Search

In this study, a model is developed to simulate the dynamics of an internal combustion engine, and it is calibrated and validated against reliable experimental data, making it a tool that can effectively be adopted to conduct emission predictions. In this work, the Ricardo WAVE software is applied to the simulation of a particular marine diesel engine, a four-stroke engine used in the maritime field. Results from the bench tests are used for the calibration of the model. Finally, the calibration of the model and its validation with full-scale data measured at sea are presented. The prediction includes not only the classic engine operating parameters for a comparison with surveys but also an estimate of nitrogen oxide emissions, which are compared with similar results obtained with emission factors. The calibration of the model made it possible to obtain an overlap between the simulation results and real data with an average error of approximately 7% on power, torque, and consumption. The model provides encouraging results, suggesting further applications, such as in the study on transient conditions, coupling of the engine model with the ship model for a complete simulation of the operating conditions, and optimization studies on consumption and emissions. The availability of the emission data during the sea trial and validated simulation results are the strengths and novelties of this work.

In the last years, an increasing attention has been devoted to ships Underwater Radiated Noise (URN), with the progressive introduction of Guidelines by international organizations such as IMO, Classification Societies voluntary notations, limits and incentives in specific areas. In this context, a large effort has been spent in the study of cavitating propeller noise since it represents the dominating noise source on ships. UNIGE is currently involved in the EU-funded LIFE-PIAQUO project, in which the main activities are related to propeller design by optimization, onboard cavitation detection during operations, noise mapping. The present paper reports motivations, aims and achievements of these activities in the first half of the project.

Acoustic cameras are powerful instruments combining an optical camera with a microphone array to obtain information about power and location of noise sources. The main aim of this study is to identify key points in the application of an acoustic camera to the characterization of port noise. An experimental campaign was carried out in the seaport of Genoa. Based on this experience, a SWOT (Strengths, Weaknesses, Opportunities, and Threats) analysis was performed. The experimental results confirm the intrinsic complexity of the noise field in ports. Several noise sources were identified and can be categorized by their duration, intensity, location and spectral content; the analysis performed allows us to propose a basic framework for the innovative application of this technique to the port noise context. Acoustic cameras can be considered viable and useful tools to characterize and monitor port noise, following at least the minimum key points highlighted in the proposed framework.

The problem of the airborne noise transmitted outside the ship represents an acoustic pollution affecting the surrounding environment and third parties. Despite this type of emission can be quite annoying and has raised serious complaints from the inhabitants of areas close to ports, the acoustic impact of vessels, to date, has not been subjected to systematic control. In this context, recent is the new class notation issued by a classification society focusing on the characterization and evaluation of the ship source. This paper aims at analyzing the provisions of this new class notation from its effectiveness in characterizing the ship as a source of airborne noise radiated outside the vessel. Monitoring campaigns and results of numerical models will be exploited to identify a new method for verifying the notation in future applications.

A reasonable prediction of the air emissions from ships at port is crucial to evaluate the impact on the surrounding inhabited zones and to evaluate and adopt effective countermeasures. A quantification of the power utilized by ships in port is crucial, since the level of emissions from an engine strictly depends on the power supplied. In order to assess the power profile of a vessel during navigation, maneuvering and docking in the port area, several approaches are possible, although experimental measurements are the most reliable source of data. This paper presents results of the post-processing analysis carried out on a large amount of emission data recorded during the navigation of two small ferries operating in the Gulf of Naples. The research activity aims to identifying the different behavior of the propulsion engine in terms of power and emissions (mainly NOx, CO2, Hydrocarbons (HC) in addition to the content of O2 in the exhausts), during the navigation and maneuvering phases of the vessel in port area. The results are presented by means of numerical tables representing the dependence between emissions patterns and significant engine operational data. The long-term goal is to use such results in connection with the simulation of the engine working conditions to derive a prediction of the emissions.

The paper covers the need of a detailed monitoring of exhaust gases emissions from the funnel of ships during manoeuvres and mooring at harbour. Just like in many other transport infrastructures, a key point for an effective control of the overall environmental impact stands in the identification of the emissions from single vehicles, in order to make possible to conceive and to put into practice targeted countermeasures. Remote sensing of such specific emissions is an issue and optical sensors are the best candidates for the purpose. The paper is based on a pilot experience carried out in the port of Naples with the aim of studying the feasibility of LIDAR measurements to characterize ship particulate emission. These preliminary measurements allowed a first evaluation of the concentration and of the flow rate of the particulate emissions, even though this was achieved by adding simplified hypotheses. Overall, this pilot campaign indicates the feasibility of using LIDAR techniques for controlling emissions (in terms of particulate matter, but also of Sulphur and Nitrogen oxides) both in stationary conditions and during the maneuvering phases of ships.

