World War II was brought to the West Coast of the United States early one morning in September
1942, when a Japanese I 25 submarine surfaced about six miles off’ Cape Blanco, Oregon. Members
of the crew scrambled onto the deck and proceeded to remove from a watertight hangar a small
seaplane – A Yokosuka E14Y1 – called a Glen by the Allies. They quickly assembled the aircraft
and hung two incendiary bombs on its underwing racks. The aircraft normally carried an observer
but, due to its attack payload, he had to be left behind for this mission.
The pilot, warrant Off’icer Fujita, took off, penetrated the forest belt of Oregon and dropped
his two bombs causing, it is thought, some serious fires. A second attack was carried out a
week later with similar results. These attacks showed that is was possible to carry out raids
from submarines, although the range and bomb loads were very restricted.
The very first aircraft launched from a submarine is attributed to the German Imperial
Navy during WWI. The German Army had advanced into Belgium and occupied the Port of Zeebrugge, famous for its giant breakwater. The German Navy then moved its U-boa ts into the port. One of the first to arrive was the U-12 commanded by Kapitanleutnant Walter Forstmann. A month later, the first contingent of the Imperial Navy’s Air Service arrived, commanded by Oberleutnant zur See Friedrich von Arnauld de la Perri ere. His unit consisted of three other officers, 55 enlisted
men and two aircraft. The aircraft, Friedrichshafen FF-29s, were twin-float biplanes, powered by 120-hp engines.
The mission of the U-boats was simple, to sink enemy shipping. However, the role of the German
Navy’s air army had still not been clearly defined. It had been created at the very beginning of the war, but what it could or should do had yet to be established.
Friedrich von Arnauld, having received no instructions, decided to develop his own missions.
He reconfigured the unarmed FF-29s to carry 26.5 pound bombs, and on Christmas Day one of his
seaplanes flew across the English Channel, up the River Thames and dropped the bombs harmlessly on the outskirts of London. Although it was chased by three British aircraft, it returned safely.
The aircraft themselves suffered more from fuel problems and faulty ignitions than they did from
Fors tmann and von Arnauld decided that if they took an aircraft to sea on the deck of a submarine
and placed it in a takeoff position, they could launch the plane by partially submerging. This
would effectively increase the range of the seaplanes. On January 6, 1915, the FF -29 was
placed across the deck of the U-12 and lashed down. The submarine left the harbour, seemingly
dwarfed by the 53-foot 2-inch wingspan, that stretched almost one-third of the submarine’s 188-
No sooner had the U-12 left the safety of the breakwater than the captain realized that the
heavy swell they were encountering might possibly endanger the operation. After less than an hour,
it was decided to launch the seaplane. Captain Fors tmann flooded the forward tanks and, despite
the pitching of the vessel, von Arnauld’s aircraft floated off the deck and took off without difficulty. He had intended to rendezvous with the submarine but decided against it. It is not known how close to the English coast the submarine was when it launched the FF- 29, but von Arnault flew along the Kent coast undetected and then made his way back to Zebrugge.
The experiment had been partially successful inasmuch as the aircraft had been carried and floated off, but it was realized that calmer seas and more secure lashing of the aircraft were required.
Von Arnauld and Forstmann were eager to try the experiment again but the German High Command
vetoed it. The idea lay dormant until 1917, when it was revived by the High Command so that the
striking power of submarines could be increased. Some of the long-range, cruise type of submarines
were to be equipped with aircraft for scouting purposes. Although plans were drawn up and designs prepared for the quick assembly and dismantling of seaplanes on board ship, the ideas were eventually abandoned.
While the idea was given up by the Germans, in 1927 the British submarine M-2 was commissioned
as an aircraft carrier. She was ideal for such an assignment because of the 12-inch gun that was
housed in a turret forward of the conning tower. The gun was removed and the turret modified to
take a specially designed reconnaissance seaplane. Many designs were considered, but the one selected was a two-seat, unarmed, wirelessequipped Peto, designed and constructed by George
Parnall and Company.
The Peto was not the first British aircraft designed for use on a submarine. In 1916, two Sopwith Schneider seaplanes were carried aboard the E22 submarine, lashed down on the deck. Even
earlier, well before 191~, an aircraft called the Bristol Burnley X was built. It was designed to
collapse and pack away on surface vessels and on submarines.
The Peto was mated with the ill-fated M-2. The little twin-floated biplane was locked onto a
carriage that rested on two rails inside the hangar on the forward deck. The hangar crew of 10 found the room inside the hangar very cramped when standing by to get the seaplane launched.
