Navy Ship Design Research Articles

Navy Enhanced Sierra Mechanics (NESM): Toolbox for Predicting Navy Shock and Damage

The US Navy is developing a new suite of computational mechanics tools (Navy Enhanced Sierra Mechanics) for the prediction of ship response, damage, and shock environments transmitted to vital systems during threat weapon encounters. NESM includes fully coupled Euler-Lagrange solvers tailored to ship shock/damage predictions. NESM is optimized to support high-performance computing architectures, providing the physics-based ship response/threat weapon damage predictions needed to support the design and assessment of highly survivable ships. NESM is being employed to support current Navy ship design and acquisition programs while being further developed for future Navy fleet needs.

Early-Stage Design for Electric Ship

One of the truisms of ship design is that the decisions of greatest impact are made in the early stages of design when the least information and the greatest uncertainty are present. In response to this, ongoing efforts in developing ship design tools are directed toward making more information available sooner and pushing decision points later. The integrated nature of electric ship in which performance of support systems directly affects performance of primary mission systems compounds this concern; design and simulation of support systems are needed earlier, and collaborative design among multiple engineering disciplines is required in the process. This paper reviews the Navy ship design process and recent developments in ship design tools to illuminate the areas in which further development is necessary.

Prospect Theory-based Real Options Analysis for Noncommercial Assets

When an engineering system has the ability to change or adapt based on a future choice, then flexibility can become an important component of that system’s total value. However, evaluating noncommercial flexible systems, like those in the defense sector, presents many challenges because of their dynamic nature. Designers intuitively understand the importance of flexibility to hedge against uncertainties. In the naval domain, however, they often do not have the tools needed for analysis. Thus, decisions often rely on engineering experience. As the dynamic nature of missions and new technological opportunities push the limits of current experience, a more rigorous approach is needed. This paper describes a novel framework for evaluating flexibility in noncommercial engineering systems called prospect theory-based real options analysis (PB-ROA). While this research is motivated by the unique needs of the U.S. Navy ship design community, the framework abstracts the principles of real options analysis to suit noncommercial assets that do not generate cash flows. One contribution of PB-ROA is a systematic method for adjusting agent decisions according to their risk tolerances. The paper demonstrates how the potential for loss can dramatically affect decision making through a simplified case study of a multimission variant of a theoretical high-speed connector vessel.

Hydrodynamic and Supportive Structure for Gated Ship Sterns: Amphibious Ship Stern Flap

Stern flaps have now been at sea for more than two decades, on a variety of U.S. Navy (USN) and U.S. Coast Guard (USCG) classes, including destroyers, cruisers, frigates, cutters, and patrol craft. Application of flaps to large-deck amphibious-type ships is a fairly recent extension of the technology. Ship performance improvements such as delivered power reduction and fuel savings, and maximum speed increases, have been proven during at-sea trials and are well documented. U.S. Navy amphibious ships contain well decks, which are accessed through large folding stern gates. When open, the gates are supported by sizable structures, which are partially submerged and affixed to the transom. A new concept, the hydrodynamic and supportive structure for gated ship sterns, i.e. the amphibious stern flap, was developed and patented by the author. This design combines a stern flap’s hydrodynamic performance surface with the stern gate support structure. The Naval Surface Warfare Center, Carderock Division (NSWCCD), has now designed and implemented this new type of integrated stern flap and gate support structure on several U.S. Navy amphibious ship classes. U.S. Navy ship design and R&D programs have resulted in amphibious stern flaps being implemented as new construction items on two new Navy amphibious ship classes and one new subclass. Fleet Readiness R&D programs have funded amphibious stern flap design, retrofit installation, and evaluation trials on two existing amphibious ships. Each amphibious stern flap design spiral, model-test series, optimization, full-scale implementation, as well as performance benefits and fuel savings will be discussed.

