Transport Ship Research Articles

Numerical Research on Hull–Propeller–Rudder–Ice Interaction of Full-Scale Polar Transport Ship in Brash Ice Channel

A strong nonlinear ice load has a significant impact on the resistance and power demand of polar transport ships under different drafts in brash ice channels. In this study, the CFD-DEM coupling method is used to investigate the self-propulsion performance of a full-scale polar transport ship in brash ice channels. The interactions between the full-scale polar transport ship, propeller, rudder, and brash ice are effectively simulated. First, the hydrodynamic performance of an open-water propeller is tested, and it is found that the numerical errors of efficiency and the experimental result are less than 8%. Then, the ice resistance, total thrust, effective power, delivered power, and propulsive efficiency of the polar transport ship under different draft conditions are studied, and the results are in good agreement with those of the self-propulsion model tests in the brash ice channel. Through a numerical simulation of self-propulsion in the brash ice channel, self-propulsion points under different drafts and brash ice thicknesses are obtained. It is found that the propeller rotation speed is closely related to the draft depth. Finally, experiments and numerical simulations of the total ice resistance are carried out under different brash ice thicknesses, and the results are consistent with those of the empirical formulas. The accuracy of the three empirical formulas under different drafts is compared. This research work determines the resistance, power demand, and propulsive efficiency of a polar transport ship under given ice conditions and speeds, as well as the self-propulsion points under different ice thicknesses. It is of great significance for the control of ships in polar navigation.

The Influence of Community Empowerment Training for Inland Water Transport Ship Loaders on Students’ Knowledge and Skills

The causes of shipping accidents, as identified by the KNKT investigation, included technical, weather, and human factors. As a result, community empowerment training was conducted in 2023 for loaders of inland waterway transport vessels Class I. This training aimed to enhance participants’ knowledge, insight, and skills regarding loading arrangements and stability testing of inland waterway vessels. The study employed a quantitative descriptive method using primary data from evaluations, including pretests and posttests administered to 30 training participants. The analysis technique utilized was the paired t-test. Results obtained through the Wilcoxon Matched Pair test indicated a significant difference between pretest and posttest scores, leading to the conclusion that participants’ knowledge improved after completing the training. The findings revealed that, out of 30 training participants, only 2 experienced a decrease in scores. Conversely, 28 participants showed positive results (positive rankings), indicating an increase in scores. The average pretest score was 73.67, which increased to an average posttest score of 92.50 following the training. These results were further supported by the significant difference shown in the paired t-test analysis. In conclusion, there was a significant improvement in participants’ knowledge after the training. It is recommended that the program be expanded to include more participants to ensure that the broader community, particularly ship operators, benefits from increased knowledge of shipping safety and proper ship loading practices.

Injection Of air control of propeller performance

With the rise of bubble lubrication technology in transport ships, the interaction between propellers and bubble flow has become increasingly important. On the basis of solving the Reynolds averaged equation and the volume fraction equation, a numerical model of the propeller in a water air mixed fluid was established using the sliding mesh technique. Based on verifying the numerical calculation model of the semi-immersed propeller, uncertainty analysis was conducted on the KP505 propeller flow numerical model, and the open water performance of the propeller was calculated to be affected by the injection position and injection volume. A linear model was established to describe the relationship between the open water performance of the propeller at the axis and the injection rate. The performance surface model was used to describe the effect of the air injection position moving towards the blade tip on open water performance at different air injection rates. The strength and dissipation of the tip vortex and hub vortex of propeller are affected by the radial air injection position. Air injection at the axis causes the hub vortex to expand and connects the tip vortex to form a vortex ring in the far field. The air injection position moves towards the blade tip, and the vortex system at the blade tip accelerates and rapidly dissipates.

Value-Focused Assessment of Container on Barge Freight Transportation Readiness

Container on Barge (COB) is a freight transport mode that utilizes barges to transport shipping containers. This mode has been relatively slow to develop in the United States compared to Europe and Asia. This research contributes a comprehensive and practical readiness assessment scorecard based on value-focused thinking for inland waterway ports to evaluate the feasibility of COB development. Based on a comprehensive literature review, the Container on Barge Readiness Assessment Scorecard covers important attributes and provides constructed measurements to assess COB port readiness. Applicability of the scorecard is demonstrated on nine global ports, and implications for engineering managers are presented.

