Ship Size Research Articles

Dominant conditions for strong resonance of an advancing containership under small-amplitude regular waves

ABSTRACT Seakeeping of a ship under waves is vital for safety, with strong resonance occurring when two conditions are met: (1) large wave loads, and (2) wave frequency being close to the natural frequency. Prior research focused on resonant phenomena, nonlinear traits, and failure modes, but the dominant condition for resonance in ocean-going ships is unclear. This study developed a mathematical model using the boundary element method (BEM) for an advancing ship under small-amplitude waves. An open-source solution was proposed, utilizing NEMOH for hydrodynamic coefficients and a Python code for dynamic equation solving. Validated with KRISO Container Ship (KCS) data, the mathematical model accurately predicts ship motions. Findings show that ship heave resonance is influenced by both conditions, but the second condition affects rolling more, and the first condition controls pitch more. This is more evident in high-speed ships and is less affected by ship size variations.

The impact of container call size - evidence from simulation modelling

We present an analysis of the impact of large container ship call sizes on the operational efficiency of container terminals as well as on hinterland modes of transport. We use standard container terminal simulation software, that can represent a realistic terminal operation. We include dynamic crane productivity, arrival time uncertainty, and deepsea vessel prioritisation in our model.Our experiments investigate the impact of introducing larger call sizes of container ships, increasing the uncertainty in arrival times of deepsea ships, and the impact of the phenomenon of split calls that are employed by the largest container ships in certain regions in the world. We differentiate between the impact on terminal operations, land-based hinterland traffic, and hinterland traffic over water, through barges and feeder vessels.Our results show that introducing large ships with large container call sizes comes with benefits and drawbacks. Benefits can be found in planning advantages for both the deepsea ships and barges and feeders handled in the terminal. Drawbacks occur as a result of operational peaks in subsystems such as the quay cranes, the stack and the land side gates. Higher uncertainty deteriorates the performance of the terminal, but the impact on the hinterland modes of transport is greater than on the large deepsea vessels. The impact of the split call is that it brings all the disadvantages of large vessels, but none of the benefits.Our analysis shows the operational impact of large call sizes on terminal operations and hinterland transport operations, based on container terminal simulations with a higher degree of realism than previous work. In addition, we offer, for the first time, insights in the impact of split calls of container ships at container terminals.

The New Requirements for International Seafarers' Comprehensive Quality due to the Large-scale and Intelligent Development of Ships

The global shipping industry is undergoing significant transformations with the large-scale and intelligent evolution of ships, which poses new demands on the skills and responsibilities of seafarers. This article explores how these trends affect the skill requirements of seafarers, including mastery of advanced technology, data analysis capabilities, safety management, emergency response, and communication and collaboration. As ship sizes increase and intelligent technologies are widely applied, the ways of navigational operations and management are undergoing revolutionary changes. Seafarers must enhance their skills to adapt to the new work environment and meet the rapid changes in the shipping industry. This article aims to provide guidance for seafarer training and education, helping them successfully face these new challenges.

Exploring the factors affecting cruise passengers’ perceptions of value for money expressed in online reviews

The complexity of cruise tourism is high, and various factors determine the product value. Value for money has an important effect on cruisers’ choices. This paper comprehensively discusses the effect of ship attributes and onboard and onshore experience on cruise passengers’ perception of value for money. This discussion is helpful for cruise companies to identify key attributes and subsequently implement improvement strategies. Taking nearly 100,000 items of tourist review data as samples, this paper primarily discusses the effect of cruisers’ nine-dimensional experience on the perception of value for money and the differences under different market positioning gleaned from content analysis, regression analysis and multi-group comparison. Results show that embarkation, cabin, dining, entertainment, service, fitness, activities, public room and shore excursion experiences have a significant effect on tourists’ perceptions of value for money. From the perspective of brand positioning, the situation of a luxury cruise is quite different from that of a standard and premium cruise, whereas the standard and premium cruise are similar. Furthermore, unlike standard and premium cruises, the physical attributes of luxury cruises such as ship size and launch year have no significant effect on tourists’ perceptions of value for money. Research results will help cruise companies improve tourist satisfaction and value for money based on market positioning and key attributes.

