Acoustic Signature - Countermeasures and Acoustic Quieting

Countermeasures and Acoustic Quieting

Warship designers aim to reduce the acoustic signature of ships and submarines just as much as they aim to reduce the radar cross sections and infra-red signals. For submarines, as a prime factor in how they can be detected the reduction of the acoustic signature is a primary goal.

The acoustic signature can be reduced by

• fitting of machinery with the best possible mechanical tolerances and designed to produce a minimum of noise.
• decoupling the machinery from the hull by mounting machinery on rubber mounting blocks.
• designing propellers to reduce cavitation, this led to the development of large slow turning propellers, today there is a preference now for pump-jet propulsors over propellers.
• the fitting of anechoic tiles to the hull, however ill fitting and loose anechoic tiles can themselves be a source of noise.
• hydrodynamic efficiency to minimise the perturbation of water.
• care in minimising protrusions from the hull.