bluuebunny/crossref_metadata_2025 huggingface dataset:
A Generic Shipyard Computer Model – A Tool for Design for Production
Authors: Chung Hyun , Lamb Thomas , Shin Jong Gye
Published: January 2021

Ship designers perform trade-offs frequently, but often without adequate information or tools to perform them. This results in many decisions that are sub-optimal. Too few tools have been developed to help the ship designer, and those that have, usually have been developed in businesses other than shipbuilding. Ship designers performing trade-off analysis are usually interested in the impact on service performance, although today more are looking at design for production impacts of their designs because of the recognition that acquisition cost is still the major life cycle cost contributor for commercial ships. Those that are considering Design for Production, attempt to develop relative costs of the alternatives by applying parametric cost estimating relationships, if available, or simply best judgment. A better tool would be a computer based generic shipyard model that the designer could use to quickly model a shipyard so that the alternative designs could be processed through the model of the shipyard and the resulting material manpower and schedule impacts be determined. Conversely, such a model could also be used to determine any necessary changes to the shipyard to make it suitable for a specific new design approach or new ship type. The paper describes a Generic Computer Shipyard Model developed as part of the graduate research sponsored by a NAVSEA Cooperative Agreement under the NA VSEA Professor of Ship Production Science, and give examples of its use as a Design for Production tool.
Adapting Commercial Shipbuilding Practices to Warship Design – Evaluation of a Hybrid Navy-Commercial Collar Detail
Authors: Schulz Erich J. , Celotto Richard C. , O'Connor Morgan P. , Malone John A.
Published: January 2021

An investigation was carried out to determine the applicability of certain commercial construction techniques to naval ships with regard to their capability to withstand weapons effects loads. Typical commercial structural details require less welding and fitting, are less labor intensive, and are therefore less expensive to construct than naval structural details. However, structural details used on naval ships must adequately resist loads that are different from those a commercial ship would encounter, specifically shock and whipping loads due to underwater explosions, and blast from air explosions. This paper documents the limited-scope investigation performed that included design, analysis, and shock testing of a candidate commercial structural detail to replace the Navy standard detail, specifically the collar used in joint connections.
Nesting of Two-Dimensional Irregular Parts Within an Irregular Boundary Using Genetic Algorithm
Authors: Sha O. P. , Kumar Rakesh
Published: January 2021

The present work aims to find an efficient and fast method for the nesting of two-dimensional Irregular or regular parts in an irregular or regular sheet using genetic and heuristic algorithms, with a view to maximizing the utilization of the sheet material. The proposed genetic algorithm gives out the best sequence and orientation of parts, using which the given heuristic generates a nested pattern with bottom left strategy. The heuristic approach makes use of the positioning technique to find out the acceptable position of each part on the sheet. The application of the proposed approach is illustrated by considering both irregular parts and irregular sheets composed of line features.
Risk-based Simulation Models for the Construction of the Mobile Offshore Base
Authors: Bender William J. , Blair Andrew N. , Ayyub Bilal M.
Published: January 2021

Several very large ocean structures have been proposed as part of the Office of Naval Research feasibility study of a Mobile Offshore Base (MOB). The MOB platform nominally is about 1500 m (l mile) by 129 m (400 ft), which is unprecedented in size and operations compared to any floating structure to date. The objective of this study was to provide a risk-informed construction feasibility assessment for five proposed MOB concepts and quantify their construction cost and schedule. The risks associated with the concepts' cost and schedule were established by comparing resource requirements to build a MOB with the US industrial capacity. These risks were then modeled and simulated using commercial simulation software to provide cost and schedule estimates that accounted for uncertainty and risks. The scope of this study was limited to the construction of the hull.
Practical Use of 3D Product Modeling in the Small Shipyard
Authors: Ross Jonathan M. , Abal Diego
Published: January 2021

Over the past several years, compelling advances have taken place in ship design three-dimensional product modeling systems. The most modern of these systems are PC-based, possess a single database, have electronic links to NC production equipment, and have interfaces with shipyard planning, production, and materials management. Small shipyards often hesitate to install one of these systems because of constraints such as the frequent need to generate one-off designs, reluctance to change from traditional 2D design, planning and production methods, small IR& D budgets, tight markets, stiff competition, and customers' desires for fast design-production turnaround. Also, the shipyard may choose from a spectrum of design systems in which the 3D product modeling systems are the most complex and expensive. Thus, small shipyards often perceive many disadvantages to purchasing ship design 3D product modeling systems, and believe the disadvantages are not sufficiently offset by advantages. These yards may be surprised to find that, in practice, a number of small shipyards have made a successful conversion to these systems, and several of these yards provide candid insights of actual advantages and disadvantages.
Dimensional Error of Assembled Blocks
Authors: Okumoto Yasuhisa
Published: January 2021

