Kinds Of Ships Research Articles

An efficient method to simulate ship self-propulsion in shallow waters and its application to optimize hull lines

Emerging environmental challenges, such as pronounced low water levels and a constantly increasing transport volume, underscore the need to address logistical complexities and to refocus attention on the performance of self-propulsion vessels in restricted and confined waters. Recognizing the demand for an accurate and efficient ship design method, we modified an actuator disk model to predict ship propulsion. This model was designed to be applicable to various kinds of ships, with special features tailored to meet the specific requirements of inland water vessels, particularly those equipped with ducted propellers. We implemented this model into the open-source CFD software library OpenFOAM to be used in conjunction with either single- or multiphase incompressible solvers. We validated this implemented model against model test data, thereby demonstrating its capability to accurately predict propulsion performance of a typical inland waterway vessel. Following validation, we employed this model in an automated optimization process, demonstrating its robust and efficient applicability for a practical user-defined case to improve a ship's afterbody lines. Meticulous grid convergence studies ensured the predictive convergence of our simulations. Our validation covered various ship speeds at three distinct water depths, ranging from a moderate water depth-to-draft ratio h/T of 2.67 to an extreme shallow water depth-to-draft ratio h/T of 1.25. We validated our simulated results against data extracted from our own previous model tests, comprising measured ship trim and ship sinkage, propeller thrust, duct thrust, propeller torque, propeller revolution rate, and propulsion power. We investigated the influence of water depth also on various parameters, such as friction and pressure distributions, free surface interactions, and velocity patterns. Finally, we integrated the developed method into an automated optimization process that we tailored for a selected test cases of the considered ship operating in water depth to draft ratios h/T of 2.67. This integrated process facilitated the systematic refinement of the ship's afterbody lines, representing a crucial step in the pursuit to enhance ship performance.

The effect of main dimensions on the preliminary design of motor yachts

The design process of motor yachts mainly relies on the experience of designers, who have confidence in the knowledge acquired from designing units with similar hull-form characteristics. However, once a new concept needs to be developed, the acquired experience on a standard platform is no longer sufficient to achieve in a short time a successful design. The design of a motor yacht implies considering multiple aspects of ship hydrodynamics: resistance, propulsion, seakeeping, and manoeuvring. Such factors have been widely discussed individually on different kinds of ships, but an appropriate joint investigation of hulls like motor yachts is missing in the open literature. Therefore, the present paper intends to cover this gap, providing guidelines for the design of motor yachts in a length range between 20 and 40 meters. As a preliminary study, a series of 15 yacht hulls has been developed, starting from a reference hull form. Seakeeping, manoeuvring, and propulsive performances have been evaluated at a reference environmental condition and speeds according to the ISO 22834:2022 guidelines. Such calculations allow for developing response surfaces of the hydrodynamic properties for the series of yachts as a function of the hull's main dimensions. As a final result, the obtained responses allow for identifying the best compromise solutions for the main dimension selection of a new motor yacht in the length range of 20-40 meters.

Review on Sensors for Sustainable and Safe Maritime Mobility

The increasingly stringent requirements—in terms of limiting pollutants and the constant need to make maritime transport safer—generated the necessity to foresee different solutions that are original. According to the European Maritime Safety Agency, the total number of reported marine casualties and incidents is 21.173 over the period 2014–2021, with a yearly average of 2.647 casualties and incidents. According to the same source, 495 cases of pollution were reported in the period from 2014 to 2021. Marine pollution by ships’ fuel and other pollutants is linked to 64.2% of all pollution. It is mandatory to offer a new kind of ship that can exploit new technologies to increase safety for people and onboard goods. It has been found that existing marine structures for maritime mobility do not have essential sensors for avoiding emergency situations such as flooding, oil spills, or health situations requiring efficient monitoring. In addition, there is a lack of legislation defining the insertion of unmanned vehicles into the actual marine infrastructure. This review highlighted the strengths and weaknesses of sensors in the maritime sector, intensifying areas of improvement for future challenges, such as sensor energy efficiency, data processing, sensor fusion methodologies, and accurate sea state description with environmental monitoring by means of unmanned vehicles.

