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.
Draft STEP application protocols, developed by the Navy Industry Digital Data Exchange Standards Committee (NIDDESC), have been issued to define the information content of a product model for a ship. The work reported in this paper combines the existing CAD models of the DDG51 Class design with a newly developed non-graphic database so that the overall information content complies with the STEP protocols. This work represents the first-time implementation of the application protocols and is a significant step in the Navy's plan to do the design of variants of the DDG51 Class totally in CAD. The combined graphic/non-graphic database is referred to as the DDG51 engineering product model. Emphasis has been placed on populating the non-graphic database with the information necessary to perform all required engineering analyses. The basic schema described in this paper may be extended to support other areas of interest, such as logistics support. technology. As a cost saving initiative and quality improvement measure, the Navy has implemented the use of 3-D Computer Aided Design (CAD). This effort required the development of leading edge CAD technology and the achievement of a cooperative (rather than competitive) success story by the two DDG51 Class shipbuilders and other industry participants. Over 2,500 drawings, many of which contain over 30 sheets per drawing, are required to build an AEGIS destroyer. Maintaining an error free design baseline defined by these drawings has proven to be a challenge in a 2-D manual environment. To improve efficiency, the entire design is being converted to 3-D CAD. The DDG51 design consists of 77 design zones. A 3-D computer generated representation of each of these zones is being developed. These models contain library parts defining equipment and machinery arrangements, structure, ventilation, electrical, and piping distributive systems.
The use of Computer Aided Design (CAD) technology in the U.S. Navy and Marine industry has evolved from a drafting based design tool to a 3-Dimensional(3D) product oriented information base, used for design, production and service lift support. One of the most significant enhancements to current CAD technology has been the incorporation or integration of non-graphic attribute information with traditional graphics data. This expanded information base or product model has enabled the marine industry to expand CAD use to include such activities as engineering analysis, production control, and logistics support. While significant savings can be achieved through the exchange of digital product model data between different agents. current graphics based CAD data exchange standards do not support this expanded information content.
The application of computers in acquisition and logistics support is to major requirement of future weapons systems acquisitions. Although the design of the SEAWOLF preceded most new DOD sponsored requirements, the program incorporated many initiatives that will serve as prototypes for most acquisitions. It The SEAWOLF Program is employing computer technology to integrate the design, production and logistic the ship's life cycle. The transportabiiity of TI electronic data from the design phase ti to construction, and on to logistics dc is key to improving efficiency and a more closely linking designer, shipbuilder and maintainer. SFAWOLF is an important step in the overall effort to improve weapons system acquisition efficiency. Five Lessons learned by SEAWOLF will be valuable in preparing other acquisition programs to take advantage of the integration of computer data bases that can bring greater success in the execution of design, production mi and logistics support phases.
Recent NAVSEA studies of a twin skeg hull form design applied to a T-AO type ship indicated many areas of possible improvement in producibility. This paper reviews the findings of producibility studies and attempts to indicate specific areas where an improvement in producibility and attendant cost savings for Navy ships are possible without any degradation in ship performance and survivability. Most available studies on producibility have an inherent trait of elaborating on details of shipyard producibility. This paper attempts to confine itself to the producibility aspect of the design phase, ending with the completion of contract design. While it is of course necessary for the Navy ship designer to know about producibility details of prospective building yards, he must be careful not to incorporate any details that may be restrictive on some of the prospective builders and thereby hinder competition.
The fundamental philosophies of Group Technology or Zone Logic Technology are accepted practices in Japanese Shipyards. The ideologies, originally conceived in the U.S. ironically, were considerably refined by the Japanese Shipbuilding and Repair Industry and since 1978, have been reimported to the U.S. The traditional system-by-system approach to work has been replaced by a zone oriented product work breakdown structure, Zone Logic Technology. This grouping of jobs if executed properl, has the potential to significant y enhance efficiency and productivity.
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.
Many common ship repair tasks result in the production of quantities of various hazardous wastes. These wastes, regardless of volume, present difficult burdens for ships and the U.S. Navy. Under the environmental laws, the responsibility for handling hazardous wastes and the liability for their ultimate disposal rests with the person or persons who create the wastes and who arrange for their disposal. Often times, however, the responsibility and liability for handling and disposing of these wastes is unclear. It is especially time when naval ships are repaired in contractor facilities and wastes are produced by the activities of ships' force, contractor personnel or some combination of the two. Further complicating the web of liability is the divergent source of the wastes. Some wastes are produced as a direct result of required maintenance work on ship systems. Other wastes may be produced in the yard by activities which are largely discretionary with the contractor. Ultimately, These wastes from all sources must be identified, packaged, stored, treated, transported and disposed. Potential future liability may arise at each step in this process.
SEAWOLF Producibility initiatives have been presented to past Ship Production Symposiums. The technical content of these papers was based on work accomplished during the SEAWOLF Detail Design effort and articulated the point of view that the SEAWOLF Producibility Program was an important step in advanced ship production. The lead shiv of the SEAWOLF Class started construction in late 1989. The opportunity now exists to validate a number of the elements of the design for production. Electric Boat Division, as Lead Shipbuilder, has the opportunity to review a number of the specific initiatives, such as Digital Data Transfer, Sectional Construction Drawings, Planning and Sequence Documents, Computer Integration of information processing and the combination of SEAWOLF products that support improved work control. The method of approach is to describe the SEAWOLF producibilitv element developed during detail -design and then assess the benefit to the shipbuilding process.
