Air-independent propulsion (AIP) is a term that encompasses technologies which allow a submarine to operate without the need to surface or use a
snorkelA submarine snorkel is a device that allows a submarine to operate submerged while still taking in air from above the surface. It was invented by the Dutch shortly before World War II and copied by the Germans during the war for use by U-Boats...
to access
atmosphericThe Earth's atmosphere is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention , and reducing temperature extremes between day and night...
oxygenOxygen Oxygen Oxygen (acid, literally "sharp", from the taste of acids) and -γενής (-genēs) (producer, literally begetter) is the element with atomic number 8 and represented by the symbol O...
. The term usually excludes the use of
nuclear powerNuclear power is power produced from controlled nuclear reactions. Commercial plants in use to date use nuclear fission reactions....
, and describes augmenting or replacing the diesel-electric propulsion system of non-nuclear vessels. The
United States NavyThe United States Navy is the sea branch of the U.S. Armed Forces. It is one of the seven uniformed services of the United States. As of 31 December 2008, the U.S. Navy had about 331,682 personnel on active duty and 124,000 in the Navy Reserve. It operates 283 ships in active service and more than...
uses the
hull classification symbolThe United States Navy, United States Coast Guard, and United States National Oceanic and Atmospheric Administration use hull classification symbols to identify their ship types and each individual ship within each type...
"SSP" to designate boats powered by AIP, while retaining "SS" for classic diesel-electric attack submarines.
AIP is usually implemented as an auxiliary source. Most such systems generate electricity which in turn drives an electric motor for propulsion or recharging the boat's
batteriesAn electrical battery is a combination of one or more electrochemical cells, used to convert stored chemical energy into electrical energy. Since the invention of the first Voltaic pile in 1800 by Alessandro Volta, the battery has become a common power source for many household and industrial...
. The submarine's electrical system is also used to provide "hotel services"—ventilation, lighting, heating etc—although this consumes a small amount of power compared to that required for propulsion.
A benefit of this approach is that it can be retrofitted into existing submarine
hullsA hull is the watertight body of a ship or boat. Above the hull comes the superstructure and deckhouse. The line where the hull meets the water surface is called the waterline.The structure of the hull varies depending on the vessel type...
by inserting an additional hull section. AIP does not normally provide the endurance or
powerIn physics, power is the rate at which work is performed or energy is converted. It is an energy per unit of time. As a rate of change of work done or the energy of a subsystem, power iswhere P is power, W is work and t is time....
to replace the atmospheric dependent propulsion, but allows it to remain submerged longer than a more conventionally propelled submarine. A typical conventional power plant will provide 3 megawatts maximum, and an AIP source around 10% of that. A nuclear submarine's propulsion plant is usually much greater than 20 megawatts.
History
In 1867
Narcís Monturiol i EstarriolNarcís Monturiol Estarriol was a Spanish Catalan engineer, artist and intellectual. He was the inventor of the first combustion engine driven submarine, which was propelled by an early form of air-independent propulsion....
successfully developed an early form of anaerobic air independent propulsion. In 1908 the Imperial Russian Navy launched the
Pochtovy submarinePochtovy was a submarine built for the Imperial Russian Navy. The boat was designed by Drzewiecki and built at the Metal Works St Petersburg in 1908. She was funded by Public subscription....
which used a gasoline engine fed with compressed air and exhausted under water.
During
World War IIWorld War II, or the Second World War , was a global military conflict which involved a majority of the world's nations, including all great powers, organized into two opposing military alliances: the Allies and the Axis...
the
GermanGermany , officially the Federal Republic of Germany , is a country in Central Europe. It is bordered to the north by the North Sea, Denmark, and the Baltic Sea; to the east by Poland and the Czech Republic; to the south by Austria and Switzerland; and to the west by France, Luxembourg, Belgium,...
firm
WalterHellmuth Walter was a German engineer who pioneered research into rocket engines and gas turbines...
experimented with submarines that used concentrated
hydrogen peroxideHydrogen peroxide is a very pale blue liquid, slightly more viscous than water, that appears colorless in dilute solution. It is a weak acid, has strong oxidizing properties, and is a powerful bleaching agent. It is used as a disinfectant, antiseptic, oxidizer, and in rocketry as a propellant...
as their source of oxygen underwater. These used
steam turbineA steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion. Its modern manifestation was invented by Sir Charles Parsons in 1884....
s, employing steam heated by burning diesel fuel in the steam/oxygen atmosphere created by the decomposition of hydrogen peroxide by a
potassium permanganatePotassium permanganate is the inorganic chemical compound KMnO
4, a water soluble salt consisting of equal mole amounts of potassium and permanganate ions. This salt, formerly known as permanganate of potash or Condy's crystals is a strong oxidizing agent...
catalyst.