This paper presents the primary factors of the dimensional error for hull blocks and offers countermeasures. It also introduces a series of recent analytical approaches as well as accuracy management using a conventional quality control method, in order to substantially increase ship productivity.
Knowledge-Based Modular Repair: Advanced Technology Applications for Ship Repair and Conversion
Authors: Stieren D.C. , Caskey G. , McLean C. , Neyhart T.
Published: January 2021

One of the projects sponsored by the U.S. Navy's Maritime Technologies (MARITECH) Advanced Shipbuilding Enterprise Initiative in 1999 is being conducted jointly by the Atlantic Marine Holding Company (AMHC) in Mobile, Alabama (which also has facilities in Jacksonville, Florida) and the Manufacturing Engineering Laboratory of the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland. This project, "Knowledge-Based Modular Repair: Advanced Technology Applications for Ship Repair and Conversion," has the following goal: to reduce cycle times and costs, and improve the precision and overall quality of repair and conversion processes conducted by American shipyards. This paper presents the work being conducted in this project, along with first-year results. The project incorporates precision metrology techniques and advanced modeling and simulation technologies into repair and conversion operations. The project is facilitating prefabrication and modular installation of structural and mechanical system components during large-scale overhaul and conversion projects by using advanced engineering technologies combined with reverse engineering and accurate, predictive modeling tools. Planning processes are being created to incorporate the technologies developed by the project into contracted work in the shipyard and to assist the customer in making informed, accurate decisions about optimum approaches to real-world projects.
XML-Based Interoperability in the Integrated Shipbuilding Environment (ISE)
Authors: Rando Thomas C.
Published: January 2021

Interoperability is one of the major challenges facing the U.S. shipbuilding industry today, and the new WWW technologies (in particular, XML) offer the opportunity for revolutionary improvements in this area. XML is being used within the Integrated Shipbuilding Environment (ISE) to achieve interoperability of shipbuilding systems technologies through the interchange of shipbuilding product information. The ISE project is a multi-shipyard project funded by the Maritech-Advanced Shipbuilding Enterprise (ASE) program. ISE has developed a reference architecture for systems technologies in the U.S. shipbuilding industry, and it has applied this reference architecture to the solution of the primary interoperability business drivers in the industry today. The ISE has identified both functional requirements and technical requirements for maritime product information sharing. This paper describes the ISE approach for using XML to accomplish application-to-application (A2A) interoperability for the shipbuilding industry.
An Improved “Make versus Buy” Strategy for Future Material Acquisition
Authors: Wilson Veasey , Wennberg Peder , DeGraw Kevin , Fleischer Mitchell
Published: January 2021

Newport News Shipbuilding has been decreasing its level of vertical integration in recent years. Today, more than two thirds of components for NNS's ships are outsourced. Desiring to invest in strategic, business-enhancing capabilities such as advanced product modeling, research and development for next-generation carriers and submarines, a one-of-a-kind carrier refueling facility, a new technology center for advanced shipbuilding and carrier integration, a corporate-wide Shared Data Environment and advanced robotics for steel fabrication, the company has reduced its investment in more "traditional" component manufacturing shops. Major facilities the company operated in Asheville, North Carolina and Greenville, Tennessee have been closed, as have several shops in or near the company's huge yard in Newport News, Virginia. To a greater degree than ever, the shipyard depends on an integrated supply chain of prime suppliers and sub-tier suppliers for its success. It is exploring further opportunities to realize a greater return on the company's investment capital. By looking at strategies on how to best integrate their manufacturing processes with suppliers who have invested their capital and resources to specialize in products and services that can reduce manufacturing costs, shipyards can retain capital for strategic investment opportunities that promote future business growth. The key to making good outsourcing decisions that will enhance a company's return on assets is a strategic approach to "Make versus Buy" decisions. The downside of outsourcing that is frequently cited by those who have worked in or depended on internal shops throughout their careers is a reduction in self-sufficiency and flexibility. Other important considerations are labor and community relations. This paper describes the process of developing an improved "Make versus Buy" process, the implementation of that process, and then measuring the results to develop a set of best practices applicable to the shipbuilding industry.
The Economics of Implementing ISO 14001
Authors: Newell Frank , Bruce George
Published: January 2021

Marine activities are environmentally sensitive, and this paper outlines waste management for a ship conversion company. Minimizing waste, reuse, recycling, and landfill are options in a hierarchy. Production process and waste handling were improved using industrial engineering and other techniques. A cost/benefit analysis showed ISO 140 as a potential source of competitive advantage as well as ensuring compliance with legislation.
A Precursor to Ergonomics Best Practices for the Shipyard Industries
Authors: Hudock Stephen D. , Wurzelbacher Steven J. , Reed Laurence D. , Hales Thomas R. , Siegfried Karl V.
Published: January 2021

