Annals of ”Dunarea de Jos” University of Galati. Fascicle XI Shipbuilding

Seakeeping performance prediction of a river-costal boat made of GRE composite materials

2024-12-04T07:55:22+02:00

The design of the river-costal vehicles imposes the assessment by several hydrodynamic and structural criteria. This research involves the evaluation of a river-costal boat made of GRE composite materials at full load condition. The boat’s navigation area covers the Danube in land and costal zones, modeled as irregular oblique waves. The analysis is based on a strip theory hydrodynamic approach and short-term statistical dynamic response approach, delivering the seakeeping performances prediction of the river-costal boat.

Alternative marine fuels for cleaner maritime transport

2024-12-03T23:34:59+02:00

To reduce greenhouse gas (GHG) emissions, according to the vision of the International Maritime Organization (IMO), a good decision-making process is needed for the classification of alternative marine fuels considered as a solution for the decarbonization of maritime transport. The paper aims to classify two alternative fuels (Liquefied natural gas (LNG) and green hydrogen obtained by electrolysis of water, in relation to four criteria (economic, technical, environmental, and social) using the specialized literature. The evaluation of the two fuels in relation to the selected criteria was carried out from a multicriteria perspective using the Analytical Hierarchy Process (AHP) method. The obtained results have shown that LNG is the best option, currently, for maritime transport, considering the operational cost, the available infrastructure, the impact on the climate, and operational safety.

Earned value management used to monitor the project costs of ballast system fabrication and installation on a cargo ship

2024-12-03T23:44:46+02:00

The development of projects in the naval field is of crucial importance for the industry. Their success depends on how their costs and duration are managed. The study aims to present how naval projects can be monitored using Earned Value Management (EVM), a technique used to evaluate their performance from the point of view of costs. The Earned Value analysis has been applied to the manufacture and installation of a ballast system on a cargo ship. The results obtained have demonstrated that savings are achieved, and the works are delayed compared to the plan.

Assessing cyber risks on board ships: A literature review

2024-12-03T23:46:57+02:00

Due to the multiple cyber-attacks that resulted in financial losses and personal information breaches, cyber security has become an essential issue for the maritime industry today. This research aims to identify the potential cyber risks associated with operational technology (OT) systems on board ships that influence the cyber security of vessels through a state-of the-art literature review. Assessment of the cyber risks on board is carried out according to their likelihood and severity, using a risk score matrix, based on which, they are classified into three categories: high risk, medium risk, and low risk. Based on the classification of cyber risks on board the ship in the three categories, the measures to mitigate them can be defined, to ensure cyber hygiene on board the ship.

On the structural analysis by a midship cargo-holds model of an oil tanker 105930 dwt

2024-12-04T07:55:23+02:00

This paper aims to analyze global-local structural analysis using a model with three tanks in the central area of an oil tanker. Taking into account the negative effects of petroleum cargo on marine fauna and flora, regulations have been imposed on the reduction of pollution of the marine environment, thus, the stresses and deformations state of tanker vessels is an aspect of great interest in the design phase. Also, the paper captures the influence of the navigation conditions on the structure of the ship's hull and the effect that sloshing in cargo tanks has on the inner hull.

Verification and validation for KCS total resistance

2024-12-03T23:49:42+02:00

This study presents CFD simulations of the KCS model ship, focusing on ship resistance, free-surface behavior, and predictions of sinkage and trim at a Froude number of 0.26. Reynolds-Averaged Navier-Stokes (RANS) equations are solved using the k-ω SST turbulence model. Verification and validation are carried out through a generalized Richardson Extrapolation method, following Stern et al. [1] methodology. Results are compared with experimental data for total resistance coefficient, sinkage, trim, and wave patterns.

Dynamic of the maritime accidents of the main types of ships from EU and their implications. A literature review

2024-12-03T23:50:58+02:00

Maritime accidents and incidents are a major concern for the shipping industry, even though unified standards exist and solutions have been identified to improve maritime navigation and minimize accidents. This study aimed to carry out a statistical analysis of maritime accidents and incidents in the period 2014-2022, of ships belonging to the EU Member States, highlighting the main shipping areas where maritime accidents occurred, the result ing consequences, the types of pollution, and the main factors leading to maritime accidents and incidents. The results showed that there were 23,814 accidents/incidents, of which 2.6% were very serious accidents, 28.5% were serious accidents, 53.9% were less serious accidents and 15% were maritime incidents.

