Ship Concept Research Articles

Hydrodynamics of the Ballast-Free Ship Revisited

In order to clarify the existence and amount of a required propulsion power reduction possible with the efficient use of the Ballast-Free Ship concept on a Seaway-size bulk carrier, additional experimental and computational hydrodynamics studies were undertaken during the past year. Experimental studies performed in the University of Michigan Marine Hydrodynamics Laboratory (MHL) are described. Computational fluid dynamics (CFD) investigations performed using Star-CCMþ at both model and full scale are also presented.

Multidisciplinary Synthesis Optimization Process in Multihull Ship Design

This paper describes the development and application of a synthesis-level multidisciplinary design and optimization (MDO) method for multihull ships. This method is unique in utilizing advanced multi-objective optimization methods, neural network (NN)-based response surface methods (RSM), and in its broad scope, integrating powering, stability, seakeeping, hullforms definition, structural weights, and cost and payload capacity into a single design tool. This MDO method is developed in the context of a multilevel hierarchy system approach where the results of the synthesis level optimization can be used for subsystem optimization and overall coordination of multilevel design system. NN-based RSM for seakeeping and powering is developed and used in the optimization process. This RSM approach moves the computational cost of such performance evaluations out of the optimization cycle, substantially reduces the optimization cost, and allows for using results of physics-based methods, such as advanced computational fluid dynamics, at the synthesis-design level of design hierarchy. Details of these methods are delineated and multi-objective optimization results are presented in the form of Pareto optimum solutions for multihull ship concepts such as trimaran sealift support ships and catamaran high-speed connector ships.

Managing empty container flows through short sea shipping and regional port systems

This paper proposes a method for managing the flow of empty containers as an integral aspect in the application of short sea shipping and regional port system operational concepts. The paper finds support for the implementation of short sea shipping along the US West Coast and argues in favour of the establishment of regional port systems to provide an appropriate institutional framework for the coordination of public and private investments in short sea shipping. Overall, the paper finds that short sea shipping represents a viable tactic in the implementation of a regional port system development strategy on the West Coast of the USA and should be considered as a possible method for alleviating landside congestion stemming from commercial traffic in major urban corridors. Specific opportunities for the implementation of this method in Southern California are found with the redirecting of empty container flows to secondary ports, as well as with international movements to and from manufacturing regions on the USA-Mexico border.

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.

Methods for Naval Ship Concept and Propulsion Technology Exploration in a CGX Case Study

Abstract In response to the Fiscal Year 2006 National Defense Authorization Act, the US Navy conducted an alternative propulsion study (APS) for surface combatants and amphibious warfare ships. The study looked at current and future propulsion technology and propulsion alternatives for three sizes of warships. In their analyses they developed 23 ship concepts, seven of which were considered medium surface combatants (MSCs). The report to Congress was based on cost analyses and operational effectiveness analyses of these variants. Their conclusions did not consider a true representative sample of feasible, non‐dominated designs in the design space. This paper revisits the APS for a fossil‐fueled MSC. It applies automated design methods with a variety of design tools, including the Advanced Ship and Submarine Evaluation Tool (ASSET), a simplified ship synthesis model (SSSM), and Model Center (MC) to improve the APS approach. It examines a range of power and propulsion alternatives using operational profiles and requirements similar to the APS in a notional MSC (CGXBMD). The automated process and tools presented in this paper provide a rational and thorough method to search a design space for non‐dominated concepts. These non‐dominated concepts represent the best basis for assessing technologies over a range of possibilities considering effectiveness, cost and risk. This automated approach and new tools are evaluated in the context of a CGXBMD case study. A number of conclusions relative to APS propulsion technologies are made. Most support the APS results.

Ship's Fuzzy Domain – a Criterion for Navigational Safety in Narrow Fairways

The concept of ship's domain plays an important role in navigating a ship. It is a criterion of safety in the process of making decisions by the navigator – in analyzing and assessing a navigational situation and in performing the right manoeuvre. This concept is particularly useful in restricted areas, including narrow fairways, which results from the fact that in such waters a manoeuvring area is restricted so that the criterion of the closest point of approach (CPA) cannot be used. This author has analyzed definitions of ship's domain and methods of its determination found in the literature on the subject. Then a method of navigational safety assessment using the fuzzy domain concept is proposed in reference to a ship in a restricted area. The concept and method of determination have been, respectively, defined and described. The method is based on relevant navigators' knowledge. The methods and tools for knowledge acquisition and representation make use of artificial intelligence. Ships and navigational areas of various size have been considered.

