This paper presents the MARHIS network, an added value aggregation of hydraulic facilities and numerical modelling tools plus field equipment from the Catalonia University of Technology and IH Cantabria. The paper presents the origin and objectives of such a network, emphasizing the applications to coastal harbour and offshore cases. This is based on a summarized description of the facilities and tools in IH Cantabria and LIM-UPC. A summarized description of the third element forming the MARHIS network (CEHIPAR) in Madrid is also presented. The next section deals with a composite modelling approach and how to develop and apply it to a) wave structure interactions and b) sediment propeller interactions. The paper ends with some conclusions about the MARHIS network and the benefits such structure should provide to composite modelling, a tough challenge for present engineering applications.