Ship Maintenance Research Articles

An integrated domain analysis approach for teleoperated systems

Teleoperated systems for ship hull maintenance (TOS) are robotic systems for ship maintenance tasks, such as cleaning or painting a ship’s hull. The product line paradigm has recently been applied to TOS, and a TOS reference architecture has thus been designed. However, TOS requirements specifications have not been developed in any rigorous way with reuse in mind. We therefore believe that an opportunity exists to increase the abstraction level at which stakeholders can reason about this product line. This paper reports an experience in which this TOS domain was analyzed, including the lessons learned in the construction and use of the TOS domain model. The experience is based on the application of extensions of well-known domain analysis techniques, together with the use of quality attribute templates traced to a feature model to deal with non-functional issues. A qualitative research method (action research) was used to carry out the experience.

Geometric Properties of Shipbuilding Structural Profiles in Probabilistic Terms to Be Used in Elastic Bending Strength Calculations

As a result of the corrosion wear, which is treated as a random phenomenon, the geometric properties of shipbuilding structural profiles (bulb plates, inverted angles/L-profiles, channels, symmetric or asymmetric Fundia T-bulbs, symmetric or asymmetric builtup T-bars, and flat bars) are presented as random functions of the ship’s age. Evenly distributed corrosion wear along each cross section’s dimension is assumed (different corrosion wear may be considered along each of the cross section’s dimensions). Taylor series approximation method is applied to present the geometric properties used for assessment of elastic bending strength in probabilistic terms. The proposed method allows for comparison between different structural profiles using as a criterion the probability that these structural profiles will meet given Renewal Criteria requirements throughout the ship’s lifetime. Based on its calculation, one can select the most reliable structural profile. The method also allows for better planning of ship repair and maintenance work. The method can also be used to reveal the already implemented risk in the existing empirical Renewal Criteria through analysis of the structural components, their location, ship’s type and size. This is one of the first steps towards development of Reliability-based Rules for building and classing of steel ships.

Virtual Shop Clusters: A New Layout Concept for a Ship Repair and Maintenance Facility

AbstractOrganic ship maintenance facilities and depots of the Navy are mostly organized as trade‐specific shops rather than by product (or process) families. For example, welders are in the weld shop, machinists are in the machine shop, pipe‐fitters are in the pipe shop, etc. There is a belief that this guild‐type organizational structure is what enables a repair facility to do almost anything, albeit at the cost of moving product all over the “factory.” This skill‐based organizational structure is identical to the functional (or department) layout that is preferred by most jobshops in the commercial manufacturing sectors. But, any company that has successfully implemented Lean Thinking has almost always replaced a Functional (or Process Village) Layout by a Cellular Layout. At the Navy's Southeast Regional Maintenance Center (SERMC), a typical repair job must visit multiple shops that pass work back and forth between them. For example, a pipe job may be sent by the pipe shop to the machine shop for re‐threading, then routed to the weld shop where it is welded to a frame, after which the welded sub‐assembly returns to the pipe shop for inspection and final assembly. Thereby, significant delays and operational wastes occur because people have to walk between the shops, discuss matters at daily production meetings, and e‐mail/phone each other to make sure that their schedules match. If activities are not completed as per schedule, the jobs get further delayed because they queue at the shops, waiting to be served. This lack of detailed (and accurate) planning and scheduling, combined with poor schedule visibility and shop floor control, is the curse of the Functional Layout that currently exists at SERMC. This paper will describe a pilot project to assess the feasibility of cellular manufacturing at SERMC. The fundamental hypothesis that was tested is that even in a repair and maintenance facility there could exist several families of repair jobs where jobs grouped into a family require similar combinations of processes, equipment, materials, etc. that can be provided by a small group of shops. In fact, several potential families of repair jobs, and the appropriate cluster of shops for each family of repair jobs, were identified using the Production Flow Analysis and Simplification Toolkit (PFAST) software. Based on these results, it was decided to implement a shop cluster (or focused factory, or repair cell) to complete any repair jobs done by the dive shop. It was recommended that the dive shop be merged with a few other shops, and be provided the necessary tools, cross‐trained personnel, equipment, and other support systems to become an autonomous multi‐function shop. Simulation using the SimCAD software from CreateAsoft Inc. (http://www.createasof.com) was used to verify the results expected from making the proposed changes. The primary analysis was intended to evaluate the benefits of implementing a focused factory in the dive shop. The secondary analysis was intended to evaluate the advantages of implementing a virtual shop cluster (or focused factory, or repair cell) in any ship repair facility like SERMC. The simulation results showed that implementing either physical cells or virtual cells based on the different families of repair jobs identified by PFAST could improve job turnaround times at any Navy ship repair facility like SERMC. Both the types of delays as well as the time values of these delays differed significantly across the existing and alternative shop configurations that were proposed.

