When Germany capitulated in 1945, the Allied authorities launched an in-depth
investigation into the perpetrators of war crimes during World War 2.
In November, Kapitänleutnant Heinz-Wilhelm Eck and the four junior officers of U-852
were tried by the British at a special military tribunal
in Hamburg for attacking a Greek steamer in the southern Atlantic.
The skipper pleaded for operational necessity, and the second-in-command alleged he was only
following orders. However, they were found guilty because of two pieces of irrefutable evidence.
When the British seized the submarine, they discovered the captain's war diary,
but they also unearthed a baffling machine like nothing they had ever seen before…
In Jeopardy
The Kriegsmarine's Type IXD2 submarines were a considerably
enlarged and special long-range version of the original Type IXs.
Equipped with four bow and two stern torpedo tubes, the 87.5-meter-long
and 10.20-meter-high U-852 submarine was laid down in Bremen and completed in June of 1943.
Unbeknownst to the Allies, she also had a unique piece of equipment among her many gadgets.
After undergoing sea trials, the Kriegsmarine dispatched the submarine
for a top-secret mission. U-852 departed on her first patrol on January 18, 1944,
under the command of Kapitänleutnant Heinz-Wilhelm Eck, steaming for the Indian Ocean. Her objective
was to assault the Allies' Far East Sea lanes and obstruct their war effort in the region.
To pull off the mission, however, the submarine had to lay low and
not attract any attention throughout her journey on the European continent.
Nevertheless, her mission was compromised within two months.
On March 13, U-852 was crossing the latitude of Freetown in the Atlantic Ocean when a lone vessel
appeared. The U-boat spotted a Greek steamer, Peleus, and Captain Eck resolved to take her down.
The German submarine stalked Peleus until nightfall, and when she was within range,
U-852 attacked with pinpoint accuracy. The Greek vessel was hit by two torpedoes that
critically damaged her, and the wreck created a considerable debris field.
Reckoning that the disaster would give their position away,
Eck ordered his junior officers to destroy all evidence of the encounter.
Consequently, Peleus was sunk with all hands.
Treasure Trove
Two weeks after the intense engagement, the German submarine ran into the British cargo
ship Dahomian off Cape Town and sank her. This time, U-852 fled the scene
and did not try to hide the evidence, an action that would come back to haunt her.
Before April was over, the submarine was sighted by the enemy while traveling through
the Indian Ocean. She was spotted by a Vickers Wellington bomber coming from Aden in Yemen.
Unable to dive after enduring severe damage from aerial depth charges,
U-852 limped back to the Somalian coast. However, six Royal Air Force bombers from
the 621 Squadron showed up to attack her before she could even reach land.
The ongoing attack forced the German skipper to run aground on a coral reef 20 kilometers
off the coast. Eck lost seven men during the engagement, and the rest fled ashore.
However, 58 crew members were captured by the Somaliland Camel Corps and the
local militia upon making it to Somali territory.
Meanwhile, a British boarding party examined the wreckage.
The Allies found Eck's War Diary, which became indisputable proof of the war crime
committed against innocent Greek sailors, but also an intriguing piece of machinery.
Known as a rotor or gyro kite, the rotary-wing device was an unpowered
aircraft that relied on lift from one or more sets of rotors to fly,
and this particular model was a Focke-Achgelis Fa 330 Bachstelze cable-towed gyro glider.
The aircraft’s objective was to serve as a lookout platform, and it was a one-of-a-kind
sea aircraft the British had never seen before. For all they’d seen during the war,
they were still more than surprised by this unique asset in the Kriegsmarine’s arsenal.
Five Times Farther
Submarines were unable to see beyond a few miles over the ocean while submerged.
However, the Germans eventually found a practical solution to this issue.
The Admiralty took several different options into consideration. One of
them was the folding Arado Ar 231 seaplane, but in the end,
the Focke-Achgelis Fa 330 proved more reliable and easier to use.
The single-seat kite included an assembly of three
blades and could be deployed on the deck of a U-boat by two crewmen.
