Submarine aircraft carrier
Submarine aircraft carriers are submarine
A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...

s equipped with fixed wing aircraft for observation or attack missions. These submarines saw their most extensive use during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

, although their operational significance remained rather small. The most famous of them were the Japanese I-400 class submarine
I-400 class submarine
The Imperial Japanese Navy submarines were the largest submarines of World War II and remained the largest ever built until the construction of nuclear ballistic missile submarines in the 1960s. They were submarine aircraft carriers able to carry three Aichi M6A Seiran aircraft underwater to their...

 and the , although a few similar craft were built by other nations' navies as well.

Except for the I-400 and AM classes, those submarine aircraft carriers which were actually built used their aircraft in a supporting role (usually for reconnaissance
Reconnaissance is the military term for exploring beyond the area occupied by friendly forces to gain information about enemy forces or features of the environment....

), unlike the typical surface aircraft carrier
Aircraft carrier
An aircraft carrier is a warship designed with a primary mission of deploying and recovering aircraft, acting as a seagoing airbase. Aircraft carriers thus allow a naval force to project air power worldwide without having to depend on local bases for staging aircraft operations...

, which describes a ship whose main function is serving as a base for combat aircraft. However, both real concepts and many fictional submarine aircraft carriers were created with the same role.

Early history (World War I)

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 was the first nation to experiment with submarine aircraft carriers, inspired by the Imperial German Naval Air Service commander Oberleutnant zur See Lothar von Arnauld de la Perière.
He commanded a unit of two reconnaissance seaplane
A seaplane is a fixed-wing aircraft capable of taking off and landing on water. Seaplanes that can also take off and land on airfields are a subclass called amphibian aircraft...

s (Friedrichshafen FF.29
Friedrichshafen FF.29
|-See also:-References:NotesBibliography...

s) in Zeebrugge
Zeebrugge is a village on the coast of Belgium and a subdivision of Bruges, for which it is the modern port. Zeebrugge serves as both the international port of Bruges-Zeebrugge and a seafront resort with hotels, cafés, a marina and a beach.-Location:...

 which had been recently occupied by the Imperial German Army in the early months of World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

One of the first U-Boats to arrive at the Zeebrugge base was Kapitänleutnant Walther Forstmann
Walther Forstmann
Captain Walther Forstmann was one of the most successful and highly decorated German U-boat commanders in the Kaiserliche Marine during World War I...

's U-12
Unterseeboot 12 (1911)
SM U-12 was a German submarine, built in 1911 and sunk off Scotland in 1915. It was the first submarine to launch a plane at sea.U-12 was a Type U 9 U-boat built for the Kaiserliche Marine. Her construction was ordered on 15 July 1908 and her keel was laid down by Kaiserliche Werft in Danzig...

, which was to play the role of submarine aircraft carrier.

Forstmann ordered the modification of the unarmed FF-29 seaplanes so they could carry 26½ lb (12 kg) bombs. This unit made history when on 25 December 1914, one of its newly modified aircraft flew across the English Channel
English Channel
The English Channel , often referred to simply as the Channel, is an arm of the Atlantic Ocean that separates southern England from northern France, and joins the North Sea to the Atlantic. It is about long and varies in width from at its widest to in the Strait of Dover...

 and up the River Thames
River Thames
The River Thames flows through southern England. It is the longest river entirely in England and the second longest in the United Kingdom. While it is best known because its lower reaches flow through central London, the river flows alongside several other towns and cities, including Oxford,...

, dropping its bombs on the outskirts of London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...

 where they did little damage. Although chased for a time by three British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 interceptors, it returned to base safely. On this first ever bombing mission it became apparent that the aircraft suffered more from fuel problems and lack of range than from British defences.