Research on parametric roll of the polar environmental transport ship based on time-domain Rankine panel method

In this study, the roll damping of a polar environmental transport ship (PETS) is estimated using viscous CFD method, and the parametric roll is simulated based on time-domain Rankine panel method. This method's reliability is validated by contrasting the simulation results with the experimental data of C11 container ship. The roll damping of C11 container ship is estimated using CFD method and improved Ikeda's method, respectively. Then, the time-domain Rankine panel method is adopted to simulate the roll motions of C11 container ship, and the simulation results are contrasted with experimental data. It confirms that the roll damping is calculated by CFD method and the roll motions of ships are simulated based on time-domain Rankine panel method has good applicability. Finally, the influence of wave steepness, wavelength, and the ratio of encounter frequency ωe to natural roll frequency ωroll on the parametric roll of PETS are studied. It is found that the maximum roll angle of PETS increases along with wave steepness. As the wavelength increases, the possibility of parametric roll for PETS is also increasing. When the parametric roll of PETS occurs, the ωe/ωroll tends to increase.

Disrupted immobilities: giving space and time to the discussion of immobility dynamics in transport shipping

Ships are technologies of maritime mobility. But sometimes ships are immobile—they stop and remain stationary for short or prolonged times. A degree of stasis inside and outside ports is both usual and essential for facilitating the movement of ships in global markets. This paper makes two important points: first, echoing existing literature, frequent stationarity (or waiting) is a normal occurrence in the industry. Second, it is not just mobilities that are disrupted via moments of stasis; immobilities themselves have distinct patterns that too can be disrupted. This nuance is vital: there is a need to understand the disruptions to immobilities rather than understanding immobilities as disruptions to the general condition of mobility, both within—and beyond—the shipping example. We argue that understanding disruptions to immobilities is vital to grasping the dynamics of shipping, alongside other (im)mobilites (car, train, plane), their conditions, and the politics that shape our world on the move. Using a data-driven approach, embracing AIS methods for exploring ship stationarity around US waters during the COVID-19 pandemic, this paper upends the assumptions of ship (im)mobilities through the example of wait times, calling for scholars to give space and time to everyday immobilities and their disruptions too.

A CFD-DEM-FEM coupling method for the ice-induced fatigue damage assessment of ships in brash ice channels

Polar transport ships frequently traverse in the brash ice channel opened by icebreakers. Although the substantial ice resistance caused by direct collisions with the level ice is avoided, the hull still encounters collisions with the brash ice, leading to periodic damage and exacerbating the fatigue issues of the hull structure. To address the fatigue challenges faced by ships sailing in the brash ice channels, this paper proposes an ice-induced fatigue damage assessment method based on the CFD-DEM-FEM. Referring to the brash ice model test conducted at the Hamburg Ship Model Basin (HSVA), a discrete element ice model and a numerical brash ice tank are established using the CFD-DEM coupling method. The simulated ship-ice interaction is compared with HSVA’s experimental results to validate the reliability of the numerical brash ice tank and ice load. The ice load time history resulting from the ship-brash ice collision is applied to the hull, and the hot spot stress time history under each fatigue sub-condition is calculated using the FEM. The improved rain-flow counting method is employed to determine the stress level of the hot spot stress time history, and the S-N curve method based on the linear cumulative damage criterion is used to calculate the total fatigue damage of hot spots. Finally, the results of the proposed method are compared with those of the LR method. This study can serve as a valuable reference for the ice-induced fatigue assessment of ships navigating in brash ice channels.

An efficient Meta-VSW method for ship behaviors recognition and application

Ship behaviors refer to the operational process such as sailing, entering into port/departure, etc., which indicate by their position, speed, and so on. The collected big data normally have been treated by unsupervised Machine Learning methods. However, the process is time consuming and lacks consideration of time continuity. From the unknown data to recognize and recur the ship behaviors is still a complex problem. Hence, this study proposes a universal Meta-trajectory Variable Sliding Window (Meta-VSW) method to provide an efficient and high-fidelity solution. In this method, the ship data were connected into the smallest units by the meta-trajectory coding, and combines with variable sliding windows to achieve fast, continuous and accurate recognition of ship behaviors. Taking an inland-water ship and a marine transport ship as examples, the validity of the method was fulfilled and compared with two commonly used algorithms, Affinity Propagation (AP) and Density-Based Spatial Clustering of Applications with Noise (DBSCAN). It has the fastest computational speed and can effectively classify the behaviors of massive unknown data from different ships. And it has good performance in capturing behavior boundaries, with the recognition accuracy up to 0.9. Then, the method was applied to analyze the operational effectively and fuel consumption.

