Ship Concept Research Articles

A novel method for evaluating ship concept performance in transport systems

Abstract Transport carries significant external costs such as climate change, accidents, pollution, and road congestion, driving national and international strategies for the development of new transport concepts. This includes shifting larger cargo volumes away from roads to more sustainable transport modes such as waterborne. The SEAMLESS project was launched in 2023 to answer to these needs by developing technology for autonomous waterborne zero-emission feeder-loop services. The realisation of such services depends on their modal competitiveness. Autonomous ships are expected to reduce transport costs and emissions, and ultimately improve logistical performance. There are, however, few published studies that quantify these impacts of autonomy. Furthermore, commercial waterborne autonomous transport services do not exist yet, limiting the possibilities for empirical analysis. Hence, research is needed to address exactly how and to what extent, autonomy improves competitiveness in different applications. This paper addresses the need for more empirical analyses of innovative waterborne transport performance, by presenting a novel method for evaluating ship concept performance in transport systems. The impacts of design choices are captured through hydrodynamic and logistical simulations. The method can be applied to transport systems consisting of both conventional and novel ship designs, operating on one or more routes including transhipments. It is implemented in the software SIMPACT and applied to a case study which establishes a shortsea feeder-loop service in the Bergen area in Norway. The Bergen municipality has decided that the container terminal is to be moved out of the city centre to reduce local traffic and emissions. However, in the absence of a competitive waterborne transport service in this region, the relocation will have the unfortunate consequence of an estimated annual net increase in regional truck traffic of 40,000 additional truck trips over 25km. By means of the proposed methodology, this paper investigates the feeder-loop concept and compare its quantified performance to truck transport and finds that competition is feasible.

Concept Design of Typhoon Power Generation Ship Using System Simulation

A concept of a typhoon power generation ship for utilizing enormous typhoon energy is proposed. This paper developed a system simulator for evaluating and designing the concept of a typhoon power generation ship using typhoon track history. A developed simulator was applied to the case study to design a typhoon power generation ship ship that operated near Japan. The case study showed that the annual power generation of the typhoon power generation ship tends to saturate and become constant earlier when the number of typhoons is small, in contrast to the improvement of power storage capacity. This result indicates that the appropriate size of the typhoon power generation ship exists at the current technology level.

Evaluation of an autonomous, short sea shipping feeder-loop service through advanced simulations

Traditionally, container-freight being shipped from central Europe to the coast of Norway has been transported either by road, or by larger containerships to central ports. For the past 3 years the AEGIS consortium has worked to develop a new, disruptive short sea shipping feeder-loop service based on mother and daughter ships [1]. The hypothesis is that introducing smaller, autonomous, battery-powered vessels into the fjords of Norway would open new business areas, provide access to remote regions, and allow shipping companies to take on cargo that could not previously be transported by water. Such a transport system has the potential of reducing cost, GHG emissions and external costs, while increasing frequency of service and the waterborne cargo volume in Europe. One of the main challenges of the mother-daughter logistic system is how transshipment affects defined key performance indicators (KPIs), especially in terms of cost. For this purpose, the SIMPACT tool [2] was developed in the H2020 projects AEGIS and AUTOSHIP. The tool allows for rapid iterations of maritime logistic systems through discrete event scheduling, and estimation of energy, fuel, emission, and cost.This paper will present results from a case-study on two different daughter ship concepts. The concepts are evaluated through cost and environmental KPIs presented in [1], in addition to external costs based on the European handbook on the external costs of transport [3].Results from the case-studies indicate that transport systems including green daughter-vessels have the potential of being cost competitive and would lower externalities compared to the baseline truck transportation system.