Later encouraged by this success, Arnauld and Forstmann theorized that they could effectively increase the range of their seaplanes by taking the aircraft to the sea on the deck of submarine and placing it in a takeoff position, then launching the planes after the sub partially submerged, allowing the plane to float off. On 15 January 1915, U-12 left their Zeebrugge base transporting one bomb-armed FF-29 on its deck. The submarine left the harbor, seemingly dwarfed by the 53 ft 2 in (16.21 m) wingspan of the fixed wing aircraft, which stretched almost ⅓ of the 188 ft (57 m) length of the small coastal patrol submarine. After U-12 had left the safety of the breakwater, however, the captain realized that the heavy swells they were encountering might swamp the aircraft and endanger the operation, he ordered the immediate launch of the seaplane.

Forstmann flooded the sub's forward tanks and despite the pitching of the boat, Arnauld in command, floated the seaplane off the deck's surface without much difficulty and took off. He had originally intended to rendezvous with the sub, but later decided against it. After gaining sufficient altitude, Arnauld's plane left for the British coast. The German officer apparently flew along the English coastline undetected and then made his way back to occupied Zeebrugge. The experiment had been successful, in the sense that the aircraft had been carried out to sea and had safely floated off the submarine's deck. However, it was obvious that some improvements were needed in the procedure and setup.

Arnauld and Forstmann proposed further development experiments to the German Naval Command, but were vetoed as their project was considered technically impracticable. The plans were kept on ice until 1917, when they were reinvestigated in the hope that they would increase the striking power of new German subs such as the long-range cruise-type Unterseeboote, which were to be equipped with aircraft for scouting purposes - little seaplanes that could be quickly assembled and dismantled onboard and kept in special compartments on deck - but the idea was eventually abandoned as the war came to an end.

Two of the aircraft designs created for that purpose were the biplane
A biplane is a fixed-wing aircraft with two superimposed main wings. The Wright brothers' Wright Flyer used a biplane design, as did most aircraft in the early years of aviation. While a biplane wing structure has a structural advantage, it produces more drag than a similar monoplane wing...

 Hansa Brandenburg W.20 and low-wing monoplane
A monoplane is a fixed-wing aircraft with one main set of wing surfaces, in contrast to a biplane or triplane. Since the late 1930s it has been the most common form for a fixed wing aircraft.-Types of monoplane:...

 Luftfahrzeug Gesellschaft L.F.G. Stralsund V.19. The first type was designed in 1917 for use aboard the Cruiser submarines that never went into service. The second model was an experimental plane of the flimsiest construction for use in the calmest of seas.

The British also experimented with the aircraft-carrying submarine concept when HM Submarine E22
HMS E22 was a British E class submarine built by Vickers, Barrow-in-Furness. She was laid down on 27 August 1914 and was commissioned on 8 November 1915.-Service history:...

 was fitted out in a manner similar to the German U-Boat. It was to be capable of launching its two Sopwith Schneider/Sopwith Baby
Sopwith Baby
-See also:...

A floatplane is a type of seaplane, with slender pontoons mounted under the fuselage; only the floats of a floatplane normally come into contact with water, with the fuselage remaining above water...

s in 1916. However, just as in the German experiment, the aircraft were carried outside and the submarine could not submerge without losing them.


Surcouf was a French submarine ordered to be built in December 1927, launched
Ship naming and launching
The ceremonies involved in naming and launching naval ships are based in traditions thousands of years old.-Methods of launch:There are three principal methods of conveying a new ship from building site to water, only two of which are called "launching." The oldest, most familiar, and most widely...

 18 October 1929, and commissioned
Ship commissioning
Ship commissioning is the act or ceremony of placing a ship in active service, and may be regarded as a particular application of the general concepts and practices of project commissioning. The term is most commonly applied to the placing of a warship in active duty with its country's military...

 May 1934. At 4,000 tons (3,600 tonnes) displacement submerged, Surcouf was the largest submarine in the world at the start of World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

. Her short wartime career is laced with controversy and conspiracy theories
Conspiracy theory
A conspiracy theory explains an event as being the result of an alleged plot by a covert group or organization or, more broadly, the idea that important political, social or economic events are the products of secret plots that are largely unknown to the general public.-Usage:The term "conspiracy...


Surcouf was designed as an "underwater cruiser
A cruiser is a type of warship. The term has been in use for several hundreds of years, and has had different meanings throughout this period...

