Courtesy the outstanding Internet web site "Covert Shores" by H.I. Sutton an aspect of German submarine development during World War Two previously totally unknown to me. All tanks to H.I. Sutton.
High-speed midget submarine of the most unusual design and capable of the most incfreible performance
MANTA! HYDROFOIL UNDER THE WAVES!
"Manta high-speed hydrofoil midget submarine, Germany, 1944"
"If necessity is the mother of invention, desperation is the mother of crazy invention. As the situation in Europe worsened for Nazi Germany during World War Two, the Kriegsmarine turned to ever more desperate ideas. Influenced by the frogmen exploits of their Italian allies, and the X-Craft operations of the British, they started building a range of midget submarines . . . These one / two man midget submarines were intended to sink Allied invasion fleets. In reality they achieved poor results. But rather than abandon this line of development, the German designs got ever more desperate. And interesting."
Manta. Click on image to see an enlarged view.
Consider strictly the operational speed of the vessel. Way beyond that of any submarine of the period or even today: "Speed: 50 knots surfaced, 30 knots submerged".
MANTA NEVER A GOING CONCERN, BUT THE IDEA WAS WORTHY? THAT I CAN ASSUME IS DEBATABLE!