The world fleet of cruise vessels is constantly growing in terms of both tonnage and number of units, with a continuous change in main characteristics. This paper answers to the need for obtaining a reliable prediction of the power installed on modern cruise ships based on data easily accessible on single units. For the purpose, a dataset of 129 cruise ships has been generated. For these vessels, the total power installed was available, together with other more common data including main dimensions, tonnage, speed, number of passengers, etc. The database has been analysed through different statistical formulations by means of a dedicated analysis software. The paper describes and discusses the analyses carried out and provides as a result the regressions with the best characteristics and performances, checked by means of a thorough analysis of residuals and selected statistical indicators.

In setting a safe route for a ship, one of the problems to face is represented by excessive roll motions deriving from resonance phenomena in adverse weather conditions. An effective prediction of the roll motion amplification is related to a proper mathematical modelling of the ship motions. Linear models may result to be inadequate in case of large roll motions, where non-linear effects dominate. This paper investigates the roll response resonance in irregular waves. The developed method aims at demonstrating the influence of the non-linear immersed hull geometry, as already acknowledged in literature for regular seas. A 6-Dof non-linear model is applied for generating the time histories of ship roll motions in irregular waves. These are fed into an optimization routine, able of finding the linear system (focusing at its natural roll frequency) that better approximates the non-linear one at a certain mean roll amplitude. The outcomes of this research are meant to support the estimation of roll resonance period accounting for non-linearities of immersed hull geometry, allowing for a more reliable solution of weather routing problems.

A new integrated method for the preliminary design of a fleet of ships for a new trade is presented. Data from two apparently separate types of analysis, based on logistics and naval architecture, are merged within an integrated logistics-fleet design framework. The procedure carries out a preliminary screening of the design space based on logistics criteria. Then, possible fleet configurations and ship designs are investigated, providing information to shipyards and ship owners for an effective selection of optimal solutions. Interactions between logistics evaluations and classic ship design assessments are highlighted. Results from a realistic test case concerning compressed natural gas transportation are presented and discussed.

A growing attention has been recently devoted to the impact of the underwater noise field generated by shipping activities on the marine fauna. A key aspect for the quantification of such impact is a proper model of the source levels radiated from the vessels. At a first level of approximation, simplified formulations based on a small number of macro-parameters describing the ship characteristics are needed to quantify the emission and, accordingly, assess the noise impact and evaluate strategies for its control. In fact, a few models of this kind are available in literature, mainly based on measurements and databases developed for military purposes. Most of these models have been tuned on old ships: this poses the question whether they are still applicable to modern commercial vessels. In the present work, spectra of a series of measurements of underwater noise emitted by commercial vessels measured in the framework of two EU FP7 projects (SILENV: www.silenv.eu and AQUO: www.aquo.eu) are analyzed and compared with the results obtained applying the available literature models. The analysis is carried out for noise emitted both at design and off-design conditions. In such conditions, the models are also compared with a proposed spectral parametrization. Focusing on the off-design conditions, a detailed narrow band analysis of a complete set of noise spectra is presented for a ship equipped with a controllable pitch propeller (CPP). The spectral peculiarities of such a propulsion plant, when operated at constant revolutions per minute (RPM) are highlighted. Results of the suggested parametrization applied to the same ship are presented together with the data of other CPP ships and a critical analysis is carried out discussing the limits of the existing predictive models.

A proper estimation of the ship accelerations, particularly in the transversal direction, is fundamental for predicting the risk of cargo shifts and inherent structural damages in severe irregular seas. A specific situation worth to be considered in this context is the so-called dead ship condition, in which the ship, because of a loss of steering capabilities, is drifting in beam waves at zero speed. Particularly in this situation, a proper modelling of ship dynamics in wave is deemed necessary for a reliable assessment of inertial loads. In this paper three time domain procedures with different accuracy are applied and compared. The aim is to investigate the dependency of inertial loads on the non-linear effects of ship geometry and on the couplings among the 6DOF of the ship. Simulations are carried out with, in input, the same irregular sea realizations in the time domain, obtained from a digitalisation of JONSWAP spectra. A technique allowing for a fine matching of the digitalised spectra to the analytical ones is developed and applied. The investigation indicates that couplings among ship motions trigger larger inertial loads and, accordingly, a larger probability of occurrence for cargo shifting and structural damages.