A Human Capital Strategy for Ship Design Acquisition Workforce Improvement: The US Navy's Center for Innovation in Ship Design

AbstractEarly in the dark days of World War II, President Roosevelt asked the Navy how it would provide the thousands of ships necessary for the numerous amphibious assault landings that were being planned. At a subsequent high‐level meeting, where John Neidermair, the Technical Director of the Preliminary Design Division at BUSHIPS (Bureau of Ships–a predecessor organization to the Naval Sea Systems Command–NAVSEA), created a concept design sketch of the now famous LSTs. It was this same BUSHIPS Ship Design organization that designed the US Navy Fleet which defeated the Japanese and German navies. And it was the BUSHIPS successor organization, NAVSEA, which designed the 600‐ship Fleet during the President Reagan build‐up of the 1980s and early 1990s. This early stage ship design capability to translate the operators' needs into technically feasible ship concepts and designs is still a core responsibility of NAVSEA. However, NAVSEA is now undertaking the grand challenge of rebuilding the Navy's ship design capabilities which were dramatically downsized during the 1990s. The Human Capital Strategy for Ship Design Acquisition Workforce Improvement is a proven road map for reconstituting the Navy's ship design capabilities and reinvigorating the naval ship design community. The Office of Naval Research (ONR) and NAVSEA made significant progress in this direction by establishing the Navy's Center for Innovation in Ship Design (CISD). CISD is accelerating the career development of ship design leaders, and is paving the way for fully implementing a Human Capital Strategy for Ship Design Acquisition Workforce Improvement.

What Is Set‐Based Design?

AbstractOn February 4, 2008, Admiral Paul Sullivan, Commander of the Naval Sea Systems Command, sent out a letter entitled: Ship Design and Analysis Tool Goals. The purpose of the widely distributed memorandum was to state the requirements and high‐level capability goals for NAVSEA design synthesis and analysis tools. In this memo, Admiral Sullivan expressed the need for evolving models and analysis tools to be compatible with, among other things, set‐based design (SBD). Admiral Sullivan's memo was a major step toward improving ship design programs with new, more powerful analytical support tools but many have asked, “What is Set‐Based Design and how does it relate to Naval Ship Design?” SBD is a complex design method that requires a shift in how one thinks about and manages design. The SBD paradigm can replace point‐based design construction with design discovery; it allows more of the design effort to proceed concurrently and defers detailed specifications until trade‐offs are more fully understood. This paper describes the principles of SBD citing improvements SBD in design practice that have set the stage for SBD, and relating these principles to current Navy ship design issues.

Influence of Human Engineering on Manning Levels and Human Performance on Ships

ABSTRACT The objectives of Human Engineering (HE) are generally viewed as increasing human performance, reducing human error, enhancing personnel and equipment safety, and reducing training and related personnel costs. There are other benefits that are thoroughly consistent with the direction of the Navy of the future, chief among these is reduction of required numbers of personnel to operate and maintain Navy ships. The Naval Research Advisory Committee (NRAC) report on Man‐Machine Technology in the Navy estimated that one of the benefits from increased application of man‐machine technology to Navy ship design is personnel reduction as well as improving system availability, effectiveness, and safety. The objective of this paper is to discuss aspects of the human engineering design of ships and systems that affect manning requirements, and impact human performance and safety. The paper will also discuss how the application of human engineering leads to improved performance, and crew safety, and reduced workload, all of which influence manning levels. Finally, the paper presents a discussion of tools and case studies of good human engineering design practices which reduce manning.

The Importance of Considering Life-Cycle Maintenance and Modernization Costs in the Design of Navy Ships

Experience with maintenance and modernization (M/M) of Navy ships has shown that life-cycle maintenance and modernization costs can significantly exceed initial acquisition costs, particularly for submarines and complex surface combatants, as shown in Fig. 1. The purpose of this paper is to draw increased attention to the influence that initial ship design has on the cost of maintenance and modernization of Navy ships, and to emphasize the need for greater consideration of these costs in Navy ship design. This paper presents several examples of actual design-related maintenance and modernization problems, along with possible design solutions, identified through a survey of U.S. naval shipyards. The paper also provides recommendations for increasing consideration of maintenance and modernization costs in Navy ship design through education, through the development of specific communication interfaces between design and maintenance and modernization production functions, and through research.

Producibility in U.S. Navy Ship Design

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. It was determined that the concept of the producible, designed-to-build ship was worth further investigation for incorporation into future designs because of potential cost savings. The paper concludes with recommendations for a method of application of producibility to the Navy ship design process for MSC-operated T-ships.

Designing Partial-Penetration Tee Joints for Naval Ships

This paper reviews development of weld design equations which can be used to analyze bevel partial-penetration tee joints. The method developed herein follows closely the development of equations for the design of square-edge partial-penetration tee joints which was presented at the 1986 Ship Production Symposium. For U.S. Navy ship design, technical authority is vested in the Naval Sea Systems Command (NAVSEA). The published NAVSEA design criteria for partial-penetration tee joints are so conservative that it is mathematically impossible to design a conventional, 100 percent efficient partial-penetration bevel tee joint. With a more rigorous engineering analysis, the alternative method for bevel joints outlined in this paper might be an acceptable replacement for the simple, though unduly conservative existing design criteria.