Many of the job processes being performed today in ship construction, repair and recycling yards do not differ significantly from those same processes as performed fifty years ago. The complexity of vessels may have increased dramatically in the past fifty years but many of the job processes have not kept pace with changes in tech-nology. Due in part to the mismatch of technology between work processes and product design, researchers at the National Institute for Occupational Safety and Health (NIOSH), in collaboration with the National Shipbuilding Research Program Advanced Shipbuilding Enterprise (NSRP ASE) and the Maritime Advisory Committee for Occupational Safety and Health (MACOSH), have conducted a series of ergonomic analyses of work processes at a number of domestic shipyards. These analyses have identified specific work processes within the shipyards that have resulted in numerous, severe, or costly musculoskeletal injuries to the shipyard work-force. The mitigation of the occupational risk factors associated with these processes was the focus of targeted ergonomic interventions.
Some Developments in Marine Technology Education in the United Kingdom
Authors: Birmingham Richard
Published: January 2021

Universities today operate in an environment that could be called dynamic, or less positively, turbulent. In this environment educational provision needs to continually evolve in response to the changing expectations of students, their employers, and their sponsors. Monitoring the changing requirements of degree programs is not easy, as not all stakeholders in the provision of education have clear channels of communication to the program providers. This paper details the motivation for developing two contrasting postgraduate programs, describes how these new initiativeshave been progressed by two separate consortia of universities in the United Kingdom, and indicates why they are of interest to international students. While the mechanisms that have led to the development of these new programs are entirely different, one being a deliberate manipulation of the qualifications needed by professional engineers and the other a response to a changing market demand, they both reflect a significant and international shift in the objectives of education for engineers.
Field-Scale Demonstration of Electrocoagulation and Enhanced Media Filtration for Treatment of Shipyard Storm Water
Authors: Pulido Maria E. , La Motta Enrique J. , Nandipati Reddy M. , Josse Juan C.
Published: January 2021

The use of electrocoagulation and enhanced media filtration was evaluated for the treatment of storm water runoff from shipyards. A 15-gallon per minute (gpm) fieldscale unit was operated at Litton Avondale Industries Shipyard in New Orleans, Louisiana. The study indicated that electrocoagulation and enhanced media filtration is a cost-effective technology for treatment of shipyard storm water runoff. This technology is simple to operate and has the potential to provide a cost-effective means to treat various process wastewaters generated in shipyards. The study also indicates a need for further research on the management of solid residuals generated in the treatment process. Further research is also needed to assess the effectiveness of this technology for the treatment of other related waste streams such as ship ballast water and bilge water.
Market Orientation Measures of the U.S. and Turkish Shipbuilding Industries: A Comparative Study
Authors: Cerit A. Guidem
Published: January 2021

The world shipbuilding industry performs in a concentrated market where the rules of competition are set internationally. The main objective of the present study was to analyze the market orientation measures in the industry, concentrating mainly on marketing research: issue analysis (external and internal environment); segmentation, targeting, differentiation and positioning strategies; marketing mix decisions, and organizational aspects of the marketing function. To assist internationally applicable results, the study was carried out in two different populations, namely the shipyards in Turkey and in the United States, and comparative results were obtained in the mentioned marketing management measures. The results prove that market segmentation, market targeting, differentiation, positioning, price, place and promotion elements differ between shipyards of the U.S. and Turkey. It is also concluded that shipyards with more developed marketing organizations approach market orientation determinants of modern marketing effectively, and that a competent approach to market orientation measures strengthens the competitive position and success in customer choices.
Condition-Based Maintenance—A Tool for Improving Productivity in Shipyards
Authors: Ross Jonathan M.
Published: January 2021

The National Shipbuilding Research Program's 2001 Strategic Investment Plan cites "reduce overhead costs associated with maintenance" as a key issue in responding to difficult Facilities and Tooling challenges. The Plan goes on to state that balancing the proper amount of preventative maintenance with reducing overhead costs is a constant struggle and recommends that studies be performed to help determine the impact of equipment downtime. However, a clear trend is already emerging that points to condition-based maintenance (CBM) as an important means to help reduce shipyard maintenance costs. In fact, CBM is being successfully applied in industries ranging from open pit coal mining to nuclear power production, as well as on board naval and commercial ships and oil production facilities. In some instances, CBM has been providing substantial equipment and facilities cost savings for over twenty years. U.S. shipyards are already implementing important aspects of CBM and have the opportunity to further this systems-oriented trend as a way to continue to trim costs through enhanced technology, improved processes, and cross boundary interactions between management, maintenance personnel, and production staff.
Implementation of an Improved Outfit Process Model
Authors: Altic Brian E. , Burns Richard M. , Fontaine B. J. , Scott Ian , Silveira John L. , Softley John
Published: January 2021

