U-480: The First Stealth Submarine
U-480 was a type VII-C U-boat. What made it different was that it was covered in anechoic tile made of synthetic rubber. The tiles were made of two layers, a first layer with holes in it and a second smooth layer on top. This rubber coating acted as soundproofing for the submarine, making it very quiet on silent running. Furthermore, the combination of rubber coating and air pockets (holes) helped absorb and scatter sonar waves.
Innovations in Submarine Technology
This means U-480 was difficult to detect both on ASDIC and on hydrophone. The system was not perfect, but it was nevertheless good enough for U-480 to be able to operate in the dreaded English Channel and sink 4 ships without ever being detected.
U-480 vanished in late February 1945. It seems the sub ran into a secret British minefield off the shores of the Isle of Wight.
Final Days of U-480
As for the tiles, the Germans did possess the technology as early as 1940 but did not seriously look into it, meaning those tiles were not used operationally before 1944. Far too late to change the tide of the war at sea.
-RBM.