The acoustic comfort in passenger cabins on board six passenger ships is analyzed in this paper. The overall noise inside cabins is first evaluated, then the effect of HVAC (Heating, Ventilation and Air Conditioning) is investigated and several criteria, typical from the civil field (Noise Criterion, Room Criterion, etc.), are applied and compared. The effect of different operative conditions in terms of revolutions per minute of engines, propellers and generators, of propeller pitch and of engine power is investigated as well, highlighting the differences in terms of measured noise and of indicators performances. The results of the study suggest that the current normative framework and regulations about noise on board ships, based on dB(A) limits only, could effectively be revised to take into account spectral components, whose effect would otherwise be neglected.

Achieving the right balance between fixed and operating costs is a key but non-trivial task for optimizing the characteristics of a fleet of ships for a new trade at a very early stage of the design. A wide range of design choices as well as a significant number of uncertainties related to the operation of the fleet affects those two expense items. In the proposed analysis, operative uncertainties rising from rough sea conditions are taken into account in a Simulation Based Design (SBD) framework for fleet generation and evaluation. The costs-benefits analysis is aimed at understanding the effects of variations in the installed power and in the ship capacity on the overall fleet performances. These two major characteristics of the ship design (and, accordingly, of the fleet of ships realizing the trade) are introduced in the numerical model considering the sea margin and the nominal capacity as free design parameters instead of fixing them as commonly done in practice. From a design point of view, this corresponds to the introduction of two new variables, enlarging the dimensions of the design space to be explored, better than relaxing the boundaries of a simpler design space. The validity of this approach is demonstrated by a practical application to the design of a fleet of Compressed Natural Gas (CNG) carriers. In this context, the effects of variations in the fuel price and in the voyage length on the optimal fleet characteristics are analyzed and the results are discussed in comparison to those coming from the reference scenario.

The prediction of propeller induced pressure fluctuations and underwater radiated noise is a subject of great and increasing interest in marine engineering. Nevertheless, the full-scale prediction of these negative effects, even though based on dedicated model scale tests represents still a challenging task. This is due to different phenomena, among which scale effects on cavitation and ship wake, confined environment and near field effects in model tests play an important role; the analysis of these problems is made difficult by the rather limited amount of available data from sea trials and to the complexities of the phenomena, most of which related to cavitation on the propeller blades, that are present in the measurements carried out in cavitation tunnels, depressurized towing tanks or circulating channels. In the present work, the subject has been studied with reference to a four blades conventional CP propeller of a coastal tanker. Cavitation tunnel tests have been carried out in two rather different facilities, at UNIGE cavitation tunnel and at SSPA large cavitation tunnel. Results from model scale tests processed with different treatments are then compared with full scale measurements performed by SSPA on the same propeller in terms of cavitation extension and radiated noise. The analysis is aimed at assessing the effectiveness of different experimental setups, testing procedures and scaling laws.

In this work, the possible exploitation of fiber-reinforced composites in the context of maritime transportation of compressed natural gas (CNG) is investigated. In addition to a more conventional steel configuration, two different fiber materials, carbon and glass, are considered as construction materials for pressure vessels (PVs) to be stored on board ships, with thickness optimized by FEM analysis. The considered scenario is represented by the transportation of CNG from an offshore well to a terminal on shore. Fleets of ships carrying CNG in pressure vessels manufactured with the investigated materials are generated by means of a ship synthesis model (SSM) software and compared on the basis of technical and economical indicators. The choice of the construction material influences considerably the weight of the PVs, which represent a major item of total ship weight and reflects directly on the general transport performances in terms of resistance, seakeeping and reliability in the service. On the other hand, capital as well as operating expenditures are considerably affected by the choice. When exploring the design space, the ship synthesis model is able, at a preliminary stage of the design, to account for the various technical and economical aspects, their implications and relationships. Results are presented of computations carried out in a specific case, identified by the annual gas production and other characteristics of the well terminal and a cruising route for the ships. The comparison is carried out on the basis of the cost per transported unit of gas and of the percentage of success in the transportation process. The computations show that the choice of the PV material has a key influence on the results in terms of optimal number, dimensions and speed of the ships.

