Acoustic signatures in a noisy ocean

Recorded signatures help sonar operators associate faint harmonics with a class or individual boat, which is why propellers and pump-jets are closely guarded. When no direct recording exists, analysts can infer parts of a profile from similar reactors, machinery, and propulsors. The ocean is crowded with competing sound from currents, temperature layers, geology, wrecks, marine life, and human activity. Protecting an SSBN's signature and patrol departure is therefore central to preserving its ability to hide.