Stealth rubber coating could make submarines nearly invisible to sonar

Computer simulations found that a material made from three layers of rubber could absorb most frequencies used for sonar, which if affixed to a submarine would make it difficult to detect

By Karmela Padavic-Callaghan

A thin coating of a rubbery material could make submarines more difficult to detect with sonar.

Sonar locates submarines by emitting sound at many different frequencies. Those sound waves reflect off the vessel as an echo which can then be detected by a receiver. But objects covered in materials that absorb sound are hard for sonar to spot.

Qingxuan Liang at Xi’an Jiaotong University in China and his colleagues have now designed a new coating for masking submarines from sonar that, if fully …