Tribological study of elastomeric bearings for marine propeller shaft system

Elastomeric compounds, due to their favourable properties like sufficient hardness, toughness and natural resistance to abrasion and corrosion, are commonly used as bearing material for propeller shaft system of Indian Coast Guard Ships. Recently unequal and non-uniform wear of these bearings has resulted in unscheduled lay off of the Coast Guard Ships. To solve this problem of bearing wear, a mixed lubrication analysis of sea-water lubricated journal bearing has been attempted in the present study. A computer code was written to estimate lubricating film thickness for a given set of load and speed condition, and to predict the lubrication regime for the specified surface roughness parameters. To validate the theoretical analysis performed in the present study, the results obtained from the computer simulation have been compared with the established studies on the water lubricated bearing. To understand the uneven wear of marine bearings, actual geometric clearances of new and worn out bearings recorded by the ship maintenance team, and the operational data (load, speed and operating hours), obtained from the log books of ICGS Sangram (AOPV) of Indian Coast Guard, are listed in the present paper. The dynamic viscosity of sea water, surface roughness of propeller shaft and bearings, and particulate contamination has been measured. Finally, the suggestions have been enlisted for proper operation of shaft-bearing system so as to maintain the wear within the permissible limits during ship's operational cycle.

액체운반용 선박을 위한 진단기능을 가지는 스마트 카고 센서 개발

본 연구에서는 화물 운송에 사용되는 운반선 중 하나인 액체운반선을 유지 관리하기위한 통합 자동화 시스템인 스마트 카고 탱커 진단 모니터링 시스템을 개발하였다. 본 연구를 통해 선박의 특수성을 고려한 선박용 능동형 스마트 센서 개발 기술을 확보하고 고신뢰성 및 내환경성을 가진 기자재를 개발하고자 하였다. 본 연구에서 제안한 카고 모니터링 시스템은 증기 압력 모니터링 부분, 카고 수위 모니터링 부분, 수위 초과 모니터링 부분, 가스 모니터링 부분, 탱크 온도 모니터링 부분으로 구성된다. 본 시스템은 각 단위 시스템으로부터 전송되는 신호의 신뢰성, 적절성 그리고 센서 자체의 이상 유무를 스스로 진단한다. 최종적으로 각 시스템의 고장진단 및 예측을 통하여 운항중인 선박에서 효과적으로 화물을 유지 관리 할 수 있도록 하는 포괄적인 통제 모니터링 시스템 개발을 목적으로 한다. This paper is to develop a monitoring system with diagnosis for smart cargo sensors that is for management and maintenance of the liquid cargo ships. The main goal of the system is to achieve the total automation system of the cargo sensor. By this study, the active smart sensor for the liquid cargo ships is designed and developed that guarantees high-confidence, stability, and durability. The proposed system consists of a monitoring part of the steam pressure, high-level monitoring, over flowing monitoring, gas monitoring, and tank temperature monitoring. The signals transferred from each unit system are used for sensor diagnosis based on confidence and accuracy. Finally, in this study, the total supervisory monitoring system is developed to maintain and manage the cargo effectively based on fault diagnosis and prognosis of the each sensor system.

A facility maintenance scheduling model incorporating opportunity and inflationary costs

This paper deals with facility maintenance scheduling model which incorporates opportunity and inflationary costs. A case study pertaining to a shipping firm has been defined as transportation models of minimising Maintenance Cost (MC), Maintenance-Inflation Cost (MIC), Maintenance-Opportunity Cost (MOC) and combined Maintenance-Opportunity-Inflation Cost (MOIC). The optimal schedules indicating the ship maintenance, idle and operation periods were deduced for each approach. For all the samples, the costs of the first model were significantly (p < 0.05) different from that of the other three models. To reduce cost and delays, decisions for scheduling maintenance of a fleet of ships would be better informed if based on maintenance and opportunity cost indices in both inflationary and non-inflationary conditions.