A rising global attention to the environmental impact of anthropogenic activities pushes towards a continuous reduction of such impact and a control, through monitoring techniques, of the main sources of pollution. The transport sector is involved, as all other field of anthropogenic activities in the efforts towards a drastic abatement of emissions. Shipping activities generate greenhouse effect gases (GHGs), affecting the environment on a global scale, and other pollutants harmful for human health and the ecosystem on a local scale. These latter aspects are particularly relevant in ports where berths are close to densely inhabited areas. Many efforts have been and will be spent to predict and quantify these emissions with the aim of controlling them but direct measurements aimed at the identification and quantification of particularly polluting substances are to be considered a key point to achieve an effective control of emissions. In the context of ports, as in any transportation infrastructure, an identification of polluting vehicles and a quantification in an objective way of their emissions is crucial to implement any control activity of the polluting emissions. The development of optical remote sensing techniques appears to be particularly promising. This work provides a state of the art of the main techniques based on optical sensors (LIDAR, LIDAR DIAL, DOAS, camera UV) possibly applied in the maritime sector, highlighting advantages and potentialities. Results of a preliminary measurement campaign are reported to show the first encouraging feedback for the feasibility of the application.

A growing attention has been recently devoted to the impact of the underwater noise field generated by shipping activities on the marine fauna. While in international treaties and conventions this problem is now well treated, from a technical point of view the quantification of the impact of underwater noise emissions from the ship is not yet consolidated. The program created allows the user to identify the sound rays generated by source and, between these, to find the beam nearest a receiver calculating the Trasmission Loss (TL). The user enters as input data the source position, the Sound Pressure Level (SPL) of the source, the depth of the backdrop, sound velocity profile, thickness of the layers in which the water column is divided, salinity, temperature and pH of sea water and the frequency of emission of the source to characterize the propagation environment. Through the Ray Tracing Theory, a technique of optical geometry that is based on the calculation of the path made by light the rays are shown on the screen. Then the rays closest to the receiver are identified and the program calculates the sound loss, divided into Geometrical Loss (due to distance between the source and the receiver), Dissipation Loss (due to the characteristics of the propagation environment) and Reflection Loss (due to the surfaces that delimit the field).In output the program will show the propagation field of the Sound Pressure Level through which in the future it will be possible to identify the emission limits to protect the marine fauna.

There is increasing concern within the scientific community about the underwater noise due to anthropogenic activity and its impact on marine life, with negative consequences on biodiversity and sea resources. In that context, the European Marine Strategy Framework Directive stated in 2008 that the anthropogenic noise due to shipping was to be mitigated. To address this issue, the European Union (EU) project “Achieve QUieter Oceans by shipping noise footprint reduction” (AQUO) ( www.aquo.eu ) started in October 2012 with a duration of four years. The project brought together experts from shipbuilding, underwater acoustics, and bioacoustics, with a multidisciplinary approach. In this paper, after giving a brief overview of the project structure, the methodology proposed by the AQUO project to set guidelines for controlling the underwater noise from commercial shipping is presented in more detail. Such a methodology is aimed at identifying the most promising strategies for the mitigation of the impact of shipping noise on marine fauna. Different technical as well as operational solutions are evaluated by taking into account the impact on marine life, the feasibility in terms of ship design, and the cost effectiveness, also considering fuel efficiency. While technical solutions are usually more effective at the design stage both in terms of costs and performance, operational solutions can potentially be adopted without any modification to the existing fleet. Furthermore, operational prescriptions can be set by national/local authorities who cannot directly intervene on ship configurations. The different solutions have been evaluated by means of numerical modeling carried out by using a Noise Footprint Assessment Model derived from the Quonops tool.

The transportation by sea of compressed natural gas is a very recent subject, prompted by recent changes in the perspectives of a possible economic exploitation of relatively small quantities of this hydrocarbon, available as by-product of oil extraction in off-shore fields. An automatic and integrated preliminary design procedure has been established to generate and evaluate feasible technical solutions for a trade of this kind. A first trial application has been carried out for a specific case, for which various feasible solutions corresponding to fleets composed of a different number of equal ships are generated. In the procedure, a parent hull shape is adopted in order to evaluate, through systematic variations of the main dimensions, all the elements necessary to perform the classical steps of the design spiral (like weight evaluation, buoyancy, trim and stability checks and motion resistance prediction) accounting for the mutual interaction between the various items. When possible and necessary, parts of the procedure have been calibrated with data from existing ships, in order to ensure realism in the predictions. This has been done with reference e.g. to the evaluation of weight items and in particular to hull weight. On the other hand, when setting boundaries to the range of variation in the ship dimensions, care has been given not to constrain the investigation domain only to existing dimensional ratios, but to let the procedure explore a wider range of solutions. A particular feature of the procedure is to include in the evaluation process the seakeeping performances in terms of added resistance in waves. This aspect interacts with the other part of the design process and influences the final outcome in terms of performance of the solution. The main implications of accounting for the increase in motion resistance are the capability of evaluating the reduction in the average speed, the corresponding reduction in the annual cargo delivery and the increase in fuel consumption (all aspects evaluated in respect to nominal conditions). The procedure, accordingly, is able to provide, in addition to several technical output identifying the various solutions (such as main dimensions, weight, power installed, seakeeping performances), indicators of the performances of the fleet in terms of annual cargo delivery, CapEx and OpEx, that can be used to rank the various solutions.

