Research

20 pages, 4465 KiB

Open AccessArticle

Ensuring Reliable and Safe Operation of Trunk Diesel Engines of Marine Transport Vessels

by Sergii Sagin, Volodymyr Madey, Arsenii Sagin, Tymur Stoliaryk, Oleksij Fomin and Pavel Kučera

J. Mar. Sci. Eng. 2022, 10(10), 1373; https://doi.org/10.3390/jmse10101373 - 26 Sep 2022

Cited by 7 | Viewed by 1494

Abstract

In this study, a method for ensuring reliable and safe operation of marine trunk diesel engines is considered. The research was carried out on 5L23/30 MAN-B&W diesel engines of a Bulk Carrier class vessel. The objective of the study was to determine the [...] Read more.

In this study, a method for ensuring reliable and safe operation of marine trunk diesel engines is considered. The research was carried out on 5L23/30 MAN-B&W diesel engines of a Bulk Carrier class vessel. The objective of the study was to determine the effect of the structural characteristics of the oil layer (wetting angle and thickness) on the operational parameters of a marine diesel engine (compression pressure, concentration of nitrogen oxides in exhaust gases and temperature of exhaust gases after the cylinder) and performance characteristics of the oil (base number, wear and contaminant elements). It has been established that an increase in the degree of the contact angles of wetting and in the thickness of the oil layer improves the heat and power and environmental performance of a diesel engine. At the same time, the decrease in compression pressure in the cylinder slows down, the temperature of gases after the cylinder decreases, and the emission of nitrogen oxides with exhaust gases decreases. Also, it was found that wear of diesel parts and oil oxidation are reduced. The study confirms the possibility of improving the reliable and safe operation of trunk-type diesel engines of maritime vessels by effective control of variables relating to the characteristics of engine oil. Full article

(This article belongs to the Special Issue Dynamic Load of Shipping)

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23 pages, 6692 KiB

Open AccessArticle

Ensuring the Environmental Friendliness of Drillships during Their Operation in Special Ecological Regions of Northern Europe

by Sergii Sagin, Oleksiy Kuropyatnyk, Arsenii Sagin, Ivan Tkachenko, Oleksij Fomin, Václav Píštěk and Pavel Kučera

J. Mar. Sci. Eng. 2022, 10(9), 1331; https://doi.org/10.3390/jmse10091331 - 19 Sep 2022

Cited by 9 | Viewed by 2171

Abstract

The features of the operation of the drillship-type vessels in special ecological regions of Northern Europe are considered. The main gap in the study of these systems is to determine the optimal degree of recirculation. The requirements of the International Maritime Organization for [...] Read more.

The features of the operation of the drillship-type vessels in special ecological regions of Northern Europe are considered. The main gap in the study of these systems is to determine the optimal degree of recirculation. The requirements of the International Maritime Organization for the emission of nitrogen oxides from the exhaust gases of marine diesel engines are given. The aim of the study is to determine the optimal degree of recirculation of exhaust gases of a 16V32 STX-MAN marine diesel. During the research, the optimal degree of exhaust gas recirculation varied in the range of 0–21%, the load on the diesel—in the range of 35–95% of the rated power. It was established that in this case, the emission of nitrogen oxides decreases up to 7.7–33.6%, the specific fuel consumption increases up to 0.2–3.5%. It was also found that the use of gas recirculation in the range of 18–21% at loads of 35–55% leads to a critical increase in exhaust gas temperature. It is advisable to use exhaust gas recirculation in the range of 6–15% to ensure the environmental friendliness of the operation of the drillships. In these modes, the maximum reduction in nitrogen oxide emissions is ensured with a minimum increase in specific fuel consumption. Future studies should be directed at the development of the criteria for the environmental stability of sea vessels. Full article

(This article belongs to the Special Issue Dynamic Load of Shipping)

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21 pages, 4559 KiB

Open AccessArticle

Static and Discrete Berth Allocation for Large-Scale Marine-Loading Problem by Using Iterative Variable Grouping Genetic Algorithm

by Dong Yin, Yifeng Niu, Jian Yang and Shaobo Yu

J. Mar. Sci. Eng. 2022, 10(9), 1294; https://doi.org/10.3390/jmse10091294 - 13 Sep 2022

Cited by 4 | Viewed by 1432

Abstract

In this paper, we study the static discrete berth allocation problems (BAPs) for large-scale time-critical marine-loading scenarios. The objective is to allocate the vessels to different types of berths so that all the vessels can be loaded within the minimum time under the [...] Read more.