Fuzzy axiomatic design-based performance evaluation model for docking facilities in shipbuilding industry: The case of Turkish shipyards

The closest relationships between ship management companies and shipyards begin with the initial design process of new ships and they continue during the life cycle of operating ships. Periodic docking facilities which can be recognized as the biggest logistical issue in the content of ship maintenance program are the critical processes from the viewpoint of ship owners. Hence, this process should be well-planned and organized to satisfy the various expectations such as quality of service, capacity limitations, and geographical advantages, by taking cost and time constraints into account. Hence, the selection problem with respect to several criteria to find the most suitable shipyards is getting more important for ship management companies. This paper investigates a systematic evaluation model on docking facilities of shipyards to provide a decision aid for technical ship managers and to perform this responsibility in an efficient manner. Multiple criteria fuzzy axiomatic design (FAD) approach is used for selection among shipyards since FAD lets us define the design interval of each criterion. The original contributions of the paper are seemed in both enhancing the theoretical frame of FAD in terms of managing group consensus and performing an application to a real case in maritime industry.

Polska przedsiębiorczość w gospodarce morskiej problemy i szanse na sukces

The goal of this text is to focus on the situation of companies in Polish naval industry and to define the condition of their activity, entrepreneurship, and their attitudes toward innovations. This discussion is a search for the answer to the question: Is it possible to see any signs of entrepreneurship in the organizations and the activities in this sector? Authors emphasize the naval companies mainly organize the sea shipping, and their business is usually complex, it needs a lot of capital, and there is fierce global competition. With the transformation of political system and Polish economical reform in this industry, it was not propitious time to growth for these companies. Both the fleet, and the shipbuilding, and their bases started to deteriorate. According to the authors, naval industry was at the disadvantage because public opinion assumed that the sea was less important to the national economy, so the fleet and shipbuilding were not economically justifiable and naval industry was the burden that slowed down the development of national economy. Fortunately this time is over, because the good trends appeared toward a growth in the naval trade, and because of boom in the sea transport, in shipbuilding and in ship maintenance.

Polska przedsiębiorczość w gospodarce morskiej problemy i szanse na sukces

The goal of this text is to focus on the situation of companies in Polish naval industry and to define the condition of their activity, entrepreneurship, and their attitudes toward innovations. This discussion is a search for the answer to the question: Is it possible to see any signs of entrepreneurship in the organizations and the activities in this sector? Authors emphasize the naval companies mainly organize the sea shipping, and their business is usually complex, it needs a lot of capital, and there is fierce global competition. With the transformation of political system and Polish economical reform in this industry, it was not propitious time to growth for these companies. Both the fleet, and the shipbuilding, and their bases started to deteriorate. According to the authors, naval industry was at the disadvantage because public opinion assumed that the sea was less important to the national economy, so the fleet and shipbuilding were not economically justifiable and naval industry was the burden that slowed down the development of national economy. Fortunately this time is over, because the good trends appeared toward a growth in the naval trade, and because of boom in the sea transport, in shipbuilding and in ship maintenance.

Obtaining Optimum Composition of Multinational Crew Based on Ship Maintenance Cost Using Artificial Neural Network

Obtaining Optimum Composition of Multinational Crew Based on Ship Maintenance Cost Using Artificial Neural Network

A Cross Sectional Analysis of Ship Maintenance Expenses

This paper introduces an econometric model to explain the determinants of expenditure in ship maintenance and repair. The data refer to 112 vessels of different types that operated in 1999 and were collected from ten Greek ship owning and management companies. On the methodological plain the best functional form is obtained when estimating a semi log-linear model. As expected from theory, the empirical results show that maintenance expenditure is positively related to utilization, age, and size. In addition, the effect of age is found to be stronger on vessels younger than 20 years. This may be due to the fact that vessels less than 20 years old can be sold more easily in the second-hand market, whereas older vessels have a shorter lifetime and are also constrained by safety regulations. Therefore, ship owners are more reluctant to spend more once the vessel passes its 4th and especially its 5th special survey. To trace the effect of company policies we included in the model company dummy variables. We found that such effects are present particularly when stores expenses are estimated separately. In turn, this suggested that company policies have still some control on maintenance expenses. Another result is that the elasticities of maintenance expenses with respect to utilization, age, and size at least in 1999 were uniformly less than one, thus revealing the existence of significant economies of scale. And still another result is that the type of ship, the flag, the classification and even the yard where maintenance takes place are significant determinants of the respective outlays.