This article covers the reliability assessment of the hull girder of a crude oil tanker, referring to a scenario in which the ship is exposed to sea loads after a damage to the bottom of the hull has occurred. A number of possible flooding configurations are examined, each one caused by a group of damage cases, characterized by different location and extent. Static loads, wave loads and residual structural resistance are determined for each damage case, with the objective of obtaining a prediction for the probability of the hull girder's failure. The various damage cases are compared to each other and unconditioned to derive the probability of failure extended to the ship's life due to a generic bottom damage. A probabilistic Bayesian Network model has been created to deal with these variables and with the dependency relationships existing between them. The results provided by the model are analyzed with the aim of identifying the parameters most influencing the problem. The work is intended to contribute to the development of a more rational treatment of accidental conditions in design structural requirements for ships.

The sustainability of anthropogenic activities at sea is recently gaining more and more attention. As regards shipping, emissions from ships into the environment of various nature (engine exhaust gases, anti-fouling paints leaching, ballast exchange, releases at sea of oil and other noxious liquid or solid cargoes, of sewage and of garbage) have been recognized as sources of pollution and therefore controlled and limited since a long time. The subject of noise emission has been identified only recently. To study the problem, the EU has funded, among others, the FP7 SILENV (Ship Innovative soLutions to rEduce Noise and Vibrations) project that run from 2010 to 2012. In the present work, the holistic approach followed within the project to characterize and control the ship as a source of noise is presented. Three types of noise emissions (in air, in water and inside the ship) are analyzed highlighting peculiarities and different strategies adopted to characterize the source, the impact on the receiver and the possible solutions to set limits to the ship emissions. The project outcome included a socalled “Green Label”: a set of new prenormative requirements defined for the three main areas mentioned above.

The present paper deals with the side effects of propellers cavitation, i.e. pressure pulses and radiated noise. These effects are gaining more and more importance for commercial ships for different reasons. Pressure pulses significantly affect comfort onboard, thus their reduction is of utmost importance for all ships carrying passengers. As regards the underwater radiated noise, in the last decade interest has shifted from navy applications to commercial ships, due to the concern for the rising background noise in the oceans. The propellers, generating noise directly in water, represent one of the main contributions to the overall underwater noise emitted from ships. Due to the complexity of the mechanisms of propeller noise generation, different complementary strategies have to be followed to properly analyze the problem, ranging from induced pressure pulses to broadband noise and cavitation. In the present work, part of the activities carried out in the framework of the collaborative EU FP7 project AQUO (Achieve QUieter Oceans by shipping noise footprint reduction, www.aquo.eu) are reported. The paper presents the investigations carried out on a specific test case represented by a single screw research vessel, which is analyzed with three different strategies: numerical calculations, model scale investigations and fullscale measurements.

In noise mapping of urban areas main sources for nuisance and sleep disturbance are roads, railways, airports and industrial plants. However, when a noise analysis of port cities is carried out, also harbor activities are to be considered as significant contributors to the ‘soundscape’. Within the harbor, ships, when berthed at wharfs and possibly busy in loading or unloading operations, represent significant sources of noise. In these conditions, in fact, some of the ship’s plants are running and high airborne noise levels may be radiated. Ships are not traditionally characterized as noise sources and their dimensions and complexity pose a challenge for the description of the acoustical field in urban areas around the port. The work presents a hybrid experimental–computational approach for the acoustical characterization of ships applied to a test case represented by a multipurpose ship. For the same ship, the propagation field is studied numerically to include an urban area around the port. The same experimental campaign is also used to introduce a new measurement procedure for an effective characterization of the ship source.

The present work is meant to investigate wave-induced global loads in a ship in realistic flooding conditions. The scenarios investigated are represented by water ingress into the forepeak and/or the portside ballast tanks of a 150,000 DWT double hull tanker in a laden condition. Seakeeping computations are performed in six flooding situations, each corresponding to different changes in displacement, trim and heel. For each of them, the wave-induced global loads and hull motions are computed in terms of response amplitude operators, using a three-dimensional linear potential seakeeping code in the frequency domain. The results, showing significant variations in the global loads with respect to the intact ship, are reported and commented on in view of their possible use in the definition of design loads for checks of the longitudinal strength of ships in accidental conditions.