Dynamic risk analysis of allision in port areas using DBN based on HFACS-PV

The increased number, speed, and size of ships leads to an increased risk of accidents in ports with restricted navigational areas. A comprehensive risk assessment is required to understand the causal mechanisms involved in accidents. This study investigated the factors causing allision accidents that occurred during ship manoeuvres in the port areas. Nonconformities obtained from 112 allision accident reports were classified qualitatively with the Human Factors Analysis and Classification System for Passenger Vessel Accidents (HFACS-PV) method. Then, temporal and causal relationships between nonconformities were evaluated quantitatively with the DBN method. As a result, the probability of an allision accident and the risk identifying factors (RIFs) affecting allision during port manoeuvres were calculated. Familiarity with the vessel, using the bridge navigation equipment and features of structures in the port area are the riskiest factors leading to allision accidents. The study is thought to contribute at a practical and strategic level to ship owners, ship personnel, pilotage services, port authorities and all relevant stakeholders in understanding the risk of allision accidents occurring in ports and developing preventive regulations.

System Dynamics Model to Improve Logistics Cost Efficiency in Fertilizer Distribution outside Java (Gresik - Medan)

Within the vast development of globalization, companies are encouraged to increase competitiveness level, in order to survive in the market. One certain way to stay competitive and retain customers is to provide such products with reasonable selling prices. Supply chain costs have a great influence upon the cost of the final product; therefore, companies are suggested to continuously improve supply chain processes regarding reducing overall costs. One industry indicated with high supply chain costs is the fertilizer industry, referring to the fact that it has a nationwide distribution system. For countries which regulate fertilizer as a subsidized product, companies must be able to provide fertilizer at an efficient price to maintain prevalence in the market. Currently, the problem faced by one of the fertilizer companies is an indication of expensive logistics costs for fertilizer distribution outside Java. The most expensive logistics costs are owned by the Medan area with variations in bulk transportation. This problem can be solved if there are alternative economic scenario designs in accordance with capabilities. The purpose of this research is to provide alternative scenarios, simulate those scenarios, and choose the most efficient scenario. The method used in this research is system dynamics and 12 scenarios were generated in this paper. Selection of the appropriate ship size and type of heavy equipment for loading and unloading cargo from those scenarios can impact in energy saving/fuel consumption and minimize operational costs. Beside cost, fertilizer deficit is also a consideration in scenario selection. From the result, scenario 3 has the lowest distribution costs with a total cost is Rp. 241,513 and the total fertilizer deficit is 0 tons, so scenario 3 is the selected alternative scenario to minimize operational cost.

A collaborative decision support framework for sustainable cargo composition in container shipping services

AbstractThis paper proposes a decision support system (DSS) for optimizing cargo composition, and resulting stowage plan, in a containership of a shipping company in collaboration with en-route ports in the service. Due to considerable growth in transportation over years, an increasing number of containers are being handled by containerships, and ports consequently. Trade imbalances between regions and recent disruptions, such as LA/LB/Shanghai port congestion, blocking of Suez canal, drought in Panama canal, typhoons at ports, COVID-19 restrictions and the lack- and then over-supply of empty containers, have resulted in an accumulation of containers in exporting ports around the world. These factors have underscored the urgency of sustainability and circular economy within the shipping industry. The demand for container transportation is higher than the ship capacities in the recent times. In this regard, it is essential for shipping companies to generate a cargo composition plan for each service by selecting and transporting containers with relatively high financial returns, while offering a realistic stowage plan considering ship stability, capacity limitations and port operations. Ultimately, the selected containers should enable a ship stowage plan which keeps the ship seaworthy obeying complex stability considerations and minimizes the vessel stay at the ports, and port carbon emissions consequently, through efficient collaboration with en-route ports. This study provides a bi-level programming based DSS that selects the set of containers to be loaded at each port of service and generates a detailed stowage plan considering revenue, stowage efficiency and quay crane operational considerations. Numerical experiments indicate that the proposed DSS is capable of returning high-quality solutions within reasonable solution times for all ship sizes, cargo contents and shipping routes, supporting the principles of the circular economy in the maritime domain.

Analysis of obstacles to lowering demurrage at grain terminals in South Korea

This study aimed to analyze the obstacles to lowering demurrage at a grain terminal. After conducting in-depth interviews with working-level staff in grain terminal, 12 factors were selected to derive key factors for reducing demurrage. The Consistent Fuzzy Preference Relations methodology, which can extract experts’ knowledge and experiences, was employed to rank the obstacles in lowering demurrage. The analysis showed that the number one factor was “inventory requirements of grain shippers” (with an importance of 0.097), followed by “capacity of storage facilities” and “port congestion” as the second and third factors, respectively. As for sub-factors, “climate (e.g., typhoon, rain, etc.)” and “ship size” were ranked 11th and 12th, respectively. The analysis indicates that experts recognized factors that can be changed by shippers and that are difficult to control as more important obstacles than cost-related factors. The findings of this study provide the working-staff of ports, grain terminals, and the government implications for reducing demurrage.

