Ship Form Research Articles

Multi‐Objective Optimization and Experimental Research of Ship Form Based on Improved Bare‐Bones Multi‐Objective Particle Swarm Optimization Algorithm

ABSTRACTShip form optimization poses a complex and high‐dimensional engineering challenge. Therefore, when conducting multi‐objective optimization research of ship forms, traditional intelligent optimization algorithms are prone to falling into local optima solution and difficult to converge. In order to effectively improve the diversity and convergence performance of the algorithm, this paper improves the bare‐bones multi‐objective particle swarm optimization (BBMOPSO) algorithm by dynamically adjusting the local and global search step sizes, and verifies the algorithm's reliability through standard function testing. Then, a multi‐objective optimization design framework with high efficiency and high integration is constructed. Taking DTMB 5512 as the research case, Free Form Deformation (FFD) method is used for hull deformation, and the proposed algorithm is used for multi‐objective optimization of resistance performance and motion response. Ship model tests were conducted on the DTMB 5512's original hull. And the numerical simulations were compared with the ship model tests. Finally, under the constructed multi‐objective optimization design framework, satisfactory solutions were obtained through the improved algorithm, which confirms the effectiveness and practicality of the improved algorithm. The results show that the algorithm improved in this paper can provide some theoretical basis and technical support for green ship design and low‐carbon shipping.

Research on the construction of multi objective coupling model and optimization method of ship form

AbstractMulti‐objective optimization of ship form can effectively reduce ship energy consumption, and is one of the important research topics of green ships. However, the computational cost of numerical simulation based on computational fluid dynamics (CFD) theory is relatively high, which affects the efficiency of optimization. Traditional subjective weighting methods mostly rely on expert's experience, which affects the scientificity of optimization. This paper effectively integrates the CFD method, the improved multi‐objective optimization algorithm and the objective weighting method to build a ship form multi‐objective optimization framework. Conduct multi‐objective optimization research on resistance and seakeeping performance of a very large crude oil carrier (KVLCC) ship. The improved bare‐bones multi‐objective particle swarm optimization (IBBMOPSO) algorithm is used to obtain the pareto front, and the kernel principal component analysis (KPCA) method is used to objectively assign the weight of each target. Finally, the optimal ship form scheme with high satisfaction was obtained. The multi‐objective optimization framework constructed in this paper can provide a certain theoretical basis and technical support for the development of ship greening and digital transformation.

Multi-objective optimisation research of ship form in waves based on Kernel principal component analysis

ABSTRACT In the process of multi-objective optimisation design of ship forms, subjective weighting methods rely on experts’ experience and have a certain impact on the scientificity of results. The objective weighting method can effectively solve this drawback and reduce the interference of human factors. Therefore, this paper proposes a multi-objective optimisation design programme for ship forms based on KPCA method, and constructs a multi-objective optimisation design framework. In this paper, the KPCA method is used to calculate the contribution rate of each indicator for objective weighting, give the comprehensive evaluation score of the optimal solution set and make decisions, solve the technical drawbacks of subjective weighting, and obtain a satisfactory optimal hull form. The results show that the automatic multi-objective optimisation design method proposed in this paper has certain engineering application value, and can provide theoretical basis and technical support for green design and manufacturing of ships.

Leisure Boat Concept Design: Study on the Influence of Hull Form and Dimension to Increase Hydrodynamic Performance

The tourism sector contributes significantly to the economic growth of the community and the country. Labuan Bajo has the potential for marine tourism, which is famous for foreign classes. The separation of the islands in Labuan Bajo requires transportation to support tourist activities to tourist destinations. One type of transportation to support the needs of marine tourism is leisure boats or recreational boats. The leisure ship must have standards of comfort, security for passenger safety, and efficient operational costs. It is necessary to have infrastructure in the form of a leisure ship that functions optimally, so research on the hull’s hydrodynamic characteristics is essential. This research aims to observe the influence of hull form variables and primary size on the hydrodynamic characteristics of the ship. The research method was the simulation method to determine the response of the hull model variation to the environmental conditions tested. Simulation testing using Maxsurf software based on resistance, stability, and seakeeping criteria. The MADM method analysis results showed that the Deep V Hull model variation had the highest score of 0.787. In the sensitivity analysis calculation, the hull form variable significantly affected resistance and stability testing with R square values of 0.6008 and 0.5930. Meanwhile, the size variable had more influence on seakeeping testing, especially roll motion, with an R square value of 0.4081.

