It was not an easy task to hunt down Kriegsmarine U-boats.
The grey wolves of the Atlantic knew precisely when to attack and when to hide from its prey.
It was even harder to destroy U-boat
pens scattered in the French coasts and the Northern Sea.
From the beginning of the war in 1939 through the end of 1942,
Allied forces had only neutralized 150 U-boats, roughly three per month.
In contrast, the Germans had a success rate of sinking 20
ships of roughly 180,000 tons per month.
The British were desperate for a solution. They could not withstand losing any more
ships and essential supplies at the hands of the stealthy U-boat hunters.
Conventional bombs had little effect against the massive concrete structures of the Kriegsmarine
submarine pens. The RAF made futile bombing raids that always had the same outcome.
A U-boat pen's roof could withstand the impact of 7,000 pounds bombs,
more than any Allied aircraft could carry at that time.
As ideas ran short of putting an end to the German threat at sea,
a peculiar animated film from Walt Disney's company inspired the Royal
Navy to begin working on a bomb that could penetrate the thickness of German bunkers.
The Britons decided to baptize this warhead with the source of their inspiration.
They called it the Disney Bomb …
An Animated Inspiration
After war broke out with Japan in 1941, Walt Disney's company,
under US Government directives, began creating animated shorts whose purpose
was to appeal to American patriots to enlist and join the war effort.
Other production companies, such as Warner Brothers Animation Studios, also created
war cartoons. Through a collaboration with the US Army Signal Corps, they made Private Snafu,
a series of cartoons aimed to educate and boost morale among the soldiers.
The character became one of the most beloved and
well-known cartoons created during the World War 2 era.
Many of these shorts were transmitted in Allied camps across the barracks of Europe,
Africa, and the Pacific. In such videos, just like posters,
magazines, and other media content forms, the Axis were portrayed as savages and purely evil.
The Axis, in return, did the same. It was standard war propaganda at its finest.
And it was from one of these types of shorts from which a group of
Royal Navy officers got the idea of developing a revolutionary bomb.
The video in question was called Victory Through Air Power, published in 1943.
In the animation, a fictional bomb penetrates a thick concrete German bunker with ease.
It explodes in a U-boat pen, dealing the Germans a heavy blow…
It is said that after watching the film, a group of Royal Navy officials had a "eureka" moment and
decided to create such a bomb if it was possible with the technology they had at the moment.
They called this imaginary bomb the Disney bomb.
Since there was no weapon capable of blowing up U-boat pens, the British Army was desperate
to develop anything that could give them the advantage against the Axis.
Germany's fortified bases and U-boat pens were scattered all over northern Europe,
built with more than 5.7 million cubic yards of concrete.
These pens were part of a series of fortified defenses the Third Reich
created to guard Europe against an Allied offensive. It was called the Atlantic Wall.
Royal Navy officer Captain Edward Terrell
is considered the visionary of the Disney bomb. He was part of the Directorate of
Miscellaneous Weapons Development when he got the idea with the other officers.
Terrell filed several patents before the war as an inventor,
including a vegetable peeling knife and a bottle for fountain pen ink. He had a
sharp eye for creating things that had immediate use in response to a solution.
The Disney bomb was one of them. Such a bomb was born with a particular purpose,
the destruction of concrete bunkers and submarine pens.
It was going to be able to penetrate up to 50 feet deep into any fortified objective.
To achieve this, Terrell designed the bomb according to Isaac Newton's
"approximation of impact depth" equation.
Also known as Young's equation,
this principle established that a long and slim projectile of high density
striking an object with a fast velocity will have a higher penetration capability.
Members of the British Admiralty were appealed by the idea. Still, the proposal had to convince
the Ministry of Aircraft Production, as it was in charge of weapon production.
The Road Research Laboratory provided Captain Terrell with US data
on 381 mm shells' performance against reinforced concrete. This helped him expand his studies of
the bomb density and speed required to fulfill the bomb's penetration.
Terrell visited Churchill's scientific advisor Lord Cherwell to convince him of his project. He
wanted to prove that the bomb could finally help put an end to U-boats' supremacy in the Atlantic,
but illness had left Churchill incapacitated.
In January 1944, months before Normandy's invasion, Churchill finally expressed his
approval for Terrell's project. He encouraged the U-boat Committee to approve the bomb.
Many officers supported the idea. Some even said (QUOTE):
"It will be a game-changer for complete sea dominance."
