Beneath the surface of the ocean, visual stealth is useless; survival depends entirely on acoustic invisibility. To hide multi-ton nuclear submarines from enemy detection, naval engineers rely on a highly classified, hyper-specialized material science: Anechoic Tiles. This technical manual breaks down the complex acoustic physics of these synthetic rubber coatings. Anechoic tiles are not just padding; they are engineered with microscopic internal voids of specific geometric shapes designed to completely absorb and dissipate the acoustic energy of active sonar pings, converting the soundwaves into microscopic amounts of heat. We dissect the brutal engineering challenges of adhering these heavy tiles to a steel hull expanding and contracting under the crushing hydrostatic pressure of the deep ocean, and how the loss of a single tile can instantly compromise a billion-dollar vessel. Dive into the science of absolute silence. Understand the intricate acoustic metamaterials that allow the most destructive warships on Earth to vanish into the deep.