In this paper, we study the static discrete berth allocation problems (BAPs) for large-scale time-critical marine-loading scenarios. The objective is to allocate the vessels to different types of berths so that all the vessels can be loaded within the minimum time under the tidal condition. The BAP is formalized as a min–max problem. This problem is rather complex as the vessels and berths are quite numerous in the large-scale marine-loading problem. We analyze this problem from a novel perspective, and find out that this problem has the characteristic of partially separable. Therefore, the iterative variable grouping genetic algorithm (IVGGA) is designed to search the near-optimal berth allocation plans. The vessels and berths are divided into subgroups, and the genetic algorithm (GA) is applied to generate the near-optimal berth allocation plans in each subgroup. To achieve the balance of loading tasks among subgroups, we propose reallocating some vessels among subgroups according to the berth allocation plans in subgroups. To guarantee the convergency of the algorithm, an iterative vessel reallocation policy is devised considering the loading tasks of different types of berths. We demonstrate the proposed algorithm in dealing with large-scale BAPs through numerical experiments. According to the results, we find that the proposed algorithm would have good performance when the number of vessels in each subgroup are kept in medium scale. Compared with the original GA, our algorithm shows the effectiveness of the iterative variable grouping strategy. The performance of our algorithm is almost not changed as the number of vessels and berths increases. The proposed algorithm could obtain efficient berth allocation plans for the large-scale marine-loading problem. Full article

(This article belongs to the Special Issue Dynamic Load of Shipping)

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18 pages, 6640 KiB

Open AccessArticle

Substantiation of Improvements for the Bearing Structure of an Open Car to Provide a Higher Security during Rail/Sea Transportation

by Oleksij Fomin, Alyona Lovska, Pavel Kučera and Václav Píštěk

J. Mar. Sci. Eng. 2021, 9(8), 873; https://doi.org/10.3390/jmse9080873 - 13 Aug 2021

Cited by 9 | Viewed by 1812

Abstract

This article presents the most frequent damage in the bearing structure of a rail car during rail/sea transportation. The study includes load modes for the bearing structure of an open car such as unloading with a grab and transportation by a train ferry. [...] Read more.

This article presents the most frequent damage in the bearing structure of a rail car during rail/sea transportation. The study includes load modes for the bearing structure of an open car such as unloading with a grab and transportation by a train ferry. It was found that the most vulnerable element of the bearing structure of an open car during unloading with a grab is the top cord. The authors suggest applying a viscous material (an elastomer) to reinforce the top cord. This solution was confirmed by means of a strength calculation, whose results showed the efficiency of the solution. The bearing structure of an open car during the train ferry transportation can be protected by mounting special fixation units on the bolster beams. The geometry of such units was chosen according to that of a chain binder. The results of the strength calculation demonstrated that the strength of the bearing structure of an open car was provided with the application of the fixation units suggested. The article also presents the results of the experimental determination of the strength of the improved bearing structure of an open car based on the finite element method and full-scale bench testing. The research conducted might be used by those who are interested in higher operational efficiency of rail cars during rail/sea transportation. Full article

(This article belongs to the Special Issue Dynamic Load of Shipping)

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20 pages, 2740 KiB

Open AccessArticle

Short Term Forecast of Container Throughput: New Variables Application for the Port of Douala

by Penn Collins Awah, Hyungsik Nam and Sihyun Kim

J. Mar. Sci. Eng. 2021, 9(7), 720; https://doi.org/10.3390/jmse9070720 - 29 Jun 2021

Cited by 7 | Viewed by 3143

Abstract

An accurate container throughput forecast is vital for any port. Since overall improvements in port performance and competitiveness can be derailed by port bottlenecks, ports need to find leverage to identify and prioritize measures to improve weak key performance indicators (KPIs) to attain [...] Read more.