Technology development for steering and stabilizers

As part of the All-Electric Ship concept the Ministry of Defence (MoD) Defence Procurement Agency Future Business Group's Marine Engineering Development Programme (MEDP) has been investigating the Electrical Actuation of Hydrodynamic Control Surfaces (ELAHCS) Programme for the Royal Navy. The project is presently examining the replacement of traditional hydraulic actuation systems for fixed-fin ship stabilizers, steering gear, and hydroplane actuation with novel electric actuation methods. As part of this programme the project has developed a technical demonstrator – a fixed-fin stabilizer actuator – which was fitted to both stabilizers on an operational Type 23 Frigate as part of a System Demonstrator Programme (SDP). This demonstrator is providing system performance and environmental data and contributing to the wider understanding of hydrodynamic control surface requirements. It is also illustrating the potential benefits of this technology which are reduced lifecycle costs, simpler installation and maintenance, improved survivability, cleaner systems, elimination of high-energy fluidic systems, and hence the associated support and training and hazards. This paper describes the development of the ELAHCS Programme, the progress of the SDP to date, and additional future exploitation of this technology for ship and submarine applications.

Research on preliminary concept of ship intended for mining poly-metallic concretions from sea bed

Research on preliminary concept of ship intended for mining poly-metallic concretions from sea bed Necessity to design and build a ship for winning Fe-Mn concretions from sea bed, and put it into operation, results mainly from decreasing land resources of mineral rough materials and increasing prices of metals. Main dimensions and parameters of such mining ship were determined by elaborating its main design assumptions and making use of suitable data on drilling ships considered similar from the point of view of attributed functions and spatial arrangement. In this paper a design study on preliminary concept of dimensions and spatial arrangement of a ship for winning poly-metallic concretions from sea bed, is presented. The study has been aimed at elaboration of an appropriate mathematical model to be applied for optimization of ship's winning system.

Electric Power Supply Quality in ship systems: an overview

Power Supply Quality (PSQ) has become an important concern for ship electric systems. Thus, deviations of voltage from nominal values and wave-shapes could cause several problems onboard. Considering that ship system electrification eventually dominates according to the All Electric Ship concept, PSQ will be a key-factor of the normal operation, survivability and safety aboard. The paper provides a coherent description and categorisation of the PSQ phenomena (causes, consequences, characteristic parameters etc.) highlighting similarities and differences between terrestrial systems and ship systems in terms of these phenomena. This overview is enriched by cross-references to relevant standards applied in shipboard applications.

Institutionalizing the Electric Warship

The Navy has invested a considerable amount of resources in developing Electric Warship technology in the past twenty years. We have witnessed a number of early technology demonstrations as well as incorporation of Integrated Power System (IPS) technology into ship programs such as LHD 8, T-AKE, DD(X), and CVN 21. Although these early adopters have paved the way for establishing the practice of electric warship design, we are now at a critical point in time for institutionalizing the electric warship. A technology is institutionalized when the following activities have occurred: ▪ Establish a common architecture and interfaces. ▪ Establish a common design processes. ▪ Incorporate the architecture and design processes into design tools. ▪ Codify the practice in government or industry specifications, standards, and guides. ▪ Teach the architecture and design process as part of a typical engineering school curriculum. This article reviews the progress in electric warship technology, describes progress (including ongoing efforts) in institutionalization, and highlights critical near term shortcomings. Some of the shortcomings in design processes and tools include: ▪ Undefined (in authoritative documentation) concepts such as zonal survivability and quality of service. ▪ Obsolete requirement terms such as “sustained speed” and “endurance speed/range” ▪ Conflicting design practices for propulsion and ship service prime mover sizing. ▪ Customized system protection strategies for different classes of ships. ▪ Ambiguous methods for the sizing of zonal distribution system components. ▪ Lack of integration of IPS design algorithms into ship concept tools such as ASSET. ▪ Lack of knowledge as to how to effectively use modeling and simulation to make electric plant design decisions for each stage of ship design. Additionally, the article details progress in updating standards and specifications, such as the Naval Vessel Rules and DOD-STD-1399. Finally, efforts to incorporate Electric Warship design into the curriculum at [RA1] traditional Naval Architecture are described.

ＣＦＤ流体力チャートに基づく曳航パイプの時間発展的ＶＩＶ応答解析

Long towed pipe is used for dilution of CO2 in the moving ship concept of ocean sequestration of CO2. Vortex Induced Vibration (VIV) is expected for the towed inclined pipe. Time marching VIV simulation method was developed and validity of the method was verified. The method is a combination of a data base of VIV hydrodynamic force on the cylinder subjected to harmonic oscillation and a time marching FEM (Finite Element Method) of underwater line structure. VIV force is calculated by CFD (Computational Fluid Dynamics) . A filter which estimates amplitude, frequency and phase of a local response of pipe from the time history of pipe vibration was developed. Using this filter, parameters of local vibration and instantaneous VIV force is evaluated by consulting the data base. The estimated VIV force is applied to the pipe and response of towed pipe is calculated by the FEM. The method was verified by comparison with experimental results carried out in the towing tank. The accuracy of the method is discussed.