Study on the Effect of Hull Attitude on the Resistance Reduction of SWATH with Airflow Injection

With the development of the green ship concept in design and construction, how to reduce the resistance to reduce fuel consumption has become a focus of ship research. As an important drag reduction method, the air lubrication method has been applied to various ship types, but it is still a new method in the study of SWATH (small waterplane area twin hull) drag reduction. In this paper, the air lubrication method is applied to a SWATH model with an overall length of 2.5 m to numerically study the influence of the hull attitude on the air coverage and resistance reduction. The grid is verified by the grid independence and the experiment results. Then, the resistance of the SWATH model under different trim angles and drafts is calculated, and the air coverage on the surface is observed. The drag reduction rates of different areas, including the strut, underwater body, and fins, are analyzed, too. The results show that the slight trim by the head is more conducive to the resistance reduction of the SWATH model, and the resistance reduction rate can reach 39.11%. The draft mainly affects the resistance reduction of the strut, and the difference is more than 10%.

Research on classification and navigational risk factors of intelligent ship

Based on combing the concept and development of intelligent ship, this paper brings forward the summary and classification of intelligent ships proposed by different institutions, and the main classification schemes are compared accordingly. Then one of these classification schemes is selected to study what are the key navigational risks under each grading level, with a detailed analysis of these risk factors. Finally, the index system of navigational risk factors for intelligent ships under different classification standards is constructed to lay a foundation for a further study of intelligent ship safe navigation, and at the same time avoid some risk factors in advance for the maritime management department, ship management companies, and ship design and research institutes.

Optimal design strategy for fuel cell-based hybrid power system of all-electric ships

The All-electric ship (AES) concept has revolutionized the maritime sector. Indeed, AES is a promising solution for modern vessels where decreasing emission pollution, suppressing fossil fuel consumption, and making economical operation are its brilliant merits. Fuel cell (FC) technology based on clean hydrogen energy sources can play a significant role in meeting these requirements in the AES platform. Because of the slow transient response of the FC, an energy storage system (ESS) is required to improve AES performance in different operation scenarios. Therefore, optimal sizing of the FC and the ESS and proper design of energy management strategy is a challenging problem. This paper proposes a systematic approach for the optimal design of hybrid FC-ESS of AES power systems. The proposed method is based on an optimization technique to determine the optimal sizing of the FCs and the ESS. Capital investment, fuel consumption, personnel electrical safety, and occupied volume of the AES power system are the main objectives. The FC size, the battery size, the scheduled output power of the FC, and the battery are the decision variables. Genetic Algorithm (GA) is used to solve the optimization problem. To validate the numerical results, the optimization problem is also solved by Mayfly Algorithm (MA) separately. To assess the feasibility of the proposed strategy, the optimal design of hybrid FC-ESS for a vessel is implemented based on the proposed method. The simulation results validate the proposed approach's sufficiency to investigate and optimize the economic, safety, and dimensional aspects of designing the FC ship's IPS. Numerical results are reported for each design aspect. Considering the minor differences of the numerical results obtained by GA and MA, the optimum points are validated by the two techniques. Using the obtained results, various perceptions can be derived from the FC ship's IPS design. For example, the IPS cost in the cases with optimum volume, weight, and safety, has 2.3%, 2.6%, and 7.3% penalties, respectively compared to the case with the minimum cost.

A system theory (STAMP) based quantitative accident analysis model for complex engineering systems

This paper is aimed to propose a hybrid accident analysis framework for complex engineering systems based on methods of the systems theoretic accident model and process (STAMP), failure modes and effects analysis (FMEA), and analytic hierarchy process (AHP). Within the scope of the proposed model, initially, an accident is qualitatively analyzed by identifying safety constraints, constructing a hierarchical control process, and specifying links between unsafe activities. As a second step, failure modes, their causes, and their consequences are determined. Lastly, the risk scores of each failure mode are calculated by analysis of obtained expert judgments. In this step, as different from the conventional FMEA, results are calculated based on the weight scores that are found according to the AHP approach of each accident factor. For the demonstration stage, a real case study is performed to present the effectiveness of the strategy. It is observed that the proposed approach allows analyzing the accident more specifically by defining each relationship between factors and root causes corresponding to the accident and prioritizing them based on the weights, which are assigned according to the accident's nature. In addition, it may be adapted for different complex engineering systems as well as it is a suitable and useful model for the accident analysis associated with smart ship concepts.

