The objective of this paper is to propose data management scheme of towing tank test and CFD data considering the reuse in design process, and to develop an integrated data management system based on the scheme. To be concrete, the data scheme is proposed by using Resource Description Framework (RDF), which is one of the technique of Linked Open Data (LOD). Towing tank test and CFD data have many kinds of data type and format including video, measured time-series data, and so on. Various kinds of type and format can be assumed for experiments and CFD softwares. But the defined data scheme enable to manage all the data and every achievement of designers can be shared. Moreover, information about procedure of the hull form design process is modeled in RDF format as well. By connecting the past achievement data to the information about design process, a hull form design assistant system is developed as a web application, on which designers are able to access required information in their required timing. In a case study, a simplified case of the actual design process is assumed, and by applying the developed system to the case, we demonstrate that the developed system can achieve the objective and is useful to make hull form design process more efficient.