with a layer of sound-absorbing rubber, or anechoic plating , to reduce detection.
The occupied pressure hulls of deep diving submarines such as DSV Alvin are spherical instead of cylindrical. This allows a more even distribution of stress at the great depth. A titanium frame is usually affixed to the pressure hull, providing attachment for ballast and trim systems, scientific instrumentation, battery packs, syntactic flotation foam , and lighting.
A raised tower on top of a submarine accommodates the periscope and electronics masts, which can include radio, radar , electronic warfare , and other systems including the snorkel mast. In many early classes of submarines (see history), the control room, or "conn", was located inside this tower, which was known as the "conning tower ". Since then, the conn has been located within the hull of the submarine, and the tower is now called the "sail ". The conn is distinct from the "bridge", a small open platform in the top of the sail, used for observation during surface operation.
"Bathtubs" are related to conning towers but are used on smaller submarines. The bathtub is a metal cylinder surrounding the hatch that prevents waves from breaking directly into the cabin. It is needed because surfaced submarines have limited freeboard , that is, they lie low in the water. Bathtubs help prevent swamping the vessel.
Single And Double Hulls
U-995 , Type VIIC/41 U-
Modern submarines and submersibles, as well as the oldest ones, usually have a single hull. Large submarines generally have an additional hull or hull sections outside. This external hull, which actually forms the shape of submarine, is called the outer hull (casing in the Royal Navy) or light hull , as it does not have to withstand a pressure difference. Inside the outer hull there is a strong hull, or pressure hull , which withstands sea pressure and has normal atmospheric pressure inside.
As early as World War I, it was realized that the optimal shape for
withstanding pressure conflicted with the optimal shape for seakeeping
and minimal drag, and construction difficulties further complicated
the problem. This was solved either by a compromise shape, or by using
two hulls; internal for holding pressure, and external for optimal
shape. Until the end of World War II, most submarines had an
additional partial cover on the top, bow and stern, built of thinner
metal, which was flooded when submerged.
After World War II, approaches split. The Soviet Union changed its
designs, basing them on German developments. All post–World War II
heavy Soviet and Russian submarines are built with a double hull
structure. American and most other Western submarines switched to a
primarily single-hull approach. They still have light hull sections in
the bow and stern, which house main ballast tanks and provide a
hydrodynamically optimized shape, but the main cylindrical hull
section has only a single plating layer. Double hulls are being
considered for future submarines in the
The pressure hull is generally constructed of thick high-strength steel with a complex structure and high strength reserve, and is separated with watertight bulkheads into several compartments . There are also examples of more than two hulls in a submarine, like the Typhoon class , which has two main pressure hulls and three smaller ones for control room, torpedoes and steering gear, with the missile launch system between the main hulls.
The dive depth cannot be increased easily. Simply making the hull thicker increases the weight and requires reduction of onboard equipment weight, ultimately resulting in a bathyscaphe . This is acceptable for civilian research submersibles, but not military submarines.
WWI submarines had hulls of carbon steel , with a 100-metre (330 ft)
maximum depth. During WWII, high-strength alloyed steel was
introduced, allowing 200-metre (660 ft) depths. High-strength alloy
steel remains the primary material for submarines today, with
250–400-metre (820–1,310 ft) depths, which cannot be exceeded on a
military submarine without design compromises. To exceed that limit, a
few submarines were built with titanium hulls.
The deepest deep-submergence vehicle (DSV) to date is Trieste . On 5
October 1959, Trieste departed San Diego for
Building a pressure hull is difficult, as it must withstand pressures at its required diving depth. When the hull is perfectly round in cross-section, the pressure is evenly distributed, and causes only hull compression. If the shape is not perfect, the hull is bent, with several points heavily strained. Inevitable minor deviations are resisted by stiffener rings, but even a one-inch (25 mm) deviation from roundness results in over 30 percent decrease of maximal hydrostatic load and consequently dive depth. The hull must therefore be constructed with high precision. All hull parts must be welded without defects, and all joints are checked multiple times with different methods, contributing to the high cost of modern submarines. (For example, each Virginia-class attack submarine costs US$2.6 billion , over US$200,000 per ton of displacement.)
