According to the team, these layers can reduce engine noise by up to 26 decibels (dB) together, which is a significant acoustic improvement. A 10dB reduction in underwater noise can cut detection range by roughly 32 percent.
So, 26dB reduction could more than halve a submarine’s sonar detection range. This targets low-frequency tonal noise, the primary way submarines are detected by sonar.
For reference, most modern submarines, especially American ones, typically have acoustic signatures between 90 dB (Ohio-class) and 130 dB (older Los Angeles-class). With ambient sea noise at between 85–95 dB due to waves, marine life, and other vessels, anything close to this effectively allows a submarine to “hide in the noise.”