Fuel consumption cost prediction model for ro-ro carriers: a machine learning-based application

ABSTRACT Shipping companies are facing rising fuel consumption costs and pressure to reduce emissions, so reducing logistics consumption costs and addressing stakeholders’ environmental concerns have become urgent tasks. This study aims to develop a ship fuel cost prediction model using statistical and machine learning methods. We analyzed a dataset from a large PCTC shipping company in South Korea containing 16,189 observations for the period from 2012 to 2021. Fuel consumption costs was predicted using features such as date, ship size, route, distance, speed, sea day, port call day, and duration. We used the CatBoost algorithm for deep learning and evaluated the effectiveness of 18 methods. The CatBoost algorithm has an R2 value of 0.976, which is better than other methods. In addition, the variables of distance, sea days, speed, duration, and port days had a significant effect on the prediction results. We determined this effect using Shapley’s additive interpretation (SHAP). This study can help PCTC companies efficiently estimate fuel consumption costs and meet environmental requirements, thereby improving operational efficiency and promoting sustainable practices in the shipping industry. We also enrich the existing body of knowledge by providing insights on predictive modeling techniques for fuel consumption costs in maritime logistics.

Turning points in leadership: Ship size in the Portuguese and Dutch merchant empires

AbstractThis paper discusses the implications of organizational control on the race for technological leadership in merchant empires. I provide an illustrative framework in which poor organizations have reduced incentives to invest, which in turn stifle technology improvements making leaders lag new entrants. In the late sixteenth century, Portugal’s large ships carried more merchandise and were more fitting of the monarch’s grandiose preferences, but they also were more prone to disaster. The merchant-controlled Dutch East India Company however, invested in smaller but more seaworthy vessels conducting more voyages at a much lower loss rate. The surviving historical evidence shows Portugal relying on large ships well into the seventeenth century suggesting her technological edge was gone by the time the Dutch dominated the Indian Ocean.

ANALYSIS OF MARITIME ACCIDENTS IN MALAYSIAN WATERS

Throughout the South China Sea and the Malacca Strait, more than 60% of all maritime trade passes each year. The rapid growth in fleet size and ship size may lead to an increase in maritime accidents. Since many maritime accidents cause serious injuries, fatalities, damage of property and monetary losses, it is essential and crucial to discuss about marine safety. In this study, a statistical analysis was performed in order to assess the number of maritime accidents that occurred in Malaysia between 2018 and 2021, as well as the percentage of accidents that occurred in each accident category and for each type of ship. The analysis also considers the age of the ship. The data that were presented also looks into a potential relationship between the age of the ship and the accident percentage. The results demonstrate that general cargo ships were the ship categories that are most vulnerable to maritime accidents; collisions were the accident type that occurs most frequently, and there were several relationships between the accident percentage and ship age. The results may be utilized to help seafarers, related government agencies and other relevant organizations promote risk prevention, create efficient risk response plans, and establish strategies to enhance the marine mechanism for managing safety in Malaysian waterways.

A tree search algorithm for uncertainty-considered consecutive discharging and loading operations between ship and offshore platform

This paper presents a combinatorial optimization problem for consecutive discharging and loading operations on a floating cargo-handling platform which is a new maritime technology for liquified natural gas redistribution. Because the discharging and loading process involves complex operations with stochastic and sequential nature, a Markov decision process model is formulated for the problem description with the objective of minimizing the ship turnaround time. Then, a tabu-based tree search algorithm allowing a look-ahead at future states is developed. Two sets of practical rules are proposed to control the local tree structure in terms of depth and breadth. The ship stability is also considered. A comprehensive analysis is conducted to determine the most suitable operation strategy for a specific platform design, followed by the analyses of the impacts of strategy parameters, ship size, operation uncertainties. The results show that a customized strategy that considers the dual-cycling operation outperforms other strategies.