THE HISTORY OF ALUMINUM AS A DECKHOUSE MATERIAL

ABSTRACTThe use of aluminum as a structural material for deckhouses goes back to the 1890s. The alloys first used had corrosion problems, so use was ended until the mid 1930s, when it was reintroduced as panels riveted to steel frames. Riveted construction was replaced with all welded construction in the 1950s. Improved alloys and welding greatly reduced corrosion problems. Cracking of the welded construction caused another maintenance problem. Aluminum continued to be the standard deckhouse material because its use reduced topside weight by one half. Aluminum's maintenance problems and poor performance in fires has led to its elimination from current ship designs. With this change in design philosophy, it appears that a chapter in U.S. Navy ship design has been closed. This paper reviews the experiences of the past, with a look toward the future use of aluminum in combatant ship design.

The Naval Ship Design/Production Interface

The paper discusses, from a ship designer's perspective, some of the current topics and issues relating to the interface between naval ship design and production. The current environment within which naval ship design activity is taking place is described. Notable current views on Navy ship design and how it might be improved are summarized. Navy design topics pertinent to improving ship producibility, operability, maintainability and survivability are discussed and examples from recent ship designs are. presented. Issues which result from apparent conflicts in current design initiatives and critiques of the Navy ship design process are highlighted and discussed. Finally, some general conclusions are drawn.

A NEW GENERATION OF HIGH‐PERFORMANCE PLANING CRAFT

ABSTRACTKey aspects of the design development of a capable yet affordable high performance craft are addressed. These aspects include the development of mission requirements, the rationale for major design decisions, performance capabilities, and system and subsystem selection. The superior performance of the design, as demonstrated by an extensive model test program, led to the decision to develop a family of advanced fast patrol boat concepts. Selected family members are also briefly introduced. The paper, furthermore, demonstrates the successful integration of many major computer‐aided design (CAD) programs currently in use for U.S. Navy ship design.

A COMPARISON OF NAVAL SHIP DESIGN AND ACQUISITION PROCEDURES IN THE U.S. AND CANADA

ABSTRACTA synopsis of Canada's unified (combined Army, Navy, and Air Force) defense organization and decision‐making structure is presented. This is followed by an explanation of the closely intertwined Defense Program Management and Life‐Cycle Management Systems and their relationship in the Canadian ship design and acquisition process. Next, U.S. Navy ship design and acquisition procedures, including recent changes in program initiation procedures, creation of the Ship Characteristics and Improvement Board (SCIB), and revision of the Defense Systems Acquisition Review Council (DSARC) milestones are reviewed. Finally, Canadian and U.S. Navy design and acquisition processes are compared.

Formulation of the U. S. Navy Ship Design Speed-Power Margin Policy

This paper describes the analyses used in deriving data which are applicable to formulation of the U. S. Navy's speed-power margin policy. Corrections made to the powering predictions and trials data for the ships in the data base, in order to achieve equitable comparisons of predicted powering performance and powering performance actually measured during full-scale trials, are described; the power margins derived from these comparisons are presented. In addition, a statistical analysis of this newly derived power margin data is described and the results are presented. It is shown that the statistically derived margin values provide an appropriate basis for a speed-power margin policy and that small changes to the current interim NAVSEC speed-power margin policy may be desirable.

Man-Computer Graphics in Preliminary Ship Design

The Naval Ship Engineering Center through its Computer Aided Ship Design and Construction Office is working toward maximum effective use of computers in the Navy's ship design process. Many batch type analyses were developed but certain naval architectural problems, such as ship hull form creation and arrangements, cannot readily be handled by the computer without human intervention. Hence, interactive graphics developments were required. The existing interactive graphics programing languages were applicable only to the hardware for which they were written. To minimize conversion problems of inevitable hardware configuration changes, a portable interactive graphics language was developed and used. The active graphics programs described herein are under continuing development and in use for hull form generation, deck and bulkhead location, and topside and internal room arrangements. In their present form, they are applicable to early stage feasibility and preliminary design. The Integrated Ship Design System (ISDS) is being developed to allow communication of all types of design programs, including interactive graphics through a common data base; so that all applicable preliminary ship design tasks can be done within the computer environment.