Application of Advanced Technology on Transport Ships as a Technological Revolution in the Maritime Industry

Application of Advanced Technology on Transport Ships as a Technological Revolution in the Maritime Industry

Baltic plastic soup recipe: Presence of paraffin increases micro- and mesoplastic contamination

Micro- (0.5–5 mm) and meso-size (0.5–2.5 cm) floating marine litter was collected in June 2022 in the southeastern part of the Baltic Sea using a manta trawl (mesh size 335 µm). Plastic items, excluding fibers and paint flakes, accounted for approximately 90.1% of the total number of collected particles in fifteen surface water samples. The contamination level ranged from (0.33–23.90)×105 items/km2 (or 0.22–15.93 items/m3, or 5–1779 g/km2, or 0.03–11.86 mg/m3). Foamed PS particles accounted for 49.2% of the total number of collected particles. The mass of paraffin in each sample was high, ranging from 1.4 to 3750 g/km2 (9.1×10–3–25.0 mg/m3), which was comparable to or greater than the mass of plastic. This study suggests that plastic particles are retained at the water surface by paraffin stains left after washing tanks on transport ships. This finding highlights an unexpected aspect of the contribution of shipping to plastic pollution in the region.

An integrated intermodal freight transportation system to avoid container supply chain disruptions in Chattogram Port of Bangladesh

An integrated intermodal freight transportation system is a derived demand to transport shipping containers from/to the seaport to/from the hinterland, instead of undertaking cargo loading and unloading activities in port-protected areas. The concept of the intermodal system is to transfer containers to nearby hinterland nodes, such as dry ports, inland rail, road, and river terminals as a part of port development, as well as increasing port efficiency and productivity. Lloyd’s List ranked Chattogram Port as the 67th busiest container port in the world as per container port throughput in 2022. Chattogram Port has small-scale intermodal facilities for off-docks/ICDs in the port city only. In addition, a pure intermodal system has been developed by one rail ICD in the capital city, Dhaka, and two RICTs nearby Dhaka, but less than 5 % of port throughput. A large-scale intermodal for serving the major cities, SEZs, EPZs, and industrial areas is absent due to planning and policy problems, as well as the unavailability of intermodal infrastructure and network. Due to an improper hinterland intermodal chain, the port faced container supply chain disruptions at the port yard and exceeded port capacity, resulting in container vessel congestion at the outer anchorage of Chattogram Port. By developing rail and road infrastructure, and utilizing natural river connectivity, it is possible to develop road, rail, and river intermodal systems, and shape an integrated intermodal freight transportation system to avoid container supply chain disruptions in Chattogram Port. To develop an integrated intermodal system, this research chose a quantitative research methodology for port throughput data analysis and forecasting future throughputs that are advanced to the intermodal model for Chattogram Port. Overall, this paper aims to develop an integrated intermodal freight transportation system to support Chattogram Port to keep and increase the record of port productivity, efficiency, and competitiveness actively. Highlights Intermodal system is a derived demand for managing hinterland and port terminals of a seaport that needs to be implemented in Chattogram Port Container supply chain disruptions to be avoided to increase the port productivity and efficiency Inland intermodal connectivity will help to increase hinterland of a seaport It is necessary to develop an integrated intermodal freight transportation system to support Chattogram Port to keep and increase the record of port productivity, efficiency, and competitiveness globally

Numerical Study on the Influence of Water Depth on Air Layer Drag Reduction

Over the years, air lubrication technology has been widely applied to maritime vessels, demonstrating its significant energy-saving and emission-reducing effects. However, the application of this technology in inland waterway transportation faces unique challenges due to the shallower water depths, particularly during low water periods. Under such conditions, the formation of the air layer and its associated drag-reduction effects may undergo alterations. Conducting research on air lubrication technology in shallow water conditions holds great practical significance for promoting its application in inland waterway vessels. Therefore, a numerical study is undertaken to examine the impact of water depth on Air layer Drag Reduction (ALDR) to promote the use of ALDR technology on inland canal boats with shallow water depths. The object was a specific river-sea direct ship model, and a groove was created at the bottom of the model with air injection. At two distinct speeds, numerical simulations were run for four different depths: deep water, moderate water, shallow water, and ultra-shallow water. A comparative examination of the air layer morphology on the ship bottom and drag reduction was conducted to investigate the impact of water depth on ALDR and confirm the viability of using ALDR technology on shallow-water navigation boats. The results indicate that due to the change in the velocity and pressure fields at the bottom of the ship, the efficiency of drag reduction and the form of the air layer on the ship’s bottom are significantly impacted by variations in water depth in restricted waters. However, the total resistance can still be significantly reduced by setting grooves on the hull with air injected in shallow waterways. Reduced frictional resistance no longer predominates the overall resistance reduction in shallow water; the proportion of the decrease in viscous pressure resistance rises and can reach up to 4.8 times the decrease in frictional resistance. The research confirms the application prospects of this technology on inland waterway transport ships.