Hull form optimization of fully parameterized small ships using characteristic curves and deep neural networks

Designing a hull form typically involves beginning with a reference hull form based on ship owner requirements, editing the hull form to satisfy the requirements, and determining the most efficient hull form. Numerical analyses using Computational Fluid Dynamics (CFD) were employed to assess the performance of the hull form. However, these analyses require extensive computational resources, making it challenging to perform thorough analyses within the design timeframe. To address this issue, this paper proposes an approach that involves defining a range of hull forms with characteristic curves, predicting their performance using Deep Neural Networks (DNNs), and subsequently determining the optimal hull form based on these predictions. Initially, the hull form of a small ship was defined using four characteristic curves and parameterized using 29 variables. Fairness optimization was performed using these characteristic curves to define the hull form surface. By varying 29 parameters, 896 different hull forms were generated, with CFD analysis conducted for each variant. These data were then used to build a DNN model capable of predicting the performance based on hull form parameters. The accuracy of the DNN model was evaluated, resulting in a Mean Absolute Error (MAE) of 2.835%. Subsequently, the DNN model is combined with a genetic algorithm to identify the optimal set of parameters for the hull form, resulting in an optimal hull form. This optimization process revealed that the optimal hull form reduced the total hydrodynamic resistance by approximately 7% compared to the initial reference design. Consequently, this study demonstrates the effectiveness of the proposed method for deriving the optimal hull form for small ships.

Retrofitting the Bow of a General Cargo Vessel Andevaluating Energy Efficiency Operational Index

Abstract This report examines the feasibility and impact of retrofitting the bulbous bow on a general cargo ship, in terms of the energy efficiency operational index (EEOI), in the areas of Western Europe and the Eastern Mediterranean. Three ship forms were developed and analysed: with a bulbous bow, without a bulbous bow, and with a modified bulbous bow. The goal in developing the ship forms and conducting the analysis was to achieve minimal differences in the ship’s characteristics with the same volumetric displacement, aided by PolyCAD software. A route was selected between two ports: Varna and Rotterdam. The labour intensity of the bulbous bow retrofitting process was evaluated and approximate values of labours costs and cost for the task were determined. The results obtained for resistance during ship motion, EEOI, and fuel consumption reductions, or increases, were compared against the retrofitting values. The return cost of retrofitting is evaluated and measured in terms of fuel saved.

Development of propulsion solutions for river-sea ships of the northern Black Sea

Conception of hull form and propulsion design of river-sea ships essentially depends on the restrictions of specific inland waterways. River-sea ships of the Northern Black Sea were historically designed for operation through the locks of European inland waterways of the former Soviet Union. River-sea vessels of the late Soviet Union were designed as simple and technological. After dramatic economical changes the ships of new generation acquired completely different features of general and propulsion design. The vessels had unusually full hull forms and azimuthal thrusters. As is shown in the paper, the full hull forms have sound economic grounds for the considered ship type. However, azimuthal thrusters have controversial features and are not non-alternative. Based on analysis of previous and current propulsion solutions their further development is proposed within the considered ship type. Hull forms designed with specially developed CFD methods are recommended as a further step toward propulsion optimality.

Designing A Practical Remote-Control Vessel Using LA Antenna Radio Frequency

One of the developments in the technology field is remote control using both wires (wired) and without wires (wireless). Wireless power can be done using signals such as infrared, bluetooth, radio frequency, and Wi-Fi. Remote control using radio frequency signals is very interesting because it can reach far distances without spending money. The purpose of this study is to develop a design and analyze the effectiveness of remote control of ships using radio LA antenna frequencies. Wireless radio frequency signals combined with Arduino can control the propeller and rudder so that the boat can be controlled remotely. This research uses a prototype method in the form of a control ship. The result of the study is that wireless remote control of the vessel can be done in open and closed spaces so that in the future it can be realized for absolute equipment control. The control on this prototype uses an LA antenna and no LA antenna. The result of the study is that the use of LA antennas is more effective than without LA antennas, in which the control distance in an enclosed space (with obstructions) without an LA antenna is as far as 100m and 500m when using an LA antenna. While the control distance in open spaces (without obstructions) without LA antennas, ships can be controlled up to distances of 1000m and 1300m when using LA antennas.