Revisiting artificial air cavity concept for high speed craft

Artificial air cavity ship concept has received some interest due to its potential on viscous resistance reduction for high speed craft. Although a small number of ships were designed and built by using this concept, further research on resistance components is required to improve the understanding of artificial air cavity forms. A method based on tank testing with wave pattern measurements to identify resistance components was adopted in the current work. Resistance tests were conducted with two forms; first of which was conventional prismatic planing hull form with a deadrise angle of 10°, and second one was an alternative form with an artificially cavity which was tested both without any air injection, and with two different air injection rates. Total resistance, running trim, sinkage, supply airflow to artificial cavity, air pressure in the cavity and wave pattern generated by the hulls were measured. Frictional resistance was calculated from wetted surface area and compared with resistance component obtained by subtracting wave pattern resistance from the total resistance. Wave pattern spectrums with air cavity configurations were compared across the speed range.

Multiple‐Objective Optimization in Naval Ship Design

ABSTRACTThis paper presents an optimization methodology that includes three important components necessary for a systematic approach to naval ship concept design. These are: ▪ An efficient and effective search of design space for non‐dominated designs▪ Well‐defined and quantitative measures of objective attributes▪ An effective format to describe the design space and to present non‐dominated concepts for rational selection by the customer.A Multiple‐Objective Genetic Optimization (MOGO) is used to search design parameter space and identify non‐dominated design concepts based on life cycle cost and mission effectiveness. A non‐dominated frontier and selected generations of feasible designs are used to present results to the customer for selection of preferred alternatives. A naval ship design application is presented.

Open Systems Architecture C41 Template

ABSTRACTThe Affordability Through Commonality Office (PMS 512) of PEO Surface Strike, in order to promote and enable the implementation of Open Systems Architecture (OSA) for Navy systems, established the Total Ship Open Systems Architecture (TOSA) Industry/Navy Integrated Product Team (IPT). TOSA has developed a notional open C4I template which incorporates an OSA. The application of OSA to C4I spaces will increase flexibility, upgradability, scalability, and adaptability and decrease total ownership cost over the lifecycle of the ship. Open systems concepts are well established in the commercial information technology (IT) field as a means to increase competition among vendors (broaden the market applicability and reduce costs). While the benefits of OSA are easily discernable for IT systems, the use of OSA for HM&E ship systems inter‐faces represents a new and unproven application. An important feature of the adaptable ship concept is the Functional Element (FE) zone, which represents physical divisions of a ship with managed functions, configurations, interfaces, and characteristics. This paper describes how the OSA process was applied to develop an example FE Zone template for a specific space, a notional Combat Information Center (CIC) zone. The resulting concept may be used to develop a family of templates to open the remaining Command, Control, Communications, Computing and Intelligence (C4I) zones on a ship.

COMPUTATION OF COBBLESTONE EFFECT WITH UNSTEADY VISCOUS FLOW UNDER A STERN SEAL BAG OF A SES

The concept of a surface effect ship (SES) is to lift the hull partly by the air cushion enclosed within two side hulls, a bow skirt and a stern seal. Consequently, it results in lower draft, resistance and motions than equivalent length catamarans in most sea states. In very low sea states, however, there is a significant design problem, which is high vertical accelerations, referred to as the cobblestone effect. The oscillations are based on resonance phenomena and are caused by the change of the cushion volume due to the incident waves. The resonance oscillations have an important damping mechanism which is derived from the air leakage flow under the stern seal bag of a SES. Hence, the accurate prediction of the leakage flow is required for the estimation of the cobblestone effect. In order to solve the unsteady flow field under the stern seal bag, a viscous flow code for numerically simulating two-dimensional incompressible flows has been developed. The governing equations to be solved are the time-dependent Navier–Stokes equations, using the artificial compressibility approach. The spatial discretization is based on a cell-centred finite volume formulation. The inviscid fluxes are evaluated by Roe's scheme with the third-order-accurate MUSCL approach. Time integration is conducted by the second-order accurate backward Euler formula and the linear equation system is solved by an approximate Newton relaxation scheme with the symmetric Gauss–Seidel iteration approach. For the resulting time integration to be conservative on a moving grid system, a geometric conservation law is introduced. A numerical procedure is presented and contributions of the viscous effects to the cobblestone effect problem are discussed.

Effects from Supercritical Ship Operation on Inland Canals

Speed of commercial displacer vessels on inland waterways is a major disadvantage in comparison to truck and railway. A solution to shift cargo from congested roads and railways to inland waterways may be with high speed vessels as those issued in coastal waters. Inland waterways are restricted in depth and often in width, which leads to hydraulic impact on bottom and banks. Screening of existing high speed ship concepts in unrestricted waters showed twin hulls (catamarans) with and without air-cushion and monohulls as technically feasible on inland waterways. Three types of high speed ships were modeled and tested in a restricted laboratory canal regarding hydraulic impacts from generation of waves, water-level variations, and flow velocities. Ship interaction with existing structures and interference with other ships, as well as channel bed and banks, were also modeled and tested. For the air-cushioned twin hull (SES-Catamaran), high speed model tests showed that water-level variation and flow velocitie...

