Search Results (157)

The growing focus on enhancing ship performance over the past decades has driven the invention of various energy-saving devices. Conducting performance analyses of these devices is essential to substantiate the claimed energy savings. However, this process is complicated by the dynamic conditions experienced by ships, such as weather and loading conditions. These factors could significantly impact the results of comparisons made between pre- and post-retrofitting performance of new energy-saving devices. This paper presents a comprehensive investigation into the performance analysis process of a general cargo vessel equipped with a Gate Rudder system, which is a twin rudder system known for its thrust-producing and energy-saving properties. A multi-input, multi-output data-driven method, utilizing in situ and weather data, is developed and applied to account for the effects of weather and loading conditions. A performance analysis is then conducted by using the data-driven models to estimate three different indicators of ship performance in terms of propulsion efficiency. The results suggest that the Gate Rudder could potentially reduce torque requirements by up to 20.70%, shaft power requirements by up to 27.58%, and fuel consumption by up to 30.35%, with the same weather and loading conditions. Full article

As an emerging energy-saving approach, bio-inspired drag reduction technology has become a key research direction for reducing energy consumption and greenhouse gas emissions. This study introduces the latest research progress on bio-inspired microstructured surfaces in the field of underwater drag reduction, focusing on analyzing the drag reduction mechanism, preparation process, and application effect of the three major technological paths; namely, bio-inspired non-smooth surfaces, bio-inspired superhydrophobic surfaces, and bio-inspired modified coatings. Bio-inspired non-smooth surfaces can significantly reduce the wall shear stress by regulating the flow characteristics of the turbulent boundary layer through microstructure design. Bio-inspired superhydrophobic surfaces form stable gas–liquid interfaces through the construction of micro-nanostructures and reduce frictional resistance by utilizing the slip boundary effect. Bio-inspired modified coatings, on the other hand, realize the synergistic function of drag reduction and antifouling through targeted chemical modification of materials and design of micro-nanostructures. Although these technologies have made significant progress in drag reduction performance, their engineering applications still face bottlenecks such as manufacturing process complexity, gas layer stability, and durability. Future research should focus on the analysis of drag reduction mechanisms and optimization of material properties under multi-physical field coupling conditions, the development of efficient and low-cost manufacturing processes, and the enhancement of surface stability and adaptability through dynamic self-healing coatings and smart response materials. It is hoped that the latest research status of bio-inspired drag reduction technology reviewed in this study provides a theoretical basis and technical reference for the sustainable development and energy-saving design of ships and underwater vehicles. Full article

With the increasingly stringent regulation of ship carbon emissions by the International Maritime Organization (IMO), improving ship energy efficiency has become a key research direction in the current shipping industry. This paper proposes and evaluates a comprehensive energy-saving solution that integrates a wind-assisted propulsion system (WAPS) and an organic Rankine cycle (ORC) waste heat power generation system. By establishing an energy efficiency simulation model of a typical ocean-going cargo ship, the appropriate optimal system configuration parameters and working fluids are determined based on minimizing the total fuel consumption, and the impact of these two energy-saving technologies on fuel consumption is systematically analyzed. The simulation results show that the simultaneous use of these two energy-saving technologies can achieve the highest energy efficiency, with the maximum fuel savings of approximately 21%. This study provides a theoretical basis and engineering reference for the design of ship energy-saving systems. Full article

To achieve efficient prediction and optimization of the energy consumption of ship central cooling systems, this paper first constructed and validated a high-precision multi-physical domain simulation model of the ship central cooling system based on fluid heat transfer principles and the physical network method. Then, simulation experiments were designed using the Box–Behnken design (BBD) method to study the effects of five key parameters—main engine power, seawater temperature, seawater pump speed, low-temperature fresh water three-way valve opening, and low-temperature fresh water flow rate—on system energy consumption. Based on the simulation data, an energy consumption prediction model was constructed using response surface methodology (RSM). This prediction model exhibited excellent goodness of fit and prediction ability (coefficient of determination R² = 0.9688, adjusted R²_adj = 0.9438, predicted R²_pred = 0.8752), with a maximum relative error of only 1.2% compared to the simulation data, confirming its high accuracy. Sensitivity analysis based on this prediction model indicated that main engine power, seawater pump speed, seawater temperature, and three-way valve opening were the dominant single factors affecting energy consumption. Further analysis revealed a significant interaction between main engine power and seawater pump speed. This interaction resulted in non-linear changes in system energy consumption, which were particularly prominent under operating conditions such as high power. This study provides an accurate prediction model and theoretical guidance on the influence patterns of key parameters for the simulation-driven design, operational optimization, and energy saving of ship central cooling systems. Full article