," intended to seek and engage in surface combat. For the first part of that mission, it carried an observation float plane in a hangar built into the after part of the conning tower; for the second part, it was armed with not only 12 torpedo tube
Torpedo tube
A torpedo tube is a device for launching torpedoes. There are two main types of torpedo tube: underwater tubes fitted to submarines and some surface ships, and deck-mounted units installed aboard surface vessels...

s but also a twin 8 in (203 mm) gun turret
Gun turret
A gun turret is a weapon mount that protects the crew or mechanism of a projectile-firing weapon and at the same time lets the weapon be aimed and fired in many directions.The turret is also a rotating weapon platform...

 forward of the conning tower. The guns were fed from a magazine holding 60 rounds and controlled by a director with a 16 ft 6 in (5 m) rangefinder
A rangefinder is a device that measures distance from the observer to a target, for the purposes of surveying, determining focus in photography, or accurately aiming a weapon. Some devices use active methods to measure ; others measure distance using trigonometry...

, mounted high enough to view a 7 mi (11 km) horizon. In theory, the observation plane could direct fire out to the guns' 15 mi (24 km) maximum range. Anti-aircraft cannons and machine gun
Machine gun
A machine gun is a fully automatic mounted or portable firearm, usually designed to fire rounds in quick succession from an ammunition belt or large-capacity magazine, typically at a rate of several hundred rounds per minute....

s were mounted on the top of the hangar.


The Regia Marina
Regia Marina
The Regia Marina dates from the proclamation of the Kingdom of Italy in 1861 after Italian unification...

(Italian Navy) developed, in the late-1920s, the Ettore Fieramosca, a submarine with a waterproof hangar for a small reconnaissance plane. They gave commissions to the Italian aircraft manufacturers Macchi and Piaggio
Piaggio based in Pontedera, Italy encompasses seven brands of scooters, motorcycles and compact commercial vehicles. As the fourth largest producer of scooters and motorcycles in the world, Piaggio produces more than 600,000 vehicles annually, with five research and development centers, more than...

 for two prototype
A prototype is an early sample or model built to test a concept or process or to act as a thing to be replicated or learned from.The word prototype derives from the Greek πρωτότυπον , "primitive form", neutral of πρωτότυπος , "original, primitive", from πρῶτος , "first" and τύπος ,...

s. The Macchi M.53
Macchi M.53

 and the Piaggio P.8
Piaggio P.8
|-See also:-External links:*...

 were developed by 1928, but the program for an Italian aircraft-carrying submarine was cancelled, and the hangar was removed from the submarine in December 1931, before the Ettore Fieramosca was delivered to the Italian navy.


The Japanese applied the concept of the "submarine aircraft carrier" extensively, starting with the J3 class of 1937-38. Altogether 42 submarines were built with the capability to carry floatplanes.

See Japanese submarine I-8
Japanese submarine I-8
The Japanese submarine I-8 was a World War II Junsen Type J-3 Imperial Japanese Navy submarine, famous for completing a technology exchange mission to German-occupied France and back to Japan in 1943....

, and I-400 class submarine
I-400 class submarine
The Imperial Japanese Navy submarines were the largest submarines of World War II and remained the largest ever built until the construction of nuclear ballistic missile submarines in the 1960s. They were submarine aircraft carriers able to carry three Aichi M6A Seiran aircraft underwater to their...


United Kingdom

After the loss of the heavy gun carrying the remaining M-class
British M class submarine
The British Royal Navy M-class submarines were a small class of diesel electric submarine built during World War I. The unique feature of the class was a 12-inch gun mounted in a turret forward of the conning tower.-Background:...

 submarines were converted to other uses. By 1928, the M2 had been fitted with a waterproof hangar and hydraulic catapult and could launch and recover a small seaplane. The submarine and her plane could then act as a reconnaissance unit ahead of the fleet. The M2 herself was lost in 1932, and plane-launching submarines were abandoned by the Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...