EHP VALUE OF MINI LNG SHIP WITH FORM FACTOR FROM PROHASKA AND IRLS METHOD USING SHIP RESISTANCE TESTING DATA

The ship model test was believed to be one of the effective methods for figuring out the boundaries and reliability of the ship's horsepower. The ship's form factor determines a full-scale ship's effective horsepower. Determination of the form factor value can be done experimentally through the Prohaska method. The new method proposed in this study is employed the regression Iteratively Reweighted Least Squares (IRLS) method by utilizing the principle dimension of the ship, such as LWL, B, CB, CP, CM, WSA, T, ∆. etc. The Indonesian Hydrodynamics Laboratory has a database of ships with various principle dimensions which have undergone the towing model test. Through the database, the form factor can be predicted with the IRLS method. The method is then verified and validated with the Prohaska method. The result shows a good agreement with the Prohaska method. The obtained results from the IRLS method also show that the EHP & Resistance calculations are identical with old fashion Prohaska methods. The residual bias factor established by the IRLS method was verified in comparison to the value of the form factor generated by the Prohaska method. Comparison between the two methods results in a small error.

Prediction of Added Resistance of Container Ships in Regular Head Waves Using an Artificial Neural Network

In this paper, an artificial neural network was used to predict the added resistance coefficient for container ships in regular head waves for various speeds. The data used for training the neural network were gathered based on performed numerical calculations using the Boundary Integral Element Method for various hull forms of container ships. The numerically obtained results were validated against the available experimental data for three benchmark container ships. The data were divided into three classes based on the ship length, and the expressions for the prediction of the added resistance coefficient for each container ship class were provided. The performance and generalization properties of the neural network were evaluated based on the normalized value of the root mean square error. The model enables reliable prediction of the added resistance coefficient within the preliminary design stage of a ship based on the ship characteristics and speed.

RESCUE OF COLLATERAL OBJECTS OWNED THIRD PARTIES DUE TO BREACH OF DEBTORS WITH SUBROGATION AS LEGAL REMEDIES IN SHIP CASES ABOVE 20 m3

Payments can also have limited consequences in the sense that these payments only result in the role of the Creditor being replaced by another Creditor and the Debtor will be faced with a new Creditor who has the right to request payment from the Debtor or what is known as Subrogation and in this study occurs in the case of ships over 20 m2 as a Hipotek . Ships can meet the criteria or requirements to become collateral for credit settlement in the form of a Hipotek. Ships As Collateral for Repayment of Credit where the Hipotek is a material right to immovable objects. Ships can be divided into two, namely those weighing above 20 m 3 and below 20 m 3 . This paper aims to find out which ships can be charged with a Hipotek, so that they can be used as collateral for credit repayment. The method used is normative legal research, namely an approach by studying the applicable laws and regulations. The conclusion of this paper is that a Hipotek is a form of credit repayment guarantee, which is regulated in Burgelik Wetboek . Hipotek can be applied to objects in the form of ships. Ships As Guarantees for Repayment of Credit where the Hipotek is a material right to immovable objects which in this study uses subrogation as a legal remedy used.

Design knowledge extraction framework and its application in multi-objective ship optimization

Currently, hull form optimization performs design space searches through an optimization algorithm to find the optimal solution and discusses the optimal result only while ignoring a large amount of optimized data. In the optimized data, there are implicit relationships between variables and between the variables and objective function, which can contribute to a better understanding of optimization problems. For the above problems, this paper studies the optimized data in hull form optimization and proposes a set of design knowledge extraction methods suitable for multi-objective ship optimization; in addition, we study the optimization of ship form lines under various working conditions using a 7500-ton inland twin-skeg bulk carrier as the research object. On this basis, the design knowledge is extracted via sensitivity analysis and self-organizing mapping neural network in data mining, and the effectiveness of the rule extraction technology is verified through a comparative analysis of the results. The concluded rules play a significant role in guiding hull form optimization.

Research on the influence factors of ship resistance and navigation drag reduction

With economic growth, ship transportation plays a major role in global logistics. The optimization of the ship form based on minimum resistance has been the research focus of ship builders for hundreds of years, but the actual process is quite complex, which also brings huge benefits. Ship drag reduction is not only conducive to industrial economic growth, but also helpful to improve the global energy consumption and environmental problems. In this paper, the Reynolds number and the Froude number are obtained by a dimensional analysis, and then the data are obtained from the model ship experiment with the same Froude number by the law of similarity. The total resistance is subdivided into four kinds with different causes, namely the friction resistance, wave-making resistance, form resistance, and additional resistance. In this way, the ship resistance can be reduced more scientifically and efficiently.