An accurate container throughput forecast is vital for any port. Since overall improvements in port performance and competitiveness can be derailed by port bottlenecks, ports need to find leverage to identify and prioritize measures to improve weak key performance indicators (KPIs) to attain growth opportunities. Prior studies had modeled container throughput from socio-economic and growth projection factors. This study aims to provide a practical method for forecasting the optimal container throughput a port can physically handle/attract given a certain level of terminal operation efficiency through random forest (RF) and multilayer perceptron (MLP) models. The study variables are derived from the port operations dimension and include ship turnaround time, vessel draft, container dwell time, berth productivity, container storage capacity, and custom declaration time. Evaluations are made based on the R-squared, NRMSE, MAE and MAPE. Model comparison is deduced with seven competing models in container throughput forecasting. The findings indicate that the RF model is a potential candidate for forecasting the engineering optimal throughput of Douala port. Model interpretation is provided through feature importance and partial dependence plots. The findings from this study will help reduce uncertainty and provide leverage for port management to spot bottlenecks and engage in better port planning and development projects which will strengthen their international competitive advantage. Full article

(This article belongs to the Special Issue Dynamic Load of Shipping)

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23 pages, 16221 KiB

Open AccessEditor’s ChoiceArticle

Cooperative Maneuvering Mathematical Modeling for Multi-Tugs Towing a Ship in the Port Environment

by Gongxing Wu, Xiaolong Zhao, Yushan Sun and Linling Wang

J. Mar. Sci. Eng. 2021, 9(4), 384; https://doi.org/10.3390/jmse9040384 - 04 Apr 2021

Cited by 14 | Viewed by 3248

Abstract

The towing operation of multi-tug-assisted ship navigation mainly relies on the experience of the captain, and there is no set of effective operation methods. Therefore, it is difficult to achieve accurate assisted navigation when multiple tugboats work in coordination. The calculation method of [...] Read more.

The towing operation of multi-tug-assisted ship navigation mainly relies on the experience of the captain, and there is no set of effective operation methods. Therefore, it is difficult to achieve accurate assisted navigation when multiple tugboats work in coordination. The calculation method of maneuverability of the towing system with multi-tug-assisted navigation is proposed in this paper. In view of the complexity of multi-tug-assisted large ship maneuvering, this article focuses on solving the problems of force analysis and maneuvering modeling between the multi-tug and ship systems. Firstly, a maneuvering mathematic model for towing ships is established, and the hydrodynamic force of the hull, rope force of the tugs, and force of wind interference are analyzed. The thrust and moment of the ducted azimuthal propeller are calculated, and the mathematical model of the tug’s cable tension is discussed. Then, the fourth-order Runge–Kutta method is used to solve the differential equations of the maneuvering motion of the ships and each tug. Based on the ship-towing process by multiple tugs, a multi-tug-assisted ship towing simulation platform was built by using the Visual Studio development tool. Finally, on the simulation platform, multi-tug longitudinal-towing-simulation experiments at different speeds were carried out, and the simulation of turning towing maneuvers under the influence of wind was done. The simulation results showed that as the towing speed increases, the initial towing speed fluctuates greatly. There is a significant drift effect on the ships by the wind force. And the wind will cause a fluctuation in the tug’s rope force. The simulation of the multi-tugs towing a ship entering the port was carried out in the port environment. The results showed that the multi-tug towing system and simulation platform may be used for the safety training of the tug’s crew. Full article

(This article belongs to the Special Issue Dynamic Load of Shipping)

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18 pages, 6509 KiB

Open AccessArticle

Aspects of Strength Testing of Tank Containers in Compliance with the Requirements of the UN Navigation Rules and Regulations

by Andrii Sulym, Pavlo Khozia, Eduard Tretiak, Václav Píštěk, Oleksij Fomin and Pavel Kučera

J. Mar. Sci. Eng. 2021, 9(3), 349; https://doi.org/10.3390/jmse9030349 - 23 Mar 2021

Cited by 3 | Viewed by 2518

Abstract

This article deals with the method of computer-aided studies of the results of tank container impact tests to confirm the ability of portable tanks and multi-element gas containers to withstand the impact in the longitudinal direction on a specially equipped test rig or [...] Read more.