Several experimental boats were produced, and one, U-1407, which had been scuttled at the end of the war, was salvaged and recommissioned into the
Royal NavyThe Royal Navy of the United Kingdom is the oldest of HM Armed Forces . From the beginning of the 18th century until well into the 20th century, it was the most powerful navy in the world, playing a key part in establishing the British Empire as the dominant world power from 1815 until the early...
as
HMS MeteoriteHMS Meteorite was an experimental U Boat developed in Germany, captured at the end of World War II, and commissioned into the Royal Navy. The submarines was originally commissioned into the Kriegsmarine in March 1945 as U-1407...
. The British built two improved models in the late 1950s,
HMS ExplorerHMS Explorer was an experimental British submarine based on the captured German high test peroxide powered U-boat U-1407. U-1407 had been scuttled following the German collapse at the end of the Second World War, was salvaged and eventually commissioned into the Royal Navy as...
, and
HMS ExcaliburHMS Excalibur was the sister ship of , the two submarines being the only High test peroxide powered submarines to be constructed by the Royal Navy...
.
The
Soviet UnionThe Union of Soviet Socialist Republics was a constitutionally socialist state that existed in Eurasia from 1922 to 1991. The name is a translation of the , tr. Soyuz Sovetskikh Sotsialisticheskikh Respublik, abbreviated СССР, SSSR. The common short name is Soviet Union, from , Sovetskiy Soyuz...
also experimented with the technology and
one experimental boat was builtS-99 — experimental submarine, the only ship of Whale class that the Soviet Union built in the early cold war period and the only soviet submarine which had a Walter engine fuelled by high test peroxide .- Design :Initial design of submarine was based at project XXVI documentation, which was...
. Hydrogen peroxide was eventually abandoned since it is highly reactive when in contact with various metals, is volatile, and submarines had a high rate of consumption. Both the British and the Soviets, the only countries known to be experimenting with it, abandoned it when the
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
developed a
nuclear reactorA nuclear reactor is a device in which nuclear chain reactions are initiated, controlled, and sustained at a steady rate.The most significant use of nuclear reactors is as an energy source for the generation of electrical power and for the power in some ships...
small enough for submarine propulsion.
It was retained for propelling
torpedoThe modern torpedo is a self-propelled explosive projectile weapon, launched above or below the water surface, propelled underwater toward a target, and designed to detonate on contact or in proximity to a target...
es by the British and the Soviet Union, although hastily abandoned by the former following the
HMS SidonHMS Sidon was launched in September 1944, one of the third group of S-class submarines built by Cammell Laird & Co Limited, Birkenhead. A faulty torpedo caused an explosion sinking it in harbour with the loss of 13 lives.-Accident:...
tragedy. Both this and the loss of the Russian Submarine
Kursk were due to accidents involving hydrogen peroxide propelled torpedoes.
Closed cycle diesel engines
This technology uses a submarine
diesel engineA diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber during the final stage of compression...
which can be operated conventionally on the surface, but which can also be provided with oxidant, usually stored as
liquid oxygenLiquid oxygen is a form of the element oxygen. It has a pale blue color and is strongly paramagnetic and can be suspended between the poles of a powerful horse shoe magnet...
, when submerged. Since the metal of an engine will burn in pure oxygen, the oxygen is usually diluted with recycled
exhaust gasExhaust gas or flue gas is emitted as a result of the combustion of fuels such as natural gas, gasoline/petrol, diesel fuel, fuel oil or coal...
. As there is no exhaust gas upon starting,
argonArgon is a chemical element designated by the symbol Ar. Argon has atomic number 18 and is the third element in group 18 of the periodic table . Argon is present in the Earth's atmosphere at 0.94%. Terrestrially, it is the most abundant and most frequently used of the noble gases...
is used.
During World War II the Kriegsmarine experimented with such a system as an alternative to the Walter peroxide system, including a variant of the Type XXVIIB
Seehund midget submarine, the "Klein U-boot". It was powered by a 95 hp Diesel engine of a type commonly used by the Kriegmarine and which was available in large numbers, supplied with oxygen from a tank in the boat's keel holding 1,250 litres at . It was thought likely that the boat would have a maximum submerged speed of and a range of , or at .