Characterizing onboard noise in ships: Insights from statistical, machine learning and advanced noise index analyses

Understanding the specific characteristics of onboard noise can significantly benefit human activity in different kinds of ships. Here, the perceived noise can significantly change from space to space in terms of both levels and frequency content, depending on location onboard in respect to the primary sources and on propagation paths. Moreover, secondary sources as ventilation systems contribute to generate a complex soundscape for each ship. In this work, noise spectra reported in the literature were collected and analyzed to obtain an overview of the noise characteristics in different spaces onboard military and commercial vessels, i.e. accommodation, navigation bridge, and other workspaces. A prevalence of high noise levels in the different spaces that can be over the commonly accepted limits was found, characterized by higher levels at low and high frequencies. Different noise indexes not yet adopted in this sector were tested on the data to derive more information about onboard noise annoyance. Supervised and unsupervised machine learning algorithms were also applied to qualitatively classify and study the collected spectra. The analysis shows the presence of different spectral typologies, i.e. balanced spectral shapes (quasi-linear decay of the noise level per octave band with no dominant frequency components) or unbalanced ones.

Optimization of Blade Position on an Asymmetric Pre-Swirl Stator Used in Container Ships

Owing to environmental regulations, ships are equipped with a pre-swirl stator (PSS), which is one of the most effective energy-saving devices (ESDs) that is widely applied to various kinds of ships. It improves energy efficiency by recovering the rotational kinetic energy of the propeller with the aid of a PSS placed in front of the propeller. In this study, an asymmetric PSS system is applied to the 2500 TEU eco-friendly liquefied natural gas (LNG) fuel feeder container ship, aimed at optimizing the position of stator blades, using a potential-based program. Additionally, a parametric study was conducted for evaluating the optimum pitch angle and blade spacing. STAR-CCM+ was used for validating the efficiency of the final design. The Samsung towing tank and large cavitation tunnel were also utilized to verify the improvement in the performance of the proposed PSS. Although the efficiency gain is not largely affected by blade position optimization, the cavitation and pressure fluctuation issues are addressed by improving the in-flow to the propeller. Therefore, blade spacing optimization of the stator is important for container ships whose cavitation performance is very significant, especially the relatively high-speed commercial vessels.

Experimental and numerical study on the parametric roll of an offshore research vessel with extended low weather deck

After over 10 years' development, the International Maritime Organization (IMO) published the 2nd Generation Intact Stability Criteria (SGISC), including Parametric Roll (PR) criteria to avoid its serious harm to the safety of ship navigation. With the trial of SGISC, ships with extended low weather deck, such as typical Offshore Research Vessel (ORV), are found may be vulnerable to PR too. Relative research on such kind of ship is insufficient, because most of previous researches focus on conventional high freeboard ships such as container ships or passenger ships. With an aim to study the PR characteristic of ships with extended low weather deck, an experimental investigation and numerical comparison investigation are carried out. The effect of highly nonlinear water-on-deck phenomena caused by ORV's extended low weather deck on PR response is specially investigated. Regarding numerical simulation of ORV's parametric roll, the effects of assessment accuracies of GZ curves in waves and roll damping coefficients are analyzed. As a result, it was found that parametric roll may occur for ORV's in adverse sea conditions when overtaking of green water is seen on the deck in following wave conditions. It is recommended to account for this specific issue when analyzing PR for ORV's.