United States

The concept was studied in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 since 1922. The American government purchased two Caspar-Heinkel U-1 disassemblable seaplanes for detachment to Anacostia Naval Station for evaluation and testing. Later, one aircraft was lost during an exhibition flight in 1923, but this provided useful technical information.

The United States Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

 accepted the construction of 12 submarine-based aircraft at different private enterprises like Cox-Klemin Aircraft
The Cox-Klemin Aircraft Corporation was an aircraft manufacturer on Long Island from 1921 to 1925.It was founded by Charles Cox and Alexander Klemin in College Point, New York....

 (from New York
New York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...

) with their Cox-Klemin XS-1
Cox-Klemin XS
-See also:...

 design (one prototype and five pre-production aircraft) and another six were ordered from Glenn L. Martin Company
Glenn L. Martin Company
The Glenn L. Martin Company was an American aircraft and aerospace manufacturing company that was founded by the aviation pioneer Glenn L. Martin. The Martin Company produced many important aircraft for the defense of the United States and its allies, especially during World War II and the Cold War...

 (from Baltimore
Baltimore is the largest independent city in the United States and the largest city and cultural center of the US state of Maryland. The city is located in central Maryland along the tidal portion of the Patapsco River, an arm of the Chesapeake Bay. Baltimore is sometimes referred to as Baltimore...

) with their design Glenn Martin MS-1, both small disassemblable seaplanes.

Both models were tested in the S-1 during October and November 1923. Later, the Cox-Klemm company attempted to develop its design with an XS-2
Cox-Klemin XS
-See also:...

 model, but the Navy lost interest in the concept. In 1931, another similar concept was born when Loening Aircraft Engineering Corporation presented its design the Loening XSL-1 a small flying boat
Flying boat
A flying boat is a fixed-winged seaplane with a hull, allowing it to land on water. It differs from a float plane as it uses a purpose-designed fuselage which can float, granting the aircraft buoyancy. Flying boats may be stabilized by under-wing floats or by wing-like projections from the fuselage...

 for submarine trials aboard the S-1, but the concept of submarine aircraft carriers was never accepted by the US Navy's submarine service.

News that the British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 submarine M2 had sunk during aircraft launching trials during 1933, and damage to the XSL-2 during aquatic testings in the Anacostia
Anacostia is a historic neighborhood in Washington, D.C. Its historic downtown is located at the intersection of Good Hope Road and Martin Luther King, Jr. Avenue It is the most famous neighborhood in the Southeast quadrant of Washington, located east of the Anacostia River, after which the...

 river area, caused the whole idea of submarine-borne aircraft to be abandoned by the U.S. Navy.


The Kriegsmarine
The Kriegsmarine was the name of the German Navy during the Nazi regime . It superseded the Kaiserliche Marine of World War I and the post-war Reichsmarine. The Kriegsmarine was one of three official branches of the Wehrmacht, the unified armed forces of Nazi Germany.The Kriegsmarine grew rapidly...

also started development of submarines capable of launching aircraft and ordered four very large "cruiser" U-boat
U-boat is the anglicized version of the German word U-Boot , itself an abbreviation of Unterseeboot , and refers to military submarines operated by Germany, particularly in World War I and World War II...

s in early 1939. These boats were to be twice as large as any existing U-boat and have a crew of 110. They were intended to carry a single Arado Ar 231
Arado Ar 231
The Arado Ar 231 was a light-weight Floatplane, developed during World War II in Germany as a scout plane for submarines. The need to be stored inside the submarine necessitated compromises in design that made this single-seat seaplane of little practical use....

 aircraft, but were canceled at the outbreak of war later that year.

Type IX D 2-"Monsun"

Another German long range U-boat was the Type IX D2 "Monsun"
German Type IX submarine
The Type IX U-boat was designed by Germany in 1935 and 1936 as a large ocean-going submarine for sustained operations far from the home support facilities. Type IX boats were briefly used for patrols off the eastern United States in an attempt to disrupt the stream of troops and supplies bound for...