The launch procedure went as follows: The pilot would ascertain from the captain when the
boat was likely to surface. As it was impossible to start the engine while submerged, the
lubricating oil in the tank and engine was heated up so as to shorten the running-up time once the
aircraft was on the catapault.
As soon as the boat surfaced, the launch crew opened the hangar door and lowered it to form part
of the launching platform. The airplane was quickly run out on its rails and locked into position at the end of the catapault, after which the wings were unfolded and locked in position.
The captain then turned the submarine into the wind and moved at such a speed as to show
sufficient wind on his indicator in the conning tower, which ensured a safe takeoff. After opening the throttles wide and making sure that his engine was running correctly, the pilot raised his hand to indicate that he was ready to take off. The captain gave the order for the catapault lever to be pulled. The aircraft shot forward, slamming the pilot and his observer back into their seats, and was launched into the air. After the seaplane had carried out its objective, it returned to the submarine, landed and taxied alongside. It was then hoisted back on board by means of a small lifting crane on top of the
hangar. Of course, all of this was possible only if the weather was calm.
The idea was never a complete success and on the night of January 26, 1933, an announcement
from the Admiralty said that the submarine M-2 had dived at about 1030 hours off Portland,
Dorset, and had not been heard of since. Destroyers and submarines searched the area and
later the same night came the news that an object had been located three miles off Portland; lying
in 17 fathoms on a sandy bottom. S;:tlvage craft and divers were sent from Portsmouth and it was
confirmed that it was indeed the M-2.
After days of frustration, the Pete was recovered from the submarine’s hangar. Badly damaged, she was taken ashore for inspection. She was not preserved. The salvage work was initially abandoned in September, although at one point the M-2 was raised to within 18 feet of the surface before a gale sprang up and the boat sank again. How the accident happened is still a mystery, but it is probable that the inner hatch to the hangar was open at the same time that the hangar doors were, perhaps through a misunderstood order.
While the British were having their problems, across the Atlantic the American Navy had shifted
its interest from submarine aircraft to small scouting aircraft carried aboard the airships USS Akron and Macon.
The U.S. Navy’s interest in submarine aircraft had started way back in 1922. Two Heinkel-Caspar
type U-1 submarine aircraft were received at NAS Anacostia towards the end of 1922. One was lost
during an exhibition flight the following year and was used for spares for the other. The flight tests were completed by the end of 1923 and, although the aircraft didn’t fly off a submarine, it did supply useful information for future designs.
The Navy accepted delivery of 12 additional submarine-based aircraft and, although built by two manufacturers, the design was the same. Six were constructed by the Cox-Klemin Aircraft
Corporation of New York and were made or wood and fabric. The other six were manufactured by the
Glenn Martin Aircraft Corporation of Baltimore and were largely made of metal. This enabled the Navy to compare the new techniques using metal rather than wood.
During October and November of 1923, tests with the Glenn Martin MS-1 were carried out aboard USS S-1. The S-1 had a complement of aircraft specialists from USS Langely aboard. Their duty
was to erect and dismantle the aircraft and stow it away in the pressure-resistant tank aft of the
conning tower. Unfortunately, it took nearly four hours to assemble the aircraft. This obviously
was unacceptable and so modifications had to be made to cut down the assembly time. The
modifications were carried out by the Naval Aircraft Factory at Philadelphia and, although the
aircraft was delivered to them late in 1923, it was nearly two years before the modifications were
In the summer of 1926, the complete cycle of assembly, launching, recovery and stowage of the
modified Cox-Klemin XS-1, now designated XS-2, was assigned to the S-1 • By the end of October, the
launching crew had become so proficient with the modified aircraft that they could have the machine
assembled, launched, afloat and with engine turning in 12 minutes. It took them only 13
minutes to recover, dismantle and stow away, which was a truly remarkable feat when compared with
four hours on the original aircraft. The XS-2 had an effective scouting radius of approximately 130
Up to 1931, a number of tiny, foldaway aircraft were designed and submitted to the Navy, but none
were adopted. In 1931, the Navy did purchase a Loening XSL-1 amphibian for submarine trials, but
a number of modifications had to be carried out to improve its all-around performance. Although
it was tested aboard the S-1, it was not accepted by the submarine service. Many reasons were
given, including one which rumored that Naval Aviators did not relish the double hazardous duty
aboard the old S boats!