The German work was subsequently expanded upon by the Soviet Union who invested heavily in this technology, developing the small 650 ton
Quebec-classThe Quebec-class submarine was the NATO reporting name of the Soviet Project 615 submarine class, a small coastal attack submarine of the late 1950s.-Background:...
submarine of which thirty were built between 1953 and 1956. These had three diesel engines—two were conventional and one was closed cycle using liquid oxygen.
In the Soviet system, called a "single propulsion system", oxygen was added after the exhaust gases had been filtered through a lime-based chemical absorbent. The submarine could also run its diesel using a snorkel. The
Quebec had three engines: a 32D 900 bhp diesel on the centre shaft and two M-50P 700 bhp diesels on the outer shafts. In addition a 100 hp "creep" motor was coupled to the centre shaft. The boat could be run at slow speed using the centreline diesel only.
Because liquid oxygen cannot be stored for any great length of time these boats could not operate far from a base. It was also a dangerous system; at least seven submarines suffered explosions, and one of these,
M-256M-256 was a Project 615 short-range attack diesel submarine of the Soviet Navy. She was commissioned into the Baltic Fleet.-Design:...
, sank following an explosion and fire. They were sometimes nicknamed
cigarette lighters. The last was scrapped in the early 1970s.
The
German NavyThe German Navy The German Navy The German Navy (Deutsche Marine is the navy of Germany and part of the Bundeswehr (German Armed Forces).The German Navy traces its roots back to the Imperial Fleet (Reichsflotte) of the revolutionary era of 1848–1852 and more directly to the Prussian Navy, which...
's former
Type 205 submarineThe Type 205 was a class of diesel-electric German hunter-killer U-boat submarines. They were single-hull vessels optimized for the use in the shallow Baltic Sea. The Type 205 is a direct evolution of the Type 201 class with lengthened hull, new machinery and sensors...
U1 was fitted with an experimental 3000 horsepower (2.2 MW) unit.
Closed cycle steam turbines
The
FrenchFrance , officially the French Republic , is a country located in Western Europe, with several overseas islands and territories located on other continents. Metropolitan France extends from the Mediterranean Sea to the English Channel and the North Sea, and from the Rhine to the Atlantic Ocean...
MESMA (Module d'Energie Sous-Marine Autonome) system is being offered by the French shipyard DCNS. MESMA is available for the
Agosta 90BThe Agosta class submarines are French diesel attack submarines used by Spain, Pakistan and formerly by France. The French Navy grouped this model of non-nuclear submarine in their most capable class as an océanique, meaning "ocean-going." A modernised version built for Pakistan, the Agosta 90B,...
and Scorpène class submarines. It is essentially a modified version of their nuclear propulsion system with heat being generated by
ethanolEthanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug, best known as the type of alcohol found in alcoholic beverages and in modern thermometers. Ethanol is one of the oldest recreational drugs...
and oxygen. A conventional steam turbine power plant powered by steam generated from the combustion of ethanol (grain alcohol) and stored oxygen at a pressure of 60 atmospheres. This pressure-firing allows exhaust carbon dioxide to be expelled overboard at any depth without an exhaust compressor.
Each MESMA system costs around $50–60 million. As installed on the Scorpène, it requires adding a new 8.3 meter (27 foot), 305 tonne hull section to the submarine, and results in a submarine able to operate for greater than 21 days underwater, depending on variables like speed, etc.
An article in Undersea Warfare Magazine notes that: “although MESMA can provide higher output power than the other alternatives, its inherent efficiency is the lowest of the four AIP candidates, and its rate of oxygen consumption is correspondingly higher.”
Stirling cycle engines
The
SwedishSweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe...
shipbuilder
KockumsKockums AB is a shipyard in Malmö, Sweden owned by the German shipyard HDW in Kiel. HDW itself is a subsidiary of the German ThyssenKrupp Marine Systems....
has constructed three
Gotland classThe Gotland class attack submarines of the Swedish Navy are modern diesel-electric submarines. They are the first submarines in the world to feature a Stirling engine air-independent propulsion system, which extends their underwater endurance from a few days to weeks...
submarines for the
Swedish NavyThe Swedish Navy is the naval branch of the Swedish Armed Forces. It is composed of surface and submarine naval units – the Fleet – as well as marine units, the so-called Amphibious Corps ....
which are fitted with an auxiliary Stirling engine which uses liquid oxygen and diesel fuel to drive 75 kilowatt generators for either propulsion or charging batteries. The AIP endurance of the 1,500 tonne boats is around 14 days at five knots (9 km/h).
