Comparison between measured and predicted airborne noise sources on the external surface of a cruise ship

In recent years, reducing airborne noise radiated from ships, particularly from passenger vessels, has progressively become a priority for shipping companies, reflected in contractual specifications for new constructions and in new class notations from Classification Societies such as Lloyd’s Register, RINA, ABS, DNV, and Korean Register. This study focuses on airborne noise emitted from cruise ships by external sources, including ventilation, air conditioning systems, main and auxiliary engine through inlet/outlet grids and funnels. Onboard noise measurements carried out at external grids are compared with predicted sound power levels derived from models incorporating internal machinery, ducts, and silencers. Data from campaigns on twin ships enable comparisons between predicted and measured values and a first evaluation of fluctuations among different realisations of the same design. Uncertainties in measurements, predictions, and their correlation are quantified and discussed. The study emphasizes the importance of integrating advanced noise mitigation strategies in the design phase to meet evolving standards and of improving the ship acoustical digital twin model.