Annual dilated convolutional LSTM network for time charter rate forecasting

Time charter rates must be predicted accurately to assist sensible decisions in the global, highly volatile shipping market. Time charter rates are affected by multiple factors, such as second-hand ship prices, order book, Libor interest rate, etc. However, not all factors convey predictive features to anticipate the future of time charter rates. Therefore, extracting predictive features from multiple driving time series from the shipping market is crucial for forecasting purposes. Accordingly, this paper proposes a novel convolutional recurrent neural network for time charter rates forecasting under the multi-variate phenomenon. The proposed network first extracts features from the monthly time series using a novel convolutional filter, the annual dilated filter. The annual dilated convolutional filter can extract the predictive features effectively and impose a sparse input structure to prevent overfitting. Then, a recurrent neural network learns the temporal information from the convoluted features. An extensive comparison study with many baseline models, including the persistence (Naïve I), statistical models, and the state-of-art networks, is conducted on the time charter rates of six kinds of ships. The empirical results demonstrate the proposed model’s superiority in forecasting the time charter rates.

FAKTOR-FAKTOR YANG BERHUBUNGAN DENGAN ANGKA KUMAN PADA PERALATAN MAKAN DI RUMAH MAKAN WILAYAH PERIMETER DAN BUFFER AREA PELABUHAN SAMPIT

Sampit Seaport is a berth for various kinds of ships, including passenger ships, cargo ships, Crude Palm Oil ships. In 2019 of 15 eating utensil that was inspected the number of germs as many as 13 eating utensil unqualified of health and there are reports 1 prospective ship passenger who experienced diarrhea during Lebaran homecoming. Monitoring the bacteriological quality of eating utensil is one of the keys to prevent foodborne diseases. This study aims to determine the factors associated to the number of bacteria on eating utensil including washing water, eating utensil materials, eating utensil washing techniques, eating utensil drying techniques and eating utensil storage at Sampit Seaport. This was an observational study with a cross-sectional design. The population in this study were all of the eating utensil in 10 restaurants located in the perimeter and buffer area of the Sampit Seaport. The number of samples in this study were 60 eating utensil. Data analysis was univariate and statistical test using the Pearson Chi Square. The results showed that 28 (46.67%) did not meet the bacteriological requirements. The results of statistical analysis showed that there was a association between washing water (p=0.013), The results showed that 46.67% is unqualified the bacteriological requirements storage (p=0.001) to the total plate number on eating utensil. In addition, there was no association between eating utensil material (p=0.560), washing technique (p=0.174), and drying technique (p=0.174) with the Total Plate Number on eating utensil. It can be concluded that there was a associationbetween washing water and storage of eating utensil to total palre count on eating utensil. Suggestions for restaurants is to pay attention of sanitation hygiene to eating utensil that used in the restaurant.

On the origin, foundational designs and first manufacture of the modern catamaran

The complete history of the modern catamaran has not yet been written. On 25 November 1916, Spanish engineer Leonardo Torres Quevedo patented a new kind of ship, which he called the ‘Binave’, the Spanish equivalent of ‘Twin Ship’. For the first time ever, a multihull steel vessel was patented and constructed, driven by two propellers powered by two Hispano-Suiza marine engines. The location of the main engines inside each hull, as well as the propellers, was exactly the same as it is nowadays in modern catamarans. Torres Quevedo’s ‘Twin Ship’ was the first step towards a change of mentality, from the classic monohull vessel to something different. This revolution was required in order to minimize the total resistance of a ship (frictional or wave-making and wave-breaking resistance, for example) and, consequently, to be able to reach the higher speeds that are achieved today. This article traces the history of the catamaran and explains its evolution, taking into special consideration the innovations carried out by Torres Quevedo between 1916 and 1918.

PERSPECTIVES FOR A WIND ASSISTED SHIP PROPULSION

For three different wind propulsion technologies, the energy saving potential of sea going cargo vessels are discussed: a kite, a Flettner rotor and a Dynarig-sail. The energy saving potential can be increased significantly if the route can be optimized when using a wind assisted ship propulsion. The increase of travelling time due to a route adoption is within the frame of the commonly accepted uncertainty in supply chains and can be limited or adjusted in the route optimization software as a parameter. The calculated saving potential depends on several parameters: the considered wind propulsion system, the route, the kind of ship (bulker, multipurpose carrier, tanker), as well as the ship speed and the weather. The cost-effectiveness of the installation of a wind propulsion system strongly depends on the fuel price, the ship speed and the international policy concerning the ship emissions.