KockumsKockums AB is a shipyard in Malmö, Sweden owned by the German shipyard HDW in Kiel. HDW itself is a subsidiary of the German ThyssenKrupp Marine Systems....
has also delivered Stirling engines to Japan. The new Japanese submarines will all be equipped with Stirling engines. The first submarine,
SōryūThe Sōryū class submarine or 16SS is a new class of diesel-electric submarine being built in Japan for use by the Japan Maritime Self-Defense Force...
, in the class was launched on 5 December 2007 and were delivered to the navy in March 2009.
Fuel cells
SiemensSiemens AG is Europe's largest engineering conglomerate. Siemens' international headquarters are located in Berlin and Munich, Germany. The company is a conglomerate of three main business sectors: Industry, Energy and Healthcare with a total of 15 Divisions.Worldwide, Siemens and its subsidiaries...
has developed a 30-50 kilowatt fuel cell unit. Nine of these units are incorporated into
HowaldtswerkeHowaldtswerke-Deutsche Werft is a German shipbuilding company, headquartered in Kiel. In 2009 it was the largest shipyard in Germany and has more than 2,400 employees. It has been part of ThyssenKrupp Marine Systems owned by ThyssenKrupp, since 2005...
Deutsche Werft AG's 1,830t submarine
U31, lead ship for the
Type 212AThe German Type 212 is a highly advanced design of non-nuclear submarine developed by Howaldtswerke-Deutsche Werft AG for the German Navy. It features diesel propulsion and an additional air-independent propulsion system using Siemens proton exchange membrane hydrogen fuel cells...
class of the
German NavyThe German Navy The German Navy The German Navy (Deutsche Marine is the navy of Germany and part of the Bundeswehr (German Armed Forces).The German Navy traces its roots back to the Imperial Fleet (Reichsflotte) of the revolutionary era of 1848–1852 and more directly to the Prussian Navy, which...
. The other boats of this class and HDW's AIP equipped export submarines (
Type 209 modType 209 is a class of diesel-electric attack submarine developed exclusively for export in the late 1960s and constantly been modernized by Howaldtswerke-Deutsche Werft of Germany...
and
Type 214The Type 214 is a diesel-electric submarine developed by Howaldtswerke-Deutsche Werft GmbH . It features diesel propulsion with an air-independent propulsion system using Siemens polymer electrolyte module hydrogen fuel cells...
) use two 120 kW modules, also from Siemens.
After the success of
HowaldtswerkeHowaldtswerke-Deutsche Werft is a German shipbuilding company, headquartered in Kiel. In 2009 it was the largest shipyard in Germany and has more than 2,400 employees. It has been part of ThyssenKrupp Marine Systems owned by ThyssenKrupp, since 2005...
Deutsche Werft AG's in its export activities, several builders have developed their own fuel-cell auxiliary units for submarines but until today no other shipyard has a contract for a submarine so equipped.
Nuclear power
Nuclear reactors have been used for 50 years to power submarines, the first being
USS NautilusUSS Nautilus was the world's first operational nuclear-powered submarine and the first vessel to complete a submerged transit across the North Pole....
. The
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
,
FranceFrance , officially the French Republic , is a country located in Western Europe, with several overseas islands and territories located on other continents. Metropolitan France extends from the Mediterranean Sea to the English Channel and the North Sea, and from the Rhine to the Atlantic Ocean...
, the
United KingdomThe United Kingdom of Great Britain and Northern Ireland is a sovereign state located off the northwestern coast of continental Europe. It is an island country, spanning an archipelago including Great Britain, the northeastern part of Ireland, and many small islands...
,
RussiaRussia , officially known as both Russia and the Russian Federation , is a country in northern Eurasia . It is a semi-presidential republic, comprising 83 federal subjects...
, the
People's Republic of ChinaThe People's Republic of China , commonly known as China, is the largest country in East Asia and the most populous in the world with over 1.3 billion people, approximately one-fifth of the world's population...
, and
IndiaIndia, officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the south, the Arabian Sea on the west, and the Bay of Bengal...
are the only countries known to operate nuclear powered submarines. Five of these six countries also have permanent seats on the
United Nations Security CouncilThe United Nations Security Council is one of the principal organs of the United Nations and is charged with the maintenance of international peace and security. Its powers, outlined in the United Nations Charter, include the establishment of peacekeeping operations, the establishment of...
and are the only countries allowed to possess nuclear weapons according to the
Nuclear Non-Proliferation TreatyThe Treaty on the Non-Proliferation of Nuclear Weapons, also Nuclear Non-Proliferation Treaty is a treaty to limit the spread of nuclear weapons, opened for signature on July 1, 1968...
