Model experiments on sound transmission from engineroom to accommodation in motorships 1

Sound transmission, both airborne and structureborne, from engine room to accommodation was investigated on board a 14000-DWT shelterdeck dieselmotor ship with accommodation around the engine casing near midship. Typical ship noise in cabins is shown not to originate in engine room airborne noise. This is in agreement with data obtained by other workers. As mathematical models for sound radiation by decks and bulkheads did not explain the experimental facts satisfactorily and further experiments on board were impossible, a 1 : 10 scale model was built. It consists of one side of the casing with two adjacent decks, stiffeners, deck beams etc. made from steel plate. A model cabin is mounted between the decks. Airborne sound transmission in model and prototype turned out to be very similar. Consequently structureborne sound transmission was investigated. Agreement again is satisfactory. The model is now in use for studying resiliently mounted exhausts and other piping. This research was carried out under contract with the Nederlands Scheeps-Studiecentrum TNO (Netherlands Ship Research Centre TNO).