A functional approach to reassessing the legal status and navigational rights of ships and ship-shaped structures

Advancements in technology have prompted the emergence of several new kinds of ships and ship-shaped structures, including floating offshore platforms, unmanned maritime vehicles (UMVs), and unmanned merchant ships; this raises questions for international shipping regulations about their legal status and navigational rights. The legal status of a ship under the United Nations Convention on the Law of the Sea (UNCLOS), as well as other relevant international instruments, is different from that of a non-ship, since the latter does not have legal rights of international navigation. However, neither customary international law, nor the UNCLOS, provides a clear definition for the term “ship”, though different definitions of “ship” have been given in different international conventions and national statutes for their own purposes. This paper attempts to propose a functional approach, based on ships’ main functions of navigation and transportation, to reassessing the legal status and navigational rights of ships and ship-shaped structures. By following the functional approach, this paper clarifies that a ship having navigational rights means any self-propelled water-going vessel for the transportation of goods, passengers, and other objects, including vessels to be used for military or public service purposes. Based on this definition, the paper further finds that: 1) Floating offshore systems (including floating platforms and drill ships) should be regarded as ships when they are navigating in the waters; 2) most of the UMVs, being regarded as ship equipment or attachments, can only reflect their mother ship status; and 3) ocean-going bulkers and smaller container vessels that may be able to switch to unmanned operation should also be recognized as having the legal status of ships. • Applying a functional approach to distinguishing ships and ship-shaped structures. • Developing a model for defining “ship” for assessing its navigational rights. • Floating platforms can be regarded as ships when they navigate in the waters. • Most of the unmanned maritime vehicles can only reflect their mother ships' status. • Unmanned merchant ships may acquire ships' navigational rights after proving safety.

Review and Prospects for Autonomous Observing Systems in Vessels of Opportunity

This paper focuses on the state of the art on Autonomous Observing Systems (AOS) used in Vessels of Opportunity (VOO) for collecting in situ atmospheric, oceanic and biogeochemical data. The designation Vessels of Opportunity includes all kinds of ships, even if not having scientific goals, which may carry proper devices that autonomously measure environmental variables. These vessels can be merchant, military, research, cruise liners, fishing, ferries, or even private yachts or sailing boats. The use of AOS can provide the opportunity for highly refined oceanographic data and improved derived data estimation, for local, regional or global scales studies. However, making the collected information accessible, both for scientific and technical purposes, provides a challenge in data management and analysis, which must, above all, ensure trusted useful data to the stakeholders. An overall review of the systems implemented is presented. This includes the definition of objectives, the recruitment of vessels and a review on the installation of proper acquisition devices; the selection and collection of Essential Oceanic Variables (EOV); the mechanisms for transmitting the information, and the quality control analysis and dissemination of data. The present and future capabilities of VOO for measuring EOV, within the Portuguese context are referred.

Influence of U or V degree of stem on vulnerability of parametric rolling

Objectives This paper selects the U or V degree of ships' stems as the research target for identifying its influence on parametric rolling vulnerability. Methods Three kinds of ships were chosen as the parent ships: a container ship, fishing vessel and fishery administration ship. Three series of ships were generated by changing the U or V degree of these parent ships' stems using the free-form deformation method. Each series contained five newly created ships for a total of 15 new ships. The parametric rolling vulnerability of the ships was assessed and the rule of the influence of the U or V degree of the stem on vulnerability to parametric rolling was obtained from the assessment results. Results The assessment results show that changing the form of the stem from a V section to a U section has an advantageous impact on vulnerability to parametric rolling. Conclusions The research in this paper provides a technical basis for the application of parametric rolling vulnerability criterion in China, and can provide valuable references for hull form design.

