From MIKE KOSS (299-1987) we learn that certain U-Boats were covered with rubber toward the end of the War? This rubber coating was meant to defeat SONAR and ASDIC and was actually two layers of rubber on the boat. The first or inner coating, had many holes in it, all shaped and spaced scientifically to deflect and/or absorb SONAR pulses. The second or outer coating was smooth to maintain the streamlined shape of the boat.

This coating was called 'ALBERRICH' from a character in a famous German fairy tale, the Neibellungenlied, in which this character named Alberrich could make himself invisible by putting on a magic coat. This rubber was the magic coat the U-BootWaffe hoped would make the boats invisible to ASW forces.

From all indications, it did not provide the anticipated results.