National Steel and Shipbuilding Company (NASSCO) has successfully planned and executed several projects directed toward increasing their competitiveness in the shipbuilding marketplace. Among these has been the common goal of implementing outfit design and manufacturing processes that will result in performance improvements. Previous outfit projects, such as MARITECH Ship Factory Transformation Project and Parametric Standard Machinery Units, have focused on key improvement strategies in targeted shipbuilding process areas with positive results. This paper describes the pilot implementation project that was undertaken to establish an onblock and on-board design and construction process. This is a process by which interim product family components are competitively assembled and installed for new construction shipbuilding. Most of the projects completed by NASSCO thus far have been broadly based, focusing on overall development of standard products and processes. This project placed a further focus on these, along with manufacturing processes, workstation definition, production information, and multiskilled tradespeople. These combined elements have been seen as the logical next steps toward process competitiveness.
Discussion of “Methodology Used to Calculate Naval Compensated Gross Tonnage Factors” by John Craggs, Damien Bloor, Brian Tanner, and Hamish Bullen
Authors: Lamb Thomas
Published: January 2021

I have been working in this area for the past 9 years. As the Craggs et al paper states, I have presented a number of papers on the subject (Lamb 1998, Lamb 2002, Lamb & Hellesoy 2001, Lamb & Knowles 1999, Storch et al 1995). The Craggs et al paper is the second publication I have seen by others about naval ship compensation coefficients. The other was Brian Tanner's paper presented at the Royal Institution of Naval Architects meeting last year describing how the British Ministry of Defence with First Marine International has been working on this matter for the past 2 years.
Reply to Thomas Lamb Discussion of "Methodology Used to Calculate Naval Compensated Gross Tonnage Factors"
Authors: Craggs John , Bloor Damien , Tanner Brian , Bullen Hamish
Published: January 2021

We would like to thank Tom Lamb for his further contribution to the debate on compensation coefficients for naval vessels. Our response to some of the issues and comments he has raised are as follows.
Shipbuilding Productivity Rates of Change in East Asia
Authors: Koenig Philip C. , Narita Hitoshi , Baba Koichi
Published: January 2021

Overseas shipyards routinely deliver oceangoing merchant vessels at prices that are a fraction of what the best-performing U.S. shipbuilders are able to quote. Despite efforts to attain commercial competitiveness, it is not clear that the performance gap between the U.S. industry and international shipbuilders is closing. In fact, at least in the case of the U.S. industry compared with the global industry leaders (Japan and South Korea), it is possible that the productivity gap may be widening as a result of the process of relentless performance improvement that has been under way for years in those two nations. In this working paper, we provide a quantitative indication of the rates of change in productivity in Japanese and South Korean shipyards during recent decades. Accompanying this are some comments on the environment that has produced these productivity improvement rates. With this paper, we hope to contribute to an understanding of the dynamics of international competition in the merchant shipbuilding industry.
STEP for Shipbuilding: A Solution for Product Model Data Exchange
Authors: Benthall L. , Briggs T. , Downie B. , Gischner B. , Kassel B. , Wood R.
Published: January 2021

An international standard (ISO 10303) has been created to facilitate the exchange of product models between diverse computer-aided design (CAD) systems. Informally known as STEP (standard for the exchange of product model data), this specification has been under development since the mid 1980s, and parts of it were approved as international standards beginning in 1994. Efforts to expand STEP to meet the needs of the shipbuilding industry have been in work for many years and are nearing completion. By early 2003, it is expected that four application protocols to facilitate the transfer of information relating to ship structures, piping, and heating, ventilation, and air-conditioning will have been approved as international standards and become part of the overall STEP standard. This article discusses the successful efforts to expand STEP to meet the needs of the shipbuilding industry, as well as outlining the various implementation and testing projects that have been undertaken to ensure the validity and success of these new standards.
Development of a System for Prediction and Visualization of Welding Deformations of Stiffened Plates
Authors: Seo Seung Il , Noh Jae Gyu
Published: January 2021

To prevent problems caused by welding deformation, preparation in the design stage is necessary. Countermeasures in the design stage are also the most cost-effective method. In this study, to give designers information on the welding deformations, a system to calculate and visualize the welding deformations is developed. The model to visualize the deformation is the stiffened plate common in the ship structure. To increase computational efficiency, theoretical solutions to calculate the deformations of plate and stiffener are used instead of numerical analysis. Also, to ensure accuracy, experiments to estimate bending moments causing the welding deformations are performed. A computer program written with Visual C++ is developed for interactive data input, calculation of welding deformations, and display of deformed shape. Designers can change the design in the early stage after checking the deformed shape with this system.
After 25 Years, Where Are We?
Authors: Sizemore John M.
Published: January 2021