Monumento a Julio Argentino Roca: huellas del silencio

La escultura que es objeto de nuestra investigación está dedicada al ex presidente de la nación (1880-1886 y 1898-1904), Julio Argentino Roca. La misma, emplazada sobre la avenida que lleva su mismo nombre y la calle Perú, en la ciudad de Buenos Aires, ha sido realizada por José Luis Zorrilla de San Martín, e inaugurada en 1941.
 Todo el conjunto escultórico parece una especie de nave, que serena y tranquilamente navega hacia el centro neurálgico del poder. Representa el proyecto en el que estábamos embarcados como país, por decisión de una élite. En esa época surgían los nuevos proyectos de traza en la ciudad de Buenos Aires. Un planteo de ciudad diagonal y racional, proyectada al estilo boulevard francés. Esta racionalidad en la traza escondía la violenta imposición de un progreso ciego, en el cual se creyó como si se tratara de una nueva religión, sin importar los medios con los cuales llegaría a imponerse.
 

Clean energy production by PEM fuel cells on tourist ships: A time-dependent analysis

This manuscript presents a clean energy solution for marine applications, investigating both the choice of the most promising production and storage technologies and, in a second step, the best operational management in order to satisfy a ship's energy demand. The case study subject of the analysis is a ferry, with a capacity up to 200 people, operating on the artificial lake of Itaipu hydroelectric plant (on the border between Brazil and Paraguay). In the framework of new international rules, aimed at clean and sustainable solutions, in particular in Emission Control Areas, PEM fuel cells are a promising technology for onboard power generation. In this paper a PEM fuel cell system is investigated in detail, analyzing the best operative strategy in terms of energy efficiency, CO2 emissions and costs, in comparison with the state-of-the-art solution for ships (fuel oil ICEs). The analysis is performed with two dedicated software tools, both developed at the University of Genoa: the first is a tool modeled to support the preliminary design and the choice of the most promising solutions for maritime applications; the second is a software program for thermo-economic analysis of energy systems in time-dependent conditions, aimed at determination of the best operative strategy, minimizing operative costs.The proposed approach has general validity thus it can also be applied to different kinds of ships, even considering different technologies for energy generation and storage.

Reverse Dispersion Entropy: A New Complexity Measure for Sensor Signal.

Permutation entropy (PE), as one of the powerful complexity measures for analyzing time series, has advantages of easy implementation and high efficiency. In order to improve the performance of PE, some improved PE methods have been proposed through introducing amplitude information and distance information in recent years. Weighted-permutation entropy (W-PE) weight each arrangement pattern by using variance information, which has good robustness and stability in the case of high noise level and can extract complexity information from data with spike feature or abrupt amplitude change. Dispersion entropy (DE) introduces amplitude information by using the normal cumulative distribution function (NCDF); it not only can detect the change of simultaneous frequency and amplitude, but also is superior to the PE method in distinguishing different data sets. Reverse permutation entropy (RPE) is defined as the distance to white noise in the opposite trend with PE and W-PE, which has high stability for time series with varying lengths. To further improve the performance of PE, we propose a new complexity measure for analyzing time series, and term it as reverse dispersion entropy (RDE). RDE takes PE as its theoretical basis and combines the advantages of DE and RPE by introducing amplitude information and distance information. Simulation experiments were carried out on simulated and sensor signals, including mutation signal detection under different parameters, noise robustness testing, stability testing under different signal-to-noise ratios (SNRs), and distinguishing real data for different kinds of ships and faults. The experimental results show, compared with PE, W-PE, RPE, and DE, that RDE has better performance in detecting abrupt signal and noise robustness testing, and has better stability for simulated and sensor signal. Moreover, it also shows higher distinguishing ability than the other four kinds of PE for sensor signals.