The European AQUO project started in October 2012, in the scope of the FP7 European Research Framework, for three years duration. The final goal is to provide policy makers with practical guidelines and solutions, in order to mitigate underwater noise footprint due to noise radiation from ships. For a maritime area under consideration, mitigation solutions can be split into two categories: the first one is to reduce the underwater noise emission of the noisiest vessels sailing in the area, and the second one is related to ship traffic management. The present paper addresses the first type, and the purpose is to assess the efficiency of different mitigation measures, corresponding to the dedicated task 5.2 of AQUO Project. First, an overview of a comprehensive list of possible mitigation measures is presented. Then, study cases corresponding to reference vessels are defined and several mitigation measures are tested in order to give an estimation of the reduction of ship source level (underwater radiated noise). To achieve this task, different modeling techniques and experimental results from previous tasks of AQUO Project are used. Special care must be taken on the relative importance of the part of radiated noise due to internal machinery and engines, and the part due to propeller(s). The analysis of the result allow identifying the most promising solutions.

The continuous development of design tools and analysis procedures has allowed propeller performances to increase progressively during years following more and more stringent design requirements . High propeller efficiency and avoidance of erosive cavitation are considered nowadays basic requests for a well designed propeller. However this may not be enough to meet the requirements of high added value ships such as passengers ships, mega yachts, research vessels, naval vessels etc. These kinds of ship need a propulsion system not only with good efficiency but also with low levels of vibrations and noise transmitted inside the ship and with low underwater radiated noise. Moreover, the above mentioned ships often work in a rather wide range of operational condition. Actually, the possibility to operate at reduced speed regards almost all kinds of ships, due to the increasing attention to fuel consumption and exhaust gas emissions, and the related tendency towards slow steaming. Speed reduction may be obtained in different ways. In the case of ships equipped with CPPs, in principle it may be achieved reducing RPM at constant pitch or reducing pitch at constant RPM; the latter is usually preferred when a power take off is present. This results in working conditions far from design ones for the propeller; Cavitation and related radiated noise may increase significantly in similar situations, despite the speed reduction is felt to be generally beneficial for the purpose. In this work, the effect of different speed reduction strategies on cavitation and radiated noise is studied by means of cavitation tunnel tests of four CPPs including both single screw and twin screw configurations.

There is a rising concern about the environmental status of the seas of our planet. Such concern regards several kinds of anthropogenic activities and their impact on the marine ecosystems. Part of the adverse effects are recognised to be due to various forms of acoustic emissions generated by human activities related to the exploitation of sea resources and to shipping. The main regulatory bodies at international level, in the last decade, have started to look into the problem with the aim of monitoring the environmental status of marine waters, in particular the acoustical aspects) identify the situations where the anthropogenic impact is most intrusive and study and promote future actions for its control and reduction. The present work reports about the development and validation of a simulation tool able to predict the noise field generated by a set of ships sailing in a specific area. The simulation is based on real traffic data derived from the Automatic Identification System (AIS) normally used to monitor shipping traffic and on specific data characterising the environment of the zone of interest. The tool is meant to provide the Regulator with a means to study the present situation (with on-line AIS data) and/or study the effectiveness of possible measures devoted to reduce the acoustical impact of shipping by design and/or operative requirements. Motivation, bases and characteristics of the developed procedure are described in the paper, where a first validation of the tool is presented on the basis of data regarding a sea area off Barcelona (Spain). Data include AIS records, environmental parameters and underwater sound levels surveyed by an hydrophone placed in the area. The work has been developed in the framework of the collaborative project AQUO (Achieve QUieter Oceans by shipping noise footprint reduction), funded by the European Commission within a call of the 7th Framework Programme dedicated to the assessment and mitigation of noise impacts of the maritime transport on the marine environment, coordinated topic “The Ocean of Tomorrow”.

This paper presents spectral analyses of the underwater noise radiated by ships equipped with controllable pitch propellers. The noise measurements were performed at sea for three different ship's types. Each ship passage was characterized by a specific combination of propeller rotational speed and propeller pitch, allowing to investigate the variations of the radiated noise spectrum at different settings of the pitch-RPM combination law. Neglecting the low-frequency contributions, the focus is on the analysis of the broadband patterns in the range 100 Hz to 4 kHz A parameterization derived from a basic spectral pattern is adopted: the noise spectrum shape is approximated with a flat level magnitude up to a reasonable frequency followed by a logarithmic decay. An investigation of the relationship between the considered parameters and the actual ship condition is proposed along with a comparison with the predictions provided by classic Ross and Whales-Heitmeyer ship noise models.