It was true. The U-boats were the only thing that
stopped the Allied forces from complete control of the seas.
Terrell was approached by the Air Technical Section of the US Air Corps to further take his
project. He showed the Admiralty a mockup under the wing of an American B-17 Flying Fortress.
It was May 1944, and all the attention was focused on D-Day and Operation Neptune.
It would not be until 1945 when the Disney bombs would show their power.
British Made. American Equipped
The Disney bombs were a British invention, but they would only be used by the US Air Force.
No RAF bomber Command ever used them during the war. The project was part
of the exclusive cooperation agreement between the US Air Force and the British Royal Navy.
The B-17 Flying Fortresses were the only aircraft capable of carrying such bombs.
The B-17s carried Disney bombs in pairs. As they were too big for the bomb bay,
one had to be carried under each wing.
Cameras were fitted to the aircraft so that each
bomb's trajectory and its effects upon impact could be recorded.
Testing began in the first days of 1945 in Southampton.
With the footage recorded from the cameras above the B-17s, engineers were able to
gather data related to the Disney bombs' trajectory, accuracy, and impact effects.
Calibrations were made to increase the accuracy and
the flight path of the rocket-accelerated bomb.
To increase the speed and thus impact the rocket's power, the Disney bomb was upgraded.
The Allies Hunt the Hunters
The first Disney attacks occurred in February and March 1945.
The objective was in the port of IJmuiden, Netherlands. This site had two fortified pens.
The Kriegsmarine housed Schnellboote E-boats.
One of the pens was protected by a 10-foot thick concrete roof.
The second pen had 12 feet of concrete with a 3-foot layer separated by an air–gap.
This added additional protection against heavy bombardments.
18 Disneys were dropped from nine B-17s of the US 92nd Bomb Group on February 10.
After the first successful raid, a second attack occurred in March.
The result was successful. The Disney bombs made their way through the layers of concrete.
The second bombing raid that used Disney bombs took place on March 30. The objectives were the
Valentin submarine pens located in Farge's port, near Bremen in the heart of Germany.
The pens were not entirely complete. They were in the process of assembling Type-21 U-boats.
The 15 ft thick roofs of Valentine were hit by more than 60 Disney bombs. Nonetheless,
all but one hit the target, but overall damage caused the Germans to abandon the facility.
As the war reached an end, the last attack with Disney bombs took place in Hamburg on April 4,
1945. A bombing squad of 24 B-17s attacked various fortifications
obscured by the heavy bombing the city had been suffering for the last days.
In total, more than 158 Disney bombs were dropped before the war ended.
Post-war Implementations
The RAF continued bombing tests with the Disney in June 1945, although the bombings
were carried by the US Air Force on behalf of the RAF because they had no aircraft for the tests.
As part of Project Ruby, a 1946 joint Anglo-American program was
created to test the range of concrete penetrating bombs.
For the objective, they used the German bunkers on the island of Heligoland and the Valentin pens.
The bombs dropped at both locations were inactive because the purpose was not to observe the effects
of bomb explosions but rather to test concrete penetration and the bomb casings' strength.
76 Disney bombs were dropped on Heligoland.
They were loaded with different explosive charges, such as shellite, RDX, and TNT. At Valentin, 34
Disneys were dropped, with 12 of them inactivated and the remaining 22 with the rockets firing.
The average penetration performance of the Disney bomb was 14 feet 8 inches of concrete.
The maximum penetration achieved was 16 ft 8 inches.
One bomb penetrated the Valentin's concrete roof and its 3-foot thick concrete floor.
The impact was so powerful that the bomb only came
to a stop when it reached the sand of the structure's foundations.
Although the bomb had good penetration capabilities, it had some problems.
The reliability of the rocket booster ignition had a failure rate of around 37% during the trials.
Other bombs broke up as they impacted their target due to flaws in the steel casing.
As an additional suggestion from later studies, it was noted by Air Force data that the warhead
of the Disney bomb was too small for the future objectives it was going to be used up against.
To successfully hit a large fortified facility, such as the Valentine pens, more than a dozen
bombs would be required to get the desired effect of penetration and destruction of the objective.
More than 70 years after the tests of 1945, on January 27, 1945, the remains of an inactive
Disney bomb was found in the roof of Watten bunker, in France, the first place in which the
US and British conducted tests. The Disney bomb still had its 500-pound explosive charge intact.