Engine power limitation (EPL) to comply with EEXI requirements. study on an LPG tanker

2024-12-03T23:53:01+02:00

The study analyses the Energy Efficiency Existing Ship Index (EEXI), a regulation introduced by the International Maritime Organization (IMO) to enhance energy efficiency in maritime transport and reduce greenhouse gas emissions. Focusing on a semi-refrigerated LPG tanker, the research explores compliance strategies, including engine power limitation (EPL). The reduction of engine power by 24% resulted in a decrease in ship speed, meeting EEXI requirements with minimal impact on performance. Additionally, ship manoeuvrability was assessed through turning circle simulations before and after EPL. The findings confirmed that the vessel’s manoeuvrability remains within IMO standards, ensuring both efficiency and operational safety.

The reduction of the main engine’s power for a 15000 tdw chemical tanker regarding the achievement of EEXI and its influence on manoeuverability

2024-12-03T23:54:01+02:00

EEXI was established as a measure for assessing the energy efficiency of existing vessels and aims to reduce CO2 in order to achieve IMO regulations. The purpose of this study is to calculate the EEXI for a 15000 twd chemical tanker and further evaluate the impact of this change on ship manoeuvrability. EEXI estimations were conducted using different approaches while manoeuvrability performances were evaluated by means of different simulation programs. The purpose of this study revolves around striking a balance between optimal operation and achieving energy efficiency.

On local strength analysis in critical conditions of mooring and towing for a chemical tanker

2024-12-03T23:55:25+02:00

Mooring and towing equipments ensure stability, control and safety in stationary (mooring) and transit (towing) situations. Mooring equipment is responsible for securing a vessel in place at a dock, pier, or offshore structure. Proper mooring equipment and reinforcements ensure that the vessel remains safely secured despite the influence of environmental loads. Towing equipment is essential for moving ship over short or long distances, either due to mechanical failures of the vessel or to relocate it. Towing is especially critical in rescue operations. The study involves a chemical tanker detailed strength check at mooring (at pier) and towing (on relocation) cases. In both cases the worst scenario was taken into consideration.

Securing innovation at sea: Cyber risk management for SMEs in ship design

2024-12-03T23:56:37+02:00

This paper examines the critical cybersecurity landscape faced by maritime SMEs engaged in Ship Design, analysing their vulnerability to various cyber threats including ransomware, phishing attacks, and supply chain compromises. Through a comprehensive review of recent industry reports, regulatory frameworks, and cybersecurity incidents, we identify key risk factors and assess their potential impact on SMEs' operations, reputation, and competitive advantage. Our analysis reveals that maritime SMEs face disproportionate challenges in cybersecurity due to resource constraints, complex supply chain relationships, and the increasing sophistication of cyber threats targeting intellectual property. The paper presents a structured approach to cyber risk management based on established frameworks, emphasizing the protection of valuable intellectual property while maintaining operational efficiency. We propose practical recommendations for implementing robust cybersecurity measures within the resource constraints typical of SMEs, including strategies for threat detection, incident response, and recovery planning.

On a river-barge numerical strength analysis in head design wave loads

2024-12-03T23:58:05+02:00

The FEM approach is a well-established computational technique for solving the governing equations of structural mechanics under various loadings. To delve deeper into the FEM approach, we focus on the floating structure of a river barge. This study aims to determine a structure's structural capacity by applying admissible stress criteria following the DNV rules. The structural analysis involves a comparative study of stress levels from the equivalent design wave loads for two river-barge operational conditions, light, and full cargo cases.