Aerial visual data-driven approach for berthing capacity estimation in restricted waters

Coastal ship berth planning and management necessitate accurate identification of ship position and size, yet this is complicated by the presence of diverse ship types and mixed distribution patterns. Traditional survey-based and position-tracking ship monitoring methods have limitations in reflecting the precise spatial information of coastal ships and their surroundings. This paper introduces a novel aerial visual data-driven methodology to estimate the berthing capacity of sheltered space for stationary ships in geographically dispersed water areas. To measure the berthing capacity, image data from an unmanned aerial vehicle (UAV) survey is collected to reflect the spatial information of all types of ships. A deep learning-based computer vision algorithm is used to automatically detect, identify, and classify ships in sample images. Additionally, we introduce the occupancy factor to empirically quantify the spatial proportional correlation between the ship size and the requisite berthing capacity. A validation test of the proposed method is conducted across all sheltered spaces in Hong Kong, and the UAV survey yields over 7,000 informative images of all types of local ships. The ship identification algorithm achieves an average identification rate of 98.6%, demonstrating higher accuracy and reduced labor and time consumption than observational survey and manual counting methods. Findings indicate that the suggested sheltered space for individual ships is 7.75 times the ship size. The approach provides greater flexibility in estimating berthing capacity for mixed berthing forms in extensive or geographically dispersed water bodies, thereby having the potential to support the design of berths, anchorage areas, and typhoon shelter facilities in coastal regions.

Derivation of Optimum Outfit Density for Surface Warships based on the Analysis of Variations in Work Content and Workforce Density and Productivity with Ship Size

The potential impact of a ship’s outfit density on the labor hours required for production, sustainment, and upgrade has been discussed within the domain of warship design for decades. For fixed ship mission, systems capabilities, crew size, specification complexity and maturity, other producibility characteristics, and work schedule, as a ship’s size varies, required production labor hours are impacted in two ways—first by a change in work content and second by a change in worker productivity with available space. Because these impacts are inversely related, there exists an optimum ship size and outfit density that minimizes required labor hours. This paper describes an analysis of optimum outfit density to minimize production labor hours for complex modern surface combatants. The key relationship between available space and worker productivity is defined based on data from multiple industries. This relationship is then used along with knowledge of surface combatant design and shipbuilding processes and production labor requirements to identify an optimum range of overall outfit density to target during ship design. This derived optimum range is validated with other related research and reference to the outfit densities of existing modern surface combatants and what is known about their ease of build. Also discussed are 1) alternative ship design and production paradigms that might allow for ships with higher outfit densities while maintaining efficient production, maintenance, and upgrade and 2) implications of the relationship between available worker space and worker productivity for shipyard planning and work execution.

Productivity and Financial Analysis of Fishing Effort with Handline at Kutaraja Oceanic Fishing Port Aceh Province

Production of catches on hand line fishing gear at Kutaraja Ocean Fishing Port has declined. This is seen from the level of fish production produced, which was 2.407.580 tons in 2018, compared to in 2019 which was 2.285.750 tons. The fishing business, which has become one of the livelihoods of the Indonesian people, is a little riskier than other businesses because the fish, which are the play target of this business, are constantly moving dynamically. The research objective was to determine productivity per GT, Trip, and ABK on hand line fishing gear and to determine the financial feasibility analysis of fishing effort on hand line fishing gears at Kutaraja Ocean Fishing Ports. The benefits of this research are to increase knowledge and insight regarding productivity and financial analysis of the fishing line effort. The method used in this study is a survey method. The data analysis method used in this research is descriptive. The results showed that the value of productivity per trip with large-size ships has a high amount of production compared to smaller ship sizes. Hand line fishing with a vessel size >30 GT has a relatively long payback period, <5 years. While ships with a height of 5 GT, 6 GT, 9 GT, 22 GT, and 24 GT have a payback period of <3 years.

АСПЕКТИ ЦИФРОВІЗАЦІЇ ПРАВИЛ ЗАПОБІГАННЯ ЗІТКНЕННЯ СУДЕН

The study is devoted to the development of proposals that would allow for a more complete consideration of the requirements for actions to avoid ships in various situations. On the basis of the analysis of methods for ensuring safe avoidance it is established that the most suitable variant of setting safety limits can be considered as target domains. It is noted that when passing by target at long distance, it is necessary to take into account in domain the features of own ship and that target. The first vessel is considered as a point when solving the problems of collision avoidance in this case. When it is necessary to pass by at a short distance, the size of the own ship is not taken into account in the target domains. Own ship is represented as a rectangle with sides equal to her length and width. It is noted that the most appropriate way to prevent collisions with navigational obstacles is to use the boundaries of safe bearing, distances, lanes, depths (isobaths, "no go areas" contours) in onboard collision avoidance systems. These boundaries should be stored in the system memory. An indicator for determining the significance of a change in course or/and speed is proposed. The method is chosen and the duration of maneuver calculation is found with its help, at which the results obtaining will be considered in real time. The necessity to disregard point (b) in COLREGs Rule 14 when automatically determining the type of situations is justified, as its taking into account reduces the number of existing variants of approaching ships with the risk of collision on opposite courses. A refined list of binary situations affecting the choice of maneuvers in free waters in normal visibility is presented. The actions answering the binary situations and not contradicting COLREGs are proposed for power driven ships and vessels with different navigational status in free waters in normal visibility. Eight types of acceptable action zones were identified and prioritized to select maneuvers in the presence of moving and stationary obstacles. The maneuver option is selected in the zone with the highest priority. Keywords: collision avoidance, domain of danger, binary situations, compliance with COLREGs, zones of acceptable actions

