Methods of improving the level of pre-contract design definition and the quality of information relating to steelwork are described. This information is combined with a comprehensive database of manufacturing process information to provide a system for estimating the work content of the main structural steelwork of ships such as ro-ro vessels. Procedures are described which facilitate consistent estimates to be made while minimizing data handling requirements and increasing the flexibility of the method at the concept design stage.
Much attention has been given in recent years to the problem of reducing ship construction costs. This has primarily emphasized the improvement of production techniques, processes and management controls. There is a great deal that can be accomplished in reducing ship construction costs, however, by improving the producibility of the design of the ship. The design of a more producible ship requires concurrent product and process design. Various principles and techniques can be applied throughout the design process in order to reduce the construction manhours required by ensuring that the manufacturing attributes are considered. This paper identifies some of the key principles involved and describes the techniques for applying the principles. A practical approach to estimating the cost benefit of alternative designs by estimating the labor input differential between the designs 25 also presented. Finally, specific examples of the application of the producibility techniques to several recent ship designs are included.
The application of Computer Aided Design (CAD) and Manufacturing (CAM) techniques in the marine industry has increased significantly in recent years, With more individual designers and ship yards using CAD within their organizations, the pressure to transfer CAD data between organizations has also increased. The Navy/Industry Digital Data Exchange Standards Committee (NIDDESC) prow-ales a mechanism for public and private organizations to cooperate in the development of digital data transfer techniques.
David Taylor Research Center is just commencing investigations into a new manner of defining future fleet architectures. The cost of current performance-driven ship designs has increased at a rapid rate. While it is true that a warship designed with insufficient performance is of meager utility it is also true that the heat performing warship design is of no utility if never built. Both performance and affordability are required if sufficient numbers of ships are to be built to counter the threat. By designing a future fleet architecture with producibility as a major requirement from the start we hope to impact the acquisition cost significantly. One battle force concept titled Distribute, Disperse, Disguise and Sustain suggests two fundamental surface ship types; the Carrier of Large Objects (CLO) and the Scout Fighter. A CLO feasibility design in progress Carrier Dock Multimission is outlined to inform shipbuilding researchers of an initiative that promises to have significant impact on naval ship procurement and provide increased visibility within the U.S. Navy on producibility issues.
In October 1989, A Ship Design for Producibility Workshop was held by the Naval Sea Systems Command (NAVSEA) at the David Taylor Research Center (DTRC). The purpose of the workshop was To develop the framework of a plan to integrate producibility concepts and processes into the NAVSEA Ship Design Process. The major recommendations of the workshop included initiatives related to increased training of NAVSEA design engineers in modem ship production concepts, development of producibility design tools and practices for use by NAVSEA design engineers, improved cost models, implementation of produability strategies for ship design process improvements, modification to existing acquisition practices, and improved three-dimensional (3-D) digital data transfer. The workshop was one of NAVSEA s first Total Quality Leadership (TQL) initiatives and was subsequently expanded into the Ship Design, Acquisition and Construction @AC) Process Improvement Project. This paper reports on the major findings and recommendations of the workshop, the near term accomplishments since the workshop, and the long range strategic plan for continuously improving producibility in the Naval Ship Design Process.
The shipyards in this country have spent a sizable amount of money to modernize their methods of fabrication to increase construction. The shipbuilding industry is a labor intensive business based on small orders of ships that does not allow for total automation in the near term, if ever. One area of a shipyard that has minor or limited changes is the structural design office. The manual drafting of working drawings is basically the same as the methods used in the 1950's. A number of yards have restructured the working drawing to assembly type drawings. This is a major change assisting in the construction of the ship, but is still limited in scope. The present method does not allow for an orderly progression into the application of computers. The development of working drawings to assist construction is-poor and this stagnation has restricted the design office from converting drawings to computers. The problem stems from false economy values. The idea that a limited budget for the development of working drawings will increase the yard's profit margin is a false one. Every effort, or person hour, used in design should have a direct savings in production manhours. The goal of the designer's output should be a necessary and direct part of the construction program. Many design offices may not even realize that they are not only reducing costs, but are driving them up due to poor detailing. (A complete study of the working drawing process should be made objectively by design, production and planning people). This paper may give the basic outlines for consideration. Thomas P. Gallagher, Surface Ship Structures, Head, Research, Dynamic/Highedr Performance Craft Section, Phone 202-692-9107, Naval Ship Engineering Center.
