Codenamed "Alberich" after the invisible sorcerer from Germanic Mythology, it was a thick coating of rubber for submarines that attenuated sound in the 10 to 18 kHz range to 15% of its normal strength.
Codenamed "Alberich" after the invisible sorcerer from Germanic Mythology. The coating worked in the 10 to 18 kHz range, reducing ASDIC to 15% of its normal strength.