. India has only in 2009 completed construction of its first domestically built nuclear submarine. India in the past has leased a
Charlie classThe Charlie I class submarine is a Cruise missile submarine. The Charlie I class submarine SSGN was first launched at the inland shipyard at Gorkiy in 1967 with another 10 following over a period of 5 years...
nuclear powered submarine from Russia and plans to acquire two used
Akula class submarineProject 971 Щука-Б , is a nuclear-powered attack submarine first deployed by the Soviet Navy in 1986...
s which would be used for training purposes.
BrazilBrazil , officially the Federative Republic of Brazil , is a country in South America. It is the fifth largest country by geographical area, occupying nearly half of South America, the fifth most populous country, and the fourth most populous democracy in the world. Bounded by the Atlantic Ocean...
is also known to research nuclear propulsion for submarine use. However, Air Independent Propulsion is a term normally used in the context of improving the performance of conventionally propelled submarines.
There have nevertheless been suggestions for a reactor as an auxiliary power supply, which does fall into the normal definition of AIP. For example, there has been a proposal to use a small 200 kilowatt reactor for auxiliary power (styled a "nuclear battery") to improve the under-ice capability of Canadian submarines.
Production non-nuclear AIP submarines
As of 2009, some nations have non-nuclear AIP submarines:
- the French-Spanish Scorpène-class submarine
Scorpène class submarines are a class of diesel-electric attack submarine. It features diesel propulsion and an additional air-independent propulsion , jointly developed by the French company DCNS, formerly DCN, and the Spanish company Navantia .The Chilean Navy ordered two Scorpène, which...
(1,700 tonnes) (MESMA)
- the Spanish S-80 class
The submarines of the Class S-80 of the Spanish Navy are a series of high-tech submarines. Initially there are four units, with expansion to six, two of which are already in production by the Spanish company Navantia factory in Cartagena, and whose fundamental characteristics are A new propulsion...
(2,400 tonnes) of the Spanish NavyThe Spanish Navy is the maritime arm of the Spanish Military, one of the oldest active naval forces in the world. The Armada is responsible for notable achievements in world history such the first world circumnavigation, and the discovery of a maritime path from the Far East to America across the...
- the German Type 209-1400mod
Type 209 is a class of diesel-electric attack submarine developed exclusively for export in the late 1960s and constantly been modernized by Howaldtswerke-Deutsche Werft of Germany...
(1,810 tonnes) (Fuel cell)
- the German Type 212 submarine
The German Type 212 is a highly advanced design of non-nuclear submarine developed by Howaldtswerke-Deutsche Werft AG for the German Navy. It features diesel propulsion and an additional air-independent propulsion system using Siemens proton exchange membrane hydrogen fuel cells...
(1,830 tonnes) (Fuel cell) of the German NavyThe German Navy The German Navy The German Navy (Deutsche Marine is the navy of Germany and part of the Bundeswehr (German Armed Forces).The German Navy traces its roots back to the Imperial Fleet (Reichsflotte) of the revolutionary era of 1848–1852 and more directly to the Prussian Navy, which...
and Italian NavyItalian Navy may refer to:* Pre-unitarian navies of the Italian states* Regia Marina, the Royal Navy of the Kingdom of Italy * Marina Militare, the Navy of the Italian Republic...
- the German Type 214
The Type 214 is a diesel-electric submarine developed by Howaldtswerke-Deutsche Werft GmbH . It features diesel propulsion with an air-independent propulsion system using Siemens polymer electrolyte module hydrogen fuel cells...
(1,980 tonnes) (Fuel cell)
- the Russian Project 677 Лада (Lada)
The Russian Navy's Project 677 Лада is a submarine class designed by the Russian Rubin Design Bureau. The class is sometimes referred to as the Saint Petersburg class, after the lead ship...
- the Russian Project 1650 Амур (Amur)
The Russian Navy's Project 950 Амур submarines are advertised as the export version of the Petersburg class, a highly improved version of the with much better quieting, new combat systems, and an option for air-independent propulsion.Some sources state that submarine has a crew of 18 while others...