Minimal Crew Size and Sensitive Reproductive Parameters on Multigenerational Interstellar Travel

Multigenerational interstellar travel to exoplanets, as well as manned missions to the Moon and Mars, has been investigated in the world. Defining the minimum crew size of interstellar ships is one of the most important research areas for interstellar travel, because designing multigenerational interstellar ships requires defining a critical crew size, which factors into many variables, including food production, air/water control, and propulsion. Anthropologists and astrophysicists have recently tackled with the minimum crew size of interstellar ships in the field of “Space anthropology”. Previously published computations in the field of space anthropology provided a critical crew number of 1,900- 2,000 (Sano, 2021) with constant reproductive parameters, but did not fluctuate reproductive parameters such as infertility, initial genetic diversity and number of children per woman. These parameters would fluctuate during the real multigenerational journey. Then, a more accurate estimate of the critical crew size would be obtained from the fluctuating parameters. This paper provides a critical crew size of 1,400-6,800 for interstellar travel using the fluctuating parameters, and clarifies which anthropological parameters are sensitive and how critical to be controlled aboard interstellar ships. It indicates that measuring infertility and controlling the number of children per woman for many generations onboard interstellar ships are essential to prevent extinction, and firstly quantifies the importance of high diversity of initial crew and procreation window for interstellar travel.

Judging a ship by its anchor: Bronze age stone weight anchors as indicators of ship size

Three scale models of a one-hole stone anchor found at the Uluburun shipwreck site were tested in the sea, with their dragging force history being monitored and recorded. It was found that on a sandy seabed the measured holding power of an anchor is about 37 % of its dry weight, and about 49 % of its dry weight on a rocky seabed. The results were applied to the Ma‘agan Mikhael II replica ship, and the forces acting on the ship, in different sea conditions, were compared to the holding power of the anchor. Wind velocity of 31.1 knots (16 m/s) and a current velocity of 2.9 knots (1.5 m/s), were chosen as representing extreme sea conditions. The forces acting on an anchored Ma‘agan Mikhael II ship under these conditions were calculated and extrapolated for ships of different dimensions, but with the same structure and proportions as the Ma‘agan Mikhael II using the replica scaling relations. These were compared to the holding power of the anchor, and the results can create a model that estimates the maximum size of the ship (as represented by its cargo capacity) by the mass (weight) of the anchor. This model estimates the size of a ship using a single one-hole stone anchor.

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.

Numerical analysis on the seakeeping performances of a full-scale container ship hull using strip theory

The race of taking more cargo on a ship has increased the size of ships as well as other aspects, such as their capacity and structural complexity, which affect the stability of ships. For naval architects and academics, accurately predicting seakeeping performances is difficult. In order to address this, the seakeeping performance of a container ship hall built by Korea Research Institute for Ships and Ocean Engineering (KRISO), i.e., KRISO container ship hall (KCS) is described in this research utilizing a numerical method. Maxsurf software based on strip theory was used to determine the results, where the containership hull was considered and input motions were applied with appropriate boundary conditions. Later, the ship's heading and speed were changed to see the effect of the seakeeping performance of the container ship. The current study is concentrated on systematic comparative research on the investigation of the ship's pitch, heave, and roll movements in irregular waves. It has been found that rolling motion was the highest at 22 kn at the 60° heading angle, potentially affecting ship stability. The significant amplitude analysis indicates that the roll motion is the largest at 60° of wave direction. The pitch motion response and the heave motion are near for each heading angle when the wave frequency exceeds 0.5 and 1 rad/s, respectively. The calculation findings show that seakeeping performance is directly related to ship direction and speed. Furthermore, threatening heading angles during sailing are classified, which could also help in enhancing ship stability.