In the present study, full-scale noise levels measurements on board a Ro-Pax ferry have been carried out in various compartments of the ship, both in stationary conditions (navigation) and during manoeuvres. Noise levels have been surveyed in various categories of spaces located in all decks accessible to both passengers and crew, with the purpose of giving a complete and effective picture of the acoustic climate on board. The measured noise levels have been compared with current and proposed limits for working and living spaces, obtaining a clear identification of the most critical spaces on board the ship both in respect to acoustic comfort and noise exposure of crew during working hours. In cabins, different operating conditions for air conditioning have been tested, to analyse the specific contribution to annoyance of the ventilation noise, which turned out to be in many cases determinant. Transient conditions during manoeuvres entering and leaving harbours have been analysed by spectral time histories in cabins and public spaces close to the main propulsion plant and to bow thrusters. These situations correspond to considerably high levels, which may limit significantly operation during night time.

The growth of commercial activities in the Arctic region, in particular of LNG transport, due to the recent discovery of new gas fields, brought to the development of new researches in the area of ice loads for ship structures. To consider possible collisions with ice during a design phase, simulations are often real-ized by modelling icebergs as rigid, i.e. non deformable bodies. Results obtained this way may turn out to be too conservative as the ship structure needs to be designed in order to absorb the entire amount of the impact energy. This paper describes an attempt of getting more realistic results by carrying out a collision analysis where both ice and ship are modelled as deformable. A material model describing the mechanical properties of ice is implemented in FORTRAN, for use during finite element analyses of the impact (performed using the software Abaqus CAE). The mathematical model describing ice behaviour is selected among different models present in literature. The ice model is applied in a first case to a specific situation considering a spherical iceberg of given radius impacting the side of a specific ship. The problem is decoupled, following the NORSOK method, into the analysis of a deformable iceberg impacting a rigid ship side and the analysis of the ‘mirror’ situation (rigid iceberg against a deformable ship). For the latter case, reference is made to re-sults available in literature. Outputs from the two analyses are coupled, assuming that the results, separately derived, can be jointly applied to the real case of an impact between two deformable bodies. The results ob-tained in this first application confirm that a significant part of the impact energy is actually dissipated by ice deformation, but they are still valid under the simplifying hypothesis of neglecting the contact interactions be-tween the two deformable bodies. The implemented material model is however ready for being integrated in the FEM analysis to study the coupled problem.

The Marine Strategy Framework Directive has officially stated as soon as 2008 the anthropogenic noise due to shipping were to be mitigated. The policy makers, the yards and the ship owners still strongly rely on the expert studies and guidelines to find the appropriate methodology to assess and then mitigate the acoustic pollution impact shipping on the marine biota. To address this issue, the project AQUO "Achieve QUieter Oceans by shipping noise footprint reduction" (www.aquo.eu) started in October 2012 for 3 years.

The Marine Strategy Framework Directive has officially stated as soon as 2008 the anthropogenic noise due to shipping were to be mitigated. The policy makers, the yards and the ship owners still strongly rely on the expert studies and guidelines to find the appropriate methodology to assess and then mitigate the acoustic pollution impact shipping on the marine biota. To address this issue, the project AQUO “Achieve QUieter Oceans by shipping noise footprint reduction” (www.aquo.eu) started in October 2012 for 3 years. The AQUO project was built in the scope of FP7 European Research Framework. It involves 13 partners from 8 European countries, mixes academic experts, industry representatives from yard, classification society and other acoustic and bio-acoustic specialized bodies. Addressing the anthropogenic noise pollution into the marine biota is an increasing concern which is logically paired with the increasing commercial maritime traffic. The IMO itself has recently issued a first draft guideline, to be followed up during the next MEPC, addressing this matter. In parallel to the different achievements that are effective or in progress by standardization bodies or other delegated or assigned work group, the AQUO project aims to finally issue guidelines to be taken as methodological tools. The multi-disciplinary team of this project aims to comply with expectations from the different stakeholders. First, an overview of the project is given. The objectives and the related project structure are detailed so as to better understand which axes are chosen and studied. Secondly, it is here proposed to share the recent outcomes of AQUO project. The current status of applied knowledge, related legal decisions as well as standards empowerment are essential to identify the remaining needs and consequent expected efforts. Drawing first the background rationales the noise footprint concept is then detailed. The process followed towards the main objective of mitigating the anthropogenic noise from shipping will be partly revealed and completed by the expected future work to be achieved by 2015.

