Nowadays, the cruise shipbuilding industry is growing worldwide due to an increase of the demand of this kind of holiday offer. The building of these ships, with incredible sizes, does not have a sophisticated technology compared to other ships, but these “giants” are characterized by high comfort requirements, such as those related to noise and vibrations. It is worth mentioning those related to the cabins privacy, which are evaluated by the measurement of sound insulation index.
Besides a good selection of the main pieces of machinery, an adequate general arrangement and the optimization and selection of suitable acoustic insulation, the compliance with the high comfort requirements of this kind of vessels requires a correct assembly of the accommodation in accordance with the target defined in the Specification.
For the first block it is necessary the assistance of an engineering company specialized in the vibro-acoustic design of ships like TSI. No less important is the proper selection of a recognized marine interior company such as Navaliber.
In the process to ensure the correct selection and assembly of the accommodation to install on a new built cruise ship, Navaliber requested TSI the on-site measurements of the Acoustic Reduction Index in different wall panels installed on a mock-up in the shipyard. The aim was to check the suitability of the solution and ensure the compliance with the levels defined in the Specification.
For this purpose, TSI technicians moved to the shipyard to carry out noise isolation measurements and characterize acoustically the different solutions to be implemented. With this aim in mind, an omnidirectional noise source and a calibrated sound level meter was employed. The procedure defined in ISO 16283-1, ISO 15186-2 and ISO 717-1 was followed to assess the acoustic insulation index of the panels. Furthermore, to assess the assembly of the panels and doors of the mock-up TSI used acoustic intensimetry techniques to obtain an acoustic map of each of the partitions to evaluate the transmission by flanks.
The results obtained were satisfactory and according to the applicable requirements. However, due to the concerns and good work of Navaliber, some improvements, identified in this measurement campaign, will be implemented in the final assembly of the accommodation.
Finally, it is worth mentioning the importance of these measurements to assess the efficiency of the acoustic solutions to implement in the accommodation of cruise ships. Specially, due to the high economic impact in the project in terms of time and cost if deficiencies are detected after the accommodation is installed. In this regard, the fact that the estimates of the acoustic isolation index provided by the laboratories are only valid as a first approximation shall be accounted as they are obtained in ideal conditions not replicable in ships.
Due to all of this, TSI offers the market a wide range of techniques to acoustically characterize these solutions and more than 40 years of accumulated experience to evaluate and establish the relevant design recommendations adapted to the nature of each problem.