In every human endeavor, it is wise to periodically disengage for a moment from the details of the task at hand, and from a wider perspective consider the whole. Just so, we propose a different sort of overview of robotics implementation in U.S. shipbuilding. Rather than produce yet another travelogue through the various red robots, the orange ones, the yellow ones, the green and the blue, we need to look at our present position compared with the whole journey. We also need to note some signs along the road.
Automated Generation of Weld Path Trajectories
Authors: Ames Arlo L. , Hinman-Sweeney Elaine M. , Sizemore John M.
Published: January 2021

AUTOmated GENeration of Control Programs for Robotic Welding of Ship Structure (AUTOGEN) is software that automates the planning and compiling of control programs for robotic welding of ship structure. The software works by evaluating computer representations of the ship design and the manufacturing plan. Based on this evaluation, AUTOGEN internally identifies and appropriately characterizes each weld. Then it constructs the robot motions necessary to accomplish the welds and determines for each the correct assignment of process control values. AUTOGEN generates these robot control programs completely without manual intervention or edits except to correct wrong or missing input data. Most ship structure assemblies are unique or at best manufactured only a few times. Accordingly, the high cost inherent in all previous methods of preparing complex control programs has made robot welding of ship structures economically unattractive to the U.S. shipbuilding industry. AUTOGEN eliminates the cost of creating robot control programs. With programming costs eliminated, capitalization of robots to weld ship structures becomes economically viable. Robot welding of ship structures will result in reduced ship costs, uniform product quality, and enhanced worker safety. Sandia National Laboratories and Northrop Grumman Ship Systems worked with the National Shipbuilding Research Program to develop a means of automated path and process generation for robotic welding. This effort resulted in the AUTOGEN program, which has successfully demonstrated automated path generation and robot control. Although the current implementation of AUTOGEN is optimized for welding applications, the path and process planning capability has applicability to a number of industrial applications, including painting, riveting, and adhesive delivery.
Semiadaptive Synergic-Fill Welding Tractor for Ship Unit Erection
Authors: Harwig D. , Zheng B. , Reichert C. , Huang T. , Joseph A. , Baughman B.
Published: January 2021

At most U.S. shipyards, the bottleneck for improving productivity is unit fabrication and ship erection. Fit-up during unit, super-unit, and ship erection is difficult, resulting in variable gap and mismatch, which promote defects and repair. A semiadaptive synergic-fill welding tractor was developed for improving the productivity of seam welds during erection. The tractor has many features that advanced robots have but is simple to use because it relies on operator pass planning instead of robotic path preplanning. The "synergic-fill" welding concept was developed to maximize the deployment of robust welding procedures. This was a new control process for making changes to weld bead size during fabrication using one knob. The synergic-fill welding concept was developed for flux-cored arc welding of DH36 steels for horizontal erection seams. These seams have a range of gap and require a range of weld bead sizes to uniformly fill the weld seam. Welding parameters that ensured a constant base metal dilution were optimized and programmed into the synergic control. In addition, the welding tractor was developed with a laser seam tracking vision sensor and adaptive-fill control. The new control allows the operator to intervene during welding and toggle the adaptive features on and off. A special four-axis tractor was developed to permit cross-seam and torch height control for seam tracking while oscillating the welding torch. The laser sensor was integrated with modular fixturing to permit welding with either angled or transverse oscillation. The adaptive control algorithm varied the weld size from the synergic-fill starting point that was selected by the operator. The weld bead was made proportionally larger or smaller as the joint width became larger or smaller within the process capability range. A semiadaptive control algorithm was developed for the horizontal welding application. The process was not completely automatic. The operator, who plans the position of the welding torch for each weld bead in a layer, applies the process. Further, he made weld bead size decisions based on the joint width. Once the welding system was started, it tracked the bead location as the groove width changed, controlled the torch height, and can adaptively vary bead size relative to joint width. This flexible technology will minimize the susceptibility to defects during erection welding.
Time and Cost Effects of the Coating Process
Authors: Kattan Raouf , Blakey Judie , Panosky Mark , DeVinney Scott
Published: January 2021