The French had attempted to use aircaft on board submarines but met with very limited success. Their one and only at tempt was on the 2,800 ton Surcouf, the pride of the French Submarine Services. Built in 1929, Surcouf was the second largest submarine in the world, the first being the British X-1 at 3,050 tons. A match for many surface warships, Surcouf had twin turret-mounted, eight-inch guns and formidable torpedo armament. The biggest drawback was that she was too large and too slow at diving. This meant that she was only at her best when on convoy duty and when her scout seaplane was ahead looking for enemy warships and submarines.
Surcouf had its hangar built as an integral part of the conning tower, and launch and recovery were achieved by using a crane after the submarine had stopped her engines.
Tests continued until 1942 when, on the night of February 19, Surcouf was in collision with an
American frieghter while en route to the Panama Canal. There were no aircraft on board and there
were no survivors.
To go back to the Japanese contribution to the submarine aircraft era, it all started for them
at the end of the first World War. They acquired seven war-prize U-boats from the German Navy and
adopted the best features into the design of their own submarines. The Japanese had always
shown great interest in the use of submarine scouting aircraft and purchased two HeinkelGaspar
U-1 aircraft from the Germans in 1921.
The first operational trials of the aircraft aboard a submarine did not take place until 1927
and, as with the American trials, launching operations were conducted by trimming down the
stern and floating the aircraft off. The Japanese by this time had their own design available, very
similar to the U-1 but with modifications such as a more powerful rotary engine. Although 1 t was
designed in 1925, the aircraft wasn’t built until 1927 and operated from submarine I 21 for about 18
The I 21 was too slow and too small for serious operations, so a larger boat was selected and, in
1930, the 1,~00-ton I 51 had a compressed air catapault fitted to her after deck together with a
hangar capable of taking two aircraft. Also at this time, the Japanese introduced a new aircraft,
a 6-shi E6Y1 type 91 small reconnaissance seaplane. It was a miniature copy of the British
Parnall Peto and used the same engine, the Hi tsubishi Mongoose. By 1932, eight more models
were built by Kawanishi and were known as the E6Y1-N. After aeroplanes were tested for three
years aboard the I 51, the catapault was removed and the submarine was reassigned to general
The early 1930s produced a number of giant submarines based on the design of the huge German
U-1!12 of 1918. Two of these were built with hangars capable of taking two aircraft , a the end
of the first World War. They acquired seven warprize U-boats from the German Navy and adopted the best features into the design of their own submarines. The Japanese had always shown great
interest in the use of submarine scouting aircraft and purchased two Heinkel-Gaspar U-1 aircraft from the Germans in 1921.
The first operational trials of the aircraft aboard a submarine did not take place until 1927 and, as with the American trials, launching operations were conducted by trimming down the
stern and floating the aircraft off. The Japanese by this time had their own design
available, very similar to the U-1 but with modifications such as a more powerful rotary
engine. Although it was designed in 1925, the aircraft wasn’t built until 1927 and operated
from submarine I 21 for about 18 months.
The I 21 was too slow and too small for serious operations, so a larger boat was selected
and, in 1930, the 1,400-ton I 51 had a compressed air ca tapaul t fit ted to her after deck together
with a hangar capable of taking two aircraft. Also at this time, the Japanese introduced a new
aircraft, a 6-shi E6Y1 type 91 small reconnaissance seaplane. It was a miniature copy
of the British Parnall Peto and used the same engine, the Mi tsubishi Mongoose. By 1932, eight
more models were built by Kawanishi and were known as the E6Y1-N. After aeroplanes were
tested for three years aboard the I 51, the catapault was removed and the submarine was
reassigned to general service.
The early 1930s produced a number of giant submarines based on the design of the huge German
U-142 of 1918. Two of these were built with hangars capable of taking two aircraft, a
compressed air catapault and a small crane for retrieving the aircraft. Work was completed on
these giant submarines in the mid-thirties, and later ones were built so that the aircraft could
be launched without the submarine having to stop its engines.
At this time, the Japanese were still at war with the Chinese and these submarines with their
aircraft were used in the China Sea as a deterrent against Chinese blockade runners. They
appear to have been quite successful and were still in use up to 1941. It was in 1941 that the
first submarine-borne operational monoplane came into service – the E 14Y 1 or, as it was known to
the Allies, the Glen. It became the eyes of the Japanese submarine fleet when it set sail to
challenge the United States fleet in December 1941. It carried out reconnaissance over Pea:-1
Harbor before and after the attack. Other submarines cruised the South Pacific and their
aircraft scouted the harbours of Sydney and Melbourne, Australia, and of Hobart, Tasmania.