Maritime Networking: Bringing Internet to the Sea

Maritime networks establish wireless multi-hop networks to provide wireless broadband service at sea, connecting various kinds of ships, maritime buoys, and beacons. The maritime networks possess two distinguishing characteristics highly affected by maneuver at sea-dynamic link quality and bandwidth constrained, and dynamic network topology-that warrant specific attention. Unlike land vehicles, maneuver at sea is affected by sea surface movement and wave occlusions, which can cause unstable environment with a high rate of link breakages caused by low link stability, as well as low and highly variable bandwidth. In spite of the need to achieve performance close to high-speed terrestrial wireless broadband service on land, there is only a perfunctory effort to investigate maritime networks. There is an urgent need to refresh the interest to investigate, as well as to further enhance, maritime networks. This paper presents a review of the limited research works of this topic, which revolve around the networking issues in the link, network, and upper layers, in the literature. The objective is to establish a foundation in order to motivate a new research interest in maritime networks. Open issues are also presented to foster new research initiatives in this burgeoning and exciting area.

Best operative strategy for energy management of a cruise ship employing different distributed generation technologies

This paper aims to study the application of distributed generation technologies on a naval energy system, investigating the best operating strategy for energy management throughout an annual load profile. The thermo-economic analysis is performed considering electrical and thermal load demands referred to hotel and service loads of a cruise ship (around 6 MWel), both variable with the season and the period of the day, taking into account the off-design curves and cost functions for the different generators. Four different solutions are investigated, comparing the operative strategies in terms of energy efficiency, CO2 emissions and annual costs.The analysis is performed with dedicated software for the thermo-economic time-dependent analysis, developed by the University of Genoa. The thermo-economic approach has general validity, thus it can be also applied to different kinds of ships, even considering different technologies for energy generation and storage.

Extraction of shaft frequency based on the DEMON line spectrum

Target-identification is an important technique in modern sea war. As the core device to identify targets, negative sonar analyzes noise underwater and abstracts their properties and determines its source. Shaft frequency which barely lies in the properties of the propeller differs among different kinds of ships, so this property can be regarded as a key to identify targets. This paper studied the theory and math model of the noise produced by ships. And Detection of Envelope Modulation on Noise (DEMON) is an effective technique to abstract low-frequency properties from high-frequency signals via demodulation. There are two methods to demodulate the noise, namely absolute low pass demodulation and square low pass demodulation. To improve the performance of DEMON spectrum estimation, adaptive line spectrum enhancement technology is introduced. An adaptive threshold is then set to eliminate the continuous spectrum. Then the largest common divisor algorithm is presented to calculate to shaft frequency out of the array consist of the centre frequency of these line spectrum. Simulation is conducted as described above. Two methods of demodulation is compared in this part. Brief sea experiment data processing shows that this algorithm is able to abstract the shaft frequency among the ship noise.

Achieving Integrated Care for Older People: What Kind of Ship? Comment on "Achieving Integrated Care for Older People: Shuffling the Deckchairs or Making the System Watertight for the Future?"

This paper considers an implication of the idea that proposals for integrated care for older people should start from a focus on the patient, consider co-production solutions to the problems of care fragmentation, and be at a system-wide, cross-organisational level. It follows that the analysis, design and therefore evaluation of integrated care projects should be based upon the journeys which older patients with multiple chronic conditions usually have to make from professional to professional and service to service. A systematic realistic review of recent research on integrated care projects identified a number of key mechanisms for care integration, including multidisciplinary care teams, care planning, suitable IT support and changes to organisational culture, besides other activities and contexts which assist care ‘integration.’ Those findings suggest that bringing the diverse services that older people with multiple chronic conditions need into a single organisation would remove many of the inter-organisational boundaries that impede care ‘integration’ and make it easier to address the interprofessional and inter-service boundaries.