, used in the Indian Ocean and Far East Area based in Penang (Occupied Malaya) during wartime. To aid such submarines the "Autogyro-Glider" Observation vehicle Focke-Achgelis Fa 330 "Bachstelze" (Water Wagtail) was developed. This vehicle was used in the Indian Ocean and sporadically in the Southern Atlantic, since May-June 1942.

Another plan was the use of Flettner Fl 282
Flettner Fl 282
|- References :NotesBibliography* Coates, Steve and Jean-Christophe Carbonel. Helicopters of the Third Reich. Crowborough, UK: Classic Publications Ltd., 2002. ISBN 1-903223-24-5....

A "Kolibri" recon-helicopter
A helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...

 version from long range submarines.

Such project implied the special one-place helicopter design were its fuselage was manufactured of welded steel tubing that was sized so that it could be stowed with rotor blades and landing gear removed in a compact area (5.9 ft/1.8 m in diameter by 18 ft/5.5 m long) and its pressured hangar for carriage in the U-boat plan.

There is no evidence that any Fl 282 "Kolibri" was deployed on a German submarine in wartime.


The Japanese applied the concept of the submarine aircraft carrier extensively. Altogether 47 submarines were built with the capability to carry seaplanes. Most IJN submarine aircraft carriers could carry only one aircraft, though a few types could carry two, and the giant I-400 class submarines could carry three.

B1 Type (20 units)

The B1 Type (I-15 Series) submarines (I-15, I-17, I-19, I-21
Japanese submarine I-21
was a Japanese Type B1 submarine which saw service during World War II in the Imperial Japanese Navy. She displaced 1,950 tons and had a speed of . I-21 was the most successful Japanese submarine to operate in Australian waters, participating in the attack on Sydney Harbour in 1942 and sinking...

, I-23, I-25
Japanese submarine I-25
was a B1-Type submarine of the Imperial Japanese Navy that served in World War II, took part in the Attack on Pearl Harbor, and carried out the only aerial bombing on the continental United States during wartime; during the so-called Lookout Air Raid; and the Bombardment of Fort Stevens, both...

, I-26
Japanese submarine I-26
I-26 was a Japanese B1 type submarine which saw service in the Imperial Japanese Navy during World War II. She was completed and commissioned at the Kure Dockyard on 6 November 1941, under the command of Commander Yokota Minoru....

, I-27
Japanese submarine I-27
I-27 was a submarine of the Imperial Japanese Navy which saw service during the Pacific Campaign of World War II. I-27 was commissioned at Sasebo, Japan on February 24, 1942. The sub's commander, Commander Fukumura, had a history of machine-gunning survivors of ships she had sunk, including the...

, I-28
Japanese submarine I-28
I-28 was a submarine of the Imperial Japanese Navy which saw service during the Pacific Campaign of World War II. I-28 was commissioned at Kobe, Japan on February 6, 1942. The submarine participated in the Battle of the Coral Sea in May 1942...

, I-29
Japanese submarine I-29
I-29, code-named Matsu , was a B1 type submarine of the Imperial Japanese Navy used during World War II on two secret missions with Germany, during one of which she was sunk.-Type B Submarines:...

, I-30
Japanese submarine I-30
I-30 was a Type B1 submarine of the Imperial Japanese Navy during World War II. After operating in the Indian Ocean she participated in a Yanagi mission, aimed at connecting Japan and Nazi Germany by submarine. She was the first Japanese submarine to reach Europe, arriving at Lorient, France in...

, I-31, I-32, I-33, I-34
Japanese submarine I-34
I-34 was a Kaidai Junsen Type B1 class submarine of the Imperial Japanese Navy. During World War II, while on a Yanagi mission between Japan and Germany carrying strategic raw material and information, she was sunk by the British submarine HMS Taurus using Ultra intelligence.-Commissioning:Her keel...

