Royal Institution of Naval Architects

Since the introduction of scientific disciplines into the shipbuilding process, there has been a search for optimisation of human and material resources. The current environmental crisis is putting additional pressure on global resource management and special attention to materials sourcing and utilisation. This paper discusses the potential solution for the current lack of effectiveness at early design stages, which are still based on 2D drawings. The industry is demanding a new 3D approach, which implies, first, a change in the procedures, and second, having a suitable CAD/CAM tool for the early generation of a digital mock-up, from which the project is developed throughout all design and production phases, from conceptual design to operation. The proposed solution shown in this paper would improve the general arrangement definition, with the use of CAD for the 3D definition of the compartments and the main equipment positioning; improve the naval architecture calculation; and finally improve the basic/class design stage, with better reuse of data already developed in the general arrangement model and in the definition of a 3D model of structure, with the main equipment positioning, pipes, and electrical equipment already into the model. Intelligent P&I diagrams and single-wire electric diagrams would be used at this stage and connected to the 3D model. Additionally, it will allow for early estimating of materials, weights, and associated processes. This will be further supported by the use of topology to consider design alternatives and produce early information on materials for procurement and production. The cost reduction associated with the definition of the early design stages in 3D has been estimated at around 15% of the overall design and production stages.

Warship Feasibility Studies are highly complex projects. The paper aims to highlight some of the factors inherent within industry and academia. The initial data were gathered at the VT shipyard by interviewing key personnel. The collected data are then analysed using the MS Visio flowchart package to create input/output diagrams for all existing domains. Identifying explicit and implicit links allows the existing domains to be linked and inherent domains to be identified. The resulting connection diagrams are then analysed and compared with existing literature. The analysis results in the creation of several loops depicting the data flow during feasibility studies. The 2-D loops are combined in a 3-D flowchart to further investigate the data flow across the domain interfaces and to incorporate a time scale. Carrying out in-depth domain and case studies at VT Shipbuilding has led to a continuous refinement of the 3-D loops.

ABSTRACTThis paper first provides a brief overview of the history of the American Merchant Marine as an introduction to the Merchant Marine Act of 1936. Those sections of the Act which have been deemed to be major factors in the availability of shipping capability are discussed in summary form to provide the reader with a basic understanding of construction and operating differential subsidies, mortgage guarantees, and tax exempt capital construction funds. The implementation of these provisions is then discussed, beginning with the MARINER Building Program and followed by the Cargo Ship Replacement Program and the Bulk Carrier Construction Program. The recent history of the Act is then traced to present an indication of the numerical impact of certain programs.The present status of the U.S. Merchant Fleet, with respect to its share of U.S. foreign trade, is finally discussed as one indicator of the level of defense shipping capacity now available.

ABSTRACTThis paper provides a survey of the United States Merchant Marine. It describes the overall content of the American Flag Fleet, discusses the importance and the impact of the Construction Differential Subsidy Program on shipbuilding and assesses ship construction standards such as fire protection, subdivision and automation. Detailed descriptions of typical ships with high utility in national defense roles are provided. Finally, the paper discusses ongoing research and provides some insight into future ships of the U.S. Merchant Marine.