One of the key points for the success in the construction of cruise ships is the enhancement of high standards for passengers comfort on board, especially in the living and resting areas. For this reason, one of the fields on which research in this sector is focused on is the reduction of airborne and structure-borne noise transmitted inside the cabins. At present, the floating floor arrangement is commonly used on board in order to reduce the structural noise transmitted through floors. This special floor decouples the inner floor of the cabin from the load-carrying structure of the deck. In the present study, the performances of two floating floors with innovative de-coupling materials have been analyzed. The floors were tested in the condition of unloaded floor and loaded floor. Modal analysis techniques have been applied to understand the overall results obtained in terms of general indicators.

The rising concern about the environmental impact of ship noise on the marine fauna recently pushed national and international bodies to face the problem. In the last decade a few mass strandings of cetaceans due to sea trials of navy sonars (Frantzis (1998)), enforced the interest on noise pollution effects on marine mammals. The problem of evaluating the impact of underwater noise from ships is very complex due to the difficulties in characterising the whole noise chain (source, transmission path, receiver). Standards have been recently issued aimed at the measurement of underwater noise emitted from commercial ships. As regards the transmission path, problems are linked to the correct evaluation of the transmission loss which is influenced by many environmental parameters (water temperature, salinity, pressure, bottom composition etc.) which cannot be easily monitored during measurements. Finally the actual sensibility to noise of the marine mammals it is not completely known, especially for species belonging to the Mysticetes (Baleen Whales). These problems have been analysed in the SILENV collaborative project (Ships oriented Innovative soLutions to rEduce Noise & Vibrations), devoted to the holistic analysis of noise emissions from the ship [radiation inside the ship and outside (in air and in water)].

The paper addresses the present regulatory framework regarding ship noise emissions both towards the internal spaces onboard and the external environment (in air and in water). A different level of development has been reached in the various areas for the definition of the needs for the noise control and for their implementation in a normative framework. This is due in part to the different point in time in which the different aspects were recognised to be relevant and therefore studied, assessed and regulated. The analysis of existing regulations is the basis for considering the present situation, on-going developments and possible future trends as regards the evaluation of ship noise impact on the various types of environment. The situation of the requirements developed for the maritime field appears to be in line with other fields of engineering as regards the definition of noise limits for the working environment, while the definition of comfort of living on board seems to be somehow lacking behind other fields, with possibility of taking advantage of their experience. Well established assessment procedures for external radiation in air appear to be not yet available and in this case a need for specific developments arises. Finally, for underwater noise emissions, there is availability of relatively well developed requirements, that however are not adequately correlated to the quantification of the effects of the noise emissions on the marine fauna.

More frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure combined with increased requirements to efficiency in design and execution followed by increased risk of human errors has made the need of requirements to robustness of structures essential. Further, the collapse of the World Trade Centre towers and a number of collapses of structural systems during the last 10 years has increased the interest in robustness. Typically, modern structural design codes require that ‘the consequence of damages to structures should not be disproportional to the causes of the damages’. However, despite the importance of robustness for structural design, such requirements are not substantiated in more detail, nor has the engineering profession been able to agree on an interpretation of robustness which facilitates for its quantification. In this paper, a theoretical and risk-based framework is presented which facilitates the quantification of robustness, and thus supports the formulation of pre-normative guidelines. More frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure combined with increased requirements to efficiency in design and execution followed by increased risk of human errors has made the need of requirements to robustness of structures essential. Further, the collapse of the World Trade Centre towers and a number of collapses of structural systems during the last 10 years has increased the interest in robustness. Typically, modern structural design codes require that ‘the consequence of damages to structures should not be disproportional to the causes of the damages’. However, despite the importance of robustness for structural design, such requirements are not substantiated in more detail, nor has the engineering profession been able to agree on an interpretation of robustness which facilitates for its quantification. In this paper, a theoretical and risk-based framework is presented which facilitates the quantification of robustness, and thus supports the formulation of pre-normative guidelines.

The noise generated by ships affects a wide range of receivers: crew and passengers inside the vessel, inhabitants of the coastal areas and marine fauna outside it. The time elapsed since these types of impact have been considered and the state of the art of the noise control for each of these fields is very different. The paper aims at analysing the regulatory frameworks in the various fields, underlining differences in the present level of development and suggesting possible improvements in the general approach. The paper refers to the first phase of the SILENV collaborative project (EU 7th Framework Programme).