This article deals with the method of computer-aided studies of the results of tank container impact tests to confirm the ability of portable tanks and multi-element gas containers to withstand the impact in the longitudinal direction on a specially equipped test rig or using a railway flat car by impacting a flat car with a striking car, in compliance with the requirements of the UN Navigation Rules and Regulations. It is shown that the main assessed characteristic of the UN requirements is the spectrum of the shock response (accelerations) for the interval natural frequencies of the shock pulse. The calculation of the points of the shock response spectrum curve based on the test results is reproduced in four stages. A test configuration of the impact testing of the railway flat car with a tank container is presented, and the impact is performed in such a way that, under a single impact, the shock spectrum curve obtained during the tests for both fittings subjected to impact repeats or exceeds the minimum shock spectrum curve for all frequencies in the range of 2 Hz to 100 Hz. Formulas for determining the relative displacements and accelerations for the interval natural frequencies of the shock wave are given. The research results are presented in graphical form, indicating that the experimental values of the shock response spectrum exceed the minimum permissible values; the equation of the experimental curve of the shock response spectrum in the frequency range 0–100 Hz is described by power-law dependence. The coefficients of the equation were determined by the statistical method of maximum likelihood with the determination factor being 0.897, which is a satisfactory value; a comparative analysis showed that the experimental curve of the impact response spectrum in the frequency range 0–100 Hz exceeds the normalized curve, which confirms compliance with regulatory requirements. A new test configuration is proposed using a tank car with a bulk liquid, the processes in which upon impact differ significantly from other freight wagons under longitudinal impact loads of the tank container. The hydraulic impact resulting from the impact on the tank container and the platform creates an overturning moment that causes the rear fittings to be unloaded. Full article

(This article belongs to the Special Issue Dynamic Load of Shipping)

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14 pages, 6244 KiB

Open AccessArticle

Dynamic Load and Strength Determination of Carrying Structure of Wagons Transported by Ferries

by Alyona Lovska, Oleksij Fomin, Václav Píštěk and Pavel Kučera

J. Mar. Sci. Eng. 2020, 8(11), 902; https://doi.org/10.3390/jmse8110902 - 11 Nov 2020

Cited by 33 | Viewed by 2365

Abstract

A rapid development of economic relations between states has required an introduction of combined rail/ferry transportation. A feature of this type of transportation is the possibility of wagons traveling by sea on specially equipped ships—railway ferries. However, the transportation of wagons by sea [...] Read more.

A rapid development of economic relations between states has required an introduction of combined rail/ferry transportation. A feature of this type of transportation is the possibility of wagons traveling by sea on specially equipped ships—railway ferries. However, the transportation of wagons by sea is accompanied by damage to their structures. This follows from the fact that the wagons are not adapted to this type of transportation. In addition, the design of wagons does not consider the loads that can act on them during transportation by sea. In this connection, it is important to study the dynamic loading and strength of wagons during their transportation by sea. The current work investigated into dynamic load on the carrying structure of wagons transported by ferries using mathematical and computer modelling and defined accelerations on the wagon body. The adequacy of the models was checked with an F-test. The results of strength calculation for the carrying structure of a wagon made it possible to conclude that a typical fixation diagram does not provide the admissible range of strength parameters. The current work proposed an improved fixation diagram for cars on the deck with the viscous binder. The solution was substantiated by the results of the mathematical modelling of dynamic forces, strength, and stability of the carrying structure of a wagon on the deck. The results of the work will contribute to the creation of recommendations for the transportation of wagons on ferries. The research can contribute to safe transportation of wagons by ferries, and higher efficiency of the combined transportation Full article

(This article belongs to the Special Issue Dynamic Load of Shipping)

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