Papers of Significance

Each year, outstanding papers of significance to the European maritime industry, written by members of each CEMT Society, are published on the CEMT website. Papers are copyright-free and may be downloaded from Dropbox.

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2023

Industry 4.0: Application of Machine Learning techniques to the shipbuilding industry
By: Iván Martín De Almeida, Rodrigo Pérez Fernández
Paper selected by Asociacion de Ingenieros Navales y Oceanicos

Abstract

The Marine Industry has shown special interest in implementing new technologies framed within Industry 4.0 in a commitment to digitize companies and monetize data. Machine Learning is the foundation on which data science is founded and is the main topic of this paper.

The objectives of this research were to study Machine Learning algorithms in the first sections of the paper; and analyze with these techniques the predictions made in the propulsion system of a containership of 9,500 TEUs in the next sections.  For this, two databases were developed; one considering of 34 containerships from Significant Ships documents and another consisting of 28 materials commonly used in propellers or shafts from the Level 3 database that can be found in the GRANTA EduPack 2020® software.

The results showed that when predicting brake power, a lower mean squared error (MSE) is committed for the database of containerships with each one of the Machine Learning algorithms compared to the error made by the J. Mau formula. The propulsion engine was selected based on the prediction made for the 9,500 TEUs containership. Similar results have been obtained when predicting the diameter of the propeller in comparison with classic methods. Propeller diameter was selected based on these predictions.

The results show a predictive improvement by having a lower mean squared error (MSE) in the predictions. This conclusion suggests its application in other ship systems when an estimate is required, and a database is available. The better the predictions the fewer iterations are required in the project spiral; therefore, flexibility is gained in the times.

The models made with different algorithms were assembled to gain more robustness in the prediction, achieving an increase in the value of the accuracy of the independent algorithms, with a value of 93.33%. The prediction it generates is the family of materials that best suits the input variables that were preselected. Finally, it was assembled with a MILP (Mixed Integer Linear Programming) optimization problem to obtain the material within  the family that has been predicted with the highest tensile strength, complying with a series of restrictions that have also been preselected.

An interactive program has been developed within one of the Jupyter Notebooks® that is attached to this paper, and which integrates Machine Learning prediction algorithms of the materials to be used in the propulsion system to provide greater comfort to the user when selecting input variables.

This paper is published in Spanish

This paper is published in Spanish

Non-Intrusive Cavitation Detection System, a tool to mitigate ocean noise and protect marine wildlife
By: Publio Beltrán Palomo; Luis Antonio Piqueras González-Tejero; Richard García Méndez.
Paper selected by  Asociacion de Ingenieros Navales y Oceanicos

Abstract
Although we have known about the existence of the cavitation phenomenon for more than 50 years, we are still far from being able to eliminate it from propellers due to their very principle of operation. Even with advanced CFD tools, new technologies and manufacturing processes, the cavitation phenomenon will inevitably occur from certain conditions of ship draft and propeller rotation speed.

We can distinguish three (3) direct consequences of this phenomenon: a reduction in the service life of the propeller and sometimes also the rudder and hull, a significant increase in vibrations and noise on board with direct impact on the comfort conditions of the ship, and noise pollution with negative effects on the oceans, on marine fauna and, for military vessels, on their stealth. Regarding the latter consequences, IMO is currently working on updating MEPC.1/Circ.833: "GUIDELINES FOR THE REDUCTION OF UNDERWATER NOISE FROM COMMERCIAL SHIPPING TO ADDRESS ADVERSE IMPACTS ON MARINE LIFE". For this purpose, a working group of more than 120 experts from 40 entities (countries and organizations) from all over the world has been formed, being TSI one of its most involved members.

After more than 5 years of research, which began with the AQUO Project "Achieving Quiet Oceans", funded by the 7th Framework Program of the European Union, TSI as a Spanish SME has developed and launched the first non-intrusive system capable of automatically detect this cavitation phenomenon from its onset and quantify its intensity, with sufficient accuracy to provide valuable information for its control. By having a visible and real time indicator of this phenomenon, we can act and reduce the negative effects of cavitation and control the acoustic signature of our vessel at all times.

This paper is published in Spanish

Optimization of seakeeping behavior of fishing ships by artificial neural networks
By: Pablo Romero Tello; José Enrique Gutiérrez Romero; Borja Serván Camas; Antonio José Lorente López.
Paper selected by Asociacion de Ingenieros Navales y Oceanicos

Abstract
The evaluation of seakeeping behaviour is crucial for ship operation. Traditionally it has been analysed by experimental tests and/or numerical models, nevertheless both techniques require significant testing and/or computational time respectively. With the rise of Artificial Intelligence (AI) and the exponential increase in computational capacity, the possibility of exploring the use of AI techniques in the prediction of seakeeping behaviour is opening up. On this work, a pre-trained Artificial Neural Network (ANN) will be used to evaluate the seakeeping behaviour, one of the main advantages of using these algorithms is the ability to quickly predict a large number of scenarios, compared to traditional methods. The search for fishing vessel geometries that adapt to sea conditions and operational profiles, optimizing specific metrics related to operability, is proposed. Finally, the most relevant conclusions of the work will be presented.