Towards the Testing and Validation of Autonomous Ships: Design of a Variable Stability Ship Control System

Maritime autonomous surface ships (MASSs) have received increased attention in both academic research and industrial applications in the global shipping and shipbuilding industry in recent years. According to its definition, a MASS can independently operate without human interaction. This brings the problem of how to test and evaluate the capabilities of the autonomous navigation control system developed for MASS. This paper proposes the novel concept of a variable stability ship and the design of its control system. A variable stability ship consists of a model-scaled ship, a model-following controller, and a hardware and software platform to implement its functions. The variable stability ship can replicate the dynamic responses of different reference ships despite their dissimilarities in physical parameters and hydrodynamic characteristics with the design of the model-following controller. Therefore, it can be used to test the performance of different control strategies on various ship types such that the R&D costs of physical model-based tests can be reduced, as well as shortening the time spent in developing physical ship models. Preliminary simulations are carried out to show its effectiveness and applicability.

Review of maintenance strategies for ship machinery systems

This study presents the state-of-art and future trends of the maintenance approaches to ship machinery systems. A systematic review process is conducted to identify relevant literature. Firstly, literature is examined by bibliometric analyses based on the determination of the distribution of papers by years, the top authors, papers, journals, and organisations. Then, studies in the literature are reviewed and presented. In addition, the advantages and difficulties of each maintenance strategy are discussed. Finally, an effective maintenance policy that can implement in new ship concepts such as autonomous marine vessels is introduced in line with the information from the literature. In the future, it is believed that maintenance practices will be performed via the condition-based approach when the evolution of followed maintenance operations in ship machinery systems is examined. However, it should be underlined that more effective and powerful maintenance management can be achieved by supporting the system performance monitoring with reliability and risk approaches.

The Employability of Heavy Lift Class Ships for Logistics and Maintenance and Its Application in Military Means - Part I

The purpose of this article is to present a concept of the Heavy Lift Ship already used in the maritime market, aiming to propose viable alternatives for its employability, taking as its main focus the performance of the same in military operations, however the versatility of this class of ship, allows a wide range of activities. Currently, the theme of docking, maintenance, repair and logistics is in constant evidence due to the high level demanded by operational means of navies around the world, their maintenance is of essential importance for the preparation and use of Naval Power. The implementation of a ship of this class to a fleet or fleet allows its use to perform the function of a floating dock, for example, being able to carry out the transport of other ships or floating structures. Considering the incorporation of a medium with these characteristics, it allows the performance, in addition to services related to maintenance, repair and transport, the possibility of carrying out missions together with other bodies or companies such as Petrobras, for example, in addition to supporting existing military assets and that will still be incorporated. In general, the concept of using a ship with these characteristics can be put to good use, mainly evaluating the plurality that this means can provide to a Navy.

Bulkheads’ Position Optimisation in the Concept Design of Ships under Deterministic Rules

The position of the transverse bulkheads is the most important aspect in determining the internal subdivision of the ship and has a strong impact on the general arrangement, weight distribution and capacity of the ship. Nowadays, deterministic rules still apply to various types of ships such as gas carriers, naval ships, icebreakers, etc. For these vessels a new floodable length can be defined as the extent of the ship that can be flooded, still assuring compliance with the damage stability criteria. The main objective of this paper is using the floodable lengths to optimize the position of bulkheads. The proposed methodology maximises the margin between the floodable length and the actual flooded length, which consists of two lost contiguous compartments. This method, applicable in the framework of multi-attribute decision-making techniques for ship concept design, allows identification of the minimum number of bulkheads a ship requires, quantification, and maximisation of the safety margin for compliance with deterministic damage stability criteria. This margin ensures maximum flexibility for changes that may be required in the next design phases. The proposed method, based on a multi-stage optimization, is tested on a compressed natural gas carrier to define the minimum number and position of the transverse bulkheads dividing the cargo holds.