Pulsed Semiconductor Diode Lasers as an Environmentally Efficient and Affordable Decoating Method for Shipbuilding and Ship Maintenance

Coating removal during new ship construction or ship maintenance has traditionally posed environmental and production issues. Coating removal results in a large amount of waste, and other trades cannot work in or near areas where coating removal operations are going on. Hydroblasting, an environmentally friendly method, has significantly decreased in recent years; it cannot be used on interior compartments. The dilemma has been to find a surface-preparation method that is effective yet environmentally acceptable and one that can work on the outer hull as well as on the inside compartments. Further, a method is needed to remove coatings from the new "soft" substrates. Laser devolved over the years from expensive CO2 and Nd:YAG lasers to the recent innovation of using affordable semiconductor diode lasers for coatings removal. Semiconductor diode laser decoating is a nonintrusive, nonkinetic energy process that has successfully removed coatings from a variety of substrates, such as composites, fiberglass, metal, and plastics, in a controlled manner, layer by layer, without damage, leaving the surface ready for immediate repainting. The process is very rapid (up to 400 sq ft per hour), 6 to 10 times faster on average than the present manual hand-sanding methods, and involves a minimal increase in temperature, because the energy is mostly absorbed and utilized in coating decomposition (i.e., instant pyrolization and evaporation). The only waste associated with this process is the ablated coating that is vacuumed from the surface and captured in particle filters, approximately one-third of the amount of coating originally on the surface. Diode lasers are compact, durable for shipbuilding and repair industry use, and present low operating costs. Due to delays in receiving test panels from Navy and commercial ship sources, this paper will highlight data from tests of removal of coatings similar to military epoxy/polyurethane coatings from thin-skin metallic, composite, and fiberglass structures, radome material, and for removing powder coatings. Pulsed high-energy diode laser decoating technology is now commercially and economically available for ship corrosion control and maintenance, can reduce the overall environmental impact of decoating, and can increase productivity of all the ship trades.

アブログデータを利用した就航中船舶の推進性能の分析について

Fuel saving has been becoming more important year by year not only for the cost performance but also for global environmental problems such as CO2 pollution. Appropriate ship maintenance and operation management are one of effective measures for fuel saving. In order to do that, it is necessary to monitor properly the present situation of propulsion performance of ship during her service.The paper introduces a new analyzing method of AB-Log Data from a viewpoint focusing on the relationship between transportation energy performance and AB-Log data, and shows that the new method is useful for monitoring the propulsion performance of actual ship in service.The new method mentioned above indicates that some parameters are useful for AB-Log data analysis, and that, among them, the parameter Ps/W⋅Vs3 is most informative. So, paying attention to the change of these parameters, AB-Log data analysis of 6 vessels, 2 of bulk careers, 2 of container ships and 2 of crude-oil tankers are carried out. According to the method, the analysis results show that it is possible to monitor quantitatively propulsion performance and the influence of sea conditions.

Deference and Defiance: The Changing Nature of Petitioning in British Naval Dockyards

Petitioning as a method of expressing grievances in British history was not peculiar to any particular set of individuals, but was widely used by all sections of society for a range of issues. Given its origins, however, it became ritualized as the means of labour negotiation for workers who were employed by the state, and, by the nineteenth century, by municipal authorities. This was before the institutionalization of trade unions and their recognition as representative agencies for industrial bargaining. One of these groups of workers in the state sector were naval dockyard employees, engaged in the construction, repair, and maintenance of British naval ships. For these workers, the nature of labour relations, and the importance of petitioning as an instrument of negotiation between employees and employer, was both complex and dynamic.

Incidence of Imposex in Thais orbita from Port Phillip Bay (Victoria, Australia), Following 10 Years of Regulation on Use of TBT

Imposex, the phenomenon in which induced male sex characteristics are superimposed on normal females, still occurs widely in the gastropod Thais orbita from Port Phillip Bay, and its incidence is greatest in areas that have high boating and shipping activities. Compared to 1992, both the extent and severity of imposex has reduced. By inference, this means that pollution by tributyltin (TBT) in Port Phillip Bay has decreased and that the bans limiting its use to vessels greater than 25 m in length, in place since 1989, have been effective. However, TBT pollution is still an issue at locations that are adjacent to major ports, such as the Port of Melbourne, where TBT from large ships and ship maintenance activities continues to pollute fish habitats. It is anticipated that the incidence of imposex, and therefore TBT pollution, will continue to decrease in Port Phillip Bay as long as the bans currently in place continue to be observed. If the trends observed in the present study continue, then it is unlikely, with the notable exception of commercial ports, that TBT will pose a threat to the health of fish habitats in Port Phillip Bay.