The first submarines were propelled by humans. The first mechanically
driven submarine was the 1863 French Plongeur , which used compressed
air for propulsion. Anaerobic propulsion was first employed by the
Until the advent of nuclear marine propulsion , most 20th-century submarines used batteries for running underwater and gasoline (petrol) or diesel engines on the surface, and for battery recharging. Early submarines used gasoline, but this quickly gave way to kerosene (paraffin), then diesel, because of reduced flammability. Diesel-electric became the standard means of propulsion. The diesel or gasoline engine and the electric motor, separated by clutches, were initially on the same shaft driving the propeller. This allowed the engine to drive the electric motor as a generator to recharge the batteries and also propel the submarine. The clutch between the motor and the engine would be disengaged when the submarine dived, so that the motor could drive the propeller. The motor could have multiple armatures on the shaft, which could be electrically coupled in series for slow speed and in parallel for high speed (these connections were called "group down" and "group up", respectively).
Early submarines used a direct mechanical connection between the engine and propeller, switching between diesel engines for surface running, and battery-driven electric motors for submerged propulsion.
In 1928, the
Other advantages of such an arrangement were that a submarine could travel slowly with the engines at full power to recharge the batteries quickly, reducing time on the surface or on snorkel . It was then possible to isolate the noisy diesel engines from the pressure hull, making the submarine quieter. Additionally, diesel-electric transmissions were more compact.
World War II
While the snorkel renders a submarine far less detectable, it is not perfect. In clear weather, diesel exhaust can be seen on the surface to a distance of about three miles, while 'periscope feather' (the wave created by the snorkel or periscope moving through the water), is visible from far off in calm sea conditions. Modern radar is also capable of detecting a snorkel in calm sea conditions.
The problem of the diesels causing a vacuum in the submarine when the head valve is submerged still exists in later model diesel submarines, but is mitigated by high-vacuum cut-off sensors that shut down the engines when the vacuum in the ship reaches a pre-set point. Modern snorkel induction masts use a fail-safe design using compressed air , controlled by a simple electrical circuit, to hold the "head valve" open against the pull of a powerful spring. Seawater washing over the mast shorts out exposed electrodes on top, breaking the control, and shutting the "head valve" while it is submerged.
Main article: Air-independent propulsion German Type XXI submarine
During World War II, German
Type XXI submarines (also known as
"Elektroboote") were the first submarines designed to operate
submerged for extended periods. Initially they were to carry hydrogen
peroxide for long-term, fast air-independent propulsion, but were
ultimately built with very large batteries instead. At the end of the
War, the British and Soviets experimented with hydrogen
peroxide/kerosene (paraffin) engines that could run surfaced and
submerged. The results were not encouraging. Though the Soviet Union
deployed a class of submarines with this engine type (codenamed Quebec
by NATO), they were considered unsuccessful. American X-1 Midget
Today several navies use air-independent propulsion. Notably Sweden
uses Stirling technology on the Gotland-class and Södermanland-class
Steam power was resurrected in the 1950s with a nuclear-powered steam turbine driving a generator. By eliminating the need for atmospheric oxygen, the time that a submarine could remain submerged was limited only by its food stores, as breathing air was recycled and fresh water distilled from seawater. 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. HMS Astute is among the most advanced nuclear submarines.
Nuclear power is now used in all large submarines, but due to the
high cost and large size of nuclear reactors, smaller submarines still
use diesel-electric propulsion. The ratio of larger to smaller
submarines depends on strategic needs. The US Navy, French
Diesel-electric submarines have a stealth advantage over their nuclear counterparts. Nuclear submarines generate noise from coolant pumps and turbo-machinery needed to operate the reactor, even at low power levels. Some nuclear submarines such as the American Ohio class can operate with their reactor coolant pumps secured, making them quieter than electric subs. A conventional submarine operating on batteries is almost completely silent, the only noise coming from the shaft bearings, propeller, and flow noise around the hull, all of which stops when the sub hovers in mid-water to listen, leaving only the noise from crew activity. Commercial submarines usually rely only on batteries, since they operate in conjunction with a mother ship.
Several serious nuclear and radiation accidents have involved nuclear
submarine mishaps. The
Soviet submarine K-19
Oil-fired steam turbines powered the British K-class submarines ,
World War I
Toward the end of the 20th century, some submarines—such as the British Vanguard class—began to be fitted with pump-jet propulsors instead of propellers. Though these are heavier, more expensive, and less efficient than a propeller, they are significantly quieter, providing an important tactical advantage.