Controllable robust optimization of ship concept design for quantifying uncertainty of marine water quality forecasts

Controllable robust optimization of ship concept design for quantifying uncertainty of marine water quality forecasts

Potential utilization of the weapon system tank boat in strengthening the defense of Indonesia as a maritime country

Indonesia is the largest maritime country in the world with 80 percent of its territory in the form of oceans. This makes it difficult to supervise the security and sovereignty of the Republic of Indonesia, especially in the maritime sector. Therefore, it is necessary to design a fast catamaran concept that is good and responsive as a tool for war and security in Indonesia's maritime territory. This study aims to design the concept of a Tank Boat type ship and a weapon system based on domestic weapons technology. The method used is the House of Quality data analysis technique which is the first stage of implementing Quality Function Deployment (QFD) in classifying user needs based on the level of importance so that a priority scale is obtained. From the results of the analysis using the Quality Function Deployment (QFD) method, the level of user needs for ships and weapon systems on Tank Boats based on weapons technology is obtained by determining the Benchmark Performance (BP) value for the highest to lowest design characteristics. In this case, there are several main points for the desired user needs in the operational requirements and weapon systems for the Tank Boat object, including Tank Boat has lightweight, The weapons used have high precision, Weapons must be free from ITAR (International Traffic Regulations), The flexibility of weapons to be integrated with the vehicle, The main target is a vital target or VVIP, and Security. The results of the study indicate that there is a need for a weapon system on the Tank Boat to support the defense of the Maritime State. This research is expected to be used as a starting point for further research related to ships and weapon systems that can be used on Tank Boat rides.

Determination of a maintenance strategy for machinery systems of autonomous ships

This paper proposes a hybrid multi-criteria decision-making approach to determine the best maintenance strategy for the machinery systems in autonomous ships of different levels of autonomy. The proposed methodology includes the Analytic Hierarchy Process to identify criteria weighting and the Technique for Order of Preference by Similarity to Ideal Solution to determine the best maintenance alternative. A sensitivity analysis is conducted to determine the impact of criterion weighting on the calculated rank scores and to reveal the criticality of the criteria. The study presents and considers various hybrid maintenance strategies for autonomous ship concepts as possible maintenance alternatives. The selection of the maintenance policy that combines condition-based and time-based approaches for 3rd and 4th levels of ship autonomy, as the best maintenance alternative, demonstrates the basic idea of the study. In addition, the key findings of the paper ensure crucial insights to the maritime industry in the decision-making process on the maintenance strategy that can be adapted to different types of autonomous ship concepts.

Evaluation of ammonia fueled engine for a bulk carrier in marine decarbonization pathways

This study highlights that in addition to using ammonia in the maritime sector and integrating it into the ship concept, it is a challenging option for shipowners in terms of capital and operational expenditures. In this study, the typical marine-type fuels used in the main engines of a bulk carrier were compared to ammonia in a Techno-Economic Analysis. The bulk carrier features a conventional main engine system, and operational data was acquired to determine how much ammonia was consumed. The ship is classified using the Energy Efficiency Existing Ship Index (EEXI) and the Carbon Intensity Indicator (CII). To determine its economic viability, Monte-Carlo Simulation is utilized. In addition, a cost scenario for in-service bulk carriers was developed, with an emphasis on their application. Ammonia is used to minimize petroleum consumption, but it is not cost-effective for long-term financial sustainability, and the installation cost is more than 5 million USD. MAC calculation was made according to NPV values and CO2 reduction results and 3816.42 $/tCO2e was obtained. According to the article, ammonia is more suitable for newly built marine vessels. With the study, a method that can be used in the feasibility studies of different alternative technologies for the existing ships of the shipping companies is presented in the literature.