- the Japanese Asashio
The Harushio is a Japanese diesel-electric submarine class operated by the JMSDF. The design is an evolution from the Yūshio class being slightly larger and with better noise reduction. The Asashio, has been modified to test Air-independent propulsion .-Boats:-References:* Jane's Fighting Ships...
(2,750 tonnes) (Stirling AIP) of the Japan Maritime Self-Defense ForceThe , or JMSDF, is the maritime branch of the Japan Self-Defense Forces, tasked with the naval defense of Japan. It was formed following the dissolution of the Imperial Japanese Navy after World War II. It has a large fleet with significant blue-water operating capabilities. The force is based...
- the Japanese Sōryū class submarine
The Sōryū class submarine or 16SS is a new class of diesel-electric submarine being built in Japan for use by the Japan Maritime Self-Defense Force...
(4,200 tonnes) (Stirling AIP) of the Japan Maritime Self-Defense ForceThe , or JMSDF, is the maritime branch of the Japan Self-Defense Forces, tasked with the naval defense of Japan. It was formed following the dissolution of the Imperial Japanese Navy after World War II. It has a large fleet with significant blue-water operating capabilities. The force is based...
- the Swedish Gotland class submarine
The Gotland class attack submarines of the Swedish Navy are modern diesel-electric submarines. They are the first submarines in the world to feature a Stirling engine air-independent propulsion system, which extends their underwater endurance from a few days to weeks...
(1,450 tonnes) (Stirling AIP) of the Swedish navyThe Swedish Navy is the naval branch of the Swedish Armed Forces. It is composed of surface and submarine naval units – the Fleet – as well as marine units, the so-called Amphibious Corps ....
- the Swedish Södermanland class submarine
The Swedish Södermanland class of diesel-electric submarines consist of the HMS Södermanland and HMS Östergötland. These two submarines were originally launched as Västergötland class submarines in 1987 and 1990, and have been relaunched as a new class after extensive modernization 2003 and 2004 by...
(1,500 tonnes) (Stirling AIP) of the Swedish navyThe Swedish Navy is the naval branch of the Swedish Armed Forces. It is composed of surface and submarine naval units – the Fleet – as well as marine units, the so-called Amphibious Corps ....
Sweden is going to sell its remaining two
Västergötland class submarineThe A-17 Västergötland class of diesel-electric submarines was introduced in 1987 by the Swedish Navy. The original four ships of her class, HMS Västergötland, HMS Hälsingland, HMS Södermanland and HMS Östergötland, were built between 1983 and 1988 by Kockums AB...
s to the
Republic of Singapore NavyThe Republic of Singapore Navy is the naval component of the Singapore Armed Forces , responsible for the defence of Singapore against sea-borne threats and protection of its sea lines of communications. Operating within the crowded littoral waters of the Singapore Strait, the RSN is regarded as...
after they have been refitted with Stirling AIP systems like the
Södermanland class submarineThe Swedish Södermanland class of diesel-electric submarines consist of the HMS Södermanland and HMS Östergötland. These two submarines were originally launched as Västergötland class submarines in 1987 and 1990, and have been relaunched as a new class after extensive modernization 2003 and 2004 by...
s.
- the Chinese Type 041 Yuan class submarine (Stirling AIP) of the PLAN
The People's Liberation Army Navy is the naval branch of the People's Liberation Army , the military of the People's Republic of China. Until the early 1990s, the navy performed a subordinate role to the PLA Land Forces...
Also several shipbuilders offer AIP upgrades for existing submarines:
- German Nordseewerke
Nordseewerke is a shipbuilding company located in Emden, Germany. It is now a subsidiary of ThyssenKrupp Marine Systems. The name Nordseewerke means "North Sea shipyard" in German...
(Closed-cycle diesel)
- Sweden Kockums
Kockums AB is a shipyard in Malmö, Sweden owned by the German shipyard HDW in Kiel. HDW itself is a subsidiary of the German ThyssenKrupp Marine Systems....
(Stirling), owned by German company ThyssenKruppThyssenKrupp AG is a large German industrial conglomerate, with more than 200,000 employees. The corporation consists of 670 companies worldwide. ThyssenKrupp is one of the world's largest steel producers. It operates worldwide in three business areas: steel, capital goods, and services...
- Pakistan Agosta 90B class submarine
The Agosta class submarines are French diesel attack submarines used by Spain, Pakistan and formerly by France. The French Navy grouped this model of non-nuclear submarine in their most capable class as an océanique, meaning "ocean-going." A modernised version built for Pakistan, the Agosta 90B,...
Made with cooperation with France
External links