The maritime sector is under pressure to increase ship energy efficiency and reduce greenhouse gas (GHG) emissions as a part of global decarbonization goals. Various innovative technologies are being adopted in recent years, raising concerns not only about technological feasibility but also about the economic viability of such technologies in the context of sustainable maritime practices. This study evaluates the operational performance, potential to increase energy efficiency, and economic feasibility of wind-assisted propulsion technologies such as rotor sails across different vessel types and operational profiles. As a contribution to cleaner and more efficient shipping, energy savings produced by rotor thrust were analyzed in relation to vessel dimensions and rotor configuration. The results derived from publicly available industry data including shipowner reports, manufacturer case studies, and classification society publications on 25 confirmed rotor sail installations between 2010 and 2025 indicate that savings typically range between 4% and 15%, with isolated cases reporting up to 25%. A simulation model was developed to assess payback time based on varying fuel consumption, investment cost, CO₂ pricing, and operational parameters. Monte Carlo analysis confirmed that under typical assumptions rotor sail investments can reach payback in three to six years (as the ship is also liable for CO₂ payments). These findings offer practical guidance for shipowners and operators evaluating wind-assisted propulsion under current and emerging environmental regulations and contribute to advancing sustainability in maritime transport. The research contributes to bridging the gap between simulation-based and real-world performance evaluations of rotor sail technologies. Full article

The implementation of hybrid propulsion systems in vessels has gained prominence due to their significant advantages in energy efficiency and their reduction in harmful emissions, particularly during low engine load operations. This study evaluates hybrid propulsion system applications in two different tugboats, focusing on fuel consumption and engine load across eight distinct operational scenarios, including Istanbul Strait crossings and towing and pushing manoeuvres. The scenarios incorporate asynchronous electric motors with varying power ratings, lead-acid and lithium iron phosphate batteries with distinct storage capacities, and photovoltaic panels of different sizes. The highest fuel savings of 72.4% were recorded in the second scenario, which involved only towing and pushing operations using lithium iron phosphate batteries. In contrast, the lowest fuel savings of 5.2% were observed in the sixth scenario, focused on a strait crossing operation employing lead-acid batteries. Although integrating larger-scale batteries into hybrid propulsion systems is vital for extended ship operations, their adoption is often limited by space and weight constraints, particularly on tugboats. Nevertheless, ongoing advancements in hybrid system technologies are expected to enable the integration of larger, more efficient systems, thereby enhancing fuel-saving potential. Full article

As a novel energy-saving and maneuvering device for ships, the gate rudder system (GRS) functions similarly to an accelerating duct. While providing additional thrust, its independently controllable rudder blades on either side of the propeller also enhance ship maneuverability. The GRS was first fully implemented on a container ship in Japan, demonstrating improved propulsion efficiency, fuel savings, and excellent performance in maneuvering, noise, and vibration reduction. In recent years, extensive research has been conducted on the hydrodynamic performance, acoustic characteristics, and energy-saving effects of the GRS. However, certain gaps remain in the research, such as a lack of systematic studies on optimal GRS design in the publicly available literature. Only Ahmet Yusuf Gurkan has investigated the sensitivity of propulsion performance to parameters such as rudder angle, rudder X-shift, rudder tip skewness, and blade tip chord ratio. Therefore, this study employs the JBC benchmark vessel and adopts a coupled CFD-CAESES approach to develop a matching optimization design for the GRS. The influence of geometric parameters—including GRS airfoil camber, maximum camber position, chord length, thickness, distance from the leading edge to the propeller plane, and the gap between the GRS and propeller blades—on ship propulsion performance is investigated. The sensitivity of these design variables to propulsion performance is analyzed, and the optimal GRS design is selected to predict and evaluate its energy-saving effects. This research establishes a rapid and comprehensive CFD-based optimization methodology for GRS matching design. The findings indicate that the gap between the GRS and propeller, the distance from the GRS to the stern, and the airfoil camber of the GRS significantly contribute to various performance responses. After GRS installation, the viscous pressure resistance of the JBC ship decreases, resulting in an 8.05% energy-saving effect at the designated speed. Full article