This paper is published in Spanish

Lessons learned from accidents on some major European inland waterways
By: Igor Bačkalov, Stefan Rudaković,  Milica Vidić
Paper selected by the Society of Naval Architects of Serbia

Abstract
The collection of data on accidents in inland navigation is not mandatory in many European countries. The lack of a harmonized methodology or a centralized database of information on accidents makes it difficult to have a comprehensive picture of safety on European inland waterways. The problem becomes particularly evident in light of significant navigational challenges such as the introduction of autonomous shipping. To provide a better understanding of safety in inland navigation, the paper presents the results of an analysis of data on some 700 accidents which took place on the inland waterways in Austria and Serbia, over a 15-year period (2001/ 2002–2017). The analysis identifies the safety “hot spots” and the most important safety issues on examined waterways. Contrary to the widely-accepted belief, the results do not confirm that most of the accidents could be attributed to human failures and show that the removal of human operators from inland vessels could only have a limited positive impact on safety unless other aspects (primarily related to maintenance of the fleet and the waterway) are considered. Consequently, the paper outlines the fundamental conditions in which it would be possible to reduce the human presence or even remove the crew from inland ships.

2022

Availability Analysis of an Offshore Wind Turbine Subjected to Age-Based Preventive Maintenance by Petri Nets
By: Eduard LotovskyiORCID,Angelo P. TeixeiraORCID andC. Guedes Soares *ORCID
Paper selected by Ordem dos Engenheiros I Colegio de Engenharia Naval
  • This paper analyses the production availability and the associated maintenance costs of an offshore wind turbine with a horizontal axis configuration using Petri Nets modelling with Monte Carlo Simulation.
Multi-Attribute Decision-Making Ship Structural Design
By: Tiago Pereira and Yordan Garbatov
Paper selected by Ordem dos Engenheiros I Colegio de Engenharia Naval
  • This study develops a procedure for performing multi-attribute decision-making ship structural design of a multi-purpose ship. The already designed ship is further structurally designed to comply with the requirements of the Classification Societies
Shallow-draught vessels for the Vessel Train
By: Igor Bačkalov1,Milan Kalajdžić, Nikola Momčilović, Stefan Rudaković and Milica Vidić2
Paper selected by the Society of Naval Architects of Serbia
  • The Vessel Train concept implies a convoy of digitally connected vessels whereby only the first vessel in the convoy (the “lead vessel”) is fully manned, while the remaining vessels sail with the crew off-duty (in a periodically unmanned regime) or with a reduced crew (in a partially unmanned regime)This paper discusses the challenges encountered in design of large inland container Ro-Ro vessels with extremely shallow draughts, intended for the use in the Vessel Train.

2021

Experimental Testing of Scarf Joints and Laminated Timber for Wooden Boatbuilding Applications
By: J-B R G Souppez
Paper selected by the Royal Institution of Naval Architects
  • This paper employs destructive testing to tackle two distinct cases. On the one hand, the strength of plain scarf joints as a function of their slope is evaluated. On the other hand, the effectiveness of a range of adhesives is ascertained for the purpose of laminated manufacturing. The results are compared to both solid wood and the mechanical properties assumed by modern scantling regulations, revealing significant differences
Reliability-based structural design of river-sea tankers: Still water loading effects 
By: Milorad Motok, Nikola Momcilovic, Stefan Rudakovic
Paper selected by the Society of Naval Architects of Serbia
  • This paper uses probability approach to estimate the reliability index of Rule based formulas for still water bending moment, i.e., the probability that thus obtained values will not be overcome by actual, lege artis calculated values. It is based on analyses of more than 400 load cases of 37 prominent river-sea tankers. Acquired results are also input parameters for further analyses, which would include wave induced loads and are the subject of succeeding investigations.
Mixed-Fidelity Design Optimization of Hull Form Using CFD and Potential Flow Solvers
By: G. J. Grigoropoulos, C. Bakirtzoglou, G. Papadakis, and D. Ntouras
Paper selected by the Hellenic Institute of Marine Technology
  • This paper proposes a new mixed-fidelity method to optimize the shape of ships using genetic algorithms (GA) and potential flow codes to evaluate the hydrodynamics of variant hull forms, enhanced by a surrogate model based on an Artificial Neural Network (ANN) to account for viscous effects.
A developed failure mode and effect analysis for floating offshore wind turbine support structures
By: He Li, H. Diaz and C. Guedes Soares
Paper selected by Ordem dos Engenheiros I Colegio de Engenharia Naval 
  • This paper extends the conventional failure mode and effect analysis methodology by introducing weights of its indices that are severity, occurrence, and detection as a basis to analyze the failures of the support structure of a generic floating offshore wind turbine. Critical failure causes, failure modes, as well as systems of the support structure of the floating offshore wind turbine are ascertained.
Spatial correlation analysis of near ship collision hotspots with local maritime traffic characteristics
By: H. Rong, A.P. Teixeira and C. Guedes Soares 
Paper selected by Ordem dos Engenheiros I Colegio de Engenharia Naval
  • A spatial correlation analysis of near collision clusters with local traffic characteristics is presented. The Moran’s I and Getis-Ord Gi* spatial autocorrelation methods are used to determine whether near collisions show spatial clustering from global and local perspectives. The application of the developed approach to Automatic Identification System data of the maritime traffic off the coast of Portugal shows that there are several hotspots where the density of ship near collisions is relatively high.