LAW ENFORCEMENT OF ILLEGAL FISHING IN THE IMMIGRATION PERSPECTIVE IN THE WORKING AREA OF BELAWAN IMMIGRATION OFFICE

The abundance of natural resources and the vast area of ​​the ocean in Indonesia are an attraction for the surrounding countries. This makes the case of Illegal fishing a case that is often found in Indonesian seas. One of the affected areas is Belawan seas. Based on the supervision carried out by the Ministry of Maritime Affairs and Fisheries (KKP), it is stated that illegal fishing violations often occur in EEZ (Exclusive Economic Zone) seas. One of the institutions authorized to enforce the law on illegal fishing is immigration. This study aims to see the implementation of law enforcement and immigration law strategies against foreigners who commit illegal fishing crimes in the work area of ​​the Belawan Immigration Office. This research is structured using a combination of normative and empirical research with qualitative methods using the basic theory of State Sovereignty and Effectiveness (Enforcement) of Law. The results of the study found that the Belawan Immigration Office carried out law enforcement in the form of Immigration Administration Actions namely deportation, some of the obstacles encountered in law enforcement were the lack of infrastructure in the form of ships and the limited detention room at the Medan Immigration Detention Center. The researchers also found that the legal strategy efforts carried out by the Belawan Immigration Office were preventive and repressive strategies. With Preventive Strategies in the form of coordination with Foreign Surveillance Team and Foreign Embassies, Repressive Strategies in the form of strengthening the intensity of Immigration Administrasion Action and Investigations.

Determination of the weights of external conditions for ship resistance

Ships are exposed to added resistance caused by external environmental conditions, as well as the resistance due to the ship's form and the molecular features of the water. Since ship resistance is directly related to the fuel consumption and emission production of the ship, it is an essential obstacle to overcome for more efficient navigation. One of the basic approaches applied to reduce additional resistance is route optimization, and for a correct application, the effects of external environmental conditions should be well known. In this study, an artificial neural network model, in which nine external environmental conditions (current speed, current direction, swell height, swell direction, wave height, wave direction, significant wave height, wind angle, and wind speed) are used as input and ship resistance is used as output, was developed and the weights of external environmental conditions on the resistance were calculated. The results reveal that the two most dominant conditions affecting resistance are swell direction (33%) and wave direction (28%). Accordingly, it is suggested that ships should consider these two data more while making route optimization.

Continuity with respect to the speed for optimal ship forms based on Michell's formula

<p style='text-indent:20px;'>We consider a ship hull design problem based on Michell's wave resistance. The half hull is represented by a nonnegative function and we seek the function whose domain of definition has a given area and which minimizes the total resistance for a given speed and a given volume. We show that the optimal hull depends only on two parameters without dimension, the viscous drag coefficient and the Froude number of the area of the support. We prove that, up to uniqueness, the optimal hull depends continuously on these two parameters. Moreover, the contribution of Michell's wave resistance vanishes as either the Froude number or the drag coefficient goes to infinity. Numerical simulations confirm the theoretical results for large Froude numbers. For Froude numbers typically smaller than <inline-formula><tex-math id="M1">\begin{document}$ 1 $\end{document}</tex-math></inline-formula>, the famous bulbous bow is numerically recovered. For intermediate Froude numbers, a "sinking" phenomenon occurs. It can be related to the nonexistence of a minimizer.</p>

Legal protection for sea transport passengers

In terms of transportation, safety and security issues are of particular concern. The shipping safety and security system is an important factor that must be considered and as a basis and benchmark for decision-making in determining the feasibility of shipping both in terms of facilities in the form of ships and infrastructure such as navigation systems, and the human resources involved in it. Indonesia has sovereignty over the entire Indonesian sea area, so the sea has a significant role in both the means of unifying the nation and the territory of the Republic of Indonesia, as well as the sea as an invaluable asset of the nation and the future of Indonesia. The efforts that can be made in maximizing legal protection for passengers are to improve the legal system in the shipping sector, including the substance of the provisions regarding shipping, which are further enhanced in the form of sanctions against companies, the addition of providing adequate and comfortable facilities and infrastructure for passengers, especially in the field of legal protection against losses incurred. suffered by passengers, sometimes the transportation company pays less attention to passengers who suffer losses.How to cite item: Wahyudi, R., (2022). Legal protection for sea transport passengers. Jurnal Cakrawala Hukum, 13(3)316-324. doi:10.26905/idjch.v13i3.7490.

