On May 3, 1940, HMS Seal, a British submarine, entered the waters of the Kattegat strait with a daunting mission to lay mines on the communication routes used by German ships. During an attempt to shake off the pursuit of Kriegsmarine ships, Seal struck a mine, losing any chance of submerging again.
At 03:30, the Ar.196 aircraft designated 6W+IN, piloted by Unteroffizier Böttcher with Leutnant zur See Mahrens as an observer, spotted an unidentified submarine. The pilots realized it was a hostile submarine and immediately dove at it, dropping bombs and spitting fire. Black smoke spurted from the submarine. The ship slowed and eventually came to a stop.
“We're gonna seize that shipwreck! Locate our convoy ships!”
Mahrens barked out to his pilot.
In the meantime, another same-type aircraft from the same air unit, designated 6W+EN and piloted by Unteroffizier Sackritz with Leutnant zur See Schmidt as an observer, was searching for enemy submarines. After a while, Schmidt spotted a large oil spill spreading across the water.
“This oil's leaked from a submarine! I'll fire a white rocket flare! We need to give a signal to the escort ships!”
the Leutnant cried out to his pilot.
Sackritz turned the aircraft and headed east towards the oil stretching across the sea surface. At 03:40, they finally saw the half-submerged submarine. The plane dropped a bomb. Schmidt opened fire with a machine gun at the ship's conning tower. The submarine hoisted a white flag.
Climbing down the floats, the Leutnant demanded that the British send the submarine commander on board the aircraft. The engines roared, and the plane bearing the captive took off heading for Aalborg, the location of the control headquarters of the Luftwaffe Naval Air Wing Сommander (Führer der Seeluftstreitkräfte).
Meanwhile, Böttcher kept circling around the submarine, striking terror into the British sailors that had already gone through much suffering that day. Mahrens decided to land aboard the submarine to take away secret documentation and prevent the ship from being scuttled. But right after the aircraft touched the water, pilot Böttcher noted:
“I see an aircraft bearing English camouflage, approaching us from the west!”
“Take off, now!”
The scout aircraft swept up directly from the surface of the water and took a steep turn towards the approaching English plane. Wing guns were fired. A number of successful hits tore off several of the hostile plane's lining plates, making the English pilots turn away and retreat towards the Swedish coast.
Once the enemy plane disappeared from sight, Mahrens' crew landed near the submarine and demanded that the Second Officer also step on board the plane. After that, the seaplane soared into the air and set off to the headquarters.
At Aalborg, the captives were expected by Major Hermann Lessing, Naval Air Transport Commander (Lufttransportchef See). He entered the room of the air wing headquarters and saw a barefoot man in a wet sweatshirt, standing by a large table. It was Lieutenant Commander Lonsdale, the commander of the British submarine. Shortly after, Mahrens turned up at the headquarters along with his crew and the Second Officer of the British submarine.
After Lessing learned all the details of the operation from the captives and pilots, he radioed the incident to the headquarters. The reply he received was brief:
“Send the captives and aircraft crews to me for reporting.”
In the meantime, a Kriegsmarine submarine hunter ship reached the scene. But by the time the boarding team stepped aboard the submarine, all valuable documents had been destroyed.
At 06:30, the German submarine hunter UJ-128 commanded by Kapitänleutnant Lange took Seal to tow and dragged her to the German base in Frederikshavn. HSM Seal was not of particular value for the German fleet as a combat unit. However, the torpedoes she had on board proved to be quite useful since defects had recently been found in German torpedoes. For the rest of her time, the submarine was used for propaganda and training purposes until she was sunk on May 3, 1945, during an allied air raid on Kiel.
Sometimes a true story turns out to be a lot more interesting and intriguing than fiction. If you know other fun facts and stories from naval history, tell us about them in the Comments section.