What is the purpose of anechoic tiles on a submarine hull?

• A. To reflect sound and increase hull acoustic signature
• B. To absorb sound and reduce acoustic signature
• C. To improve hull hydrodynamics
• D. To house sonar equipment

Answer: (B)

Anechoic tiles are used to quiet a submarine by absorbing acoustic energy rather than reflecting it. The hull and onboard machinery generate noise, and sonar systems listen for that sound or any echoes. A smooth metal hull tends to reflect sound, which helps a hostile sonar pick up the submarine’s presence. The tiles themselves are made of porous, rubber-like material with air-filled cavities that create many small paths for sound to travel and dissipate. When a sonar wave hits the tiled surface, much of the energy is absorbed and converted to heat rather than bounced back, and the resulting reverberations are reduced. This lowers the submarine’s acoustic signature, making it harder to detect with both passive listening and active sonar.

It’s not about reflecting sound to increase detectability, nor about improving hull shape or carrying equipment. The primary purpose is quieting the hull acoustics.