There were a number of kamikaze-type missions carried out by the Glens long-range
reconnaissance flights that gave the pilot no chance of getting back to his submarine. One
example was when submarine I 36 launched her aircraft from 300 miles off the Hawaiian Islands
and, although the pilot was able to radio back shipping information, it is persumed that he
crashed into the sea and was lost. At the end of 1941 , the Japanese had 11 submarines capable of
carrying scouting aircraft and, by the end of 1945, this number had increased to 27.
Meanwhile, in Japan, work was progressing on their secret weapon and kept so well under wraps
that the United States did not find out until after the Japanese had surrendered. The weapon
they had been working on was a giant submarine, described as I 400 class, an undersea aircraft
carrier with hangar space for three aircraft. It was !fOO feet long, displaced 3, 900 short tons on
the surface and capable of cruising for 37, 500 miles without refueling. Originally, 18 were
planned but as the war deteriorated material shortages caused the plans to be revised and only
five were actually started. By 1945, three had been completed, one was dismantled while still on
the slipway and one was destroyed in an air raid. Of three of the original five left – the I !foo, I
!101 and I !102 – two were completed as carriers and one as a supply boat.
Due to the cutbacks of the I 400 class in 1943, smaller, 2,900-ton, I 13 class submarines were
converted to carry two aircraft. Of the four converted, two were completed, while the other two
were still undergoing construction when the war ended. The I 13 class submarines had heavy-duty catapaults fitted on their forward decks, with 12-ton, electric cranes for recovering aircraft.
While the I 400 class submarines were under construction, plans were made to use the
submarines and their aircraft for a raid on the Panama Canal. The normal scouting aircraft would
be of no use, so a light submarine bomber was needed. The Japanese Navy asked the Aichi
Aircraft Company to provide them with a sui table design. One of the requirements was that the
aircraft could be catapaul t-launcbed without landing gear. The reason for this was that the
saving in weight would allow for a larger bomb load and a larger fuel supply. After the raid
had been carried out, the aircraft would return to the submarine, ditch close by, and the crew
would be recovered.
Training for the Canal raids did not progress well. The crews practiced their bombing runs on
large scale models of the Canal locks, but were often interrupted by attacks from U.S. Navy
carrier aircraft. The beginning of July 1945 brought the first submarine flotilla together,
consisting of the I 400, I 401, I 13 and I 14. The task force was equipped with 10 aircraft and,
although the two smaller boats did not have the fuel capacity for the round trip to Panama, they
were to refuel from the bigger boats.
They were provisioned for a four-month cruise but time had run out. They were diverted to
attack Ulithi Atoll where u.s. carriers were anchored. On July 16, 1945, the task force was
at tacked by carrier aircraft and the I 13 was sunk. The other boats did not press home their
attack on Ulithi and all the other submarines were still at sea when the war ended. Not one of
the giant submarines saw action in spite of all the time and money spent on them.
The final progression in the use of submarines in aviation warfare came when in March 1946 u.s.
Navy Secretary James Forrestal approved the converting of two Gato-class submarines to guided
missile launchers. The submarines that were converted were USS Carbonero (SS337) and USS Cusk
(SS348). The weapon they were to launch was the American version of the German Vl called the Loon.
The Loon was later to provide crucial experience and encouragement in the cruise missile program.
The first launch was carried out on February 12, 1947, from Cusk, while surfaced off Point
Mugu, California. This was the first time a submarine had launched a missile. Eariler tests
of the Loon had been carried out at the Naval Air Missile Test Station at Point Mugu. In these
tests, Lockheed P-80 Shooting Stars had flown alongside the missiles in case they turned off
their course and threatened populated areas. The same idea had been used during WWII, when
Spitfires and Hurricanes of the Royal Air Force flew alongside the German Vls and turned them
around by using their wingtips.
The submarines had a launching ramp installed on the deck behind the conning tower. The missile
was contained in a 10-foot by 30-foot, steel, watertight capsule. When the submarine surfaced,
the crew would open the capsule, assemble the Loon into a firing position, launch it and return
below, leaving the submarine free to submerge.
Over the next few years, many test were undertaken, culminating on May 3, 1950, when Cusk
surfaced, launched a Loon, then tracked and controlled the missile over a range of 105 miles.
The American version of the Vl disappeared soon afterwards, bringing to an end an area of
development that was soon to be superseded, but heralding the start of a new type of warfare.
Reprinted with permission from
Naval Aviation News, February, 1983