Analysis of the impact of local discretization in the area of technological cutouts on stress concentrators

2024-12-03T23:59:29+02:00

This study aims to analyze and compare the influence of steel flat bar beveling around technological cutouts on the stress state of a chemical tanker with a deadweight of 35,622 tons (TDW). Technological cutouts, which are essential for the installation of equipment, passage of cables, and other functional purposes, can cause stress concentration in the ship's structure, increasing the risk of cracking and localized failure. To assess the impact of beveling, two structural models are compared: one with steel plate beveling and one without. Using finite element analysis (FEM) through FEMAP/NX Nastran software, stresses and displacements around the cutouts are examined at four representative points along the cutout’s circumference. The results reveal significant differences in stress distribution between the two models, demonstrating the effectiveness of beveling in reducing local stress concentrations. This study provides insights into improving structural integrity and safety in ship design by addressing the risks associated with technological cutouts.

Assessing the influence of the global emissions reduction targets on the design and performances of a ship’s propulsion system

2024-12-04T00:03:28+02:00

The paper presents aspects related the influence of the global gases emissions reduction targets on the design and performances of a propulsion system for a bulk carrier. In a first stage, the key elements of the ship propulsion system: main engine and propeller have been chosen and designed. The aim was to obtain the maximum propulsive efficiency at the owner desired speed. Different combinations: diesel engine-optimal propeller have been designed and analysed from the efficiency point of view. In a second stage, considering the mandatory IMO regulations concerning CO2 emissions, the EEDI (Energy Efficiency De sign Index) has been computed for every designed case. To compliance EEDI targets, it was been necessary to reduce the ship speed, and a new propulsion system with lower speed performances has been designed. In this study, ship hull shapes were given and EEDI be came an important and critical factor in the design of the ship propulsion system. Other potential pathways to achieve emissions reduction targets will need to be identify in a future study.

Stability for a parallelepipedal crane using auto-ship soft-ware

2024-12-04T00:04:31+02:00

The paper presents the stability analysis of a parallelepipedal crane barge, under operational and environmental scenarios, using the AutoShip software, specifically ModelMaker and AutoHydro packages. The characteristics of the crane are length of 42.59 m, breadth of 20.19 m, depth of 1.50 m and a construction height of 3.5 m. The design of the crane was imported from Rhinoceros using .IGES file to software package ModelMaker from AutoShip. The stability analysis wore made in AutoHydro software package from AutoShip. The main contribution of the paper is to highlight the usefulness and efficiency (in terms of rapidity and accuracy) of using software tools (AutoHydro from the package AutoShip) to study nautical qualities (buoyancy and stability) of a parallelepipedal crane barge in several exploitation scenario.

About antifouling solutions to protect ship’s hull

2024-12-04T00:10:20+02:00

Antifouling solutions are essential for protecting ship hulls from marine organisms like algae, barnacles, and molluscs, which can slow down the ship and increase fuel consumption. They are crucial for maintaining a ship's efficiency and longevity by protecting the hull from marine growth, which can slow the vessel and increase fuel consumption. Modern antifouling methods, such as specialized paints, copper-based coatings, self-polishing surfaces, silicone coatings, ultrasonic systems, and electrolytic solutions, offer effective ways to combat biofouling. These solutions not only improve operational performance but also contribute to environmental sustainability by reducing the need for frequent cleaning and minimizing the release of harmful biocides into the water. The ongoing development of innovative antifouling technologies will continue to enhance the protection and efficiency of maritime vessels.

On the electric propulsion of rive ships

2024-12-04T00:14:08+02:00

Electric propulsion for river ships is an exciting and promising development in the maritime industry. This technology involves using electric motors powered by batteries instead of traditional internal combustion engines. Advances in battery technology, such as lithium ion batteries, have made electric propulsion more viable and cost-effective. It is generally more efficient than internal combustion engines, leading to a better fuel economy and lower operational costs and it produces significantly less pollution compared to traditional engines, which burn heavy oil. This helps reduce greenhouse gas emissions and other pollutants like NOx and particulate matter. In plus, electric motors are quieter than traditional engines, making electric ships more suitable for operations in urban areas and sensitive environments. There are also some ships using hybrid systems that combine electric propulsion with traditional engines, allowing them to switch between power sources depending on the situation.

The influence of the constructive shapes of aluminum profiles on impact phenomena

2024-12-04T00:11:59+02:00

The purpose of this study is to analyze the results obtained from the impact for aluminum profiles in four constructive variants, two with connections and two with bevels.The forms significantly influence the results from a quantitative and qualitative point of view, making it possible to recommend the choice of the type of profile.