Numerical Water Impacts of 2D Hull Forms using Dynamic Overset Meshing

The phenomenon of slamming is often the critical design load for high-performance marine craft. Slamming involves the solid-fluid impact of a hull structure, resulting in large forces acting on the structure from the large volume of water displaced in a very short time frame. Due to its importance in the design and operation of marine craft, the impact of ship forms into water has been the focus of a significant body of literature. These studies have primarily focused on rigid shapes, so the effects of hydroelasticity have not been examined in detail. This paper presents a robust and practical methodology for simulating water impacts involving overset meshing and the Volume of Fluid (VOF) method using the Ansys Fluent 2021 R1 Computational Fluid Dynamics (CFD) solver. The framework involves a high resolution dynamic overset mesh attached to the body in a coarse static Cartesian background mesh. Results for a simple 2D wedge impact are compared to experimental and analytical results and a good agreement to the validation material is observed. A 2D transverse section based on the IMOCA60 racing yacht Banque Populaire VIII is then analysed to obtain impact force and pressures. Results capture the peaked pressure distributions characteristic of slamming, with possible effects of air entrapment. The methodology presented is applicable for designers of high-performance sailing craft to improve the prediction of hydrodynamic loading on their hull-form designs. The overset method can quickly and easily be applied to a number of different geometries and impact events with minor changes between models.

Ośrodki węzłowe i kontakty transbałtyckie pomiędzy społecznościami północno-zachodniej Rusi i ziem polskich w X stuleciu

The inflow of oriental silver to the lands of Western Slavdom, through the centers of Eastern Europe via the Baltic Sea, was the main determinant of material contacts between the communities of the two regions of the continent. However, they show only one direction – namely, from east to west. The results of the latest research show their second aspect, this time relations from west to east. To the centers located in the north-western zone of Eastern Europe arrived ceramic vessels specific to pottery of the North-Western Slavic territory or people who made them there on the spot. In addition, Tornow type vessels have been registered in Gorodok on the Lovat river. The chronological framework of the occurrence of these artefacts corresponds to the times when the strongholds in the Tornow-Klenica zone were liquidated. Staraya Ladoga and Wolin played a leading role in these relations. Both strongholds served as nodal points, where the forms of trans-Baltic shipping were combined with the inland navigation routes leading deep into both areas. The material culture of the communities of these settlements is also characterized by a number of similarities. Large buildings of post-and-plank construction were discovered there, erected at the end of the 9th and the beginning of the 10th century. The presence of large houses that stand out in the landscape of both centers is also perceptible in the second half of the 10th century. The material culture registered inside and in the vicinity of these wooden structures indicates that they could have been the seats of people involved in long-distance trade who can be regarded as “trade diasporas”. Their attributes included wooden anthropomorphic idols, balances and weights, and artifacts of Oriental origin. This article is an attempt to initiate a new Polish-Russian discussion on the cultural ties between the communities of Polish lands and Rus’ in the early Middle Ages.

Theoretical manual of ‘YTU DEEP’ SHIP motion program

The theoretical background for an in-house seakeeping code ‘YTU DEEP’ that calculates heave, roll and pitch motions of displacement ships is established in this paper. The code consists of two main parts: frequency and time-domain calculations. Two-dimensional added mass and damping coefficients are calculated by using Ursell's multipole expansion theory. Lewis conformal mapping technique is used together with Tasai's method to compute the sectional hydrodynamic coefficients. The strip theory of Salvesen et al. is used to obtain the global hydrodynamic coefficients. The damping values for the roll motion are calculated by using Ikeda's method. Excitation terms for pitch and heave motions are computed by using head seas approximation. The excitation term for roll motion is predicted by using low steepness waves approximation. For frequency domain code validation, Response Amplitude Operators for the AME CRC hulls motions are plotted at different forward speeds and in head waves. The results are compared with the experimental results and a good agreement is observed. For time-domain calculations, Cummins' method is utilized which used the sectional hydrodynamic coefficients in the frequency domain. The coupled pitch & heave and uncoupled roll motion equations are solved via the 4th order Runge Kutta Method. The solution of Cummins equations is tested for a container and passenger ship form simulation in bow quartering waves. A user-friendly interface is created for performing both frequency and time-domain simulations. Pre-processing, solution, and post-processing are applied with a MATLAB code. The proposed seakeeping code aims to create a quick and efficient ship motion program.