2020

A real-time speed modulation system to improve the operational ability of autonomous planning craft in a seaway 
By: H Allaka, A Levy, D Levy, T Triebitz and M Groper
Paper selected by the Royal Institution of Naval Architects
  • This study focuses on developing a control system to enhance the seaworthiness of Autonomous high-speed Planing Crafts (APCs). APCs operating at high-speed in a seaway encounter very high vertical accelerations which pose a hazard to payload and crafts' structural integrity. Therefore, for safety operation of APCs in a seaway it is proposed to employ a system termed vision-aided speed modulation system (VSMS). 
Safety of autonomous inland vessels: An analysis of regulatory barriers in the present technical standards in Europe
By Igor Bačkalov.
Paper selected by the Society of Naval Architects of Serbia
  • This paper presents an analysis of technical regulations addressing the safety of inland cargo vessels in Europe, in light of the developments leading towards the introduction of autonomous ships in inland navigation.
Damage Stability of River Cruisers: A Case for Harmonization of International Regulations
By: I Bačkalov and M Vidić.
Paper selected by the Society of Naval Architects of Serbia
  • Rapid growth of the river cruising industry brings the safety of inland passenger ships into spotlight. A review of the existing safety regulations, however, exposes the fact that a common international regulatory framework for inland vessels currently does not exist. The paper presents damage stability assessment of a state-of-the-art European inland passenger vessel (the so-called river cruiser) performed according to the requirements of the regulations which are presently in force in Europe and worldwide.
The Digital Twin in the Marine & Offshore Industry: One concept, multiple adaptations  
By: Jose Esteve
Paper selected by The Association Technique Maritime et Aéronautique
  • Nowadays the term “Digital Twin” is seen very frequently in presentations, teasers and brochures. But what does it really imply? The proposed paper will look at the different proposals of “Digital Twin” that can be seen currently promoted for the Marine & Offshore industry and try to clarify the differences between them, both in content and their expected purpose. As a point of reference Bureau Veritas will present their proposed meaning to “Digital Twin”, illustrated by their initiatives around Asset Integrity Management and 3D Digital Classification. The author does not attempt to be exhaustive in all the possible uses of “Digital Twin” but expect to cover a sufficient range and points of comparison to help the readers to evaluate if a “Digital Twin” fits their needs better than another “Digital Twin”

2019

The Sophistication Of Early Stage Design For Complex Vessels 
By: Professor D Andrews. 
Paper selected by The Royal Institution of Naval Architects
  • It is considered that this paper, which was a synthesis of his previously published research on ship design, was a seminal paper which sets the benchmark for ship designers looking to exploit new technology and techniques. As such, the paper was considered to be essential reading for all naval architects and marine engineers, and not just those working in concept design
Improving the nautical performance of a surface ship with the Hull Vane® appendage
By: Hugo Ferré; Philippe Goubault; Camille Yvin; Bruno Bouckaert
Paper selected by the Association Technique Maritime et Aéronautique
  • The optimisation of propulsive performance of ships is a primary and daily issue during design phases. For combat ships, the constant search for increasing operability through the improvement of seakeeping performance, acoustic discretion and manoeuvring ability is also a concern. For this reason, Naval Group studied the hydrodynamic impacts of the integration of the appendage Hull Vane® on a monohull. The appendage has been designed and optimized specifically for this hull, then compared by CFD computations with several geometries of more classic aft appendages such as wedges, interceptors and flaps. Significant gains on resistance and propulsive power were obtained, and exceeded largely what is obtained with more classic stern appendages. This analysis was completed by model tests, with and without the Hull Vane®