Risk dynamics for marine systems: towards a bio-inspired framework for dynamic risk assessment

AbstractThe development of innovative, complex marine systems, such as autonomous ship concepts, has led to risk-based approaches in design and operation that provide safety level quantification and continuous risk assessment. The existing approaches to dynamic risk assessment mainly aim at updating accident probabilities for specific risk scenarios, based on knowledge of system operation and failure, as well as on past accident and failure information. However, for innovative marine systems that include complex interactions, our ability to identify anything that might go wrong is very limited, which may lead to unidentified risks, and failure data may not be available. This paper presents the foundations of a framework for dynamic risk assessment, which is equally applicable to manned and autonomous ships and mainly relies on information about the safe operational envelope and real-time information regarding deviations from safety. Inspiration is drawn from how the biological immune system identifies the risk of infection in a dynamic environment. The objective is to show the feasibility and benefits of our approach for quantifying the operational risk of marine systems. This paper provides the conceptual basis for developing ship specific applications and describes a process for dynamic risk assessment that is methodologically based on artificial immune systems. To demonstrate the implementation of our framework, we described, an illustrative example that involves a ship in a grounding scenario. The results show that the bio-inspired assessment process and risk description can reflect the changes of the risk level of a marine system.

WIND ASSISTED PROPULSION: INVESTIGATIONS ON THE USE OF SHIP HOLISTIC MODELS FOR PERFORMANCE ANALYSIS

Wind propulsion is one of the most promising technologies to reduce carbon intensity of ships. However, with variable thrust production and induced drift action, sail’s contribution to propulsion is to be evaluated in different ways from traditional propulsors. For sail retrofit projects, where vessels are initially designed to be optimal at single transit speeds with propulsion engine, wind assistance may also induce a degradation of operational efficiency and limit the extend of energy savings. For these reasons, performance analysis should evolve to account for complex energy transfers between propulsion domain and energy systems. A novel Modelica based model is presented in this article, where manoeuvres and energy modelling are used jointly to predict overall efficiency of wind assisted ship concepts. The model is used to evaluate the impact of retrofitting 4 Flettner rotors on the Duisburg test case (DTC) equipped with diesel engines mechanical propulsion system, with oil fired and exhaust gases steam plants and electricity generation from gensets and turbogenerator. Finally, from the analysis of DTC performance in a sweep of wind conditions, potential solutions to increase sailing efficiency are presented, offering new research directions in vessel design adaptation to natural propulsion.

Autonomous ship concept evaluation – Quantification of competitiveness and societal impact

The prospect of large-scale international adoption of autonomous ships has led to expectations of reduced costs and emissions for waterborne transport of goods. This is commonly attributed to the possibility of removing manning from the ship, which enables more efficient ship designs and reduced operational costs. So why have we not seen a multitude of autonomous ship building projects? There are several reasons for this, including immature technology and regulations. However, there is another reason which has received less attention; the lack of quantifiable evidence for the benefits arising from investing in autonomous ships. There are some case studies on the impact of autonomy on transport cost, but there is no established method for evaluating the effects of an investment in autonomous ships. This paper will present Key Performance Indicators (KPIs) developed to enable such quantification. Furthermore, the developed KPIs are chosen not only to enable quantification of benefits but also to be calculable based on data which it is reasonable to assume that are available or obtainable at a concept stage.

Task strategy optimization for multi-state system based on virtual ship

The task success ratio of the complex system in the coworking situation is studied. In the existing task strategy, the equipment fault during the subsequent task is underestimated, resulting in unreasonable task progress and prone to task failure. A new strategy that takes into account subsequent faults is proposed for this problem. A concept of the virtual ship is introduced by digital simulation with the background of a navy vessel's sailing task. The new strategy is used for real-time fault prediction of complex task systems and dynamic optimization of the remaining task processes. A group of deviation coefficients is defined. With the coefficients, the new strategy is compared to the existing one. The results show that the new strategy improves the task success ratio at the cost of speed stability. After changing the task parameters, it is found that this new strategy can reduce not arriving ratio and thus improve the task success ratio when the task redundancy time coefficient is low; And when the redundancy time coefficient is extremely high or low, the difference between the two strategies is small. In sensitivity analysis, the influence of changing equipment reliability parameters on task success ratio in different strategies is investigated.

Transferring neurointerventionalists saves time compared with interhospital transfer of stroke patients for endovascular thrombectomy: a collaborative pooled analysis of 1001 patients (EVEREST)

BackgroundInterhospital transfer of stroke patients (drip and ship concept) is associated with longer treatment times compared with primary admission to a comprehensive stroke center (mothership concept). In recent years, studies...