The Royal Netherlands Navy operates a low-frequency active sonar consisting of a combination of a towed sonar source and receiver array in order to detect and classify objects underwater. The operation involves transmitting high power underwater sound towards an object and detecting the echo reflected by the object. Operating a towed source at high source levels implicates that sound is inadvertently radiated towards the vessel which is towing the source. A structural-acoustic interaction between the underwater noise and the ship's hull causes the ship structure to be excited. The structure borne sound is radiated into the crew's accommodation as airborne noise by the floors, walls and ceilings and may be perceived as disturbing. Using analytical and empirical transfer functions, a model was made for the irradiation of the ship's hull, the hull's acoustic response, the propagation of structure borne noise through the ship structure and the radiation of airborne noise into accommodation spaces. The model results were verified with measurements acquired during a sea trial. The validated noise transfer model may be used to assess the effectiveness of noise control measures aiming to reduce the noise exposure levels in accommodation spaces.