This paper will review both the preproduction and production factors that influence the shipbuilding process in shipyards. It will identify those areas where shipyards commonly have problems in managing the coating process and describe some of the opportunities they have for improvement of these activities. Historically, the painting process has been seen at best as an inconvenience to the real task of building ships from steel and outfit. The coating process is often afforded little weight in the planning process of building a ship. Most paint managers and their personnel often have a very clear idea of the problems they encounter during the coating process, but often their communication is not treated with any weight during the planning of the next vessel. Coating selection is all too often more a function of good selling and low price, with a guarantee of quality, of course, rather than a systematic analysis of the yard's needs to match process and program requirements. It is important that the coating process, which accounts for an increasing percentage of man-hours and rework, should be given a clear voice at the preproduction stage of the vessel to prevent unnecessary problems in production.
Remotely Operated Vehicle Use Within Shipyards
Authors: Dituri Joseph
Published: January 2021

Ships and repair facilities have a great deal of underwater work. Often these facilities and ships do not know the extent of required work because it is underwater. They may not even know whether underwater work is required. Certain situations may also require a diver to perform "security" swims to assess danger. Currently, in order to have a diver visualize a potential problem, shipyards and repair activities are required to generate 2 to 4 hours of paperwork. The ship is also required to tag out at least sonar, screw, and active suctions and discharges, which can take 3 to 4 hours. Couple these delays with a delicately balanced dive schedule for overworked divers and the "customer" could wait 48 hours to find out if they need to work underwater. A video class remotely operated vehicle (ROV) could be employed to decrease customer wait time. These ROVs can be deployed from a pier or ship with 110 v AC and perform most of these "quick look" jobs. The ROV requires minimal tag out and does not require any task group instruction or work package. An added feature of the ROV is the ability to take digital footage for review by experts who can provide oversight without actually being on site.
Improvements of Flux-Copper Backing Welding Quality
Authors: Okumoto Yasuhisa , Baba Osamu
Published: January 2021

Flux-copper backing process welding is a high-speed, one-sided automatic welding process that is a type of submerged arc welding. Although it has been widely applied for the joining of flat skin plates in shipbuilding, a couple of problems with this process still exist: longitudinal cracks occur in the vicinity of the end point, and transverse cracks occur on the back surface. The data in this study were collected in the production site of Ishikawajima-Harima Heavy Industries Company Ltd, Kure Shipyard. The causes of failures were examined, and countermeasures were studied. Concerning the longitudinal cracks, the behavior of plate deformation during welding was investigated, and the end tab plates and the tack welding method were improved in order to reduce the rapidly increased transverse distortion of the joining plates. Concerning the transverse cracks, the dispersal figure of the reverse flux to form the backing bead was observed, the relation between the flux spraying height and the welding quality was investigated, and the height was standardized. In addition, welding heat input was also examined and regulated to avoid the transverse cracks.
Study of the Literature to Assess the Future of India’s Shipbuilding Industry
Authors: Bunch Howard M.
Published: January 2021

Several industrial sectors within India are at the cutting edge of technology and world class in their sector capabilities. Sadly, the shipbuilding industry is not one of these sectors at the moment. It is uncompetitive in cost and in delivery time, and most of the major shipyards must be heavily subsidized to remain open. The reason for an investigation of the Indian shipbuilding industry would be to develop a better understanding of why it is so uncompetitive and to project its future direction.
Theoretical Approach to Profit-Maximizing Design Margin Selection
Authors: Meyer Jan , Whitcomb Clifford A.
Published: January 2021

Design margins on speed or weight (to name just two) are used to ensure performance of a ship design given uncertainties in the design models or the production process. Although facing a high probability of meeting all performance requirements is very desirable, this assurance also comes at a price. When designers have the choice to set multiple margins, which all have some interacting effect on the vessel's performance, the problem of choosing a profit-optimal margin combination becomes nontrivial. This paper outlines a theoretical approach to margin selection using Pareto frontiers and summarizes Whitcomb and Meyer (2000) in which this theory is applied using numerical methods.
Naval Compensated Gross Tonnage Coefficients and Shipyard Learning
Authors: Craggs John , Bloor Damien , Bullen Hamish , Tanner Brian
Published: January 2021

In 2001 the UK Ministry of Defence and First Marine International embarked on a study to determine compensated gross tonnage (CGT) coefficients for naval vessels. This paper is a summary of the latest work, which has established trends of CGT coefficient by ship type and determined the correlation between the proportion of outfit, average compartment size, and the coefficient. A method of separating ship from organizational learning to determine a shipyard's core productivity and the first of class performance drop-off, which is related to the use of best practice, is also proposed. This has allowed the core productivity and cost performance of shipyards in some of the principal naval shipbuilding nations to be compared. Lower compensation coefficients imply lower work content per gross ton. The ship designer and the customer both have an influence on the work content and hence the compensation coefficient. The study has indicated that there is a wide variation in the work content associated with the acquisition practices of different customers. The methodology used to calculate the CGT coefficient is set out in a previous paper by the same authors, "Methodology used to calculate naval CGT factors," which was presented at the 2002 Ship Production Symposium in Boston, Massachusetts. The study has continued to receive the close cooperation and support of some leading UK and continental European commercial and naval shipbuilders who have provided information and validated the findings.
Laser-Fabricated Structural Shapes for New Construction, Overhaul, and Repair
Authors: Blomquist Paul A. , Orozco Nelson , Patch David
Published: January 2021