Energy-saving device (ESD) plays an important role in mitigating the emission of greenhouse gases in ship industry. It is necessary to study a promising ESD, a gate rudder, for its great potential in promoting energy efficiency. In the present study, ship resistance and self-propulsion simulations were conducted to investigate the energy-saving effects of gate rudder using a viscous in-house CFD solver. First, verification and validation studies were performed to estimate the accuracy and reliability of the numerical method and the results are in good agreement with experimental data. Afterward, resistance and self-propulsion simulations of a crude carrier equipped with the conventional rudder and the gate rudder were carried out respectively. Ship resistance and self-propulsion characteristics with different sailing velocities and propeller revolution rates were compared to study the energy-saving ability of the gate rudder as well as its effects on ship hydrodynamic performance. The results indicate that the gate rudder can greatly optimize the energy efficiency of the ship. Meantime, the ship equipped with the gate rudder shows better resistance and propulsion performance in a self-propelled state. Full article

The Hybrid Contra Rotating Propeller is a developing propulsion system that combines a conventional single-shaft propeller with a POD propeller to achieve high energy-saving performance through a Contra Rotating Propeller. In this paper, a new towing tank test method for the Hybrid Contra Rotating Propeller was suggested. By conducting seven patterns of propeller open-water tests and measuring the individual propeller performance and the interaction between the propeller and the POD, the propeller’s mutual interaction can be obtained. Towing tank tests for a study ship were conducted, and the analyzed results are shown. There exists the effect of the wake of the propeller open boat at an unusual (reversed) test layout, which simulates the Hybrid Contra Rotating Propeller, and this effect must be removed for the accurate estimation of the ship’s performance. In conventional towing tank test methods, this effect on the front propeller was obtained and used to correct the performance of the total unit of the Hybrid Contra Rotating Propeller. The presented method allows for the correct removal of the open boat effect on the performance of each propeller and the propeller mutual interaction, resulting in more accurate power estimation. Furthermore, by using the individual performance of two propellers and interaction terms, the presented method enables us to conduct a power estimation at an arbitrary revolution rate of two propellers. Full article

The objective of the presented work is the stern duct design for the JBC (Japan Bulk Carrier) hull form. Since the original duct only provides a 0.6% resistance reduction, an innovative duct will be proposed to improve the ship resistance and propulsion performance. The duct section geometry is based on the NACA (National Advisory Committee for Aeronautics) 4-digit foil series. First, we analyze whether the wake flow field and total resistance of the ship are improved, and then we investigate the self-propulsion performance for the selected ones. The research tool is the CFD (Computational Fluid Dynamics) software OpenFOAM 9 with the viscous free surface flow field modelled by the VOF (Volume of Fluid) method and the SST (Shear Stress Transport) k–ω turbulence model. The propeller effect is implemented by the MRF (Multi-Reference Frame). Compared to the original duct, two ducts, namely, NACA 7908 and NACA 6.3914, show the best (2.8%) resistance reduction in the bare hull condition. By installing both ducts, the propeller thrust decreases 6 and 5% to reach the self-propulsion point, and the behind-hull efficiency increases 7 and 6%. Both ducts save the energy, i.e., effective horsepower, by 4.3%, and produce obvious flow acceleration, achieving around 10% higher effective wake factor (1 − w). The nominal and propeller wakes are improved as well. Full article

Maritime transport accounts for approximately 3% of global greenhouse gas (GHG) emissions, a figure projected to rise by 17% by 2050 without effective mitigation measures. Achieving zero-emission shipping requires a comprehensive strategy that integrates regulatory frameworks, alternative fuels, and energy-saving technologies. However, existing studies often fail to provide an integrated analysis of regulatory constraints, economic incentives, and technological feasibility. This study bridges this gap by developing an integrated model tailored for international maritime transport, incorporating regulatory constraints, economic incentives, and technological feasibility into a unified framework. The model is developed using a predictive approach to assess decarbonization pathways for global shipping from 2018 to 2035. A multi-criterion decision analysis (MCDA) framework, coupled with techno-economic modeling, evaluates the cost-effectiveness, technology readiness, and adoption potential of alternative fuels, operational strategies, and market-based measures. The results indicate that technical and operational measures alone can reduce emissions by up to 44%, while market-based measures improve the diversity of sustainable fuel adoption. Biofuels, particularly BISVO and BIFAME, emerge as preferred alternatives due to cost-effectiveness, while green hydrogen, ammonia, and biomethanol remain unviable without additional policy support. A strict carbon levy increases transport costs by 46%, whereas flexible compliance mechanisms limit cost increases to 14–25%. The proposed approach provides a robust decision-support framework for policymakers and industry stakeholders, ensuring transparency in evaluating the trade-offs between emissions reductions and economic feasibility, thereby guiding future regulatory strategies. Full article