Magnetohydrodynamic drive (MHD) was portrayed as the operating
principle behind the titular submarine's nearly silent propulsion
system in the film adaptation of
The Hunt for Red October
The success of the submarine is inextricably linked to the
development of the torpedo , invented by
Robert Whitehead in 1866. His
invention is essentially the same now as it was 140 years ago. Only
with self-propelled torpedoes could the submarine make the leap from
novelty to a weapon of war. Until the perfection of the guided torpedo
, multiple "straight-running" torpedoes were required to attack a
target. With at most 20 to 25 torpedoes stored on board, the number of
attacks was limited. To increase combat endurance most World War I
submarines functioned as submersible gunboats, using their deck guns
against unarmed targets, and diving to escape and engage enemy
warships. The importance of guns encouraged the development of the
The ability of submarines to approach enemy harbours covertly led to
their use as minelayers . Minelaying submarines of
World War I
After World War II, both the US and the USSR experimented with
submarine-launched cruise missiles such as the
The strategic mission of the SSM-N-8 and the P-5 was taken up by submarine-launched ballistic missile beginning with the US Navy's Polaris missile, and subsequently the Poseidon and Trident missiles.
A submarine can have a variety of sensors, depending on its missions. Modern military submarines rely almost entirely on a suite of passive and active sonars to locate targets. Active sonar relies on an audible "ping" to generate echoes to reveal objects around the submarine. Active systems are rarely used, as doing so reveals the sub's presence. Passive sonar is a set of sensitive hydrophones set into the hull or trailed in a towed array, normally trailing several hundred feet behind the sub. The towed array is the mainstay of NATO submarine detection systems, as it reduces the flow noise heard by operators. Hull mounted sonar is employed in addition to the towed array, as the towed array can't work in shallow depth and during maneuvering. In addition, sonar has a blind spot "through" the submarine, so a system on both the front and back works to eliminate that problem. As the towed array trails behind and below the submarine, it also allows the submarine to have a system both above and below the thermocline at the proper depth; sound passing through the thermocline is distorted resulting in a lower detection range.
Submarines also carry radar equipment to detect surface ships and
Civilian submarines, such as the DSV Alvin or the Russian Mir submersibles , rely on small active sonar sets and viewing ports to navigate. The human eye cannot detect sunlight below about 300 feet (91 m) underwater, so high intensity lights are used to illuminate the viewing area.
Main article: Submarine navigation The larger search periscope , and the smaller, less detectable attack periscope on HMS Ocelot
Early submarines had few navigation aids, but modern subs have a
variety of navigation systems. Modern military submarines use an
inertial guidance system for navigation while submerged, but drift
error unavoidably builds over time. To counter this, the crew
occasionally uses the
Global Positioning System
Main article: Communication with submarines
Military submarines use several systems to communicate with distant
command centers or other ships. One is
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 SUPPORT SYSTEMS
With nuclear power or air-independent propulsion , submarines can
remain submerged for months at a time. Conventional diesel submarines
must periodically resurface or run on snorkel to recharge their
batteries. Most modern military submarines generate breathing oxygen
by electrolysis of water (using a device called an "Elektrolytic
Fresh water is produced by either an evaporator or a reverse osmosis unit. The primary use for fresh water is to provide feedwater for the reactor and steam propulsion plants. It is also available for showers, sinks, cooking and cleaning once propulsion plant needs have been met. Seawater is used to flush toilets, and the resulting "black water " is stored in a sanitary tank until it is blown overboard using pressurized air or pumped overboard by using a special sanitary pump. The blackwater–discharge system is difficult to operate, and the German Type VIIC boat U-1206 was lost with casualties because of human error while using this system. Water from showers and sinks is stored separately in "grey water " tanks and discharged overboard using drain pumps.
Trash on modern large submarines is usually disposed of using a tube called a Trash Disposal Unit (TDU), where it is compacted into a galvanized steel can. At the bottom of the TDU is a large ball valve. An ice plug is set on top of the ball valve to protect it, the cans atop the ice plug. The top breech door is shut, and the TDU is flooded and equalized with sea pressure, the ball valve is opened and the cans fall out assisted by scrap iron weights in the cans. The TDU is also flushed with seawater to ensure it is completely empty and the ball valve is clear before closing the valve.
The interior of a British E-class submarine . An officer supervises submerging operations, c. 1914–1918.
A typical nuclear submarine has a crew of over 80; conventional boats typically have fewer than 40. The conditions on a submarine can be difficult because crew members must work in isolation for long periods of time, without family contact. Submarines normally maintain radio silence to avoid detection. Operating a submarine is dangerous, even in peacetime, and many submarines have been lost in accidents.
Midshipmen learn to pilot the submarine aboard USS West Virginia .
Most navies prohibited women from serving on submarines, even after
they had been permitted to serve on surface warships. The Royal
On 8 December 2011, British Defence Secretary Philip Hammond
announced that the UK 's ban on women in submarines was to be lifted
from 2013. Previously there were fears that women were more at risk
from a build-up of carbon dioxide in the submarine. But a study showed
no medical reason to exclude women, though pregnant women would still
be excluded. Similar dangers to the pregnant woman and her fetus
barred females from submarine service in
Women have served on US
Both the US and British navies operate nuclear-powered submarines that deploy for periods of six months or longer. Other navies that permit women to serve on submarines operate conventionally powered submarines, which deploy for much shorter periods—usually only for a few months. Prior to the change by the US, no nation using nuclear submarines permitted women to serve on board.