Increasingly, fabricated structural shapes are replacing hot-rolled shapes in new vessel construction. Designed for high structural efficiency, these custom shapes can be made from materials not available in hot-rolled form. Although most production is carried out at present using conventional welding and cutting processes, high-power industrial laser processes are being developed. A recent project, titled Laser Fabricated Shapes for Naval Applications, has started the task of developing a laser-based comprehensive system for the cutting and welding of structural shapes, as well as qualifying the laser welding process and the product of the process. It is expected that the use of laser cutting and welding will allow dramatic improvements in accuracy, quality, and productivity. While the greatest application will be in the new construction arena, custom-fabricated shapes can have beneficial impact on overhaul and ship alteration projects. Aspects of system integration, product design, production, inspection, and cost issues are explored.
Preconstruction Priming: A Cost-Effective Solution to Painting Ship Ballast Tanks
Authors: Fultz Benjamin S.
Published: January 2021

In both Asia and Europe, preconstruction primers (PCP) are routinely used and retained as an integral part of the coating system. The retention of PCPs can significantly reduce the painting cost of new ship builds. The cost of protective coatings (paint) application in new construction can be upwards of 10% of the total ship cost. The process is labor intensive; therefore, it is logical that most savings are derived from reducing labor steps. Retaining PCP eliminates the necessity of a second blast operation, thus reducing labor cost and hazardous waste disposal cost. This paper addresses the feasibility of retaining PCP as the permanent primer for protective coatings systems applied in such high-performance areas as exterior hull, underwater bottom, and most importantly ballast tanks. Should the retention of PCP be proven as a viable option, the process of coatings application can be improved resulting in significant cost savings. Spending of new construction dollars will not be necessary to remove the PCP prior to the application of high-performance coating and lining systems. The test program discussed in this paper was based on work sponsored by the National Shipbuilding Research Program Advanced Shipbuilding Enterprise (NSRPAES) and the US Navy. The Surface Preparation and Coatings Panel, SP3, of the Ship Production Committee formulated the program and provided direction during the course of the work. The Ship Production Committee is one of SNAME's nine technical and research committees, and consists of the chairman supported by the ship production major initiative panel chairs and selected others.
A Comprehensive Line-Heating Algorithm for Automatic Formation of Curved Shell Plates
Authors: Shin Jong Gye , Ryu Cheol Ho , Nam Jong-Ho
Published: January 2021

Line heating is a method used in the production of highly curved plates in the shipbuilding process. Line-heating process is generally regarded as one of the outdated technologies in the modernized and automated shipbuilding process. No piece of information in the line-heating process is either quantified or computerized. These drawbacks have restricted the automation of line-heating process and, as a result, the entire shipbuilding process. Therefore, a new automated line-heating process based on quantitative and computerized heating information has been sought. This paper describes a comprehensive algorithm for an automated line-heating process. By focusing on the overview of the complete algorithm, this paper integrates the components of the algorithm that have been separately published by the authors. The overall procedure of the automated line-heating process, including shell piece modeling, shell development, cylindrical approximation for curved plates, computation of heating information, and measurement and surface comparison, is discussed. The comprehensive algorithm is adjustable for different heat sources and measuring methods, without incurring fundamental changes in algorithm. The proposed line-heating algorithm has been implemented and transferred to some shipyards for customized applications. Simulation of automated line-heating facility
A Modeling and Simulation of Production Process in Subassembly Lines at a Shipyard
Authors: Shin Jong Gye , Lee Kwang Kook , Woo Jong Hun , Kim Won Don , Lee Jang Hyun , Kim Se Hwan , Park Ju Yong , Yim Hyunjune
Published: January 2021