As the focus on climate action and sustainable development of the shipping industry intensifies, the maritime sector has intensified its focus on decarbonization. Although the ferry sector accounts for a small part of the global fleet, it plays a crucial role in specific regions. This study examines data from an energy monitoring system installed on a double-ended Estonian ferry over the period from 2022 to 2024. The empirical results clearly show that targeted adjustments can lead to substantial fuel consumption reductions as the optimal operation of the vessel requires equal power from the aft and fore engines particularly when operating under cold or icy conditions. Additionally, the research finds that real-time energy monitoring together with integrating environmental factors supports energy efficiency and fulfilling regulatory requirements. The analysis reveals that environmental corrections and balanced decision-making can generate fuel savings and extended emission reductions. The suggested framework offers ferry operators practical and economical ways of meeting sustainability requirements. Full article

The International Maritime Organization (IMO) is the regulator for the safety and pollution prevention of ships. They have set an ambitious target of driving International Shipping to achieve net-zero greenhouse gas (GHG) emissions in 2050 by the process of decarbonization of shipping. Decarbonization of shipping is integral to sustainability, as it can reduce GHG emissions and provide a clean environment in a world that is conducive to the good health and well-being of our future kith and kin. Decarbonization of shipping may be achieved using alternate low-carbon fuels, a more efficient ship operation to save energy, or redesigning the ship’s hull. The purpose of this article is to conduct a bibliometric analysis of the research papers conducted in the past decade on the initiatives adopted by the shipping industry to work towards the net-zero goal. This study utilizes the Scopus database, renowned for its extensive collection of scientific papers. Moreover, to analyze and visualize the data, the bibliometric software tools VOSviewer 1.6.20, Bibliometrix 4.4.0, and Harzings’ 8.17.4863 have been used. These tools facilitated the assessment of the research output in this bibliometric study. Our findings reveal a steady increase in publications over the years, with a notable rise in research interest from 2015 onward. The most frequently discussed topics include greenhouse gases, emission control, and energy efficiency, with notable contributions from the United Kingdom, China, and Scandinavian countries. The study also highlights the leading journals publishing about this research area. Future research directions include exploring alternative fuels and more inclusive policy frameworks for maritime decarbonization. Full article

The share of European shipbuilding in the world market, with the constant exception of the cruise ship niche, has been in continuous decline for decades, while at the same time, state-supported Asian competitors are recording accelerated growth. With the already long-standing ban on subsidizing the shipbuilding industry by EU member states, its shipyards can maintain their market position primarily by continuously improving business processes, including adopting Industry 4.0 doctrines. In order to contribute to the European shipyards’ competitiveness growth, the authors of this paper use the case study methodology to investigate the applicability of blockchain technology in the process of financing the construction and purchase of ships according to a bareboat charter model, which is recognized as risk-balanced for all parties involved in the process. The empirically analyzed implementation of the blockchain application of smart contracts, using the example of three ships built and purchased according to the proposed model, theoretically results in an almost one-year shortening of the financing process, with a significant reduction in the costs of legal activities. The originality of this study is also emphasized by the correlation of smart contracts and the process of early ship outfitting in the sense of the possible improvement in its level, thus achieving savings in working hours and energy and ultimately shortening the process of realizing the shipbuilding project. Full article

This study examines the energy savings in a ship’s central cooling system using feedforward control with IMC (Internal Model Control)-based PID tuning. A central cooling system is essential for maintaining the temperature of the engine and other major machinery, thereby improving the overall energy efficiency. The seawater pump in the central cooling system consumes a relatively large amount of power, which makes efficient operation essential. This study compared the power consumption of variable-speed seawater pumps based on actual operational data from a ship. By incorporating a feedforward PI controller into the IMC-based PI-PID controller combinations, this study simulated energy savings. The results indicate that the proposed controller combined with the feedforward PI controller reduces the power consumption of seawater pumps compared with conventional methods. Simulation tests were conducted using approximately 11 days of operational data to verify the effectiveness of the proposed control strategy in achieving energy savings. The proposed controller combination saves approximately 277.4 kWh of power over 11 days compared to conventional control methods. Full article