Contamination of Heavy Metals in Marine Sediment Cores from Victoria Harbour, Hong Kong

The physical characteristics, and concentrations of major and trace metals, in 6 m long sediment cores from five marine locations in Hong Kong have been determined. Core chronologies have been reconciled with dredging, construction, and other anthropogenic activities taking place since 1900. Sedimentation rates varied by an order of magnitude, from the more open harbour environments to enclosed ones. The most critical pollutant in the cores, copper, had normalized enrichment factors between 2.8 and 312 at the five sites, and surficial concentrations >6 g kg −1 in the upper sediment of the Typhoon Shelter sampling site. Whereas the Cu, Ni and Cr pollution largely dates from the post-industrial period, Zn and Pb pollution have a longer history from the construction, maintenance and anchorage of ships. Individual trace metal fluxes varied from one location to another by factors >1500, and the magnitudes in the Typhoon Shelter were generally greater than values at other polluted harbour environments.

Collaboration Management with Software Agents (1st report)

This paper proposes the architecture of collaborative working environment ACE, an agent-based collaboration environment. Users of the system can work in collaboration with others via message, which is managed by Message Management System (MMS) at the center of the system. To give collaboration assistance to users, ACE has three agents in MMS and a personal Desktop Agent for each user : Repository Agent collects messages between users, Address Match Agent gives suggestion of members' list for community organization, and Topic Management Agent logs communication session. Agents in the ACE speak Agent Communication Language to provide appropriate information for their users. A simple prototype of ACE system has been built and evaluated by a scenario of distributed ship maintenance, which requires collaboration of workers on land and at sea.

An ISO 9000 Pilot Project in Navy Ship Repair

AbstractA major goal of the U.S. Navy's Fleet maintenance and modernization strategy is to reduce the cost and time of ship availabilities, while improving the quality of the work performed. A pilot project was commissioned by the Commander Naval Surface Force Atlantic Fleet (COMSUR‐FLANT) to explore the benefits of performing ship maintenance using the quality processes of an ISO 9000 registered private shipyard. This pilot project included a reduced presence, in the area of QA Inspection and Verification (I&amp;V) points, on the part of the local U.S. Navy Supervisor of Shipbuilding, Conversion and Repair (SUP‐SHIP). The benefits and risks of this pilot project were measured against past practices of accomplishing ship maintenance using SUPSHIP on‐site inspection oversight and government quality assurance procedures. The shipyard workload of formal inspections was reduced by 28 percent. The Navy inspection workload was reduced by 59 percent. Quantitative comparisons are made to previous similar maintenance periods. No reduction in work quality was observed. The changed roles of the ship's Port Engineer and the SUPSHIP Project Manager are described. Conclusions and recommendations regarding this project and future ones are made.

An ISO 9000 Pilot Project in Navy Ship Repair

ABSTRACT A major goal of the U.S. Navy's Fleet maintenance and modernization strategy is to reduce the cost and time of ship availabilities, while improving the quality of the work performed. A pilot project was commissioned by the Commander Naval Surface Force Atlantic Fleet (COMSURFLANT) to explore the benefits of performing ship maintenance using the quality processes of an ISO 9000 registered private shipyard. This pilot project included a reduced presence, in the area of QA Inspection and Verification (I&amp;V) points, on the part of the local U.S. Navy Supervisor of Shipbuilding, Conversion and Repair (SUPSHIP). The benefits and risks of this pilot project were measured against past practices of accomplishing ship maintenance using SUPSHIP on‐site inspection oversight and government quality assurance procedures. The shipyard workload of formal inspections was reduced by 28 percent. The Navy inspection workload was reduced by 59 percent. Quantitative comparisons are made to previous similar maintenance periods. No reduction in work quality was observed. The changed roles of the ship's Port Engineer and the SUPSHIP Project Manager are described. Conclusions and recommendations regarding this project and future ones are made.

Ship maintenance scheduling by genetic algorithm and constraint-based reasoning

Ship maintenance scheduling is a process to decide start times of maintenance activities that satisfy all precedence and resource constraints and optimize the ship availability. In this paper, ship maintenance scheduling is modelled as a constraint satisfaction problem (CSP). The variables of CSP are the start times and its domain values are the start and horizon of the schedule. To solve the ship maintenance scheduling problem in the Royal Malaysian Navy, we have adopted a constraint-based reasoning (CBR) which requires start times of the first activities of maintenance cycles to solve the problem by the CBR. Thus, we adopt a genetic algorithm (GA) to find the start times of the first activities. The simulation results showed the effectiveness of the present hybrid algorithm.