In order to simulate material flow in a subassembly line at a shipyard, the product, process, and resources are modeled for the subassembly process. The subassembly line is selected from a large shipyard and consists of several subprocesses, such as base joining, piece alignment, tack welding, and robot welding processes. The analysis and modeling procedure were carried out using the Unified Modeling Language (UML), an object-oriented modeling methodology, and Integration Definition (IDEF), a functional modeling tool. Initially, the characteristics of the shop resources were analyzed using the shipyard data and the layout of the subassembly line was designed with the resources. A production process was then modeled using the resources and the layout. The production process modeling of the subassembly lines was performed using the discrete event simulation method. Using the constructed resource and process model, the productivity and efficiency of the line were investigated. Variations in the resource performance, such as a new welding robot and the number of workers, were examined to simulate changes in productivity. It can be seen that bottlenecks occur in different places according to the nature of new resources. The proposed model is viewed three-dimensionally in a virtual environment so that space allocations for the resources and interferences between objects can be easily investigated.
Integrated Multiple Attributive Decision Support System for Producibility Evaluation in Ship Design
Authors: Turan Osman , Alkaner Selim , Ölçer Aykut i.
Published: January 2021

Ship design today can be viewed as an ad hoc process. It must be considered in the context of integration with other design development activities, such as production, costing, quality control, and so forth. Otherwise, it is possible for the designer to design a ship that is difficult to produce, requires high material or labor cost, or contains some design flaws that the production engineers have to correct or send back for redesigning before production can be done. Any adjustment required after the design stage will result in a penalty of extra time or cost. Deficiencies in the design of a ship will influence the succeeding stages of production. In addition to designing a ship that fulfills producibility requirements, it is also desirable to design a ship that satisfies risk, performance, cost, and customer requirements criteria. More recently, environmental concerns, safety, passenger comfort, and life-cycle issues are becoming essential parts of the current shipbuilding industry. Therefore, "design for X paradigm" should also be considered during the ship design stages. An integrated multiple attributive decision support system for producibility evaluation in ship design (PRODEVIS) is developed to use by industry and researchers in evaluating the producibility of competing ship designs and design features during the early stages of ship design by taking into account cost, performance, risk, and "design for X paradigm" attributes. This developed approach is a fuzzy multiple attributive group decision-making methodology where feasible design alternatives are conducted by a ship production simulation technique. In this approach, an attribute-based aggregation technique for a heterogeneous group of experts is employed and used for dealing with fuzzy opinion aggregation for the subjective attributes of the ship design evaluation problem. The developed methodology is illustrated with a case study.
Shipbuilding Facility Planning and Design: A Product-Centric Approach
Authors: Traband Mark T. , Finke Daniel A. , Hadfield Joe , Santos Robert
Published: January 2021

Much of the emphasis on facility design for shipbuilding has focused on improved processes and material flow, whether in the panel lines, block assembly, unit erection, or dry-dock operations. However, the analysis performed during planning for a new structural fabrication facility at the Quonset Point site of Electric Boat Corporation indicates that excessive, non-value-added time is spent in material movement, job setup, and locating resources (crane, service material, inspection equipment, etc.). Although these problems are evident in many shipbuilding operations, they are especially problematic in submarine fabrication, where the structural components are high value added, production volumes are low, movement of in-process products is costly, and inspection requirements are stringent. In planning for the new facility for structural fabrication, Electric Boat is using a product-centric approach. The goal is to define manageable families of products and design a facility to ensure that all of the resources required by these products are readily available during their fabrication. In this paper the authors first present the methodology used to develop process models for the product families at Electric Boat. These process models provide critical input to the design team determining space, equipment, and manpower requirements for the new facility. The authors then discuss the design process for a new facility focused on the production of structural product families for submarines.
Reducing Coatings Rework in New Construction, Overhaul, and Ship Repair
Authors: Dillon Jim
Published: January 2021

Coatings application is one of the top construction costs in the shipbuilding industry. Rework typically represents the greater part of the total cost of coatings application. A relational database is a powerful tool to manage rework. This paper will present a coatings database that was developed and implemented at Northrop Grumman Newport News.
Collaborative Engineering in the Shipbuilding Environment
Authors: Abal Diego , Alonso Fernando , Freire David
Published: January 2021

The shipbuilding market is more and more under pressure to reduce construction schedules and manufacturing costs. The amount of engineering work has drastically increased due to the general acceptance of the "design for production" strategy. Furthermore, shipowners are demanding very complex ships that require larger engineering capacity. All these factors lead to an increase in the design capacity and the number of man-hours involved in engineering activity. On the other hand, the tendency of most shipyards is to reduce the work force of their engineering departments. This fact negatively affects the shipbuilding market. The large shipyards seek to increase their design capacity by subcontracting a substantial part of the engineering, particularly the detail engineering, to several design agents. Therefore, the engineering work is performed by a set of design offices working simultaneously in different locations and sharing common information. Further, different agents (shipyards, engineering offices, classification societies, equipment suppliers, etc.) participate in the shipbuilding process. These agents require close coordination. Thus, the use of collaborative engineering tools is a very important factor in coping with these demands of the market. Recent improvements in telematics, particularly the availability of cost-effective digital communication services, have made it possible to perform efficient collaborative engineering from different locations.