Non-Destructive Material Analysis of Whetstones Discovered in Grain Transport Ship of the Early Joseon Period

Non-Destructive Material Analysis of Whetstones Discovered in Grain Transport Ship of the Early Joseon Period

Assessment of Selected Alternative Fuels for Spanish Navy Ships According to Multi-Criteria Decision Analysis

Climate change and environmental degradation are growing concerns in today’s society, which has led to greater awareness and responsibility regarding the need to adopt sustainable practices. The European Union has established the goal of achieving climate neutrality by 2050, which implies a significant reduction in greenhouse gas emissions in all sectors. To achieve this goal, renewable energies, the circular economy, and energy efficiency are being promoted. A major source of emissions is the use of fossil fuels in different types of ships (from transport ships to those used by national navies). Among these, it highlights the growing interest of the defense sector in trying to reduce these emissions. The Spanish Ministry of Defense is also involved in this effort and is taking steps to reduce the carbon footprint in military operations and improve sustainability in equipment acquisition and maintenance. The objective of this study is to identify the most promising alternative fuel among those under development for possible implementation on Spanish Navy ships in order to reduce greenhouse gas emissions and improve its capabilities. To achieve this, a multi-criteria decision-making method will be used to determine the most viable fuel option. The data provided by the officers of the Spanish Navy is of great importance, thanks to their long careers in front of the ships. The analysis revealed that hydrogen was the most suitable fuel with the highest priority, ahead of LNG, and scored the highest in most of the sections of the officials’ ratings. These fuels are less polluting and would allow a significant reduction in emissions during the navigation of ships. However, a further study would also have to be carried out on the costs of adapting to their use and the safety of their use.

Remote monitoring and fault diagnosis of transport ships and engineering dredging ship propulsion systems based on data fusion algorithm

Remote monitoring and fault diagnosis of transport ships and engineering dredging ship propulsion systems based on data fusion algorithm

Economic and emission assessment of LNG-fuelled ships for inland waterway transportation

As the main transportation channel, the huge shipping volumes of inland rivers lead to significant emissions from ships. Inland shipping has an increasing demand for the development of green ships. Liquid natural gas (LNG) is considered to be an ideal marine fuel because of its many advantages. This paper aims to assess the economy and CO2 emission reduction of LNG-fuelled ships on inland waterway transportation, under the context that the uniqueness of inland waterway transportation, as well as cargo transportation regulations and policies are taken into account. Firstly, considering the preferential policies for LNG-fuelled ships and the mandatory use of shore power for oil-fuelled ships, we proposed a fuel consumption calculation formula and established economic and emission assessment models for inland ships. Then, we examined these models with simulation examples of three main cargo types, i.e. dry bulk, containers and dangerous goods, transported on the Yangtze River. The optimal ranges of LNG-fuelled ship size were given under various credible scenarios designed according to the transportation systems. The results show: (1) The optimal range of dead-weight tonnage (DWT) of LNG-fuelled ships for dry bulk, container and dangerous goods are between 3,000–5,000 DWT, 3,000–4,000 DWT and 2,000–3,000 DWT, respectively. (2) LNG-fuelled dry bulk ships of about 10,000 DWT or more are uneconomical compared to oil-fuelled ships of the same tonnage. (3) Smaller LNG-fuelled ships, such as dry bulk ships of less than 1,500 DWT, container and dangerous goods ships of less than 2,000 DWT, or ships serving longer routes of approximately more than 1,000 km have most significant unit CO2 emission reduction than oil-fuelled ships of the same tonnage. (4) Excessive waiting time at locks will reduce the economic feasibility and unit CO2 emission reduction of LNG-fuelled ships. Finally, we obtained a series of important management significances by simulating the changes of some variable parameters in real situations. These conclusions can provide some theoretical foundations for the development of LNG-fuelled or other green ships in inland waterways, and guide the government in formulating policies to promote the green transformation of the inland shipping industry.

Flow control over a circular cylinder using vortex generators: Particle image velocimetry analysis and machine-learning-based prediction of flow characteristics

Controlling the flow around circular cylinders is crucial to mitigate vortex-induced vibrations and prevent structural damage in a range of applications, such as marine and offshore engineering, tall buildings, long-span bridges, transport ships, and heat exchangers. In this study, we aimed to control the turbulent flow structure around a circular cylinder by placing vortex generators (VGs). We examined the flow structure using particle image velocimetry (PIV). This enabled quantitative data acquisition, intuitive flow visualization, and drag coefficient determination from PIV data. We developed artificial neural network (ANN) models that successfully predict both mean and instantaneous flow characteristics for different scenarios. Our findings show that using VGs elongated the wake and increased vortex formation lengths while reducing velocity fluctuations and the drag coefficient. A minimum drag coefficient of 0.718 was achieved with VGs oriented at α = 60° & β = 60°, reducing the drag by 35.3% compared to the bare cylinder. The drag coefficient exhibited a substantial inverse correlation with both wake and vortex formation lengths. This study is significant for controlling flow structures, providing detailed insights into the near-wake region, and highlighting the potential applications of machine learning in fluid dynamics.