Fleet Mix Mission Effectiveness Analysis

ABSTRACT With increasing awareness of the importance of taking a Total Ship Systems approach to the evaluation, development, and design of Navy ships, Mission Effectiveness Analysis is becoming a driving force in naval ship design. Shrinking defense budgets demand that our navy carefully structure its future fleet to achieve the highest possible combat capability within available funding. As part of the DOD 5000.2 acquisition process, any new shipbuilding program requires an Analysis of Alternatives (AoA) of all design options before proceeding with preliminary design. Measures of Effectiveness (MOEs) must be developed for the AoA to accurately rank several ship concepts across a broad range of missions. This paper describes a general MOE analysis method, as well as a new model which uses nine MOEs to compare a mix of existing ships and new ship concepts acting together as a task force. Results from a sample analysis of two new designs will be presented.

An Arsenal Ship Design Affordable, Advanced Warfighting Capabilities

ABSTRACT The Navy's “Arsenal Ship Concept of Operations [1]” and “Ship Capabilities Document (SCD) [2]” address a need for the design of a large missile platform that can carry massive and precise firepower, accomplish long‐range strike, and perform flexible targeting and multidimensional theater defense consistent with the policies of “Forward… From the Sea [3]” and “Operational Maneuver from the Sea [4].” The ship is designed to be a large missile magazine that receives its launch orders from remote air, land or sea forces. It is fully integrated into the joint command and control structure to assist current forces in the opening days of conflict. A major design goal of the Arsenal Ship is to limit the crew size to 50 personnel through the use of system automation, redundancy and equipment reliability, while meeting an additional constraint of limiting the sailaway price to 550 million dollars.The Total Ship Systems Engineering (TSSE) design team at the Naval Postgraduate School (NPS) in Monterey, CA used a modified repeat of the T‐AO 201 class oiler. The selection of this hull is based on mass tonnage for survivability, carrying capacity for approximately 500 vertically launched missiles and budget constraints that militate against a new hull design. The midship section of the ship is fitted with 64 eight‐cell Concentric Canisterized Launcher (CCL) modules. The Cooperative Engagement Capability (CEC) is incorporated in the design to provide the controlling platform the ability to remotely fire the Arsenal Ship's missiles.The design was performed at NPS under the direction of author Calvano by a group of fifteen officer students, which included authors Chase, Baumann and Null. It is believed that the at‐sea experience and thorough analysis from the officers involved has resulted in a sensible design of a creative and highly realistic solution to the Navy's call for an Arsenal Ship of the 21st Century.

Autonomic Ship Concept

ABSTRACTThe Autonomic Ship concept as developed by the Carderock Division, Naval Surface Warfare Center's Innovation Center addresses leveraging advanced computer technology to achieve total systems integration, automation and manning reduction in future ships. The concept integrates distributed architecture, information technologies, and modular systems that utilize the four Autonomic principles; fault tolerant systems, software objects, ubiquitous computing and task and functional analysis. Simply, the vision of the Autonomic Ship can be described as a ship where the people decide what to do and the ship makes it happen.

SHIP IMPACT STUDIES

A major role of the naval architect is assessing the value of future equipments and costs of requirements to the Navy. The means of doing this is a series of ship feasibility studies. Setting R&D priorities or establishing the requirements for a new ship class often means 40 to 100 of these studies. The paper presents, in an appendix, the titles of a sample series of impact studies from the early stage design of the DDG-51: 7 baselines with a total of 52 excursions. The amount of work is so demanding that the nature of the process itself is often obscured by the massive amount of output. There is no “universal” system impact; the ship impact assigned to something is dependent on a series of factors. It depends on what baseline ship is chosen, if the ship is near a machinery step function, in what order the questions are asked, what the subsystems of that ship are, whether a knee in the curve has been reached, fleet operational preferences, the fact that savings are not cumulative and inherent flaws in the process. The paper discusses how changes in basic ship architecture alter the results of ship impact studies. A second appendix describes three generations of destroyers (CL-51, DD-963 and the DDG-51) of similar displacement but with radically different ship impact responses. The variable nature of ship impact results is why “savings” of systems which are widely advertized in technical society papers and new-system-advocate pitches are sometimes not found in procurement ship studies. The users of the ship impact studies (the OpNav requirement writers and the R&D investment selectors) should understand the strengths and weakness of assessing ship impact. They should also understand the need to prepare design tools in advance and the need to study the impact on future ship concepts rather than existing ships.