The vehicle was a simple metal frame construction that held the
seat and the mast in addition to the vertical tailplanes, landing skids,
and a simplified control scheme that was handled by a stick.
The airframe had no fuselage skinning, making it an ideal and cheap platform for mass production.
Also, the airflow created as the ship steamed through the
surface acted upon the rotors and spun them up into the air.
Afterward, with an observer/pilot aboard, the kite could be deployed behind the submarine
and raised to an altitude of 120 meters above the vessel. Tethered to the submarine by a cable line,
the autogyro kite could then be towed at a distance of 150 meters.
With such an advantageous position aloft, the observer had a 360-degree view and could see
much farther than the approximately five nautical miles of visibility of the crewmen conning tower,
surveying the sea at a range of up to 25 nautical miles or 46 kilometers.
When not in use, the rotorcraft was stowed in two watertight compartments
located just aft of the conning tower. If the weather was favorable,
it took no more than four minutes for the crew to assemble or disassemble the kite.
However, heavier weather conditions significantly hindered the operation.
Recovering the Fa 330 meant winching it back to the deck and then dismantling and stowing it,
a process that took about 20 minutes.
But in case the U-boat captain was forced to abandon the rotor kite on the surface,
the tether had to be released before sending the Fa 330 to the depths as if it had never existed.
For all of its advantages, the clever piece of engineering could not be used very often.
Allied air cover in many theaters of the war posed a considerable threat to the U-boat fleet.
As a result, only the U-boats operating in the far southern region of the Atlantic
and into the Indian Ocean could deploy the Fa 330 without being compromised.
Tactical Value
Laid down in March of 1941, U-181 was another Type IXD2 submarine in service with the German fleet.
Like her sister U-852, U-181 was an enhanced version of Type IX and had a
displacement of 1,610 tons when surfaced and roughly 1,800 tons fully submerged.
She was commissioned in May of 1942 under the command of Kapitänleutnant
Wolfgang Lüth and attached to the 12th flotilla not long after.
Unbeknownst to the Allies, she was equipped with the unusual rotor kite.
Through late 1942 and into 1943, U-181 claimed 22 ships patrolling the waters
off South Africa and Mozambique, earning her skipper a promotion
and the Knight's Cross of the Iron Cross with Oak Leaves, Swords, and Diamonds.
Even so, only one of them was spotted, intercepted, and sunk with the aid of the
gyro kite. It was the Greek steamer Efthalia Mari, which was attacked on August 6, 1943.
Primarily operating in areas not overrun by patrolling enemy aircraft
and fielded operationally in small numbers,
the Fa 330s provided limited tactical value in the grand scheme of the war. In fact,
no more than a couple hundred units were built, and they all served in Type IX U-boats.
Nevertheless, the British weren’t aware of its actual reach and influence,
and when they found an intact example, they studied the design thoroughly.
State-of-the-Art Technology
U-852's Captain Eck and his officers answered to justice
during the Nuremberg Trials after the war. They were the only Kriegsmarine submariners
to be tried for war crimes perpetrated during World War 2 and were convicted
at a British military tribunal in Hamburg for their crimes against the Peleus crew.
The gyro kite found in the wreck was thoroughly studied by the British government,
who conducted successful experiments towing Fa 330s behind ships and jeeps.
Even so, the prospect of the intriguing autogyro system faded away after the war ended.
Innovative helicopter technology and compatibility aboard warships did not take long to overshadow
any benefits of the towed model. As more adequate battlefield solutions came forward
-with helicopters becoming a key component of maritime operations- the concept was forgotten.
Even so, the Bachstelzes are currently showcased in several museums around the world.
Some units can be found at the National Museum of the United States Air Force in Dayton, Ohio,
and the Steven F. Udvar-Hazy Center in Chantilly, Virginia.
Today, warships have a fixed helicopter flight deck over the
stern to launch and retrieve rotary-wing aircraft.
Notably, the value of helicopters in military operations would not be
rivaled until several decades later and into the new millennium with the arrival
of a concept Nazi engineers could only dream of: the Unmanned Aerial Vehicle or UAV drone.
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