, I-35, I-36, I-37, I-38, I-39) were the most numerous type of submarines of the Imperial Japanese Navy
Imperial Japanese Navy
The Imperial Japanese Navy was the navy of the Empire of Japan from 1869 until 1947, when it was dissolved following Japan's constitutional renunciation of the use of force as a means of settling international disputes...

 during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

. In total, 20 were made, starting with number I-15, which became the name of the series. These submarines were fast, had a very long range, and carried a single Yokosuka E14Y
Yokosuka E14Y
|-See also:-References:NotesBibliography* Francillon, Ph.D., René J. Japanese Aircraft of the Pacific War. London: Putnam & Company Ltd., 1979. ISBN 0-370-30251-6....

 seaplane, located in a hangar in front of the conning tower, which was launched by a catapult.

The series was rather successful, especially at the beginning of the war. In 1942, I-26 crippled the aircraft carrier . I-19, on 15 September 1942, fired six torpedoes at the carrier , two of which hit the carrier and crippled it, with the remaining torpedoes damaging the battleship and the destroyer
In naval terminology, a destroyer is a fast and maneuverable yet long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against smaller, powerful, short-range attackers. Destroyers, originally called torpedo-boat destroyers in 1892, evolved from...

 (The USS O'Brian was decommissioned in 1972 and was DD-725) which sank later. I-25 conducted the only aerial bombings ever on the continental United States in September 1942, when an aircraft launched from it attacked the town of Brookings, Oregon
Brookings, Oregon
Brookings is a city in Curry County, Oregon, United States. It was named after John E. Brookings, president of the Brookings Lumber and Box Company, which founded the city in 1908. As of the 2010 census the population was 6,336. The total population of the Brookings area is over 13,000, which...


AM Type (I-13,I-14)

The AM (A Modified) type submarine was a large seaplane-carrying submarine, with a hangar space for two aircraft. These giant submarines were originally of the A2 type, but their design was revised after construction started so that they could carry a second aircraft. The seaplanes were to be the Aichi M6A
Aichi M6A
The Aichi M6A Seiran was a submarine-launched attack floatplane designed for the Imperial Japanese Navy during World War II...

1 bomber carrying 1,760 lb (800 kg) bombs.

The range and speed of these submarines was remarkable (21,000 nmi/ km at 16 kn/ km/h), but their underwater performance was compromised, making them easy targets. I-13 was sunk on 16 July 1945 by the destroyer escort
Destroyer escort
A destroyer escort is the classification for a smaller, lightly armed warship designed to be used to escort convoys of merchant marine ships, primarily of the United States Merchant Marine in World War II. It is employed primarily for anti-submarine warfare, but also provides some protection...

  and aircraft action from the escort carrier  about 550 mi (890 km) east of Yokosuka. I-14 surrendered at sea at the end of the war, and was later scrapped.

Sentoku Type (I-400, I-401, I-402)

The I-400 class submarine displaced 6,500 tons (5,900 tonnes) and was over 400 ft (120 m) long, three times the size of ordinary submarines. It had a figure-eight hull shape for additional strength to handle the on-deck hangar for housing the three Aichi M6A
Aichi M6A
The Aichi M6A Seiran was a submarine-launched attack floatplane designed for the Imperial Japanese Navy during World War II...

 Seiran aircraft. In addition, it had three anti-aircraft guns and a large deck gun as well as eight torpedo tubes from which they could fire the Long Lance - the largest, longest ranged and most deadly torpedo in use at the time.

Three of the Sen Toku were built, the I-400, I-401
Japanese submarine I-401
The Sen Toku-class I-401 was once the largest submarine in the world. It was commanded by Lieutenant Commander Nobukiyo Nambu of the Imperial Japanese Navy during World War II...

, and I-402. Each had four 3,000 hp
Horsepower is the name of several units of measurement of power. The most common definitions equal between 735.5 and 750 watts.Horsepower was originally defined to compare the output of steam engines with the power of draft horses in continuous operation. The unit was widely adopted to measure the...

 (2.2 MW) engines and enough fuel to go around the world 1½ times, more than enough to reach the United States from either direction.

The submarines were also able to carry three Sei ran aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...

 (the Aichi M6A
Aichi M6A
The Aichi M6A Seiran was a submarine-launched attack floatplane designed for the Imperial Japanese Navy during World War II...