In 2011, the first class of female submarine officers graduated from
ABANDONING THE VESSEL
In an emergency, submarines can transmit a signal to other ships. The
crew can use
Submarine Escape Immersion Equipment to abandon the
submarine. The crew can prevent a lung injury from the pressure
change known as pulmonary barotrauma by exhaling during the ascent.
Following escape from a pressurized submarine, the crew is at risk of
developing decompression sickness . An alternative escape means is
Deep Submergence Rescue Vehicle
Ohio Replacement Submarine
* Future of the Russian
List of submarine operators
* Australia –
* Bangladesh – Type 035G submarine
* Britain – List of submarines of the Royal
* ^ The New Shorter Oxford English Dictionary, Clarendon Press,
Oxford, 1993, Vol. 2 N-Z
* ^ "Worlds Biggest Submarine". Retrieved 21 May 2013.
* ^ Joann Taisnier Hannon (
Jean Taisnier (1508–1562)), Opusculum
perpetua memoria dignissimum, de natura magnetis et eius effectibus
(Köln (Cologne, "Colonia"), (Germany): Johann Birckmann, 1562), pp.
43-45. Available from: Bavarian State Library From p. 43: "Ne autem
Lector nostra dicta videatur refutare, arbitratus ea, quae miracula
putat, naturae limites excedere, unica demonstratione elucidabo,
quomodo scilicet quis in fundum alicuius aquae aut fluvij, sicco
corpore intrare possit, quod me vidisse in celebri Oppido & Regno
Tolleti affirmavi, coram piae memoriae Carolo Quinto Imperatore, I
will elucidate a unique demonstration, namely, how one can penetrate
to the bottom of any water or river while remaining dry, which, I
assert, I saw in the celebrated city and kingdom of Toledo in the
presence of Emperor Charles V of blessed memory and a multitude of
other spectators.) From p. 44: "Nunc venio ad experientiam praedictam,
Tolleti demonstratam a duobus Graecis, qui Cacabo magnae amplitudinis
accepto, orificio inverso, funibus in aere pendente, tabem & asseres
in medio concavi Cacabi affigunt, … " (Now I come to the experiment
mentioned above: in Toledo, it was shown by two Greeks, who, I
understand, attached to a cauldron (cacabus) of great size —
opening inverted held in the air by ropes — a beam and poles inside
of the hollow cauldron … ) The German Jesuit scientist Gaspar Schott
(1608–1666) quoted Taisnier's account and mentioned that Taisnier
had witnessed the demonstration in 1538. Gaspar Schott, Technica
Curiosa, sive Mirabilia Artis, Libris XII. … (Nuremberg
(Norimberga), (Germany): Johannes Andreas Endter & Wolfgang Endter,
1664), Liber VI: Mirabilium Mechanicorum (Book 6: Wonders of
mechanics), p. 393. From p. 393: " … quod nihilominus Anno 1538 in
Hispaniae oppido Toleto &c. coram piae memoriae Carolo V. Imperatore,
cum decem propemodum millibus hominum experientia vidi." ( … that
nevertheless I saw the experiment in the year 1538 in
* Histoire des sous-marins: des origines à nos jours by Jean-Marie
Mathey and Alexandre Sheldon-Duplaix. (Boulogne-Billancourt: ETAI,
* DiMercurio, Michael; Benson, Michael (2003). The complete idiot's
guide to submarines. Alpha. ISBN 0-02-864471-9 .
* Redford, Duncan. The Submarine: A Cultural History From the Great War to Nuclear Combat (I.B. Tauris, 2010) 322 pages; focus on British naval and civilian understandings of submarine warfare, including novels and film.
Submarines before 1914
* Gardiner, Robert (1992). Steam, Steel and Shellfire, The steam
warship 1815–1905. Annapolis, Maryland: Naval Institute Press. ISBN
1900/RUSSO-JAPANESE WAR 1904–1905
* Jentschura, Hansgeorg; Dieter Jung; Peter Mickel (1977). Warships
of the Imperial Japanese
* Blair, Clay (1975). Silent Victory: The U.S.
* Hide and seek: the untold story of
Wikimedia Commons has media related to SUBMARINES .
LISTEN TO THIS ARTICLE (info/dl )
This audio file was created from a revision of the