Морской транспортный флот и техническая оснащенность портов СССР в период экстенсивного экономического роста (1956–1972 гг.)

The dynamics of the number, deadweight, average age and average deadweight of the ships of the sea transport fleet of the USSR in 1956-1972 is studied. Comparison with similar indicators of previous periods and indicators of the world transport fleet is made. The reasons for the increase in the tonnage of the marine fleet and changes in its structure are formulated. The provision of coastal and foreign trade transportation with Soviet tonnage has been studied. The number and deadweight of the ships of the transport fleet of the USSR are analyzed by types of ships and countries of construction. The average annual growth rates of tonnage, the average annual growth rates of transportation volumes by MMF ships and the volumes of transportation of the world transport fleet are compared. It is concluded that a significant increase in the tonnage of the Soviet merchant fleet compensated for the increase in the volume of traffic and did not compensate for the increase in their range. The reasons and the conclusion are stated about the lag in the development of the USSR sea trade ports when compared with the development of the transport fleet. The influence of natural conditions on the development of seaports and the characteristics of transport ships is determined. The level of technical equipment of the Soviet seaports is studied, it is compared with the level of technical equipment in previous periods and with the equipment of the largest seaports of the world. The dynamics of the availability of transport equipment and the level of integrated mechanization in the ports of the USSR are studied. The factors influencing the specialization of ports in the command-administrative and market economies are formulated. The dynamics of container cargo transshipment volumes in the seaports of the Soviet Union is studied. Comparison was made with the container cargo transshipment volumes of Great Britain ports are compared with those of Japan, the Netherlands, Belgium, West Germany and the USA.

Research on re-liquefaction of cargo BOG using liquid ammonia cold energy on CO2 transport ship

Aiming at the problems of large power consumption in the CO2 BOG re-liquefaction process and waste of marine fuel cold energy on very environmentally friendly ammonia-powered CO2 transport ships, a system that uses liquid ammonia cold energy for CO2 BOG re-liquefaction process is designed. Using the simulation software Aspen HYSYS to establish the process flow and simulate the system, comparison between simulation results and power consumption of common BOG reliquefaction technology, it is found that the system can save up to 43.30 % of the power consumption. The calculation model of system cold energy utilization efficiency and system exergy efficiency was established and the results were summarized. The results show that the maximum cold energy utilization efficiency of liquid ammonia is 77.50 %; the maximum system exergy efficiency is 73.95 %, which can realize the efficient utilization of the liquid ammonia cold energy. The economics of the system on the whole route of the typical ship are calculated and analyzed, use this system can greatly reduce the power consumption and fuel consumption of refrigeration during the CO2 BOG re-liquefaction process, and has good economic benefits.

Analysis of the Relationship Between Foreign Sea Transportation Visits and Gross Domestic Product Regional in the Processing Industry Sector

Sea transportation is also very much needed in the processing industry for ships and passengers and the flow of goods. Suppose the incoming ship can be seen as a sender of goods or the processing industry itself. This is supported very well by the cargo and costs for sea transportation, with much cargo at a relatively low cost. Analyzing the relationship of foreign sea transportation with the regional GDP of the processing industry sector. From ship visits consisting of total and units to passenger visits consisting of passenger arrivals and departure, for variable analysis using correlation and hypothesis testing. The results of overseas sea transportation with the GDP Regional the processing industry are for the correlation results of ship visits from units (0.613) with a strong and total correlation (0.596) with a moderate correlation, for passenger arrivals (0.262) and passenger departures (0.280) both have a low correlation relationship, for the unloading flow of goods (0.607) has a strong correlation. So the visits of foreign sea transportation ships with the GDP Regional of the processing industry sector have a significant relationship of (0.00) from the unit or total ships; for passenger visits, both do not have a substantial relationship for passenger arrivals (0.141) and passenger departures (0.115). The flow of unloading of goods has a significant relationship of (0.00). The greater the number of ship visits and the flow of unloading of goods, the higher the GDP Regional of the Processing Industry Sector, but the increasing number of passenger visits has no relation to the GDP Regional of the Processing Industry Sector.