), each carrying a 1,760 lb (800 kg) bomb 650 mi (1,050 km) at 360 mph (580 km/h). Its name was combination of sei ("clear sky") and ran ("storm"), literally "storm out of a clear sky," because the Americans would not know they were coming. It had a wing span of 40 ft (12 m) and a length of 38 ft (11.6 m). To fit the aircraft into the hangar, the wings of the aircraft were folded
Folding wing
A folding wing is a design feature of aircraft to save space in the airfield, and time, and is typical of naval aircraft that operate from the limited deck space of aircraft carriers. The folding allows the aircraft to occupy less space in a confined hangar because the folded wing normally rises...

 back, the horizontal stabilizer
A tailplane, also known as horizontal stabilizer , is a small lifting surface located on the tail behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed wing aircraft such as helicopters and gyroplanes...

s folded down, and the top of the vertical stabilizer
Vertical stabilizer
The vertical stabilizers, vertical stabilisers, or fins, of aircraft, missiles or bombs are typically found on the aft end of the fuselage or body, and are intended to reduce aerodynamic side slip. It is analogical to a skeg on boats and ships.On aircraft, vertical stabilizers generally point upwards...

 folded over so the overall profile of the aircraft was within the diameter of its propeller. A crew of four could prepare and get all three airborne in 45 minutes, launching them with a 120 ft (37 m) catapult
A catapult is a device used to throw or hurl a projectile a great distance without the aid of explosive devices—particularly various types of ancient and medieval siege engines. Although the catapult has been used since ancient times, it has proven to be one of the most effective mechanisms during...

 on the fore deck of the giant submarine.

Future designs

There are no known submarine carriers in use today, but several concepts exist that could provide a design in the future allowing an attack force to move entirely underwater, attack without warning, and vanish again. Against this there is the unavoidable fact that a submarine aircraft carrier would be tactically very limited with any attempt to use it to maintain air coverage forcing it to spend large amounts of time on the surface and as a result negating the advantage of being submersible. A marginally more viable role would be carrying out sudden surprise strikes on vulnerable targets. The cost of overcoming the engineering challenges of carrying an aircraft the size of a modern strike fighter combined with such a limited tactical role means that it is unlikely that any navy would consider their construction worthwhile.

There are, however, several projects to develop UAV
Unmanned aerial vehicle
An unmanned aerial vehicle , also known as a unmanned aircraft system , remotely piloted aircraft or unmanned aircraft, is a machine which functions either by the remote control of a navigator or pilot or autonomously, that is, as a self-directing entity...

 launch and recovery capabilities. There are three known methods for doing so: launching out of a standard torpedo tube, out of an ICBM vertical launch tube, or from a custom designed unit (probably residing in the sail). The US Navy is a primary driver and customer for this capability, recognising the need for more advanced littoral combat capability, to counter growing area-denial asymmetric threats. The German type 212 submarines will have the capability to launch UAVs.

Another idea is to modify jet fighters into seaplanes, so they are capable of taking off and landing on water, then retrieved by the submarine carrier. This would remove the need of building a runway on the submarine itself.

See also

  • Fictional submarine aircraft carriers
    Fictional submarine aircraft carriers
    The following is a list of submarine aircraft carriers that have only appeared in various fiction media.-Anime:* The OVA series Macross Zero featured the submarine aircraft carrier Auerstädt as the principal support vessel for Anti-UN forces operating around Mayan Island...

  • List of undersea-carried planes
  • Flying submarine
    Flying submarine
    A flying submarine or submersible aircraft is a craft able both to fly or travel under water.-History:The Soviet Union tried to develop a flying submarine during World War II. The design could have operated at 150 knots in the air and 3 knots in the water. Metal plates sealed the engines shut...

  • USS Macon (ZRS-5)
    USS Macon (ZRS-5)
    USS Macon was a rigid airship built and operated by the United States Navy for scouting. She served as a "flying aircraft carrier", launching Curtiss F9C Sparrowhawk biplane fighters. In service for less than two years, in 1935 Macon was damaged in a storm and lost off California's Big Sur coast,...

    Flying Aircraft Carrier

External links

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